Acinetobacter

Appl Environ Microbiol, 1999 Jan, 65(1), 221 - 30
Production of wax esters during aerobic growth of marine bacteria on isoprenoid compounds
Rontani JF, Bonin PC, Volkman JK.
This paper describes the production of isoprenoid wax esters during the aerobic degradation of 6,10,14-trimethylpentadecan-2-one and phytol by four bacteria (Acinetobacter sp . strain PHY9, Pseudomonas nautica {IP85/617}, Marinobacter sp . strain CAB {DSMZ 11874}, and Marinobacter hydrocarbonoclasticus {ATCC 49840}) isolated from the marine environment . Different pathways are proposed to explain the formation of these compounds . In the case of 6,10, 14-trimethylpentadecan-2-one, these esters result from the condensation of some acidic and alcoholic metabolites produced during the biodegradation, while phytol constitutes the alcohol moiety of most of the esters produced during growth on this isoprenoid alcohol . The amount of these esters formed increased considerably in N-limited cultures, in which the ammonium concentration corresponds to conditions often found in marine sediments . This suggests that the bacterial formation of isoprenoid wax esters might be favored in such environments . Although conflicting evidence exists regarding the stability of these esters in sediments, it seems likely that, under some conditions, bacterial esterification can enhance the preservation potential of labile compounds such as phytol.

Med Dosw Mikrobiol, 1998, 50(1-2), 9 - 19
{Utilization of siderophores from the Acinetobacter genus by staphylococcal bacilli}; Szarapinska-Kwaszewska J et al.; The ability of iron utilizing by means of siderophores produced by donor strains--the members of the genus Acinetobacter (8 strains) by 24 staphylococcal strains was investigated . All the donor strains synthesized hydroxamate class siderophores and six strains also catecholate class . The majority of staphylococcal strains could utilize these siderophores . Most strains utilized siderophores from A . juni 321 and A . johnsonii 349 strains . Only three staphylococcal strains were not be able to utilize siderophores from all donor strains.

Zentralbl Veterinarmed B, 1998 Nov, 45(9), 551 - 9
{Model investigations of the impedance effectiveness conerning bacterial relevant to food hygiene}; Schulenburg J et al.; The impedance technique mostly meets today's requirements of microbiological rapid methods . At relatively high prime cost for the equipment the advantages are marked by low personnel and material costs as well as swiftness combined with highly flexible usage . The method is applicable for both quantitative and qualitative examinations but can fail occasionally in total count determination, especially if the sample material contains heterogeneous microbes . In model investigations with 53 strains of 17 different genera Enterobacteriaceae strains, Aeromonads and Enterococcus strains proved to be highly impedance effective . Lactobacillus strains and Pseudomonads as well as Staphylococcus aureus strains showed a low impedance effectiveness . Several strains, for example of the genera Micrococcus, Acinetobacter and Brochothrix, did not show any changes of the medium impedance under the chosen conditions . Criterion for characterization of impedance effectiveness was the impedance detection time starting with identical initial counts (10(3) cfu/ml) . Impedance effectiveness of microbes was determined at highly varying degree by the parameters of generation time, lag-phase duration and relative activity . This can lead either to wrong negative (underestimations) or wrong positive (overestimations) results of bacterial count.

Rev Assoc Med Bras, 1998 Oct-Dec, 44(4), 283 - 8
{In vitro antimicrobial activity of cefpirome compared to other broad-spectrum beta-lactam drugs against 804 clinical isolates from 9 Brazilian hospitals}; Sader HS et al.; OBJECTIVE: To evaluate the in vitro activity of the fourth-generation cephalosporin cefpirome in comparison to that of ceftazidime, ceftriaxone, cefotaxime and imipenem in a multicenter study involving nine hospitals from six cities (four States) . MATERIAL AND METHOD: A total of 804 isolates from patients hospitalized in either intensive care units or Oncology/Hematology units was evaluated . The isolates were collected between June and November of 1995, i.e . before cefpirome became commercially available in Brazil, and susceptibility tested by broth microdilution following the NCCLS procedures . All isolates resistant to cefpirome were retested by E-test . RESULTS: Against Enterobacteriaceae (n = 344), cefpirome demonstrated an activity 2 to 32-fold higher than that of the third-generation cephalosporins (TGCs) and similar to that of imipenem . The percentages of Enterobacteriaceae susceptible were: 88%, 69% and 96% for cefpirome, TGCs and imipenem, respectively . The cefpirome spectrum was greater or equal than that of imipenem against Citrobacter freundii, Enterobacter aerogenes, Morganella morganii and Serratia marcescens . Against Acinetobacter sp . (n = 77), cefpirome was slightly more active than ceftazidime; however, the percentages of isolates resistant to these compounds were high (84% and 88%, respectively) . The activities of cefpirome, ceftazidime and imipenem were very similar against P . aeruginosa isolates (n = 128), with MIC50(mg/ml)/percent susceptible of 8/59%, 8/62% and 4/62% respectively . Against aerobic gram-positive bacteria, the cefpirome activity was 4 to 16-fold higher than that of TGCs but 2 to 8-fold lower than that of imipenem . CONCLUSION: The results suggest that, in Brazil, cefpirome has a spectrum of activity which is higher than that of the TGCs against aerobic gram-negative (Enterobacteriaceae and non-Enterobacteriaceae) and gram-positive bacteria and similar to that of imipenem against some Enterobacteriaceae species and P . aeruginosa.

Acta Microbiol Pol, 1998, 47(2), 213 - 7
Electron-microscopic observation of adherence of Acinetobacter baumannii to red blood cells; Gospodarek E et al.; It is now recognized that Acinetobacter spp . play a significant role in the colonization and infection of patients admitted to hospitals . The virulence factors of A . baumannii remains largery unknown . In this study, the adherence of A . baumannii to several species of red blood cells was investigated . The ruthenium red staining was used for electron microscopic studies . The results obtained in electron microscopy and the hemagglutination studies suggested that the thin and long fimbriae of A . baumannii participated in adhesion of these bacteria to red blood cells.

Am J Infect Control, 1998 Dec, 26(6), 552 - 7
Low-level colonization and infection with ciprofloxacin-resistant gram-negative bacilli in a skilled nursing facility; Lee YL et al.; BACKGROUND: We report a 1-year surveillance study that evaluates colonization and infection with ciprofloxacin-resistant gram-negative bacilli (CR GNB) and the relation to quinolone use and other possible risk factors in a proprietary skilled nursing facility (SNF) with no history of outbreaks . METHODS: Rectal swabs obtained quarterly were streaked on MacConkey agar with ciprofloxacin discs (5 microg) to screen for CR GNB and later were speciated and the antimicrobial susceptibilities were confirmed by standardized disc-diffusion tests . RESULTS: The mean prevalence of CR GNB colonization was 2.6% (range 0.9% to 5.3%) . The colonization frequency was higher in the last survey than it was in the first survey . CR GNB-colonized strains included Pseudomonas species (21%), but more than half were non-Pseudomonas enterics such as Acinetobacter baumannii (25%), Proteus mirabilis (17%), and Providencia stuartii (13%) . None of the patients who had colonization with CR GNB had subsequent infections with the same species . Patients with colonization had more exposure to ciprofloxacin and they were more likely to have been recently admitted from an acute-care hospital and have decubitus ulcers . During the study period, of 336 patients surveyed, 98 (29%) patients developed suspected infections and cultures were done; the infection rate was 4.7 per 1000 patient days . Of these infected patients, 59 (60%) were infected by GNBs; the infection rate was 2.3 per 1000 patient days . Nineteen percent of the GNB infections were treated with a quinolone . (Overall, quinolones constituted about 17% of antibiotic usage in the SNF) . Only 3 (5%) of the patients infected with GNB were infected with CR GNB, including Pseudomonas and Providenci a species . The CR GNB infections involved multiple sites, multiple organisms, and long length of stay in the SNF . CONCLUSIONS: The findings indicate that in this community SNF, a low frequency of colonization or infection with CR GNB existed . Whether continued moderate use of quinolones will lead to increasing levels of CR GNB will require further study.

Am J Infect Control, 1998 Dec, 26(6), 544 - 51
Methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii: an unexpected difference in epidemiologic behavior; Bernards AT et al.; BACKGROUND: The Dutch guideline on hospital policy for the prevention of nosocomial spread of methicillin-resistant Staphylococcus aureus (MRSA) states that patients transferred from hospitals abroad must be placed in strict isolation immediately on admission to a hospital in the Netherlands . Three patients colonized with both MRSA and a multiresistant Acinetobacter were transferred from hospitals in Mediterranean countries to 3 different hospitals in the Netherlands . Despite isolation precautions, Acinetobacter spread in 2 of the 3 hospitals, whereas nosocomial spread of MRSA did not occur . METHODS: For outbreak analysis, the Acinetobacter isolates, identified as Acinetobacter baumannii by the use of amplified ribosomal DNA restriction analysis, were comparatively typed by 4 methods . Comparison of isolation measures in the hospitals was performed retrospectively . RESULTS: In the 2 hospitals in which nosocomial spread of Acinetobacter occurred, most of the epidemiologically related isolates were indistinguishable from the index strains . In these 2 hospitals, isolation measures were in concordance with those recommended for the prevention of contact transmission . The precautions of the hospital in which no outbreak occurred included the prevention of airborne transmission . CONCLUSIONS: Precautions recommended for multiresistant gram-negative organisms are insufficient for the prevention of nosocomial spread of multiresistant Acinetobacter . The airborne mode of spread of acinetobacters should be taken into account, and guidelines should be revised accordingly.

Rev Med Chil, 1998 Aug, 126(8), 978 - 80
{Priapism in a patient with chronic myeloid leukemia}; Rojas B et al.; Priapism is a rare complication of hematological diseases . Among leukemia, it is most frequently seen in patients with chronic myeloid leukemia, due to the high leukocyte counts that these patients achieve . We report a 22 years old male who presented with a priapism lasting more than 24 hours . Thirty six hours after admission and subsequent to a leukopheresis, penile relaxation was obtained . Despite good hematological response to therapy, an extensive penile and uretral necrosis, associated to an Acinetobacter infection, ensued between the fourth and fifth day of admission, that required surgical treatment.

Clin Infect Dis, 1998 Nov, 27(5), 1286 - 90
Suppurative Acinetobacter baumanii thyroiditis with bacteremic pneumonia: case report and review; Yu EH et al.; Suppurative thyroiditis is rare, and the major pathogens are Staphylococcus and Streptococcus species . We present a case caused by Acinetobacter baumanii, which has never before been reported . We review another 191 cases from the English-language literature (1980 to April 1997) and make a comparison with a review of 224 cases (1900-1980) . As the numbers of immunocompromised patients increase, cases of suppurative thyroiditis are increasing . Pneumocystis carinii has become an important pathogen . Most patients (83.1%) with bacterial infections were euthyroid, whereas those with fungal or mycobacterial infections tended to be hypothyroid (62.5%) and hyperthyroid (50%), respectively.

Antibiot Khimioter, 1998, 43(10), 19 - 23
{Selection of antibacterial therapy for treatment of infections in elderly patients}; Belousov IuB et al.; Examination of 60 elderly outpatients with lower respiratory tract infections (LRTI) revealed that 73 per cent of the patients isolated the pathogen associations and only 27 per cent isolated the monocultures . Grampositive cocci including Streptococcus pneumoniae were isolated from 70 per cent of the patients, Haemophilus influenzae and H.parainfluenzae were isolated from 20 per cent of the patients and Acinetobacter spp., Citrobacter spp., Enterobacter spp., Proteus spp . and Pseudomonas aeruginsa were isolated from 10 per cent of the patients . The patients were treated with ciprofloxacin, cefaclor or amoxycillin/clavulanic acid . Ciprofloxacin proved to be the most efficient agent . The regimens of the ofloxacin use in a dose of 400 mg orally once a day or in a dose of 200 mg intravenously twice a day for 2-4 days followed by the oral use for 6-8 days in the treatment of 24 patients with LRTI hospitalized into a therapeutic unit were compared . it was shown (pharmacokinetically as well) that the regiment with the drug use in the single dose was more efficient . Lomefloxacin was suggested to be the most advantageous drug in the treatment of elderly patients with LRTI because of its easy use, practically no dependence of the pharmacokinetics on the patient age and almost no nephrotoxic action.

Diagn Microbiol Infect Dis, 1998 Oct, 32(2), 101 - 5
Antimicrobial activity of merocyanine 540: a photosensitizing dye; Dunne WM Jr et al.; The antimicrobial activity of merocyanine 540 (MC 540), a photosensitizing dye previously used to purge malignant cells from autologous bone marrow grafts, was evaluated against a panel of Gram-positive and Gram-negative bacteria and Candida albicans in the presence and absence of light . In the absence of light, MC 540 demonstrated no antibacterial activity against any of the organisms tested . When combined with increasing intervals of photoillumination, growth inhibition was observed with all Gram-positive organisms tested except Mycobacterium fortuitum . Photosensitizing growth inhibition was also observed with Moraxella catarrhalis but not with any other Gram-negative bacilli including members of the Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophila, or Burkhoderia cepacia . These results suggested that differences in cell wall structure confer resistance to the photodamaging effects of the dye . MC 540 exhibited no antimicrobial activity against C . albicans in the presence or absence of light.

J Infect, 1998 Jan, 36(1), 5 - 15
Bacteriophages show promise as antimicrobial agents; Alisky J et al.; The emergence of antibiotic-resistant bacteria has prompted interest in alternatives to conventional drugs . One possible option is to use bacteriophages (phage) as antimicrobial agents . We have conducted a literature review of all Medline citations from 1966-1996 that dealt with the therapeutic use of phage . There were 27 papers from Poland, the Soviet Union, Britain and the U.S.A . The Polish and Soviets administered phage orally, topically or systemically to treat a wide variety of antibiotic-resistant pathogens in both adults and children . Infections included suppurative wound infections, gastroenteritis, sepsis, osteomyelitis, dermatitis, empyemas and pneumonia; pathogens included Staphylococcus, Streptococcus, Klebsiella, Escherichia, Proteus, Pseudomonas, Shigella and Salmonella spp . Overall, the Polish and Soviets reported success rates of 80-95% for phage therapy, with rare, reversible gastrointestinal or allergic side effects . However, efficacy of phage was determined almost exclusively by qualitative clinical assessment of patients, and details of dosages and clinical criteria were very sketchy . There were also six British reports describing controlled trials of phage in animal models (mice, guinea pigs and livestock), measuring survival rates and other objective criteria . All of the British studies raised phage against specific pathogens then used to create experimental infections . Demonstrable efficacy against Escherichia, Acinetobacter, Pseudomonas and Staphylococcus spp . was noted in these model systems . Two U.S . papers dealt with improving the bioavailability of phage . Phage is sequestered in the spleen and removed from circulation . This can be overcome by serial passage of phage through mice to isolate mutants that resist sequestration . In conclusion, bacteriophages may show promise for treating antibiotic resistant pathogens . To facilitate further progress, directions for future research are discussed and a directory of authors from the reviewed papers is provided.

J Clin Microbiol, 1998 Dec, 36(12), 3674 - 9
Comparison of phenotypic and genotypic techniques for identification of unusual aerobic pathogenic gram-negative bacilli; Tang YW et al.; Rapid and accurate identification of bacterial pathogens is a fundamental goal of clinical microbiology, but one that is difficult or impossible for many slow-growing and fastidious organisms . We used identification systems based on cellular fatty acid profiles (Sherlock; MIDI, Inc., Newark, Del.), carbon source utilization (Microlog; Biolog, Inc., Hayward, Calif.), and 16S rRNA gene sequence (MicroSeq; Perkin-Elmer Applied Biosystems Division, Foster City, Calif.) to evaluate 72 unusual aerobic gram-negative bacilli isolated from clinical specimens at the Mayo Clinic . Compared to lengthy conventional methods, Sherlock, Microlog, and MicroSeq were able to identify 56 of 72 (77.8%), 63 of 72 (87.5%), and 70 of 72 (97.2%) isolates to the genus level (P = 0.002) and 44 to 65 (67.7%), 55 of 65 (84.6%), and 58 of 65 (89.2%) isolates to the species level (P = 0.005), respectively . Four Acinetobacter and three Bordetella isolates which could not be identified to the species level by conventional methods were identified by MicroSeq . In comparison to the full 16S rDNA sequences, the first 527 bp provided identical genus information for all 72 isolates and identical species information for 67 (93.1%) isolates . These data show that MicroSeq provides rapid, unambiguous identification of clinical bacterial isolates . The improved turnaround time provided by genotypic identification systems may translate into improved clinical outcomes.

Scand J Infect Dis, 1998, 30(4), 421 - 3
Appearance of resistance to meropenem during the treatment of a patient with meningitis by Acinetobacter; Nunez ML et al.; A case is reported of a patient who developed Acinetobacter meningitis after an external ventricular drainage system had been fitted for control of intracranial pressure . During the process, nine strains of Acinetobacter isolated from her cerebrospinal fluid were indistinguishable by analysis of total genomic DNA by pulse-field gel electrophoresis . The first eight strains were sensitive to meropenem and imipenem (MICs < 1 g/l) . The MIC of the last one, which had been recovered after 32 days during two courses of treatment with meropenem, increased to > 32 g/l for meropenem, while with imipenem the increase was minimal (MIC = 1.5 g/l) . The microorganism persisted in the central nervous system despite the administration of different antimicrobials, including intraventricular aminoglycosides and six changes in the external ventricular system . The patient died 68 days after admission to the intensive care unit from bilateral cerebral ischemic lesions, intraventricular hemorrhage and cerebral edema with endocraneal hypertension, the Acinetobacter ventriculitis also contributing to this state.

J Urol, 1998 Dec, 160(6 Pt 1), 2229 - 31
Polymerase chain reaction amplification of bacterial 16S rRNA genes from cold-cup biopsy forceps; Keay S et al.; PURPOSE: In looking for a possible infectious cause for interstitial cystitis (IC), we previously determined that bladder tissue specimens from both IC patients and controls were uniformly positive by polymerase chain reaction assay (PCR) for bacterial 16S ribosomal RNA genes from various genera including Escherichia, Propionobacterium, Acinetobacter, and Salmonella . We therefore determined whether the biopsy forceps might be contaminated with bacterial DNA . MATERIALS AND METHODS: A total of 23 samples were obtained following disinfection of 6 cold-cup bladder biopsy forceps (2 to 5 specimens from each forceps over a period of 19 months) . DNA was extracted from each sample, and PCR performed using nested primers from a highly conserved region of the bacterial 16S rRNA gene . Amplified DNA was purified and sequenced, and the sequences obtained were compared with bacterial rRNA gene sequences recorded in GenBank . RESULTS: Thirteen of 23 forceps specimens were positive by PCR for bacterial DNA, including at least one rinse from each of the 6 forceps . In comparison, none of 9 negative control specimens (sterile distilled water put into tubes and processed in the same manner as forceps rinses) had detectable bacterial DNA . Sequence data indicated the presence of a predominant organism in 12 of the 13 positive specimens, with >95% homology to DNA from several different genera of bacteria including Escherichia, Propionobacterium, Stenotrophomonas and Pseudomonas . CONCLUSIONS: These data indicate that reusable bladder biopsy forceps are frequently contaminated with bacterial DNA . Tissue specimens procured with such instruments therefore are inappropriate sources to look for the presence of bacterial pathogens by PCR.

J Bacteriol, 1998 Nov, 180(22), 5822 - 7
Expression of alkane hydroxylase from Acinetobacter sp . Strain ADP1 is induced by a broad range of n-alkanes and requires the transcriptional activator AlkR; Ratajczak A et al.; In Acinetobacter sp . strain ADP1, alkane degradation depends on at least five essential genes . rubAB and xcpR are constitutively transcribed . Here we describe inducible transcription of alkM, which strictly depends on the presence of the transcriptional activator AlkR . alkR itself is expressed at a low level, while a chromosomally located alkM::lacZ fusion is inducible by middle-chain-length alkanes from heptane to undecane, which do not support growth of ADP1, and by long-chain-length alkanes from dodecane to octadecane, which are used as sources of carbon and energy . The putative AlkM substrate 1-dodecene is also an effective inducer . Products of alkane hydroxylase activity like 1-dodecanol prevent induction of alkM expression . alkM is expressed only in stationary phase, suggesting its dependence on at least one other regulatory mechanism.

Zentralbl Bakteriol, 1995 Oct, 282(4), 372 - 83
Comparative classification of Acinetobacter baumannii strains using seven different typing methods; Seltmann G et al.; A group of 49 Acinetobacter baumannii strains obtained from several hospital outbreaks and some sporadic cases were typed by biotyping, antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), plasmid typing, multilocus enzyme electrophoresis, whole-cell protein profile, and Fourier-transform infrared (FT-IR) spectroscopy . All these methods have shown a high degree of reproducibility and are capable of recognising strains from the same epidemiological event . However, their power to discriminate between epidemiologically unrelated strains varies, with PFGE being superior to the other methods investigated . FT-IR spectroscopy, which has not yet been used for typing of Acinetobacter strains, proved to be a very rapid and highly reproducible method, but was somewhat limited in its discriminating power.

Zentralbl Bakteriol, 1998 Oct, 288(2), 175 - 80
Serotyping of clinical isolates of Acinetobacter baumannii and genospecies 13 capable of growth at 44 degrees C: detection of four new serovars; Traub WH; Four new serovars (sv 35-38) were detected among clinical isolates of Acinetobacter baumannii and the unnamed genospecies 13 capable of growth at 44 degrees C . Polyclonal rabbit antisera were serovar-specific . None of them cross-reacted with 34 previously recognized servars of A . baumannii and genospecies 13 nor with 26 serovars of genospecies 3.

Rev Esp Cardiol, 1998 Sep, 51(9), 769 - 71
{Dehiscence of a composite aortic graft (Bono and Bentall technique) secondary to Acinetobacter endocarditis}; Alvarez J et al.; Acinetobacter sp . are gram-negative bacteria and usually resistant to multiple antibiotics . They are a customary cause of nosocomial infections, but are uncommon etiologic agents of endocarditis . We present a case of endocarditis caused by Acinetobacter iwoffi in a composite aortic graft with a St . Jude prosthetic valve, using the Bono and Bentall procedure, complicated with multiple graft dehiscenses causing first a peritube pseudoaneurysm and finally severe paraprosthetic valve regurgitation to the left ventricle which required emergency surgery.

Res Microbiol, 1998 Sep, 149(8), 557 - 66
Characterization of oligonucleotide probes for the identification of Acinetobacter spp., A . baumannii and Acinetobacter genomic species 3; Lagatolla C et al.; The 16S-23S intergenic spacer regions of four Acinetobacter genomic species belonging to the A . calcoaceticus-A . baumannii (Acb) complex, i.e . genomic species 1 (A . calcoaceticus), genomic species 2 (A . baumannii), genomic species 3 and Tjernberg and Ursing (TU) genomic species 13, have been cloned and sequenced . Sequence analysis led to the discovery of a single copy of IIe and Ala tRNA genes within each spacer . Sequence comparison allowed the identification of a 192-base-pair long highly conserved sequence between the 3' end of the 16S rRNA and the 5' end of the tRNA(Ala) genes . Moreover, two short regions, which were specific to, respectively, genomic species 2 and 3, could be identified . Oligonucleotides corresponding to these sequences were constructed and tested for the ability to hybridize with chromosomal DNA extracted from Acinetobacter belonging to different genomic species and with chromosomal DNA of other bacterial genera . One of these oligonucleotides was demonstrated to be useful as a sensitive and specific probe for A . baumannii . A less sensitive probe for Acinetobacter genomic species 3 was also developed.

Biol Chem, 1998 Aug-Sep, 379(8-9), 1207 - 11
PQQ as redox shuttle for quinoprotein glucose dehydrogenase; Jin W et al.; The role of pyrroloquinoline quinone (PQQ) as a redox shuttle between an electrode and the active site of soluble quinoprotein glucose dehydrogenase (sGDH) from Acinetobacter calcoaceticus has been investigated using both electrochemical and spectrophotometric methods . Reversible redox behavior of PQQ was observed at cystamine-modified gold electrodes . sGDH is able to reduce free PQQ, i.e . PQQ that is not bound to the enzyme and therefore could act as a mediator between the enzyme and the cystamine-modified electrode . The second order rate constants for the reduction of PQQ by sGDH are 6 x 10(3) M(-1) S(-1) and 64 M(-1) S(-1) in the absence and in the presence of calcium ions, respectively . Similarly, the interaction with a second redox protein is realized via the PQQ shuttle . Using DC voltammetry, the reduction rate of cytochrome c (cyt c) by PQQH2 was determined to be on the order of 10(4) M(-1) S(-1)

Syst Appl Microbiol, 1998 Mar, 21(1), 33 - 9
Evaluation of amplified ribosomal DNA restriction analysis for identification of Acinetobacter genomic species; Dijkshoorn L et al.; Further to a previous study, the usefulness of amplified ribosomal DNA restriction analysis (ARDRA) for identification of Acinetobacter genomic species (DNA groups) was tested . A set of 202 Acinetobacter strains of 18 described genomic species and 17 unclassified strains were used . Restriction patterns obtained with a standard panel of restriction enzymes CfoI, AluI, MboI, RsaI and MspI allowed for separation of 11 DNA groups . With the additional use of restriction enzymes BfaI and BsmAI, five other (genomic) species could be differentiated, leaving only A . haemolyticus and DNA group 13BJ/14TU unseparated . With the standard panel of enzymes, ten new ARDRA profiles were noted in 14 unclassified strains . Two other unclassified strains had a profile in common with DNA group 15BJ, but were differentiated from this DNA group by restriction with bfaI . One remaining unclassified strain could not be differentiated from DNA group 17 by the standard panel of enzymes or by the enzymes BfaI and BsmAI . Results demonstrate the utility of ARDRA for identification of most genomic species of Acinetobacter . Furthermore, new ARDRA profiles that were shared by several unclassified strains may indicate so far undescribed genomic species in the genus.

Gen Physiol Biophys, 1998 Jun, 17(2), 105 - 16
Binding modes of PCBs to a degrading enzyme: a receptor-mapping study; Hornak V et al.; The binding site of a PCB-degrading enzyme was mapped using the published data on biodegradation rates of individual PCB congeners by the Acinetobacter P6 strain . For this purpose an approach allowing for multiple binding modes of individual congeners, resulting from the symmetry of the biphenyl skeleton, was used . The effect of substitution patterns and conformational flexibility of individual congeners on their binding to a protein were investigated . The resulting map of the binding site is described by three parameters that indicate the importance of positions 4, 5', 5, 2' in a basic substitution pattern, the first two being favourable while the other two unfavourable for binding . An incorporation of conformational energy dependences of individual ligands into the model showed that ligand's conformation is either not a limiting factor for binding or that ligands bind in their relaxed conformations.

J Hosp Infect, 1998 Sep, 40(1), 27 - 34
The prognostic factors of adult gram-negative bacillary meningitis; Lu CH et al.; Seventy-seven patients with Gram-negative bacillary meningitis (GNBM), 57 males and 20 females, aged 17-86 years, were identified at Kaohsiung Chang Gung Memorial Hospital, over an 11-year period . Fifty-four infections were community-acquired, and 23 were nosocomial; 49 were spontaneous and 28 occurred after head surgery or neurosurgery . The organisms most frequently involved were Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter . Rarer pathogens included Citrobacter species, Serratia marcescens, Enterobacter cloacae, and Proteus mirabilis . All patients who did not receive appropriate antibiotic therapy died . The mortality in those treated with appropriate antibiotics was 28% . Other statistically significant prognostic factors included septic shock, initial level of consciousness, hyperosmolar hyperglycemic nonketotic coma, disseminated intravascular coagulation, high cerebrospinal fluid lactate levels and leucocytosis . In the multiple logistic regression analysis, only appropriate antimicrobial therapy and septic shock were strongly associated with mortality even after adjusting for other potentially confounding factors . Despite the high mortality, management can be improved by early diagnosis, early use of appropriate antibiotics, and correction of underlying and associated medical derangement.

J Clin Microbiol, 1998 Nov, 36(11), 3415 - 6
In vitro activities of ampicillin-sulbactam and amoxicillin-clavulanic acid against Acinetobacter baumannii; Pandey A et al.; In vitro susceptibility patterns of newer beta-lactamase-inhibiting antibiotics ampicillin-sulbactam (A/S) and amoxicillin-clavulanic acid (A/C) for 100 consecutive isolates of Acinetobacter baumannii obtained from various clinical samples were studied . The A/C MIC for 86% of the strains was more than 16/8 microgram/ml, whereas there was an A/S MIC of more than 16/8 microgram/ml for only 38% of the strains . This showed that A/S has significantly superior in vitro activity compared to A/C against A . baumannii, although, theoretically, both should have similar activities . The therapeutic superiority of A/S over A/C needs to be studied, or else the breakpoints for these agents in in vitro tests need to be redefined.

J Biol Chem, 1998 Oct 23, 273(43), 28122 - 31
Characterization of a novel branched tetrasaccharide of 3-deoxy-D-manno-oct-2-ulopyranosonic acid . The structure of the carbohydrate backbone of the lipopolysaccharide from Acinetobacter baumannii strain nctc 10303 (atcc 17904); Vinogradov EV et al.; For the first time, the tetrasaccharide Kdoalpha2-->5Kdoalpha2-->5(Kdoalpha2-->4)Kdo (Kdo is 3-deoxy-D-manno-oct-2-ulopyranosonic acid) has been identified in a bacterial lipopolysaccharide (LPS), i.e . in the core region of LPS from Acinetobacter baumannii NCTC 10303 . The LPS was analyzed using compositional analysis, mass spectrometry, and NMR spectroscopy . The disaccharide D-GlcpNbeta1-->6D-GlcpN, phosphorylated at O-1 and O-4', was identified as the carbohydrate backbone of the lipid A . The Kdo tetrasaccharide is attached to O-6' of this disaccharide and is further substituted by short L-rhamnoglycans of varying length and by the disaccharide D-GlcpNAcalpha1-->4D-GlcpNA (GlcpNA, 2-amino-2-deoxy-glucopyranosuronic acid) . The core region is not substituted by phosphate residues and represents a novel core type of bacterial LPS . The complete carbohydrate backbone of the LPS is shown in Structure I as follows: where Rha is rhamnose . Except were indicated, monosaccharides possess the D-configuration . Sugars marked with an asterisk are present in non-stoichiometric amounts.

Pathol Biol (Paris), 1998 Apr, 46(4), 245 - 52
{Bacteria of the Acinetobacter genus}; Joly-Guillou ML; Bacteria of the Acinetobacter genus received little attention for many years because of their weak pathogenic potential and changing taxonomy . Since the introduction starting in the 1980s of an ever increasing number of antimicrobials, these organisms have demonstrated their ability to adapt . They are causing an increasing number of nosocomial infections, most notably in intensive care units . The selection pressure exerted by antimicrobials and the use of increasingly invasive diagnostic and therapeutic procedures are the main factors that promote emergence of Acinetobacter in high-risk patients . Acinetobacter exhibit a high level of resistance to antimicrobials and are capable of persisting in hostile environments (humidity or dryness, presence of some antiseptics) . As a result, they can cause nosocomial outbreaks . Identification of carriers and colonized patients, rigorous isolation, and scrupulous cleaning procedures are effective control measures . Despite these efforts, however, Acinetobacter baumannii now contributes a significant proportion of nosocomial infections.

Pathol Biol (Paris), 1998 Jun, 46(6), 385 - 94
{An Acinetobacter baumanii outbreak at the Versailles Hospital Center}; Pina P et al.; A . baumannii is a multiresistant bacteria which is recognised as responsible for nosocomial infections and hospital outbreaks . The control of these outbreaks depends on the strain's typing and on the fight's policy against nosocomial infections . An outbreak of A . baumannii is occurred to patients who were hospitalized in Centre Hospitalier de Versailles . To investigate this outbreak, we have determined the biotype (Bouvet's method), the succeptibility pattern (disk diffusion and agar dilution results were analysed with the hierarchical classification and main component analysis) and the total DNA macrorestriction pattern (Pulse Field Gel Electrophoresis using SmaI restriction enzyme) . A risk factors for A . baumannii acquisition were delineated in case-control study . During 2 years, 38 patients have been infected or colonized to A . baumannii . Thirty two patients were hospitalized in ICU . We studied 38 non repetitive clinical isolates and 9 strains of the patient's rooms . Four biotypes were defined by the Bouvet's typing method . Fourteen groups were obtained when succeptibility results were analysed with the hierarchical classification and 6 with the main composant analysis . The molecular typing permit us to define 4 epidemic and 6 sporadic strains . All the epidemic strains were isolated on ICU hospitalized patients . Our study has shown wide contamination in patient's rooms (Water tap, dry surfaces, patient's mattresses...) . Environmental objects have been a major risk factor for A . baumannii acquisition . The control of this outbreak has been possible by application of hygienic measures (hands washing, isolment, meticulous cleaning of the ICU and environmental controls) . No new case is occurred in the last year . Typing methods and case-control study are necessary to investigate cross-infections and take efficient measures against these outbreaks.

Pathol Biol (Paris), 1998 Jun, 46(6), 380 - 4
{Bacteria isolated from protected bronchopulmonary samples: variation as a function of the previous length of stay in the recovery room}; Bert F et al.; We retrospectively reviewed the variation of the organisms recovered from 403 protected bronchopulmonary specimens in three surgical intensive care units according to the time elapsed from admission . The predominant pathogens during the four first days were Haemophilus influenzae (33.3%), Staphylococcus aureus (18.2%), mostly methicillin susceptible strains, and Streptococcus pneumoniae (14.3%) . After the fourth day, they were progressively replaced by typical nosocomial bacteria such as methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii . For Pseudomonas aeruginosa and cephalosporinase-producing Enterobacteriaceae, strains resistant to third generation cephalosporins occurred significantly later than the susceptible strains . These results indicate that the time elapsed from intensive care unit admission has a major influence on the bacteriology of respiratory tract infections, but no clear cut-off point between early-onset and late onset pneumonia is evident.

Res Microbiol, 1997 Dec, 148(9), 777 - 84
PCR-amplified 16S and 23S rDNA restriction analysis for the identification of Acinetobacter strains at the DNA group level; Garcia-Arata MI et al.; The genus Acinetobacter is phenotypically rather homogeneous, but genotypically heterogeneous . In this study, a simple method based on restriction analysis of a PCR-amplified large fragment (4.5 kb) of most of the ribosomal operon (16S and 23S ribosomal genes and the spacer in-between) was investigated . Sixty-seven collection strains belonging to the 20 DNA groups proposed until 1993 were studied . Using the enzyme Sau3AI, 25 DNA profiles were obtained . Strains belonging to DNA groups 1, 3, 6, TU13 and TU15 showed two profiles each, and DNA groups 4, 5 and 7 showed profiles with variants showing less intensive additional bands . The remaining 12 groups showed 12 different profiles . The profiles obtained were DNA-group-specific except for one profile which was shared between the unnamed DNA group 3 and a rarely encountered genotypically related DNA group . These two DNA groups could be separated by using the enzyme Hinf1 . Twenty-five additional clinical isolates previously characterized by standard DNA-DNA hybridization were selected in a double-blind fashion for identification at the DNA group level to check the reliability of the assay . All strains were correctly identified at the DNA group level . PCR-amplified 16S and 23S rDNA restriction analysis is both an accurate and rapid method for the identification of Acinetobacter at the DNA group level.

Res Microbiol, 1997 Mar-Apr, 148(3), 237 - 49
Molecular characterization of an n-alkane-degrading bacterial community and identification of a new species, Acinetobacter venetianus; Di Cello F et al.; Twenty-five bacterial strains isolated from the Venice lagoon and implicated in the degradation of n-alkanes, n-alkanols, n-alkanals and n-alkanoates were characterized in molecular and physiological terms . The isolates were grouped by amplified ribosomal DNA restriction analysis (ARDRA) into seven clusters, corresponding to seven species, six of which were identified on the basis of 16S rDNA sequencing . Genetic variability among strains was shown by random amplified polymorphic DNA (RAPD) . Only strains of the new species Acinetobacter venetianus grew with n-alkanes (C10, C14 and C20) and their respective oxidation products as sole carbon sources . Strains of the other three species identified thrived on n-alkane oxidation products (n-alkanols, n-alkanals, n-alkanoates) . The other three species were not able to grow on any of the substrates tested . Analysis of plasmid content showed that only A . venetianus strains harboured plasmids . These plasmids contained sequences homologous to the Pseudomonas oleovorans alkBFGH genes.

Eur J Clin Microbiol Infect Dis, 1998 Jun, 17(6), 377 - 84
Bacteraemia in the adult intensive care unit of a teaching hospital in Nottingham, UK, 1985-1996; Crowe M et al.; Bacteraemia is an important cause of morbidity and mortality in the intensive care unit . In this study the distribution of organisms causing bacteraemic episodes in patients in the adult intensive care unit of a large teaching hospital was determined . Particular emphasis was placed on the type of organisms isolated from community- and hospital-acquired bacteraemia, the suspected source of infection, the possible risk factors associated with bacteraemia, and outcome . The incidence of bacteraemia and fungaemia increased from 17.7 per 1000 admissions in 1985 to 80.3 in 1996 . A total of 315 episodes of bacteraemia and fungaemia were documented over a 12-year period, of which 18% were considered community-acquired and 82% hospital-acquired . Gram-positive and gram-negative bacteria accounted for 46.9% and 31.5% of the episodes, respectively . Polymicrobial infection accounted for 17.8% and fungi for 3.8% of the episodes . Staphylococcus aureus (22.5%), Staphylococcus epidermidis (7.6%), and Streptococcus pneumoniae (7.9%) were the predominant gram-positive bacteria implicated, whereas Escherichia coli (6%), Enterobacter cloacae (7%), Klebsiella aerogenes (3.8%), Pseudomonas aeruginosa (5.1%), and Acinetobacter spp . (3.8%) were the predominant gram-negative bacteria isolated . The two most common sources of infection were the respiratory tract (39.7%) and an intravascular line (24.5%), but in 8.9% of episodes the focus of infection remained unknown . Bacteraemic patients stayed in the unit for a longer period (12 days) than did non-bacteraemic patients (3 days) . The overall mortality related to bacteraemia and candidaemia was 44.4% . Surveillance of bacteraemia in the intensive care unit is important in detecting major changes in aetiology, e.g., the increasing incidence of gram-positive bacteraemia, the emergence of methicillin-resistant Staphylococcus aureus in 1995, and the emergence of Enterobacter cloacae . It is of value in determining empirical antimicrobial therapy to treat presumed infection pending a microbiological diagnosis and in directing the development of guidelines for infection prevention, e.g., guidelines for central venous catheter care.

Antimicrob Agents Chemother, 1998 Oct, 42(10), 2759 - 61
Characterization of IS18, an element capable of activating the silent aac(6')-Ij gene of Acinetobacter sp . 13 strain BM2716 by transposition; Rudant E et al.; Insertion sequence IS18 was detected by analysis of the spontaneous aminoglycoside resistant mutant Acinetobacter sp . 13 strain BM2716-1 . Insertion of the element upstream from the silent acetyltransferase gene aac(6')-Ij created a hybrid promoter that putatively accounts for the expression of the aminoglycoside resistance gene . The 1, 074-bp IS18 element contained partially matched (20 out of 26 bases) terminal inverted repeats, one of which overlapped the 3' end of a 935-bp open reading frame potentially encoding a protein related to the transposases of the IS30 family . IS18 was found in 6 out of 29 strains of Acinetobacter sp . 13 but not in 10 strains each of A . baumannii and A . haemolyticus.

J Bacteriol, 1998 Oct, 180(19), 5058 - 69
Mutation analysis of PobR and PcaU, closely related transcriptional activators in acinetobacter; Kok RG et al.; Acinetobacter PobR and PcaU are transcriptional activators that closely resemble each other in primary structure, DNA-binding sites, metabolic modulators, and physiological function . PobR responds to the inducer-metabolite p-hydroxybenzoate and activates transcription of pobA, the structural gene for the enzyme that converts p-hydroxybenzoate to protocatechuate . This compound, differing from p-hydroxybenzoate only in that it contains an additional oxygen atom, binds to PcaU and thereby specifically activates transcription of the full set of genes for protocatechuate catabolism . Particular experimental attention has been paid to PobR and PcaU from Acinetobacter strain ADP1, which exhibits exceptional competence for natural transformation . This trait allowed selection of mutant strains in which pobR function had been impaired by nucleotide substitutions introduced by PCR replication errors . Contrary to expectation, the spectrum of amino acids whose substitution led to loss of function in PobR shows no marked similarity to the spectrum of amino acids conserved by the demand for continued function during evolutionary divergence of PobR, PcaU, and related proteins . Surface plasmon resonance was used to determine the ability of mutant PobR proteins to bind to DNA in the pobA-pobR intergenic region . Deleterious mutations that strongly affect DNA binding all cluster in and around the PobR region that contains a helix-turn-helix motif, whereas mutations causing defects in the central portion of the PobR primary sequence do not seem to have a significant effect on operator binding . PCR-generated mutations allowing PobR to mimic PcaU function invariably caused a T57A amino acid substitution, making the helix-turn-helix sequence of PobR more like that of PcaU . The mutant PobR depended on p-hydroxybenzoate for its activity, but this dependence could be relieved by any of six amino acid substitutions in the center of the PobR primary sequence . Independent mutations allowing PcaU to mimic PobR activity were shown to be G222V amino acid substitutions in the C terminus of the 274-residue protein . Together, the analyses suggest that PobR and PcaU possess a linear domain structure similar to that of LysR transcriptional activators which largely differ in primary structure.

Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi, 1994 Aug, 27(3), 133 - 9
{Assessment of a new four-hour diagnostic kit--RapID onE system for the identification of enteric bacteria}; Lee JH et al.; RapID onE System is a newly developed four-hour rapid diagnostic kit for the identification of enteric bacteria . To know the effectiveness of this system, we used 125 strains of oxidase-negative, gram-negative bacilli for this evaluation . Except for Acinetobacter calcoaceticus, all the bacilli belong to family Enterobacteriaceae . The bacterial strains of this assessment belong to 12 genera and 20 species . Among them, 84 strains were freshly isolated from clinical specimens and 41 strains were frozen (-70 degrees C) stock clinical isolates . The results show that 115 (92.0%) strains were correctly identifed to the species level . It yielded 92.9% and 90.2% of correct identification of fresh isolates and frozen stocks, respectively . In this paper, the reading criteria of RapID onE System would also be discussed.

Klin Padiatr, 1998 Jul-Aug, 210(4), 256 - 60
{Bacteremic episodes in pediatric oncologic patients, especially caused by the Streptococcus viridans group}; Berner R et al.; BACKGROUND: The management of infectious complications plays a major role in the care for pediatric cancer patients . The majority of infections in the neutropenic patient present as fever of unknown origin without recovering a pathogen from the blood stream . The careful evaluation of bacteremic episodes is essential, since knowledge of the bacterial spectrum expected is crucial for the successful anti-infective treatment . PATIENTS AND METHODS: From 1985 to 1995 all bacteremic episodes in pediatric oncology patients at the University Children's Hospital Freiburg were retrospectively analyzed with respect to the pathogens encountered, the antibiotic susceptibility profile and the underlying conditions . RESULTS: Overall, 113 bacteremic episodes were encountered in pediatric oncology patients, 68 of them in patients with hematological malignancies, and 45 in patients with solid tumors . In both patient groups, gram-positive bacteria were predominant with 72% and 58%, respectively . In patients with hematological malignancies, viridans streptococci were the most frequently isolated pathogens (35%) with a relevant morbidity (29% of patients developed a severe sepsis syndrome and/or ARDS), but were found only in 9% of patients with solid tumors . In 28% of patients with leukemia or lymphoma, gram-negative rods were cultured, in 6% Pseudomonas spec., in 4% Acinetobacter spec., and in 18% enterobacteria . In patients with solid tumors, in 38% gram-negative rods were isolated, 7% Pseudomonas spec., 16% Acinetobacter spec., 16% enterobacteria . In 3 patients, fungemia was observed . The antibiotic susceptibility profile was quite favorable in both, gram-positive and -negative bacteria: none of the gram-positive isolates was resistant to vancomycin, none of the Staphylococcus aureus isolates was resistant to oxacillin . All gram-negative bacteria were fully susceptible to ceftazidime, imipenem and ciprofloxacin . CONCLUSION: Gram-positive bacteria account for 2/3 of all bacteremic episodes in pediatric oncology patients . Streptococcus viridans was the most important pathogen in hematological malignancies accounting for a significant, pathogen-specific morbidity.

FEMS Microbiol Lett, 1998 Aug 15, 165(2), 357 - 62
Comparison of ARDRA and recA-RFLP analysis for genomic species identification of Acinetobacter spp; Jawad A et al.; The genus Acinetobacter is subdivided into genospecies on the basis of DNA relatedness of strains . Phenotypic tests are insufficient to identify the genospecies to which an isolate belongs . The effectiveness of two previously described PCR-based methods for genospeciating Acinetobacter spp . was compared using a group of 32 well-characterised strains representing six genospecies . Amplified ribosomal DNA restriction analysis (ARDRA) correctly identified all 32 strains . Using restriction fragment length polymorphism (RFLP) of recA PCR amplimers, only six of the 32 strains were correctly identified . Heterogeneity in the recA gene sequence was demonstrated within five of the genospecies . ARDRA proved to be a reliable method whereas analysis of recA RFLP profiles did not enable the genospecies of most of the isolates of Acinetobacter spp . to be determined.

Southeast Asian J Trop Med Public Health, 1998 Mar, 29(1), 96 - 9
Bacterial pathogens (non-Mycobacterium) from sputum culture and antimicrobial susceptibility; Srifuengfung S et al.; Sputum culture of patients at Siriraj Hospital, Bangkok was 49.84% positive for bacterial pathogens in 1994 and 40.95% in 1995 . The average incidence of gram-negative rods was 3.11 fold more than the combination of gram-positive cocci and gram-negative cocci . The most common gram-negative rod was Pseudomonas aeruginosa, followed by either Klebsiella pneumoniae or Acinetobacter anitratus depending on year . The most common coccus was Staphylococcus aureus . From both years, the number of Haemophilus influenzae, Streptococcus pneumoniae, Burkholderia pseudomallei and Nocardia spp isolated were 122, 93, 13 and 11 strains respectively . For antimicrobial susceptibility, P . aeruginosa was sensitive to ceftazidime, imipenem, gentamicin, amikacin, netilmicin, ciprofloxacin (range 56-89%) . S . aureus (MSSA) was sensitive to common used drugs . S . aureus (MRSA) was sensitive to co-trimoxazole, fosfomycin, vancomycin (range 57-100%) and resistant to most drugs.

JPEN J Parenter Enteral Nutr, 1998 Sep-Oct, 22(5), 291 - 6
Total nutrient admixtures appear safer than lipid emulsion alone as regards microbial contamination: growth properties of microbial pathogens at room temperature; Didier ME et al.; BACKGROUND: The extraordinary growth properties of most microorganisms in 10% and 20% lipid emulsions has led to the Centers for Disease Control and Prevention recommendation that if lipids are given through an i.v . line, the administration set should be replaced every 24 hours rather than the usual 72-hour interval used for crystalloid solutions, including those used for conventional total parenteral nutrition . For nearly 15 years, parenteral alimentation has been given as a total nutrient admixture (TNA), with the glucose, amino acids, and lipid mixed within the same bag and infused continuously over 24 hours . METHODS: We prospectively studied in a representative TNA (17.6% glucose, 5% amino acids, 4% lipid; pH 5.6, osmolality 1778) and in a control solution, 5% dextrose-in-water (D5%/W), the growth properties at 4, 25, and 35 degrees C of three isolates each of Staphylococcus epidermidis, Staphylococcus aureus, Enterobacter cloacae, Klebsiella oxytoca, Serratia marcescens, Acinetobacter calcoaceticus, Stenotrophomonas maltophilia, Pseudomonas aeruginosa, Burkholderia cepacia, Flavobacterium spp, and Candida albicans, and two isolates of Staphylococcus saprophyticus, the species that are most likely to contaminate TNA during preparation or administration and that have been implicated in >95% of all outbreaks and sporadic cases of nosocomial bloodstream infections traced to contaminated parenteral admixtures reported in the world literature . RESULTS: Growth in TNA at 25 and 35 degrees C occurred with only two species, C . albicans and S . saprophyticus, and only after 24 to 48 hours; D5%/W allowed growth at 25 degrees C of two gram-negative species, S . marcescens and B . cepacia . CONCLUSIONS: We conclude that TNA is a poor growth medium for most nosocomial pathogens and is no better than D5%/W . The need to replace administration sets every 24 hours with TNA should be reconsidered and ideally be studied in a prospective randomized trial.

J Antimicrob Chemother, 1998 Aug, 42(2), 161 - 9
Comparison of the modified Stokes' method of susceptibility testing with results obtained using MIC methods and British Society of Antimicrobial Chemotherapy breakpoints; Gosden PE et al.; The majority of clinical microbiology laboratories in the UK use comparative disc diffusion methods based on the Stokes' method to determine antibiotic susceptibility . The technical validity of the results obtained from the modified Stokes' method of disc testing and how they relate to MIC data are not known . We studied susceptibility testing using a modified Stokes' disc diffusion method for a wide range of clinical isolates against which MICs had been determined by collaborators not involved with the disc testing evaluation . Results indicated that for 1301 organism-antibiotic combinations the number of major errors (where resistant strains were reported as sensitive) was 21/468 (4.4%) and the number of minor errors (where sensitive strains were reported as resistant) was 14/713 (1.9%) using ciprofloxacin breakpoints of 0.5 and 2 mg/L . There was good correlation between the disc susceptibility test and the MIC for 119 isolates of Enterobacteriaceae tested with the exception of Serratia spp . Excluding Serratia spp . the number of major errors for Enterobacteriaceae was 1/200 (0.5%) . Data revealed 2/25 (8%) major errors for Pseudomonas aeruginosa and 1/45 (2.2%) for Acinetobacter spp . Haemophilus influenzae showed a number of unexpected categorization errors . The modified Stokes' method performed accurately for Staphylococcus aureus and coagulase-negative staphylococci when tested for susceptibility to gentamicin, erythromycin, teicoplanin and vancomycin . No major errors were reported for Streptococcus pneumoniae and beta-haemolytic streptococci . Problems occurred with the detection of antibiotic resistance in Enterococcus spp . Major errors were seen for ampicillin (2/12 strains), teicoplanin (5/6 strains) and vancomycin (5/13 strains) using a 30 microg disc but only 1/13 strains using a 5 microg disc . Overall, from our data, the modified Stokes' disc diffusion antibiotic susceptibility test showed an unacceptable number of major errors but an acceptable number of minor errors.

Appl Environ Microbiol, 1998 Sep, 64(9), 3499 - 502
Antibiotic resistance in Acinetobacter spp . isolated from sewers receiving waste effluent from a hospital and a pharmaceutical plant; Guardabassi L et al.; The possible increase of antibiotic-resistant bacteria in sewage associated with the discharge of wastewater from a hospital and a pharmaceutical plant was investigated by using Acinetobacter species as environmental bacterial indicators . The level of susceptibility to six antimicrobial agents was determined in 385 Acinetobacter strains isolated from samples collected upstream and downstream from the discharge points of the hospital and the pharmaceutical plant . Results indicated that while the hospital waste effluent affected only the prevalence of oxytetracycline resistance, the discharge of wastewater from the pharmaceutical plant was associated with an increase in the prevalence of both single- and multiple-antibiotic resistance among Acinetobacter species in the sewers.

Appl Environ Microbiol, 1998 Sep, 64(9), 3290 - 9
Substrate specificity of and product formation by muconate cycloisomerases: an analysis of wild-type enzymes and engineered variants; Vollmer MD et al.; Muconate cycloisomerases play a crucial role in the bacterial degradation of aromatic compounds by converting cis,cis-muconate, the product of catechol ring cleavage, to (4S)-muconolactone . Chloromuconate cycloisomerases catalyze both the corresponding reaction and a dehalogenation reaction in the transformation of chloroaromatic compounds . This study reports the first thorough examination of the substrate specificity of the muconate cycloisomerases from Pseudomonas putida PRS2000 and Acinetobacter "calcoaceticus" ADP1 . We show that they transform, in addition to cis,cis-muconate, 3-fluoro-, 2-methyl-, and 3-methyl-cis, cis-muconate with high specificity constants but not 2-fluoro-, 2-chloro-, 3-chloro-, or 2,4-dichloro-cis,cis-muconate . Based on known three-dimensional structures, variants of P . putida muconate cycloisomerase were constructed by site-directed mutagenesis to contain amino acids found in equivalent positions in chloromuconate cycloisomerases . Some of the variants had significantly increased specificity constants for 3-chloro- or 2,4-dichloromuconate (e.g., A271S and I54V showed 27- and 22-fold increases, respectively, for the former substrate) . These kinetic improvements were not accompanied by a change from protoanemonin to cis,cis-dienelactone as the product of 3-chloro-cis,cis-muconate conversion . The rate of 2-chloro-cis,cis-muconate turnover was not significantly improved, nor was this compound dehalogenated to any significant extent . However, the direction of 2-chloro-cis,cis-muconate cycloisomerization could be influenced by amino acid exchange . While the wild-type enzyme discriminated only slightly between the two possible cycloisomerization directions, some of the enzyme variants showed a strong preference for either (+)-2-chloro- or (+)-5-chloromuconolactone formation . These results show that the different catalytic characteristics of muconate and chloromuconate cycloisomerases are due to a number of features that can be changed independently of each other.

Pediatr Infect Dis J, 1998 Aug, 17(8), 716 - 22
Outbreak of Acinetobacter spp . bloodstream infections in a nursery associated with contaminated aerosols and air conditioners; McDonald LC et al.; BACKGROUND: Acinetobacter spp . are multidrug-resistant bacteria that grow well in water and cause infections with unexplained, increased summer prevalence . In August, 1996, eight infants acquired Acinetobacter spp . bloodstream infection (A-BSI) while in a nursery in the Bahamas; three infants died and an investigation was initiated . METHODS: A case patient was defined as any newborn in the nursery during August 6 to 13, 1996, with A-BSI . To identify risk factors for A-BSI we conducted a retrospective cohort study and performed environmental cultures and air sampling using settle plates . The genetic relatedness of environmental isolates was assessed by pulsed field gel electrophoresis . RESULTS: Of 33 patients in the nursery 8 (24%) met the case definition . Patients with peripheral iv catheters were more likely to develop A-BSI (8 of 21 vs . O of 10, P < 0.05) . Multivariate analysis among patients with iv catheters indicated that only exposure to one nurse was an independent risk factor for developing A-BSI (P < 0.005) . Nursery settle plates were more likely to grow Acinetobacter spp . than were settle plates from other hospital areas (8 of 9 vs . 0 of 5, P < 0.005); cultures from nursery air conditioners also grew Acinetobacter spp . Environmental isolates were genetically diverse . After installation of a new air conditioner in May, 1995, A-BSIs occurred more frequently during months of increased absolute humidity or environmental dew point . CONCLUSIONS: Acinetobacter spp . may cause nosocomial BSI and death among infants during periods of polyclonal airborne dissemination; breaks in aseptic technique during i.v . medication administration may facilitate transmission from the environment to the patient . Environmental conditions that increase air conditioner condensate may predispose to airborne dissemination via contaminated aerosols and increase the risk of nosocomial A-BSI.

J Bacteriol, 1998 Sep, 180(17), 4466 - 74
Similarities between the antABC-encoded anthranilate dioxygenase and the benABC-encoded benzoate dioxygenase of Acinetobacter sp . strain ADP1; Bundy BM et al.; Acinetobacter sp . strain ADP1 can use benzoate or anthranilate as a sole carbon source . These structurally similar compounds are independently converted to catechol, allowing further degradation to proceed via the beta-ketoadipate pathway . In this study, the first step in anthranilate catabolism was characterized . A mutant unable to grow on anthranilate, ACN26, was selected . The sequence of a wild-type DNA fragment that restored growth revealed the antABC genes, encoding 54-, 19-, and 39-kDa proteins, respectively . The deduced AntABC sequences were homologous to those of class IB multicomponent aromatic ring-dihydroxylating enzymes, including the dioxygenase that initiates benzoate catabolism . Expression of antABC in Escherichia coli, a bacterium that normally does not degrade anthranilate, enabled the conversion of anthranilate to catechol . Unlike benzoate dioxygenase (BenABC), anthranilate dioxygenase (AntABC) catalyzed catechol formation without requiring a dehydrogenase . In Acinetobacter mutants, benC substituted for antC during growth on anthranilate, suggesting relatively broad substrate specificity of the BenC reductase, which transfers electrons from NADH to the terminal oxygenase . In contrast, the benAB genes did not substitute for antAB . An antA point mutation in ACN26 prevented anthranilate degradation, and this mutation was independent of a mucK mutation in the same strain that prevented exogenous muconate degradation . Anthranilate induced expression of antA, although no associated transcriptional regulators were identified . Disruption of three open reading frames in the immediate vicinity of antABC did not prevent the use of anthranilate as a sole carbon source . The antABC genes were mapped on the ADP1 chromosome and were not linked to the two known supraoperonic gene clusters involved in aromatic compound degradation.

J Chemother, 1998 Aug, 10(4), 320 - 5
Bacteremia due to multiresistant gram-negative bacilli in neutropenic cancer patients: a case controlled study; Krcmery V Jr et al.; The aim of this study was to see if multiresistant Gram-negative bacteremias (MRGNB) are associated with specific risk factors and/or higher mortality in comparison to sensitive GNB (SGNB) . Both groups, 51 patients and 102 controls, were matched for sex, age, underlying disease and neutropenia . In addition there were no significant differences in the incidence of cytotoxic chemotherapy administered, vascular catheter insertion and catheter as source of bacteremia and etiology of bacteremia . The proportion of Klebsiella-Enterobacter, Pseudomonas aeruginosa, Acinetobacter spp . and Stenotrophomonas maltophilia was similar in both groups . Prior surgery (21.6% vs 7.6%, p<0.02) was significantly associated with SGNB . Previous prophylaxis with quinolones (45.1% vs 24.5%, p<0.045), and prior therapy with broad spectrum antibiotics (41.2% vs 27.5%, p<0.05) were significantly more frequently observed among patients than controls . Patients with bacteremia due to MRGNB were also significantly more frequently infected with resistant bacteria . Attributable mortality was similar (15.7% vs 13.75%, NS) in both groups, however cure rates were lower among MRGNB patients . Crude mortality was higher among patients (35.3% vs 13.75%, p<0.01) in comparison to controls . In conclusion, prior antimicrobial prophylaxis and therapy with several classes of antimicrobials represents a significant risk for development of resistance . Mortality due to multiresistant Gram-negative bacteremias was higher in comparison to bacteremias due to susceptible organisms.

Microbiology, 1998 Aug, 144 ( Pt 8), 2085 - 93
rRNA-targeted fluorescent in situ hybridization analysis of bacterial community structure in river water; Kenzaka T et al.; An improved in situ hybridization technique, HNPP-FISH, using 2-hydroxy-3-naphthoic acid 2'-phenylanilide phosphate (HNPP) and Fast Red TR was applied to analyse the community structure of planktonic bacteria in river water . Oligonucleotide probes specific for the domain Bacteria (EUB338) and five bacterial groups {Flavobacterium-Cytophaga; Burkholderia-Pseudomonas (rRNA III)-authentic Alcaligenes; Vibrio-Aeromonas; Pseudomonas (rRNA I): the genus Acinetobacter} were used to investigate the bacterial community structure at two sites differing in organic carbon pollution level . At the eutrophic site, 54-68% of all cells visualized by staining with DAPI (4',6-diamidino-2-phenylindole) could be detected with probe EUB338 . In samples from the oligotrophic site, 39-45% of the total cells hybridized with EUB338 . At the eutrophic site, approximately 50% of the total cells were identified with the five group-specific probes; the bacterial community structure was dominated by the Flavobacterium-Cytophaga group and Burkholderia-Pseudomonas (rRNA III)-authentic Alcaligenes group . At the oligotrophic site, only 26-38% of the total cells were identified with the five group-specific probes . The community structure at the oligotrophic site was similar to that at the eutrophic site, although the percentage of EUB338-detectable cells differed . No appreciable change was found in the community structure during the sampling period at either site . The improved HNPP-FISH technique should be a useful tool for the analysis of microbial community composition.

J Appl Microbiol, 1998 Jun, 84(6), 1069 - 84
Microbial communities of printing paper machines; Vaisanen OM et al.; The microbial content of printing paper machines, running at a temperature of 45-50 degrees C and at pH 4.5-5, was studied . Bacteria were prevalent colonizers of the machine wet end and the raw materials . A total of 390 strains of aerobic bacteria were isolated and 86% of these were identified to genus and species by biochemical, chemotaxonomic and phylogenetic methods . The most common bacteria found at the machine wet end were Bacillus coagulans and other Bacillus species, Burkholderia cepacia, Ralstonia pickettii, and in pink slimes, accumulating in the wire area and press section, species of Deinococcus, aureobacterium and Brevibacterium . Paper-making chemicals also contained species of Aureobacterium, B . cereus, B . licheniformis, B . sphaericus, Bordetella, Hydrogenophaga, Klebsiella pneumoniae, Pantoea agglomerans, Pseudomonas stutzeri, Staphylococcus and sometimes other enteric bacteria, but these did not colonize the process water . Yeasts and moulds were not present in significant numbers . A total of 131 strains were tested for their potential to degrade paper-making raw materials; 91 strains were found to have degradative activity, mainly species of Burkholderia and Ralstonia, Sphingomonas and Bacillus, and enterobacteria produced enzymes which degraded paper-making chemicals . Stainless steel adhering strains occurred in slimes and wire water and were identified as Burkholderia cepacia, B . coagulans and Deinococcus geothermalis . Coloured slimes were formed on the machine by species of Deinococcus, Acinetobacter and Methylobacterium (pink), Aureobacterium, Pantoea and Ralstonia (yellowish) and Microbulbifer-related strains (brown) . The impact of the strains and species found in the printing paper machine community on the technical quality of paper, machine operation, and as a potential biohazard (Hazard Group 2 bacteria), is discussed.

Clin Infect Dis, 1998 Aug, 27 Suppl 1, S117 - 24
Clinical problems posed by multiresistant nonfermenting gram-negative pathogens; Quinn JP; In this review I will briefly survey the role of Pseudomonas aeruginosa, Acinetobacter baumanii, Stenotrophomonas maltophilia, and Burkholderia cepacia as opportunistic pathogens . A common feature of these organisms is intrinsic resistance to multiple antibiotics . All of these organisms can be recovered from the environment, commonly cause device-related infections, are often resistant to disinfectants, and have the potential to spread from patient to patient via fomites or the hands of medical personnel . Newer clinical syndromes will be emphasized, including the increasing importance of P . aeruginosa infections in patients with AIDS, as well as the role of carbapenems in selecting for A . baumanii and S . maltophilia and the unique niche of B . cepacia in patients with cystic fibrosis.

Clin Infect Dis, 1998 Aug, 27 Suppl 1, S93 - 9
Resistance mechanisms in Pseudomonas aeruginosa and other nonfermentative gram-negative bacteria; Hancock RE; Nonfermentative gram-negative bacilli are still a major concern in compromised individuals . By far the most important of these organisms is Pseudomonas aeruginosa, although Acinetobacter baumannii (previously Acinetobacter calcoaceticus), Stenotrophomonas maltophilia (previously Pseudomonas and Xanthomonas maltophilia), and Burkholderia cepacia (previously Pseudomonas cepacia) are also of substantative concern because of their similar high intrinsic resistances to antibiotics . The basis for the high intrinsic resistance of these organisms is the lower outer-membrane permeability of these species, coupled with secondary resistance mechanisms such as an inducible cephalosporinase or antibiotic efflux pumps, which take advantage of low outer-membrane permeability . Even a small change in antibiotic susceptibility of these organisms can result in an increase in the MIC of a drug to a level that is greater than the clinically achievable level . In this review, the major mechanisms of resistance observed in the laboratory and clinic are summarized.

J Food Prot, 1998 Jun, 61(6), 700 - 3
Bacterial populations associated with the dirty area of a South African poultry abattoir; Geornaras I et al.; Bacterial populations associated with three sample types from the neck region of poultry carcasses in the dirty area of an abattoir were characterized . Sample types before and after scalding were skin only, feathers only, and a skin and feather combination . The neck skin of carcasses after the defeathering processing stage was also sampled . Bacterial populations associated with water from the scald tank, rubber fingers at the exit of the defeathering machine, and air in the dirty area were also characterized . Bacterial colonies (751) were randomly isolated from yeast extract-supplemented tryptone soya agar plates exhibiting 30 to 300 colonies . Micrococcus spp . were isolated in the highest proportion from pre-and postscalded carcass samples (63.5 to 86.1% of isolates), regardless of the sample type . Conversely, Enterobacteriaceae (40.3%), Acinetobacter (19.4%), and Aeromonas/Vibrio (12.5%) species predominated on neck skin samples taken from mechanically defeathered carcasses . Isolates from the rubber fingers were, however, predominantly Micrococcus spp . (94.4%) . Bacterial groups isolated in the highest proportion from scald tank water samples were Micrococcus spp . (38.3%), species of Enterobacteriaceae (29.1%), and lactic acid bacteria (17.0%) . Corynebacterium spp., species of Enterobacteriaceae, and Micrococcus spp . were dominant on air settle plates.

Indian Pediatr, 1998 Jan, 35(1), 27 - 32
Acinetobacter sepsis in newborns; Mishra A et al.; OBJECTIVE: To evaluate the clinico-epidemiological profile of Acinetobacter sepsis in neonates . DESIGN: Retrospective study . SETTING: Level II Neonatal Care Unit . SUBJECTS: 79 neonates with blood culture positive for Acinetobacter . METHODS: Relevant information was collected on a predesigned proforma from the case records and analyzed for clinical and epidemiological characteristics . RESULTS: The incidence of Acinetobacter septicemia was 11.1/1000 live births . Fifty-five babies were hospital born, 24 were outborn . Out of these, 64.6% babies were born at term and 40.5% had a birth weight of 2500 g or more . A cluster of 53 cases was seen between May and September 1995 . In cases with early onset sepsis (onset < 7 days of postnatal age), difficulty in breathing (n = 54), chest retraction (n = 35) and refusal to feed (n = 46) were seen more commonly as compared to late onset sepsis (p < 0.05) . Complications observed included meningitis, bleeding manifestations and necrotising enterocolitis in three, six and five babies, respectively . The organism was sensitive to ciprofloxacin (96.2%), amikacin (92.4%) and gentamicin (87.3%) . A response rate of 52.4% was observed with Ciprofloxacin in babies not responding to cefotaxime and amikacin combination . The overall mortality was 13.9% . CONCLUSION: Nosocomial Acinetobacter sepsis may affect fullterm, appropriate for gestational age babies . Clinical presentation is indistinguishable from Gram negative septicemia . Life threatening complications can also occur . Ciprofloxacin may prove to be useful drug in resistant cases.

Eur J Clin Microbiol Infect Dis, 1998 Apr, 17(4), 282 - 5
Carbapenem resistance mediated by beta-lactamases in clinical isolates of Acinetobacter baumannii in Spain; Lopez-Hernandez S et al.; Four patients colonized/infected with carbapenem-resistant strains of Acinetobacter baumannii are described . The first patient had a decubitus ulcer infection and had been on intravenous imipenem for 50 days . Two other patients, from whom Acinetobacter baumannii was isolated from urine, were hospitalized in the same ward as the first patient . The fourth patient had been mechanically ventilated in the intensive care unit for 4 month and had nosocomial pneumonia . He had been on intravenous meropenem for 1 month . Minimum inhibitory concentrations (MICs) of imipenem (128 mg/l) and meropenem (> 128 mg/l) were the same for the isolates from the first three patients, and all of these isolates had the same repetitive extragenic palindromic polymerase chain reaction (rep-PCR) pattern . The MICs of carbapenems were lower for patient 4's isolate, which also had a different rep-PCR pattern . Beta-lactamases that hydrolyzed imipenem were detected in all four isolates; isoelectric points were 8.6-7.7 in the first three isolates and 6.8-7 in the fourth isolate.

Eur J Clin Microbiol Infect Dis, 1998 Apr, 17(4), 247 - 53
Detection of bacteraemia in patients with fever and neutropenia using 16S rRNA gene amplification by polymerase chain reaction; Ley BE et al.; Episodes of fever and neutropenia are common complications of treatment for cancer . The use of prophylactic and early empirical antibiotics has reduced mortality but decreases the sensitivity of diagnostic tests based on culture . The aim of this study was to determine the potential of a broad diagnostic approach (eubacterial) based on 16S rRNA gene amplification and sequencing to augment cultural methods of diagnosis of bacteraemia in patients with fever and neutropenia in a regional paediatric oncology centre . One hundred eleven patient-episodes of fever and neutropenia were evaluated during the study period, 17 of which were associated with positive blood cultures, as follows: Staphylococcus epidermidis (n = 6 episodes), Enterococcus faecium (n = 2), Streptococcus sanguis (n = 3), Streptococcus mitis (n = 3), Staphylococcus aureus (n = 1), Micrococcus spp . (n = 1), and Stenotrophomonas maltophilia (n = 1) . Eubacterial polymerase chain reaction (PCR) detected bacterial DNA in nine of 11 blood culture-positive episodes for which a sample was available for PCR; the species identified by sequence analysis were identical to those derived from the conventional identification of the cultured isolates . Bacterial DNA was detected in 20 episodes (21 bacterial sequences) associated with negative blood cultures, 18 of which occurred in patients who were receiving antibiotics at the time of sample collection . The species presumptively identified by partial 16S rRNA gene sequencing were as follows: Pseudomonas spp . (n = 6 episodes), Acinetobacter spp . (n =5 ); Escherichia spp . (n = 3); Moraxella spp . (n = 3); Staphylococcus spp . (n = 2); Neisseria spp . (n = 1); and Bacillus spp . (n = 1) . The results of this study suggest that molecular techniques can augment cultural methods in the diagnosis of bacteraemia in patients who have been treated with antibiotics.

J Clin Microbiol, 1998 Sep, 36(9), 2522 - 9
Comparison of amplified ribosomal DNA restriction analysis, random amplified polymorphic DNA analysis, and amplified fragment length polymorphism fingerprinting for identification of Acinetobacter genomic species and typing of Acinetobacter baumannii; Koeleman JG et al.; Thirty-one strains of Acinetobacter species, including type strains of the 18 genomic species and 13 clinical isolates, were compared by amplified ribosomal DNA restriction analysis (ARDRA), random amplified polymorphic DNA analysis (RAPD), and amplified fragment length polymorphism (AFLP) fingerprinting . ARDRA, performed with five different enzymes, showed low discriminatory power for differentiating Acinetobacter at the species and strain level . The standardized commercially available RAPD kit clearly enabled the discrimination of all Acinetobacter genomic species but showed great polymorphism between isolates of Acinetobacter baumannii . AFLP fingerprinting with radioactively as well as fluorescently labelled primers showed high discriminatory power for the identification of 18 Acinetobacter genomic species and typing of 13 clinical Acinetobacter isolates . Compared to radioactive AFLP, fluorescent AFLP was technically fast and simple to perform, and it permitted analysis with an automated DNA sequencer . Fluorescent AFLP seems particularly well suited for studying the epidemiology of nosocomial infections and outbreaks caused by Acinetobacter species.

Zhonghua Yi Xue Za Zhi (Taipei), 1998 Jul, 61(7), 408 - 13
Activity of cefepime compared with other antibiotics against gram-positive bacteria and cefuroxime-resistant gram-negative bacteria; Wang FD et al.; BACKGROUND: Cefepime is a new, parenteral, fourth-generation antibiotic that is stable in the presence of Bush group 1 beta-lactamases . In vitro activity of cefepime, cefuroxime, ceftazidime, ciprofloxacin and imipenem against Gram-positive cocci and cefuroxime-resistant Gram-negative bacilli was studied . METHODS: The agar dilution method described by the US National Committee for Clinical Laboratory Standards was used to determine the minimum inhibitory concentrations of antibiotics tested . These included cefepime, cefuroxime, ceftazidime, ciprofloxacin and imipenem . The tested clinical isolates included Gram-positive cocci (methicillin-sensitive coagulase-negative staphylococci, methicillin-resistant coagulase-negative staphylococci, methicillin-sensitive Staphylococcus aureus, methicillin-resistant S aureus, Streptococcus pyogenes, viridans streptococci, Streptococcus pneumoniae, group D enterococci) and cefuroxime-resistant Gram-negative bacilli (Escherichia coli, Klebsiella pneumoniae, Acinetobacter spp, Pseudomonas aeruginosa, Enterobacter cloacae, Serratia marcescens, Burkholderia cepacia and Xanthomonas maltophilia) . RESULTS: The activity of cefepime against most Gram-negative bacilli other than B cepacia and X maltophilia is better than that of ceftazidime . However, cefepime is less active against these Gram-negative bacilli than ciprofloxacin and imipenem . The activity of cefepime against B cepacia and X maltophilia is less than that of ceftazidime or ciprofloxacin . Among Gram-positive cocci, cefepime was active against most isolates of methicillin-sensitive staphylococci, S pyogenes, viridans streptococci and S pneumoniae . However, cefepime has poor activity against methicillin-resistant S aureus and enterococci . CONCLUSIONS: Due to its extended spectrum of activity, cefepime has potential use as suitable empiric monotherapy for the treatment of a variety of community- and hospital-acquired infections.

J Hosp Infect, 1998 Jul, 39(3), 235 - 40
Exceptional desiccation tolerance of Acinetobacter radioresistens; Jawad A et al.; The taxonomy of the genus Acinetobacter, which includes several important nosocomial pathogens, has been confused due to a lack of discriminatory phenotypic characteristics for identification . Molecular methods such as amplified ribosomal DNA restriction analysis (ARDRA) now enable the accurate identification of species . Ten clinical isolates of Acinetobacter radioresistens had genospecies confirmed by ARDRA but the APJ 20NE system, commonly used in clinical microbiology laboratories, mis-identified them as Acinetobacter lwoffii . Desiccation resistance of Acinetobacter spp . is an important attribute for their survival in the clinical environment . We investigated the ability of A . radioresistens to survive desiccation using an established glass surface model and compared the results to A . lwoffii and Acinetobacter baumannii . The 10 strains of A . radioresistens were extremely resistant to desiccation and survived for an average of 157 days at 31% relative humidity (RH) . In contrast, two strains of A . lwoffii and three strains of A . baumannii survived for an average of three and 20 days respectively, at 31% RH, which was used as an approximation to climatic conditions in UK hospitals . A . radioresistens is thus well adapted for survival in the hospital environment and carriage on human skin and yet it is reported less frequently than A . lwoffii amongst clinical isolates . Cases of A . radioresistens infection may be under-reported due to mis-identification as A . lwoffii and further studies that use molecular identification methods are required to elucidate the role of A . radioresistens in human disease.

J Hosp Infect, 1998 Jul, 39(3), 195 - 206
Changing bacterial ecology during a five-year period of selective intestinal decontamination; Lingnau W et al.; The development of bacterial resistance during selective decontamination of the digestive tract (SDD) is controversial . We studied effects on bacterial resistance one year before and during a randomized, placebo-controlled trial of SDD in a surgical intensive care unit . We randomized patients within two different topical regimens (PTA, PCA) or placebo, administered four-times daily to both the oropharynx and gastrointestinal tract . All patients received intravenous ciprofloxacin (200 mg b.d.) for four days . Both SDD regimens successfully reduced aerobic Gram-negative intestinal colonization . There was no increase in resistance of Enterobacteriaceae or Pseudomonas aeruginosa . Acinetobacter calcoaceticus developed multi-resistance over one year, but differences between groups were not significant . We detected a shift towards Gram-positive organisms . Oxacillin-resistant Staphylococcus aureus increased in concert with ciprofloxacin resistance, from 17 to 80.7%, and frequencies of resistance were significantly higher in SDD patients (P < 0.001) . Resistance of coagulase-negative staphylococci (CNS) to oxacillin increased initially (25 to 66.9%), but values returned to baseline in controls . Ciprofloxacin resistance in CNS remained higher (P < 0.001) in SDD-treated patients (52.5 vs . 23.3%) . The incidence of late respiratory tract infections was unaltered by the prophylactic regimen (SDD 35.2%; Placebo 41.2%; n.s.) . We cannot recommend SDD as a prophylactic tool in critically ill patients.

Ann Intern Med, 1998 Aug 1, 129(3), 182 - 9
Nosocomial Acinetobacter baumannii infections: microbiological and clinical epidemiology; Villers D et al.; BACKGROUND: Acinetobacter baumannii is an important opportunistic pathogen that is rapidly evolving toward multidrug resistance and is involved in various nosocomial infections that are often severe . It is difficult to prevent A . baumannii infection because A . baumannii is ubiquitous and the epidemiology of the infections it causes is complex . OBJECTIVE: To study the epidemiology of A . baumannii infections and assess the relation between fluoroquinolone use and the persistence of multidrug-resistant clones . DESIGN: Three case-control studies and a retrospective cohort study . SETTING: A 20-bed medical and surgical intensive care unit . PATIENTS: Acinetobacter baumannii was isolated from 45 patients in urine (31%), the lower respiratory tract (26.7%), wounds (17.8%), blood (11.1%), skin (6.7%), cerebrospinal fluid (4.4%), and sinus specimens (2.2%) . One death was due to A . baumannii infection . MEASUREMENTS: Antimicrobial resistance pattern and molecular typing were used to characterize isolates . The incidence of A . baumannii infection and the use of fluoroquinolones were calculated annually . RESULTS: Initially, 28 patients developed A . baumannii infection . Eleven isolates had the same antimicrobial susceptibility profile, genotypic profile, or both (epidemic cases), and 17 were heterogeneous (endemic cases) . A surgical procedure done in an emergency operating room was the main risk factor for epidemic cases, whereas previous receipt of a fluoroquinolone was the only risk factor for endemic cases . The opening of a new operating room combined with the restriction of fluoroquinolone use contributed to a transitory reduction in the incidence of infection . When a third epidemiologic study was done, previous receipt of a fluoroquinolone was again an independent risk factor and a parallel was seen between the amount of intravenous fluoroquinolones prescribed and the incidence of endemic infection . CONCLUSION: Epidemic infections coexisted with endemic infections favored by the selection pressure of intravenous fluoroquinolones.

Eur J Biochem, 1998 Jul 1, 255(1), 255 - 61
Negative cooperativity in the steady-state kinetics of sugar oxidation by soluble quinoprotein glucose dehydrogenase from Acinetobacter calcoaceticus; Olsthoorn AJ et al.; Steady-state-kinetics investigations were carried out for the oxidation of aldose sugars by soluble quinoprotein glucose dehydrogenase (GDH) from Acinetobacter calcoaceticus using N-methylphenazonium methyl sulfate (PMS) as artificial electron acceptor . As is not uncommon for a dye-linked dehydrogenase, the enzyme showed ping-pong behaviour and double-substrate inhibition . However, under conditions that avoided its masking by sugar-substrate inhibition as much as possible, negative kinetic cooperativity with respect to sugar substrate oxidation by this enzyme was demonstrated . Arguments are presented that exclude trivial factors as a cause for the phenomenon observed . Experimental data could be fitted with an equation accounting for biphasic cooperativity containing two sets of apparent kinetic parameters, V1 and K1, and V1 and K2, representing the enzyme's Michaelis-Menten behaviour at low and high substrate concentrations, respectively . Assuming that subunit interaction causes the cooperativity effect, the sets express the performance of soluble GDH's two subunits in two states of mutual interaction . From fitting the experimental data for several sugars with this equation, it appeared that their V1 values were similar, although their K1 values varied considerably . This showed that the cooperativity effect dramatically changes the performance of soluble GDH, as reflected by the V2 and K2 values for glucose (in phosphate buffer) being about 10-fold and 100-fold higher than the V1 and K1 values, respectively . Substituting the Ca2+ involved in activation of pyrroloquinoline quinone (PQQ) in soluble GDH by Sr2+ affected the cooperativity effect (an increase of the K1 value) but not the two turnover rates of the hybrid enzyme for glucose . The data suggest that the two catalytic cycles of soluble GDH have different rate-limiting steps compared with that of PQQ-containing methanol dehydrogenase.

Carbohydr Res, 1998 Jan, 306(1-2), 257 - 63
Structure of the O-7 antigen from Acinetobacter baumannii; Haseley SR et al.; The polymeric O-antigen was isolated from the lipopolysaccharide of the reference of the reference strain for Acinetobacter baumannii serogroup O-7 . Both the lipopolysaccharide and the isolated polymer reacted with the homologous antiserum . Monosaccharide analyses and NMR spectra showed that the polymer had a hexasaccharide repeating unit constructed from residues of L-rhamnose (4) and N-acetyl-D-glucosamine (2) . The following structure for the repeating unit was established by means of detailed interpretation of the NMR spectra, methylation analysis, and chemical degradations . The tetrasaccharide backbone is identical to that for the O-10 antigen of A . baumannii, which has alpha-D-ManpNAc as the lateral substituent in place of the disaccharide present in the O-7 antigen . {formula: see text}

Burns, 1998 Jun, 24(4), 354 - 61
Burn septicaemia: an analysis of 79 patients; Bang RL et al.; Out of 943 patients treated from June 92 to May 96 at the burns unit of the Al-Babtain Centre for Plastic Surgery and Burns, Kuwait, 280 (30%) required admission to the burns intensive care unit (ICBU) and were studied retrospectively . Seventy-nine (28.2%) developed clinically and microbiologically proven septicaemia . Forty-four (56%) were males, 35 (44%) females with a mean age of 26 years (range 45 days to 75 years) and mean total body surface area burn (TBSA) of 46% (range 10-90%) . Sixty-two had flame burns, 16 a scald and one had an electric burn . These 79 patients had a total of 118 septicaemic episodes . Sixty (76%) had only one and 19 (24%) had multiple episodes of septicaemia . Fifty-four (68%) had their first episode within 2weeks, though the maximum number of episodes was between 6 and 10 days postburn . Septicaemia was also observed in 13% of patients within 3 days postburn . Out of the 118 episodes, 48 were due to methicillin resistant Staphylococcus aureus (MRSA), 17 due to methicillin resistant Staphylococcus epidemidis (MRSE), 15 to Pseudomonas, 12 to Acinetobacter, four to Streptococcus, another four to Enterococci, two to Klebsiella, one due to Serratia and 15 to more than one organism . Once the septicaemia was diagnosed appropriate therapy was instituted . Fifty-six (71%) patients had 143 sessions of skin grafting and the mortality was low in operated patients . Twenty-three (29.1%) patients died . The low mortality rate was probably due to factors such as continuous clinical and microbiological surveillance leading to quick detection of aetiology, appropriate antibiotic therapy, care for nutrition and early wound cover . This study suggests that flame burn patients are more vulnerable to sepsis . Onset of septicaemia may be as early as 3 days and commonly within 2 weeks . A surface wound is the likely source of entry to the blood stream . Gram positive organisms are dominant in the aetiology . Early detection and appropriate treatment including wound coverage result in a better outcome.

Appl Environ Microbiol, 1998 Aug, 64(8), 3110 - 3
Specific ribosomal DNA sequences from diverse environmental settings correlate with experimental contaminants; Tanner MA et al.; Phylogenetic analysis of 16S ribosomal DNA (rDNA) clones obtained by PCR from uncultured bacteria inhabiting a wide range of environments has increased our knowledge of bacterial diversity . One possible problem in the assessment of bacterial diversity based on sequence information is that PCR is exquisitely sensitive to contaminating 16S rDNA . This raises the possibility that some putative environmental rRNA sequences in fact correspond to contaminant sequences . To document potential contaminants, we cloned and sequenced PCR-amplified 16S rDNA fragments obtained at low levels in the absence of added template DNA . 16S rDNA sequences closely related to the genera Duganella (formerly Zoogloea), Acinetobacter, Stenotrophomonas, Escherichia, Leptothrix, and Herbaspirillum were identified in contaminant libraries and in clone libraries from diverse, generally low-biomass habitats . The rRNA sequences detected possibly are common contaminants in reagents used to prepare genomic DNA . Consequently, their detection in processed environmental samples may not reflect environmentally relevant organisms.

FEMS Microbiol Lett, 1998 Jul 1, 164(1), 169 - 75
Distribution of mevalonate and glyceraldehyde 3-phosphate/pyruvate routes for isoprenoid biosynthesis in some gram-negative bacteria and mycobacteria; Putra SR et al.; Labeling experiments using {1-13C}acetate or {1-13C}glucose were performed with opportunistic pathogenic bacteria, with innocuous bacteria related to pathogenic species or with phytopathogenic species . The labeling pattern was determined in the isoprenic moiety of ubiquinone or menaquinone derivatives . These experiments showed that Acinetobacter, Citrobacter, Erwinia, Pseudomonas, Burkholderia, Ralstonia and Mycobacterium synthesize their isoprenoids via the mevalonate-independent glyceraldehyde 3-phosphate/pyruvate route . Enzymes of this novel bacterial metabolic route, which is apparently absent in vertebrates and man, therefore represent potential targets for a novel type of antibacterial drugs.

Lett Appl Microbiol, 1998 May, 26(5), 359 - 62
Detection of carboxypeptidases as taxonomic markers for gram-negative bacteria; Perry JD et al.; The use of seven benzoyl-L-amino acids for the detection of carboxypeptidase activities in strains of Gram-negative aerobic and facultatively anaerobic bacteria is reported . A simple overnight assay was designed using ninhydrin for the demonstration of the amino acid released by hydrolysis . Detection of carboxypeptidase activity was shown to have some taxonomic relevance within the Enterobacteriaceae; it was also useful for differentiation within the genus Acinetobacter and for distinction between Pseudomonas aeruginosa and Pseudomonas fluorescens.

Arch Virol, 1997, 142(12), 2329 - 45
A catalogue of T4-type bacteriophages; Ackermann HW et al.; The T4-type of bacteriophages is broadly defined on the basis of particle morphology . It occurs in enterobacteria (125 representatives), acinetobacters, aeromonads, pseudomonads, and vibrios (16 isolates) . In addition, 18 apparently unrelated phages with prolate heads and contractile tails are found in a wide range of bacteria . A descriptive catalogue of these phages is presented . The T4-type probably originated in precursors of enterobacteria.

J Chemother, 1998 Jun, 10(3), 236 - 42
Bacteremia and fungemia in pediatric versus adult cancer patients after chemotherapy: comparison of etiology, risk factors and outcome; Krupova I et al.; One hundred and eighteen (118) episodes of bacteremia and fungemia in children with cancer were compared to 401 episodes of bacteremia and fungemia in adults with cancer to assess differences in etiology, risk factors and outcome . A retrospective univariate analysis was performed of all episodes of bacteremia in national pediatric and adult cancer institutions appearing in 1990-1996 . A total of 519 episodes of bacteremia were assessed and compared . Both cancer centers differed in prophylactic antibiotic policies . About 50% of adults but less than 5% of children received quinolone prophylaxis during neutropenia, even though the empiric antibiotic therapeutic strategy was similar . There were differences in etiology between the groups: staphylococci and Stenotrophomonas maltophilia were more frequently observed in children (P<0.01), Pseudomonas aeruginosa and Acinetobacter spp . in adults (P<0.05) . Gram-positive bacteremia was surprisingly more commonly observed in adults (65.7% vs 33.3%, P<0.01) . Mixed polymicrobial bacteremia occurred more commonly in adults (31.8% vs 7.6%, P<0.001) than in children . Analysis of risk factors did not observe differences in risk factors except for underlying disease (acute leukemia was more frequently observed in children -48.3% vs adults 33.7%, P<0.05 and prophylaxis: (prior prophylaxis with quinolones was more common in adults (47.5%) than in children (2.5%) P<0.0001) . Overall and attributable mortality in pediatric bacteremia was significantly lower than in adults (P<0.03).

J Chemother, 1998 Jun, 10(3), 215 - 20
Further studies of transferable antibiotic resistance in strains of Pseudomonas aeruginosa from four clinical settings in three countries; Blahova J et al.; This paper describes transferability of antibiotic resistance determinants in clinical isolates of Pseudomonas aeruginosa resistant to imipenem, cefotaxime and ceftazidime obtained from different clinical settings in three different countries . Two strains of Enterobacteriaceae (Escherichia coli K-12 and Proteus mirabilis P-38) and two strains of P . aeruginosa (PAO and ML) were used as recipient strains . The conjugative transfer of resistance was very specific, i.e . donor strains of P . aeruginosa transferred individual resistance determinants either to recipient strains E . coli K-12 and P . mirabilis P-38, or to P . aeruginosa PAO or ML . In a case when three different species (P . aeruginosa, Acinetobacter calcoaceticus, Stenotrophomonas maltophilia) were isolated from a single patient, a block of resistance determinants was transferred both to Enterobacteriaceae and P . aeruginosa recipients . A single plasmid with rather specific properties was suspected of being exchanged among strains of these different species . It was recommended to study the overall situation of transferability of individual resistance determinants in bacterial strains belonging to various species of nosocomial bacteria, especially of P . aeruginosa, by using a rather specific methodology.

J Chemother, 1998 Jun, 10(3), 208 - 14
In vitro activity of piperacillin/tazobactam versus other broad-spectrum antibiotics against nosocomial gram-negative pathogens isolated from burn patients; Mokaddas E et al.; Burn patients are at high risk for nosocomial infections due to multiresistant bacteria, a large proportion of which are gram-negative . Tazobactam, a potent inhibitor of beta-lactamases, extends the spectrum of piperacillin to include many beta-lactamase producing bacteria . Consequently, it was decided to evaluate the activity of piperacillin/tazobactam in comparison with that of eight other antibiotics that are usually used for therapy against gram-negative bacterial infections in our burn unit . All consecutive gram-negative isolates from wounds, blood, respiratory tract, urine etc . from burn patients considered to be clinically significant were tested for their susceptibility to piperacillin/tazobactam, piperacillin, ceftazidime, cefotaxime, ceftriaxone, ciprofloxacin, gentamicin, amikacin and imipenem, determined by disk diffusion test . The zone inhibition was interpreted according to NCCLS recommendations . A total of 948 strains, isolated during the period of July, 1994 to September, 1995, made up of Pseudomonas spp (326), Acinetobacter spp (268) and Enterobacteriaceae (354), were tested . Overall piperacillin/tazobactam showed superior activity over the other antibiotics except for imipenem . Of the 948 isolates, 87% were susceptible to the combination, 56% to the three third generation cephalosporins, 69% to ciprofloxacin, 59% to the aminoglycosides and 97% to imipenem . Piperacillin/tazobactam showed strikingly superior activity over piperacillin alone against Acinetobacter spp followed by Enterobacteriaceae and the least against Pseudomonas . The emergence of Acinetobacter spp as a dominant gram-negative pathogen in burn patients and its high level of resistance against most of the antibiotics tested except piperacillin/tazobactam (87%) and imipenem (100%) were significant in light of the epidemiology of burn infections and treatment . This study suggests that piperacillin/tazobactam holds good promise against gram-negative infections in burn patients.

Eur J Clin Microbiol Infect Dis, 1998 Mar, 17(3), 171 - 6
Surveillance of an adult intensive care unit for long-term persistence of a multi-resistant strain of Acinetobacter baumannii; Webster CA et al.; Sporadic infections with Acinetobacter spp., punctuated with prolonged outbreaks of infection involving larger numbers of patients and a particular epidemic strain of Acinetobacter baumannii, have occurred in the adult intensive care unit (ICU) of Nottingham University Hospital since 1985 . The aim of this study was to screen patients admitted to the ICU for three or more days during a non-outbreak period in 1994-1995 and to use DNA fingerprinting techniques to compare any isolates of Acinetobacter spp . with isolates obtained from the same ICU during the previous ten years . In the present study, almost 20% of the ICU patients screened during 1994-1995 became colonized with Acinetobacter spp . The commonest species isolated from patients was Acinetobacter baumannii; five different strains were identified by random amplified polymorphic DNA fingerprinting, including the epidemic strain responsible for outbreaks of infection in 1985-1986 and 1992-1993 . Environmental sampling yielded Acinetobacter spp . from one or more samples on four occasions; Acinetobacter radioresistens was the commonest species isolated, and Acinetobacter baumannii (not the epidemic strain) was isolated on only one occasion from the environment . The long-term persistence of a potentially epidemic strain in the ICU, even during a non-outbreak period, indicates a need for continued vigilance . Consequently, periodic patient and environmental surveillance, combined with typing of isolates, is recommended for ICUs where significant outbreaks of Acinetobacter infection have occurred in the past.

Blood Coagul Fibrinolysis, 1998 Apr, 9(3), 227 - 32
Reconstituted recombinant factor VIII can be safely infused continuously for at least three days: it is a poor microbial growth medium; Didier ME et al.; Reconstituted recombinant factor VIII (FVIIIrec) loses little biologic activity at room temperature for up to seven days and continuous infusion is convenient, effective hemostatically and requires less FVIIIrec concentrate than treatment by conventional bolus injections . However, the potential for bacterial contamination, with proliferation to high levels that can cause bacteremia, is a concern with continuous infusion . We studied the growth properties at 4, 25 and 35 degrees C in reconstituted FVIIIrec (Kogenate) and at 25 degrees C in 5% dextrose in water (D5%W) of three isolates each of Staphylococcus epidermidis, Staphylococcus aureus, Enterobacter cloacae, Klebsiella oxytoca, Serratia marcescens, Acinetobacter calcoaceticus, Stenotrophomonas maltophilia, Pseudomonas aeruginosa, Burkholderia cepacia, Flavobacterium spp . and Candida albicans, species most likely to contaminate infusate during preparation or administration and which have been implicated in more than 95% of all outbreaks and sporadic cases of nosocomial bloodstream infection traced to contaminated admixtures, biologic agents or medications administered parenterally . Reconstituted FVIIIrec allowed growth of only three species at 25 degrees C and 35 degrees C: S . marcescens, S . maltophilia and P . aeruginosa; logarithmic growth appeared only after 24-48 h . D5%W allowed growth of two gram-negative species, S . marcescens and B . cepacia . We conclude that reconstituted FVIIIrec (Kogenate) is a poor growth medium for most nosocomial pathogens, comparable with D5%W . If reconstituted aseptically, continuous infusion of reconstituted FVIIIrec should be safe, and it should not be necessary to replace the container or tubing more frequently than every 3 days, an administration schedule that can provide effective hemostasis at lower cost.

Eur J Biochem, 1998 Jun 1, 254(2), 404 - 12
Cloning and characterization of 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) transferase genes (kdtA) from Acinetobacter baumannii and Acinetobacter haemolyticus; Bode CE et al.; 3-Deoxy-D-manno-oct-2-ulosonic acid (Kdo) transferases (KdtA) are multifunctional glycosyltransferases with primary structures of low similarity . Totally degenerated primers were deduced from two stretches of identical amino acids between known KdtA sequences and used to amplify by PCR a kdtA-specific fragment from Acinetobacter baumannii ATCC 15308 DNA which was then applied as a probe for the cloning and sequencing of the complete Kdo transferase gene . With conserved PCR primers for this structural gene from A . baumannii ATCC 15308, also kdtA genes of A . baumannii ATCC 19606 and A . haemolyticus ATCC 17906 were obtained, cloned from the chromosome and sequenced . The genes coded for proteins with similarities to known Kdo transferases . Within the genus Acinetobacter, the identity and similarity of the deduced amino acid sequences were 71% and 84.5%, respectively . The kdtA sequences of both A . baumannii strains were identical and possessed a TTG start codon, whereas ATG was found in the case of A . haemolyticus . The genes from Acinetobacter and kdtA from Escherichia coli K-12 were expressed in the Gram-positive bacterium Corynebacterium glutamicum . In vitro tests confirmed the function of the gene products as Kdo transferases, which transferred mainly two Kdo residues to a synthetic lipid A precursor of E . coli . Also, no differences between the cloned kdtA genes from A . baumanniii, A . haemnolyticus and E . coli were observed when tetraacyl or hexaacyl lipid A were tested, since all transferases acted more efficiently on the former . With limiting amounts of acceptor, all Kdo transferases were able to transfer a third Kdo residue with varying efficiency.

New Horiz, 1998 May, 6(2 Suppl), S30 - 45
Ventilator-associated bacterial pneumonia: challenges in diagnosis, treatment, and prevention; Craven DE et al.; Ventilator-associated pneumonia (VAP) is a common infection in intensive care unit patients that results in high mortality and morbidity and increased duration of hospital stay . Clinical diagnostic methods are sensitive, but lack specificity . Quantitative analysis of specimens from the lower respiratory tract increases specificity . Bacteria causing VAP may originate from the patient's endogenous flora, other patients or hospital personnel, or from environmental sources . Aspiration or direct inoculation are the major routes of bacterial entry into the lower respiratory tract . The bacterial inoculum and host response in the lung are important factors for pathogenesis . Late-onset nosocomial pneumonia is often caused by Pseudomonas aeruginosa, Acinetobacter species, and Staphylococcus aureus . Streptococcus pneumoniae and Haemophilus influenzae, however, are the more common pathogens in early-onset disease . Oropharyngeal and gastric colonization with bacteria, cross-infection, as well as the indiscriminate use of antibiotics or invasive devices substantially increase the risk of VAP . An understanding of the epidemiology and pathogenesis of VAP, along with implementation of appropriate preventive measures, are needed to decrease the incidence, morbidity, and mortality associated with VAP.

J Clin Microbiol, 1998 Jul, 36(7), 1938 - 41
Survival of Acinetobacter baumannii on dry surfaces: comparison of outbreak and sporadic isolates; Jawad A et al.; Acinetobacter spp . are important nosocomial pathogens reported with increasing frequency in outbreaks of cross-infection during the past 2 decades . The majority of such outbreaks are caused by Acinetobacter baumannii . To investigate whether desiccation tolerance may be involved in the ability of certain strains of A . baumannii to cause hospital outbreaks, a blind study was carried out with 39 epidemiologically well-characterized clinical isolates of A . baumannii for which survival times were determined under simulated hospital conditions . The survival times on glass coverslips of 22 strains isolated from eight well-defined hospital outbreaks in a German metropolitan area were compared with the survival times of 17 sporadic strains not involved in outbreaks but rather isolated from inpatients in the same geographic area . All sporadic isolates have been shown by pulsed-field gel electrophoresis to represent different strain types . There was no statistically significant difference between the survival times of sporadic strains of A . baumannii and outbreak strains (27.2 versus 26.5 days, respectively; P < or = 0.44) by the Wilcoxon-Mann-Whitney test . All investigated A . baumannii strains, irrespective of their areas of endemicity or epidemic occurrence, have the ability to survive for a long time on dry surfaces . Antimicrobial susceptibility testing showed that A . baumannii outbreak strains were significantly more resistant to various broad-spectrum antimicrobial agents than sporadic strains . Both desiccation tolerance and multidrug resistance may contribute to their maintenance in the hospital setting and may explain in part their propensity to cause prolonged outbreaks of nosocomial infection.

Infection, 1998 May-Jun, 26(3), 155 - 9
Gram-negative bacteremia in non-neutropenic patients: a 3-year review; Gikas A et al.; The causative organisms, clinical manifestations, factors influencing prognosis, and other epidemiological characteristics of 81 episodes of bacteremia due to gram-negative organisms, in non-neutropenic patients, were studied retrospectively during a 3-year period (1992-1994) at the Department of Internal Medicine of the University Hospital of Heraklion, Crete, Greece . The gram-negative bacteremia incidence was 2% and the overall mortality 12% . All 81 patients had fever; Escherichia coli was the most frequent organism isolated (from 47 patients--58%) and was associated with shock (9/47), disseminated intravascular coagulation (DIC) (8/47), anuria (5/47), adult respiratory distress syndrome (ARDS) (3/47), and pneumonia (1/47) . Other less frequent gram-negative microorganisms were Klebsiella spp . (ten patients; 12%), Pseudomonas spp . (7; 7%), Salmonella spp . (5; 6%), Enterobacter spp . (5; 6%), Proteus spp . (3; 3.4%), Stenotrophomonas spp . (3; 3.4%), and Acinetobacter spp . (1; 1.2%) . ARDS . shock, DIC, anuria, presence of central venous catheter, urinary catheter, unknown origin of infection and inappropriate treatment were significantly associated with a higher death rate . Early initiation of appropriate therapy was the most important intervention that favorably affected the outcome of gram-negative bacteremias in this patient population.

Mil Med, 1998 Jun, 163(6), 389 - 91
Ventilator-related Acinetobacter outbreak in an intensive care unit; Cox TR et al.; An outbreak of 16 cases of ciprofloxacin-resistant Acinetobacter baumannii (calcoaceticus subspecies anitratus) infections occurred during a 7-month period in a medical intensive care unit . Fifteen of the patients developed pneumonia associated with ventilator support . Possible sources considered in the outbreak investigation were sinks, ice, personnel, patients on multiple antibiotic therapy, reusable ventilator circuits, and hemodialysis . The equipment and environment associated with the outbreak were cultured . Patients on ventilators were significantly more susceptible to Acinetobacter nosocomial infection compared with the rest of the patients in the medical intensive care unit (p < 0.05) . Sputum cultures were only 5% sensitive to ciprofloxacin and gentamicin, but they were 100% sensitive to imipenem (p < 0.0001) . Uncloaking imipenem was a significant contributing factor in controlling this outbreak . Once outbreak control measures were instituted, Acinetobacter isolates dropped from 77 (during the outbreak year) to 9 (during the subsequent year) and no new pneumonia cases occurred.

Infect Immun, 1998 Jul, 66(7), 3365 - 71
Identification and sequence analysis of a 27-kilobase chromosomal fragment containing a Salmonella pathogenicity island located at 92 minutes on the chromosome map of Salmonella enterica serovar typhimurium LT2; Wong KK et al.; Using a genomic approach, we have identified a new Salmonella pathogenicity island, SPI-4, which is the fourth Salmonella pathogenicity island to be identified . SPI-4 was located at 92 min on the chromosome map and was flanked by the ssb and soxSR loci . The DNA sequence covering the entire SPI-4 and both boundaries was determined . The size of SPI-4 was about 25 kb and it contains 18 putative open reading frames (ORFs) . Three of these ORFs encode proteins that have significant homology with proteins involved in toxin secretion . Another five ORFs encode proteins that have significant homology with hypothetical proteins from Synechocystis sp . strain PCC6803 or Acinetobacter calcoaceticus . The rest of the ORFs encode novel proteins, one of which has five membrane-spanning domains . SPI-4 is likely to carry a type I secretion system involved in toxin secretion . Furthermore, a previously identified locus (ims98), which is required for intramacrophage survival, was also mapped within the SPI-4 region . These findings suggested that SPI-4 is needed for intramacrophage survival.

Int J Food Microbiol, 1998 May 5, 41(1), 59 - 72
Predictive models as means to quantify the interactions of spoilage organisms; Pin C et al.; The purpose of this paper is to quantify the interactions of some groups of spoilage organisms that can be usually found in refrigerated meat stored in air, such as: Enterobacteriaceae, Pseudomonas, Acinetobacter, Psychrobacter, Shewanella, Carnobacterium, Lactobacillus, Leuconostoc, Brochothrix and Kurthia spp . The growth of these organisms was studied in the range of temperature 2-11 degrees C and pH 5.2-6.4, which is characteristic of refrigerated meat . The main growth parameters (maximum specific growth rate and lag time) were modelled by multivariate quadratic polynomials of temperature and pH . The interactions of the organisms were analyzed by comparing their growth models obtained in isolation with those obtained in mixture . The difference between the models was quantified by statistical F-values which were used to measure how much the growth of an organism or group of organisms was affected by others and which of them dominated their joint growth.

Biochim Biophys Acta, 1998 May 11, 1397(3), 257 - 61
Characterization of Bradyrhizobium japonicum pcaBDC genes involved in 4-hydroxybenzoate degradation; Lorite MJ et al.; The pca structural genes encode enzymes that participate in the conversion of protocatechuate to succinate and acetylcoenzyme A . A 3 . 05-kb region of the Bradyrhizobium japonicum strain USDA110 genome has been characterized, which contains the pcaB, pcaD and pcaC genes . The predicted protein sequences of the three genes have extensive homologies with beta-carboxy-cis,cis-muconate cycloisomerase (PcaB), beta-ketodiapate enol-lactone hydrolase (PcaD), and gamma-carboxymuconolactone decarboxylase (PcaC), respectively, from Acinetobacter calcoaceticus and Pseudomonas putida . The DNA sequence revealed that the pca genes are probably arranged in a single transcriptional unit, pcaBDC, similar to that described in P . putida . A pcaB deletion mutant constructed by marker exchange mutagenesis lost the ability to use 4-hydroxybenzoate or protocatechuate as the only carbon source, demonstrating functionality of the characterized genes in catabolism of hydroxyaromatics by B . japonicum . Furthermore, 4-hydroxybenzoate and protocatechuate became toxic for the pcaB mutant, indicating that hydroxyaromatics catabolism serves both nutritional and detoxifying purposes.

Support Care Cancer, 1998 May, 6(3), 291 - 4
Predictors of mortality in bacteremic cancer patients: retrospective analysis of 64 deaths occurring among 262 bacteremic episodes; Spanik S et al.; A total of 262 bacteremic episodes were observed in cancer patients in a single cancer institution during the last 7 years, and the recorded outcome was death in 65 . The 65 patients who died (24.8% overall mortality) were divided retrospectively into two subgroups: (a) those who died of underlying disease with bacteremia (45 cases, 16.9% crude mortality) and (b) those who died of bacteremia (20 patients, 7.7% attributable mortality) . Comparison of several risk factors in subgroups of patients who achieved a cure (197 cases) and of those who died and whose deaths were attributable (20 cases) revealed six risk factors that were associated with attributable mortality: (1) chemotherapy-induced neutropenia (P < 0.03), (2) Acinetobacter/Stenotrophomonas spp . bacteremias (P < 0.001), (3) liver failure (P < 0.001), (4) inappropriate therapy (P < 0.0001), (5) organ complications (P < 0.003) and (6) multiresistant organisms (P < 0.001) . Enterococci and Pseudomonas aeruginosa, surprisingly, were found more frequently in those who died of an underlying disease with bacteremia than among patients who were cured (17.6% vs 7.6%, P < 0.05 and 29.1% vs 13.8%, P < 0.02) . Those who died of infection had higher numbers of positive blood cultures, with 2.05 per episode, than did those who died of underlying disease with bacteremia (1.82) or those who were cured (1.51) . Other risk factors, such as underlying disease, type of chemotherapy, origin of bacteremia, age, and catheters did not predict either overall or attributable mortality within the study group.

J Mol Biol, 1998 May 1, 278(2), 339 - 47
Functional characterization of the low-molecular-mass phosphotyrosine-protein phosphatase of Acinetobacter johnsonii; Grangeasse C et al.; The ptp gene of Acinetobacter johnsonii was previously reported to encode a low-molecular-mass protein, Ptp, whose amino acid sequence, predicted from the theoretical analysis of the nucleotide sequence of the gene, exhibits a high degree of similarity with those of different eukaryotic and prokaryotic phosphotyrosine-protein phophatases . We have now overexpressed the ptp gene in Escherichia coli cells, purified the Ptp protein to homogeneity by a single-step chromatographic procedure, and analysed its functional properties . We have shown that Ptp can catalyse the dephosphorylation of p-nitrophenyl phosphate and phosphotyrosine, but has no effect on phosphoserine or phosphothreonine . Its activity is blocked by ammonium molybdate and sodium orthovanadate, which are strong inhibitors of phosphotyrosine-protein phosphatases, as well as by N-ethylmaleimide and iodoacetic acid . Such specificity of Ptp for phosphotyrosine has been confirmed by the observation that it can dephosphorylate endogenous proteins phosphorylated on tyrosine, but not proteins modified on either serine or threonine . In addition, Ptp has been shown to quantitatively dephosphorylate two exogenous peptides, derived respectively from leech hirudin and human gastrin, previously phosphorylated on tyrosine . Moreover, site-directed mutagenesis experiments performed on Cys11 and Arg16, which are both present in the sequence motif (H/V)C(X5)R(S/T) typical of eukaryotic phosphotyrosine-protein phosphatases, have demonstrated that each amino acid residue is essential for the catalytic activity of Ptp . Taken together, these data provide evidence that Ptp is a member of the phosphotyrosine-protein phosphatase family . Furthermore, in search for the biological function of Ptp, we have found that it can specifically dephosphorylate an endogenous protein kinase, termed Ptk, which is known to autophosphorylate at multiple tyrosine residues in the inner membrane of Acinetobacter johnsonii cells . This represents the first identification of a protein substrate for a bacterial phosphotyrosine-protein phosphatase, and therefore constitutes a possible model for analysing the role of reversible phosphorylation on tyrosine in the regulation of microbial physiology .

Biochemistry, 1998 May 12, 37(19), 6810 - 8
Reconstitution of membrane-integrated quinoprotein glucose dehydrogenase apoenzyme with PQQ and the holoenzyme's mechanism of action; Dewanti AR et al.; Membrane-integrated quinoprotein glucose dehydrogenase from Acinetobacter calcoaceticus was produced by heterologous expression of the gene for it in an Escherichia coli recombinant strain . The apoenzyme (lacking the cofactor pyrroloquinoline quinone, PQQ) was solubilized with Triton X-100 and purified to homogeneity . Reconstitution of the apoenzyme to full activity in the assay was achieved with a stoichiometric amount of PQQ in the presence of Mg2+ . Just as for other PQQ-containing dehydrogenases where Ca2+ fulfills this role, Mg2+ anchors PQQ to the mGDH protein and activates the bound cofactor . This occurs in a precise way since high anomer specificity was found for the enzyme toward the sugars tested . Although the steady-state-type kinetics were as expected for a dye-linked dehydrogenase (ping-pong) and the PQQ in it was present in oxidized form, addition of glucose to the holoenzyme resulted in a very slow but continuous production of gluconolactone; i.e., the reaction did not stop after one turnover, with O2 apparently acting as an (albeit poor) electron acceptor by reoxidizing PQQH2 in the enzyme . The surprisingly low reactivity with glucose, in the absence of dye, as compared to the activity observed in the steady-state assay appeared to be due to formation of an anomalous enzyme form, mGDH . Formation of normal holoenzyme, mGDH, reducing added glucose immediately to gluconolactone (in one turnover), was achieved by treating mGDH with sulfite, by reconstituting apoenzyme with PQQ in the presence of sulfite, or by applying assay conditions to mGDH (addition of PMS/DCPIP) . As compared to other quinoprotein dehydrogenases, mGDH appears to be unique with respect to the mode of PQQ-binding, as expressed by the special conditions for reconstitution and the absorption spectra of the bound cofactor, and the reactivity of the reduced enzyme toward O2 . The primary cause for this seems not to be related to a different preference for the activating bivalent metal ion but to the special way of binding of PQQ to mGDH.

Ann Surg, 1998 May, 227(5), 743 - 51; discussion 751-5
Utility of Gram's stain and efficacy of quantitative cultures for posttraumatic pneumonia: a prospective study; Croce MA et al.; OBJECTIVE: This prospective trial examined the efficacy of using bronchoalveolar lavage (BAL) for the diagnosis of pneumonia (PN) and the utility of Gram's stain (GS) for dictating empiric therapy . SUMMARY BACKGROUND DATA: Posttraumatic nosocomial PN remains a significant cause of morbidity and mortality . However, its diagnosis is elusive, especially in multiply injured patients . The systemic inflammatory response syndrome of fever, leukocytosis, and a hyperdynamic state is common in trauma patients, especially patients with pulmonary contusion . Bronchoscopy with BAL with quantitative cultures of the lavage effluent may distinguish between PN and systemic inflammatory response syndrome, and GS of the lavage effluent may guide empiric therapy before quantitative culture results . METHODS: Mechanically ventilated trauma patients with a clinical diagnosis of PN (fever, leukocytosis, purulent sputum, and new or changing infiltrate on chest radiograph) underwent bronchoscopy with BAL . Effluent was sent for GS and quantitative cultures . The diagnostic threshold for PN was > or =10(5) colony-forming units (CFU)/mL, and antibiotics were continued . Antibiotics were stopped for < 10(5) CFU/mL and the diagnosis of systemic inflammatory response syndrome was made . Causative organisms for PN were compared to GS . RESULTS: Over a 2-year period, 232 patients underwent 443 bronchoscopies with BAL (71% men, 29% women; mean age, 41) . The mean injury severity score was 30 . Sixty percent of the patients had pulmonary contusion, and 59% were cigarette smokers . The overall incidence of PN was 39% and was no different regardless of the number of BALs a patient had . The false-negative rate of BAL was 7% . GS identified gram-positive organisms in 80% of patients with gram-positive PN and 40% of patients with gram-negative PN . GS identified gram-negative organisms in 52% of patients with gram-positive PN and 77% with gram-negative PN . The duration of the intensive care unit stay relative to the timing of BAL was beneficial for guiding empiric therapy . BAL in week 1 primarily identified Haemophilus influenzae and gram-positive organisms; Acinetobacter sp . and Pseudomonas sp . were more common after week 1 . CONCLUSIONS: Bronchoscopy with BAL is an effective method to diagnose PN and avoids prolonged, unnecessary antibiotic therapy . Empiric therapy should be adjusted to the duration of the intensive care unit stay because the causative bacteria flora changes over time . GS of BAL effluent correlates poorly with quantitative cultures and is not reliable for dictating empiric therapy.

Mol Gen Genet, 1998 Apr, 257(6), 606 - 13
Detection of nptII (kanamycin resistance) genes in genomes of transgenic plants by marker-rescue transformation; de Vries J et al.; We have developed a novel system for the sensitive detection of nptII genes (kanamycin resistance determinants) including those present in transgenic plant genomes . The assay is based on the recombinational repair of an nptII gene with an internal 10-bp deletion located on a plasmid downstream of a bacterial promoter . Uptake of an nptII gene by transformation restores kanamycin resistance . In Escherichia coli, promoterless nptII genes provided by electroporation were rescued with high efficiency in a RecA-dependent recombinational process . For the rescue of nptII genes present in chromosomal plant DNA, the system was adapted to natural transformation, which favours the uptake of linear DNA . When competent Acinetobacter sp . BD413 (formerly A . calcoaceticus) cells containing the mutant nptII gene on a plasmid were transformed with DNA from various transgenic plants carrying nptII as a marker gene (Solanum tuberosum, Nicotiana tabacum, Beta vulgaris, Brassica napus, Lycopersicon esculentum), kanamycin-resistant transformants were obtained roughly in proportion to the concentration of nptII genes in the plant DNA . The rescue of nptII genes occurred in the presence of a more than 6 x 10(6)-fold excess of plant DNA . Only 18 ng of potato DNA (2.5 x 10(3) genome equivalents, each with one copy of nptII) was required to produce one kanamycin-resistant transformant . These experiments and others employing DNA isolated from soil samples demonstrate that the system allows reliable and highly sensitive monitoring of nptII genes in transgenic plant DNA and in DNA from environmental sources, such as soil, without the need for prior DNA amplification (e.g . by PCR).

J Chemother, 1998 Apr, 10(2), 97 - 101
Imipenem resistance in aerobic gram-negative bacteria; Modakkas EM et al.; A prospective study was undertaken to observe the emergence of resistance to imipenem, if any, among aerobic gram-negative bacteria . A total of 736 isolates were tested during 1994-95 and less than 1% of them were resistant to imipenem, whereas the next year ('95-'96) the rate increased to 11 of the 903 isolates tested . The resistant isolates during '94-'95 were all Stenotrophomonas maltophilia whereas the spectrum of resistant bacterial species increased in '95-'96 to include Pseudomonas aeruginosa, Burkholderia cepacia, Acinetobacter calcoaceticus, Enterobacter cloacae, Proteus mirabilis and Morganella morganii with a tendency to an increase in the minimum inhibitory concentration (MIC) in the later part of the year . A majority (72%) of the resistant isolates were from patients with burns, and burn wounds were most frequently infected with such organisms . These data suggest that over a period of time aerobic gram-negative bacteria may develop resistance to imipenem and the pool of such bacteria increases with extensive use of the drug . Non-fermentative aerobic bacteria tend to develop resistance faster with widespread dissemination than Enterobacteriaceae . Hospital Burn Units are a potential source of development of such resistance.

Infect Immun, 1998 Jun, 66(6), 2434 - 40
Structure-function relationship of antibacterial synthetic peptides homologous to a helical surface region on human lactoferrin against Escherichia coli serotype O111; Chapple DS et al.; Lactoferricin includes an 11-amino-acid amphipathic alpha-helical region which is exhibited on the outer surface of the amino-terminal lobe of lactoferrin . Synthetic peptides homologous to this region exhibited potent antibacterial activity against a selected range of both gram-negative and gram-positive bacteria . An analog synthesized with methionine substituted for proline at position 26, which is predicted to disrupt the helical region, abolished antibacterial activity against Escherichia coli and considerably reduced antibacterial activity against Staphylococcus aureus and an Acinetobacter strain . The mode of action of human lactoferrin peptide (HLP) 2 against E . coli serotype O111 (NCTC 8007) was established by using flow cytometry, surface plasmon resonance, and transmission electron microscopy . Flow cytometry was used to monitor membrane potential, membrane integrity, and metabolic processes by using the fluorescent probes bis-1,3-(dibutylbarbituric acid)-trimethine oxonol, propidium iodide, and carbonyl cyanide m-chlorophenylhydrazone, respectively . HLP 2 was found to act at the cell membrane, causing complete loss of membrane potential after 10 min and of membrane integrity within 30 min, with irreversible damage to the cell as shown by rapid loss of viability . The number of particles, measured by light scatter on the flow cytometer, dropped significantly, showing that bacterial lysis resulted . The peptide was shown to bind to E . coli O111 lipopolysaccharide by using surface plasmon resonance . Transmission electron microscopy revealed bacterial distortion, with the outer membrane becoming detached from the inner cytoplasmic membrane . We conclude that HLP 2 causes membrane disruption of the outer membrane, resulting in lysis, and that structural considerations are important for antibacterial activity.

Ceska Slov Farm, 1997 Oct, 46(5), 195 - 8
{Development of resistance and utilization of fluoroquinolones in a university hospital}; Vlcek J et al.; The results of a retrospective study in the Faculty Hospital, Hradec Kralove (FHHK) show a steep increase in the consumption of fluoroquinolones in the course of six years . Since 1989, when 360 defined daily doses (DDD) were administered, the consumption increased to 2,825 DDDs in 1992 and 52,162 DDDs in 1995 . At the same time, resistance to ofloxacine and ciprofloxacine was increased many times in some bacterial species isolated from patients admitted to FHHK . In the strains Pseudomonas aeruginosa, resistance to ofloxacine increased from 3% to 38% in 1995, in Serratia marcescens from 13% in 1992 to 30% in 1995 . A marked increase was observed also in Acinetobacter calcoaceticus . In the naturally highly sensitive species E . coli and Klebsiella pneumoniae no increase in resistance has been observed yet, in Enterobacter cloaceae resistance slightly increased (from 0% in 1992 to 7% in 1995) . Due to the fact that in FHHK fluoroquinolones take the first place in the consumption of antibiotics at present, an increase in resistance can be expected also in these bacteria in the future . Investigation of changes in resistance due to the consumption of fluoro-quinolones is a suitable model of a pharmacoepidemiological study (DUE-Drug Utilisation Evaluation) as the relationship of the consumption of a drug and its effect can be observed practically since the introduction of fluoroquinolones into the market.

J Clin Microbiol, 1998 Apr, 36(4), 990 - 4
Evaluation of use of a new chromogenic agar in detection of urinary tract pathogens; Samra Z et al.; CHROMagar Orientation, a new chromogenic medium, was evaluated for the detection and differentiation of gram-positive and gram-negative pathogenic microorganisms in 900 urine samples from hospitalized patients . Performance characteristics of the medium were evaluated in comparison to those of 5% sheep blood and MacConkey agars by direct inoculation of the urine samples on the three media . Four gram-negative and two gram-positive strains as well as one yeast control strain from the American Type Culture Collection were used to ensure quality control . CHROMagar Orientation succeeded in detecting all the urine pathogens that were detected by the reference media, including gram-negative bacilli, staphylococci, streptococci, and yeasts . Colony color and morphology on CHROMagar Orientation accurately differentiated Escherichia coli, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, and Acinetobacter spp . Owing to the similarity in the pigmentation produced by Klebsiella, Enterobacter, and Citrobacter isolates, the medium failed to distinguish among them; however, these isolates were easily recognized as coliforms because of their metallic blue coloration . Staphylococci were clearly perceptible: S . aureus and S . epidermidis grow in regular-size colonies that range from opaque white to yellowish, and S . saprophyticus produces opaque pink colonies . All streptococcus strains, including those from groups B and C, were detected . They grow as undifferentiated flat dry diffused colonies, and additional tests were required for identification . Enterococci were easily discriminated by their strong turquoise pigmentation and their typical growth on the agar's surface . Yeast grow in typical creamy wet convex colonies . The accuracy of antibiotic susceptibility determinations according to standard methods was also tested by picking isolates directly from CHROMagar Orientation . The results showed excellent correlation with those obtained with microorganisms picked from reference media . Owing to the ease in differentiating mixed flora on CHROMagar Orientation, antimicrobic susceptibility tests were performed directly from primary isolates in all cases without the need for subcultures.

Biochem J, 1998 Mar 15, 330 ( Pt 3), 1375 - 81
Molecular characterization of benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase II of Acinetobacter calcoaceticus; Gillooly DJ et al.; The nucleotide sequences of xylB and xylC from Acinetobacter calcoaceticus, the genes encoding benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase II, were determined . The complete nucleotide sequence indicates that these two genes form part of an operon and this was supported by heterologous expression and physiological studies . Benzaldehyde dehydrogenase II is a 51654 Da protein with 484 amino acids per subunit and it is typical of other prokaryotic and eukaryotic aldehyde dehydrogenases . Benzyl alcohol dehydrogenase has a subunit Mr of 38923 consisting of 370 amino acids, it stereospecifically transfers the proR hydride of NADH, and it is a member of the family of zinc-dependent long-chain alcohol dehydrogenases . The enzyme appears to be more similar to animal and higher-plant alcohol dehydrogenases than it is to most other microbial alcohol dehydrogenases . Residue His-51 of zinc-dependent alcohol dehydrogenases is thought to be necessary as a general base for catalysis in this category of alcohol dehydrogenases . However, this residue was found to be replaced in benzyl alcohol dehydrogenase from A . calcoaceticus by an isoleucine, and the introduction of a histidine residue in this position did not alter the kinetic coefficients, pH optimum or substrate specificity of the enzyme . Other workers have shown that His-51 is also absent from the TOL-plasmid-encoded benzyl alcohol dehydrogenase of Pseudomonas putida and so these two closely related enzymes presumably have a catalytic mechanism that differs from that of the archetypal zinc-dependent alcohol dehydrogenases.

J Photochem Photobiol B, 1998 Mar, 42(3), 211 - 8
Eradication of Acinetobacter baumannii by photosensitized agents in vitro; Nitzan Y et al.; The photodynamic effects of photosensitizers on Acinetobacter baumannii were studied . These Gram negative bacteria have recently been implicated in various infections, mainly acquired in hospitals . They have outstanding characteristics of multidrug high resistance to antimicrobial agents . The best photodynamic effect was obtained when A . baumannii cultures were treated with light activated deuteroporphyrin (Dp) at a concentration of 34 mumoles l-off and polymyxin nonapeptide (PMNP) at a concentration of 200 mumoles l-1 . At these concentrations the culture in brain heart infusion (BHI) broth was found to be sterile after l h of treatment . Some inhibition was also obtained under the same conditions with Cd-texaphyrin (Cd-Tx) in the presence of PMNP . Treatment with various other photosensitizers in the presence of PMNP exhibited only marginal antibacterial activity . The cationic photosensitizer tetra-methylpyridyl porphine (TMPyP) did not exhibit any photodynamic effect on A . baumannii when illuminated during its growth in BHI broth . Bacteria grown in nutrient broth or suspended in saline and treated by TMPyP resulted in a significant photoinactivation by the sensitizer alone even in the absence of PMNP . It was found that a high concentration of the proteins present in BHI or in serum prevent TMPyP from acting as a photosensitizer against A . baumannii . Bovine serum albumin at the same high protein concentration prevents Dp (in the presence of PMNP) to act as a photosensitizer . The anionic photosensitizer tetra-sulfonatophenyl porphine (TPPS4) did not show any photodynamic effect in high or low protein media . In this study it was found that despite the high resistance of the Acinetobacter baumannii to antibiotics, these bacteria can be significantly photoinactivated by treatment with either Dp + PMNP or TMPyP in low protein content environments . When the protein concentration is high photoinactivation efficiency depends on the type of protein present in the medium.

Epidemiol Infect, 1998 Mar, 120(2), 139 - 42
Acinetobacter bacteremia in patients with diarrhoeal disease; Iqbal Hossain M et al.; In 1994, 171 (27%) of all positive blood cultures in our hospital were due to Acinetobacter species . Of these, 138 cultures were considered significant, 91 (66%) were community-acquired and 47 (34%) were nosocomial . Most acinetobacter bacteraemia in children < or = 1 year old was community-acquired, while nosocomial infection was more common in children > 1 year old (P = 0.01) . Most children < or = 5 years old were severely malnourished . The incidence of bacteraemia was lowest during the post-monsoon to early winter months . Acinetobacter bacteraemia associated mortality was twice (16%) that of all other patients (7.7%, P < 0.0005) and accounted for 4.5% of all hospital deaths during the study period . Bacteraemia caused by Acinetobacter species is an important cause of morbidity and mortality among our patient population with diarrhoeal disease.

Antimicrob Agents Chemother, 1998 May, 42(5), 1168 - 75
Interactions of beta-lactamases with sanfetrinem (GV 104326) compared to those with imipenem and with oral beta-lactams; Babini GS et al.; Sanfetrinem is a trinem beta-lactam which can be administered orally as a hexatil ester . We examined whether its beta-lactamase interactions resembled those of the available carbapenems, i.e., stable to AmpC and extended-spectrum beta-lactamases but labile to class B and functional group 2f enzymes . The comparator drugs were imipenem, oral cephalosporins, and amoxicillin . MICs were determined for beta-lactamase expression variants, and hydrolysis was examined directly with representative enzymes . Sanfetrinem was a weak inducer of AmpC beta-lactamases below the MIC and had slight lability, with a kcat of 0.00033 s(-1) for the Enterobacter cloacae enzyme . Its MICs for AmpC-derepressed E . cloacae and Citrobacter freundii were 4 to 8 microg/ml, compared with MICs of 0.12 to 2 microg/ml for AmpC-inducible and -basal strains; MICs for AmpC-derepressed Serratia marcescens and Morganella morganii were not raised . Cefixime and cefpodoxime were more labile than sanfetrinem to the E . cloacae AmpC enzyme, and AmpC-derepressed mutants showed much greater resistance; imipenem was more stable and retained full activity against derepressed mutants . Like imipenem, sanfetrinem was stable to TEM-1 and TEM-10 enzymes and retained full activity against isolates and transconjugants with various extended-spectrum TEM and SHV enzymes, whereas these organisms were resistant to cefixime and cefpodoxime . Sanfetrinem, like imipenem and cefixime but unlike cefpodoxime, also retained activity against Proteus vulgaris and Klebsiella oxytoca strains that hyperproduced potent chromosomal class A beta-lactamases . Functional group 2f enzymes, including Sme-1, NMC-A, and an unnamed enzyme from Acinetobacter spp., increased the sanfetrinem MICs by up to 64-fold . These enzymes also compromised the activities of imipenem and amoxicillin but not those of the cephalosporins . The hydrolysis of sanfetrinem was examined with a purified Sme-1 enzyme, and biphasic kinetics were found . Finally, zinc beta-lactamases, including IMP-1 and the L1 enzyme of Stenotrophomonas maltophilia, conferred resistance to sanfetrinem and all other beta-lactams tested, and hydrolysis was confirmed with the IMP-1 enzyme . We conclude that sanfetrinem has beta-lactamase interactions similar to those of the available carbapenems except that it is a weaker inducer of AmpC types, with some tendency to select derepressed mutants, unlike imipenem and meropenem.

Eur J Biochem, 1998 Apr 1, 253(1), 194 - 201
Lys42 and Ser42 variants of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens reveal that Arg42 is essential for NADPH binding; Eppink MH et al.; The conserved Arg42 of the flavoprotein p-hydroxybenzoate hydroxylase is located at the entrance of the active site in a loop between helix H2 and sheet E1 of the FAD-binding domain . Replacement of Arg42 by Lys or Ser decreases the turnover rate of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens by more than two orders of magnitude . Rapid reaction kinetics show that the low activity of the Arg42 variants results from impaired binding of NADPH . In contrast to an earlier conclusion drawn for p-hydroxybenzoate hydroxylase from Acinetobacter calcoaceticus, substitution of Arg42 with Ser42 in the enzyme from P . fluorescens hardly disturbs the binding of FAD . Crystals of {Lys42}p-hydroxybenzoate hydroxylase complexed with 4-hydroxybenzoate diffract to 0.22-nm resolution . The structure of the Lys42 variant is virtually indistinguishable from the native enzyme with the flavin ring occupying the interior position within the active site . Lys42 in the mutant structure interacts indirectly via a solvent molecule with the 3-OH of the adenosine ribose moiety of FAD . Substrate perturbation difference spectra suggest that the Arg42 replacements influence the solvent accessibility of the flavin ring in the oxidized enzyme . In spite of this, the Arg42 variants fully couple enzyme reduction to substrate hydroxylation . Sequence-comparison studies suggest that Arg42 is involved in binding of the 2'-phosphoadenosine moiety of NADPH.

J Bacteriol, 1998 May, 180(9), 2493 - 501
Regulation of benzoate degradation in Acinetobacter sp . strain ADP1 by BenM, a LysR-type transcriptional activator; Collier LS et al.; In Acinetobacter sp . strain ADP1, benzoate degradation requires the ben genes for converting benzoate to catechol and the cat genes for degrading catechol . Here we describe a novel transcriptional activator, BenM, that regulates the chromosomal ben and cat genes . BenM is homologous to CatM, a LysR-type transcriptional activator of the cat genes . Unusual regulatory features of this system include the abilities of both BenM and CatM to recognize the same inducer, cis,cis-muconate, and to regulate some of the same genes, such as catA and catB . Unlike CatM, BenM responded to benzoate . Benzoate together with cis,cis-muconate increased the BenM-dependent expression of the benABCDE operon synergistically . CatM was not required for this synergism, nor did CatM regulate the expression of a chromosomal benA::lacZ transcriptional fusion . BenM-mediated regulation differs significantly from that of the TOL plasmid-encoded conversion of benzoate to catechol in pseudomonads . The benM gene is immediately upstream of, and divergently transcribed from, benA, and a possible DNA binding site for BenM was identified between the two coding regions . Two mutations in the predicted operator/promoter region rendered ben gene expression either constitutive or inducible by cis,cis-muconate but not benzoate . Mutants lacking BenM, CatM, or both of these regulators degraded aromatic compounds at different rates, and the levels of intermediary metabolites that accumulated depended on the genetic background . These studies indicated that BenM is necessary for ben gene expression but not for expression of the cat genes, which can be regulated by CatM . In a catM-disrupted strain, BenM was able to induce higher levels of catA expression than catB expression.

J Clin Microbiol, 1998 May, 36(5), 1404 - 7
Identification of acinetobacters on blood agar in presence of D-glucose by unique browning effect; Siau H et al.; A positive phenotypic characteristic of glucose-oxidizing acinetobacters was demonstrated with blood agar containing D-glucose . Glucose-oxidizing Acinetobacter baumannii, Acinetobacter genospecies 3, Acinetobacter lwoffii, and Acinetobacter genospecies 13 sensu Tjernberg and Ursing caused a unique brown discoloration of media supplemented with 5% blood (of horse, sheep, or human origin) and an aldose sugar (0.22 M D-glucose, D-galactose, D-mannose, D-xylose, or lactose) . The browning effect was not observed when a ketose sugar (D-fructose or sucrose) was substituted for the aldose sugar or under high osmolarity in the presence of mannitol, glycerol, or sodium chloride . Other gram-negative nonfermenters (non-glucose-oxidizing acinetobacters, Pseudomonas aeruginosa, other Pseudomonas spp., Stenotrophomonas maltophilia, Flavobacterium spp., and Moraxella spp.) did not cause similar discoloration . This novel browning effect may serve as an alternative trait for identifying glucose-oxidizing acinetobacters.

J Clin Microbiol, 1998 May, 36(5), 1245 - 50
Specificity of rabbit antisera against lipopolysaccharide of Acinetobacter; Pantophlet R et al.; Acinetobacter has been reported to be involved in hospital-acquired infections with increasing frequency . However, clinical laboratories still lack simple methods that allow the accurate identification of Acinetobacter strains at the species level . For this study, proteinase K-digested whole-cell lysates from 44 clinical and environmental isolates were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with hyperimmune rabbit sera to examine the possibility of developing a serotyping scheme based on the O antigen of Acinetobacter lipopolysaccharide (LPS) . The antisera, obtained by immunization of rabbits with 13 of the heat-killed isolates investigated, were characterized by Western blotting and enzyme immunoassay by using proteinase K-digested whole-cell lysates and phenol-water-extracted LPS as antigens . In both assays, the antisera were shown to be highly specific for the homologous antigen . In addition, assignment of Acinetobacter LPS to the smooth or the rough phenotype was shown not to be reliable when it was based only on the results obtained with silver-stained gels . O-antigen reactivity, determined by Western blot analysis, was observed with 11 of the 31 isolates, most of which belonged to the species Acinetobacter baumannii (DNA group 2) and the unnamed DNA group 3 . Interestingly, some O antigens were found in a DNA group different from that of the strain used for immunization . The results indicate that O serotyping of Acinetobacter strains is feasible and thus may provide a simple method for the routine identification of these opportunistic pathogens.

Int J Syst Bacteriol, 1998 Jan, 48 Pt 1, 75 - 89
Phylogeny of the family Moraxellaceae by 16S rDNA sequence analysis, with special emphasis on differentiation of Moraxella species; Pettersson B et al.; Thirty-three strains previously classified into 11 species in the bacterial family Moraxellaceae were subjected to phylogenetic analysis based on 16S rRNA sequences . The family Moraxellaceae formed a distinct clade consisting of four phylogenetic groups as judged from branch lengths, bootstrap values and signature nucleotides . Group I contained the classical moraxellae and strains of the coccal moraxellae, previously known as Branhamella, with 16S rRNA similarity of > or = 95% . A further division of group I into five tentative clusters is discussed . Group II consisted of two strains representing Moraxella atlantae and Moraxella osloensis . These strains were only distantly related to each other (93.4%) and also to the other members of the Moraxellaceae (< or = 93%) . Therefore, reasons for reclassification of these species into separate and new genera are discussed . Group III harboured strains of the genus Psychrobacter and strain 752/52 of {Moraxella} phenylpyruvica . This strain of {M.} phenylpyruvica formed an early branch from the group III line of descent . Interestingly, a distant relationship was found between Psychrobacter phenylpyruvicus strain ATCC 23333T (formerly classified as {M.} phenylpyruvica) and {M.} phenylpyruvica strain 752/52, exhibiting less than 96% nucleotide similarity between their 16S rRNA sequences . The establishment of a new genus for {M.} phenylpyruvica strain 752/52 is therefore suggested . Group IV contained only two strains of the genus Acinetobacter . Strategies for the development of diagnostic probes and distinctive sequences for 16S rRNA-based species-specific assays within group I are suggested . Although these findings add to the classificatory placements within the Moraxellaceae, analysis of a more comprehensive selection of strains is still needed to obtain a complete classification system within this family.

FEMS Microbiol Lett, 1998 Apr 1, 161(1), 187 - 92
In vitro interaction of the IHF-like proteins Acinetobacter junii and Proteus vulgaris with ihf sites; Krawczyk B et al.; The ability of the IHF-like proteins of Acinetobacter junii and Proteus vulgaris to interact with the H' attP and pR' ihf sites of lambda DNA was investigated . IHF from A . junii and P . vulgaris was found to bind the examined ihf sites in a way similar to IHF from Escherichia coli as shown by gel mobility shift DNA binding assays and footprinting analysis . The three IHF proteins bound to the pR' ihf site that overlaps the-35 region of that promoter and in vitro repression of transcription by each IHF was observed . These results confirm that IHF-like proteins from Gram-negative bacteria can recognize the same specific DNA sequences and appear to be important in regulation of transcription.

FEMS Microbiol Lett, 1998 Apr 1, 161(1), 125 - 8
Presence of integrons in isolates of different biotypes of Acinetobacter baumannii from Chilean hospitals; Gonzalez G et al.; Class 1 and class 2 integrons were investigated by hybridisation in 100 isolates of multiresistant biotypes of Acinetobacter baumannii from Chilean hospitals . Most isolates of A . baumannii biotype 9, the prevalent biotype, harboured integrons of class 2 (Tn7-like) whereas no integrons were detected in infrequent biotypes . Integron-carrying isolates exhibited broader antibiotic resistance patterns as well as higher resistance levels to various antimicrobials.

Diagn Microbiol Infect Dis, 1998 Feb, 30(2), 113 - 9
Multicenter evaluation of the in vitro activity of six broad-spectrum beta-lactam antimicrobial agents in Puerto Rico . The Puerto Rico Antimicrobial Resistance Study Group; Doern GV et al.; The minimum inhibitory concentrations of 6 broad-spectrum beta-lactam antimicrobial agents were determined by use of the Etest versus a total of 569 bacteria in 7 Puerto Rican hospital laboratories . These included 342 recent clinical isolates of Enterobacteriaceae, 63 Pseudomonas aeruginosa, 54 Acinetobacter species, and 110 oxacillin-susceptible staphylococci . Extended spectrum beta-lactamase production was noted among 11% of Klebsiella pneumoniae isolates . Hyperproduction of Amp C cephalosporinase was observed with > 20% of isolates of Enterobacter spp., Serratia spp., and Citrobacter freundii . The overall rank order of activity of the six beta-lactams examined in this study versus all clinical isolates was imipenem (95.8% susceptible) > cefepime (91.1%) > piperacillin/ tazobactam (82.3%) > cefotaxime (77.6%) > piperacillin (72.5%) > ceftazidime (67.0%).

Med Dosw Mikrobiol, 1997, 49(3-4), 191 - 8
{Susceptibility of clinical strains of gram-negative rods to selected beta-lactam antibiotics}; Rokosz A et al.; The aim of the study was to determine the activity of four beta-lactam antibiotics against nosocomial strains of gram-negative bacilli . Two antibiotics combined with beta-lactamase inhibitors: timentin (TIC/CLAV) and tazocin (PIP/TZB) and two carbapenems: imipenem and meropenem were applied . The clinical strains were isolated from patients hospitalized in the following wards: surgery and intensive care unit of State Clinical Hospital No 1 in Warsaw . The strains were identified in the automatic ATB system using ID 32 E and ID 32 GN strips . The susceptibility of isolates to antibacterial agents was determined in the automatic ATB system using ATB G- and ATB PSE strips . The susceptibility of the strains to imipenem, meropenem, timentin and tazocin was tested by disc-diffusion method . 157 strains of gram-negative bacilli were cultured . 100 strains were isolated from patients hospitalized in surgical ward and 57 strains from patients hospitalized in ICU . Nonfermenting rods dominated among isolated strains-91 . The results obtained indicate that multiresistant gram-negative rods causing serious therapeutic problems are often isolated from clinical specimens . The contribution of nonfermenting rods, especially Pseudomonas spp . and Acinetobacter spp . to the etiology of infections in hospitalized patients has increased . Infections caused by these strains are difficult to cure . Tazocin and carbapenems (imipenem and meropenem) are highly active in vitro against the examined strains of gram-negative bacilli.

Infect Control Hosp Epidemiol, 1998 Mar, 19(3), 188 - 90
Colonization by Acinetobacter baumanii in intensive-care-unit patients; Lortholary O et al.; We prospectively studied the value of systematic rectal swabs performed for the detection of colonization and the prediction of infections by Acinetobacter baumanii in 751 consecutive patients admitted to five intensive-care units (ICUs) over an 8-month period . Gastrointestinal tract colonization was found in 8.7% of ICU admissions . The positive and negative predictive values of rectal swabs for the detection of subsequent infection were 17% and 99%, respectively . Sensitivity and specificity were 55% and 93%, respectively . We also determined the comparative values of rectal or nasal swabs and skin cultures for the detection of A baumanii colonization in 25 patients already colonized or infected with A baumanii . The combination of rectal and nasal swabs was positive in 20 (80%) of 25 . The results of the present study suggest that detection of gastrointestinal tract A baumanii colonization is not an accurate predictor of subsequent A baumanii infection and that combined rectal and nasal swabs might be used for the detection of A baumanii colonization in ICU patients.

Appl Environ Microbiol, 1998 Apr, 64(4), 1550 - 4
Transformation of Acinetobacter sp . strain BD413 by transgenic sugar beet DNA; Gebhard F et al.; The ability of Acinetobacter sp . strain BD413(pFG4 delta nptII) to take up and integrate transgenic plant DNA based on homologous recombination was studied under optimized laboratory conditions . Restoration of nptII, resulting in kanamycin-resistant transformants, was observed with plasmid DNA, plant DNA, and homogenates carrying the gene nptII . Molecular analysis showed that some transformants not only restored the 317-bp deletion but also obtained additional DNA.

Appl Environ Microbiol, 1998 Apr, 64(4), 1175 - 9
Alkane hydroxylase from Acinetobacter sp . strain ADP1 is encoded by alkM and belongs to a new family of bacterial integral-membrane hydrocarbon hydroxylases; Ratajczak A et al.; Degradation of long-chain alkanes by Acinetobacter sp . strain ADP1 involves rubredoxin and rubredoxin reductase . We complemented a mutant deficient in alkane utilization and sequenced four open reading frames (ORFs) on the complementing DNA . Each of these ORFs was disrupted by insertional mutagenesis on the chromosome . As determined from sequence comparisons, ORF1 and ORF4 seem to encode a rotamase of the PpiC type and an acyl coenzyme A dehydrogenase, respectively . Disruption of these ORFs does not affect alkane utilization . In contrast, the two other ORFs, alkR and alkM, are essential for growth on alkanes as sole carbon sources . alkR encodes a polypeptide with extensive homology to AraC-XyIS-like transcriptional regulators . It is located next to alkM, which encodes the terminal alkane hydroxylase, but is in the opposite orientation . Sequence homologies with other bacterial integral-membrane hydrocarbon hydroxylases suggest that AlkM may be the first member of a new protein family . The genes identified here are not linked to the rubredoxin- and rubredoxin reductase-encoding genes on the Acinetobacter sp . strain ADP1 chromosome.

Eye, 1997, 11 ( Pt 6), 863 - 4
Trauma-induced Acinetobacter lwoffi endophthalmitis with multi-organism recurrence: strategies with intravitreal treatment; Crawford PM Jr et al.; Endophthalmitis and its treatment are challenging, controversial subjects . We report here a patient whose recurrent endophthalmitis required several modes of treatment.

Mol Gen Genet, 1998 Feb, 257(3), 330 - 7
The Acinetobacter calcoaceticus NCIB8250 mop operon mRNA is differentially degraded, resulting in a higher level of the 3' CatA-encoding segment than of the 5' phenolhydroxylase-encoding portion; Schirmer F et al.; The 7.5-kb polycistronic mop mRNA is differentially degraded in Acinetobacter calcoaceticus . The 4.9-kb 5' portion of the transcript contains the genes mopKLMNOP, encoding the multi-component phenol hydroxylase, and its 5' end decays three times faster than the 2.3-kb 3' portion encoding catechol 1,2-dioxygenase (catA) . Larger amounts of the catA mRNA than the mopKLMNOP mRNA are present in the cells as a result of this processing . The site for endonucleolytic cleavage is located in the intercistronic region between mopP and catA, and contains a potential stem-loop structure and a putative RNase E cleavage site . Decay of the mop mRNA in Escherichia coli depends on RNase E . Thus, we propose that an RNase E-like activity is also present in A . calcoaceticus . Expression of MopN, one polypeptide of the multi-component phenol hydroxylase, interferes with growth of A . calcoaceticus . Thus, harmful expression of MopN may be reduced by rapid decay of its mRNA, indicating that mRNA processing contributes to differential gene expression in the large mop operon of A . calcoaceticus NCIB8250.

Antimicrob Agents Chemother, 1998 Mar, 42(3), 555 - 63
In vitro and in vivo antibacterial activities of CS-834, a new oral carbapenem; Yamaguchi K et al.; CS-834 is a prodrug of the carbapenem R-95867, developed by Sankyo Co., Ltd., Tokyo, Japan . To investigate the possibility that CS-834 may be the first carbapenem usable in an oral dosage form, its in vitro antibacterial activity (as R-95867) and in vivo antibacterial activity were compared with those of cefpodoxime proxetil, cefditoren pivoxil, cefdinir, ofloxacin, imipenem, and amoxicillin . R-95867 had high levels of activity against methicillin-susceptible staphylococci and streptococci, including penicillin-resistant Streptococcus pneumoniae, as well as Neisseria gonorrhoeae, Moraxella catarrhalis, the members of the family Enterobacteriaceae (with the exception of Serratia marcescens), Haemophilus influenzae, and Bordetella pertussis; for all these strains, the MICs at which 90% of tested strains are inhibited (MIC90s) were 1.0 microg/ml or less . Against methicillin-resistant staphylococci, enterococci, Serratia marcescens, Burkholderia cepacia, Stenotrophomonas maltophilia, and Acinetobacter calcoaceticus, R-95867 showed activity comparable to or slightly less than that of imipenem, with MIC90s ranging from 2 to >128 microg/ml . The in vivo efficacy of oral CS-834 against experimental mouse septicemia caused by gram-positive and gram-negative bacteria was better than that of comparative drugs . In murine respiratory infection models, the efficacy of CS-834 reflected not only its potent in vitro activity but also the high levels present in the lungs.

J Bacteriol, 1998 Mar, 180(6), 1592 - 5
Identification and characterization of a novel competence gene, comC, required for DNA binding and uptake in Acinetobacter sp . strain BD413; Link C et al.; A gene (comC) essential for natural transformation was identified in Acinetobacter sp . strain BD413 . ComC has a typical leader sequence and is similar to different type IV pilus assembly factors . A comC mutant (T308) is not able to bind or take up DNA but exhibits a piliation phenotype indistinguishable from the transformation wild type as revealed by electron microscopy.

J Bacteriol, 1998 Mar, 180(6), 1512 - 24
PcaU, a transcriptional activator of genes for protocatechuate utilization in Acinetobacter; Gerischer U et al.; The Acinetobacter pcaIJFBDKCHG operon encodes the six enzymes that convert protocatechuate to citric acid cycle intermediates . Directly downstream from the operon are qui and pob genes encoding sets of enzymes that convert quinate and p-hydroxybenzoate, respectively, to protocatechuate . Prior to this investigation, the only known regulatory gene in the pca-qui-pob cluster was pobR, which encodes a transcriptional activator that responds to p-hydroxybenzoate and activates transcription of pobA . The pca and qui genes were known to be expressed in response to protocatechuate, but a protein that mediated this induction had not been identified . This study was initiated by characterization of a spontaneous mutation that mapped upstream from pcaI and prevented expression of the pca genes . Sequencing of wild-type DNA extending from the translational start of pcaI through and beyond the location of the mutation revealed a 282-bp intergenic region and a divergently transcribed open reading frame, designated pcaU . Downstream from pcaU are two open reading frames encoding proteins similar in amino acid sequence to those associated with the oxidation of acyl thioesters . Inactivation of pcaU reduced the induced expression of pca structural genes by about 90% and impeded but did not completely prevent growth of the mutant cells with protocatechuate . PcaU was expressed in Escherichia coli and shown to bind to a portion of the pcaI-pcaU intergenic region containing a sequence identical in 16 of 19 nucleotide residues to a segment of the pob operator . Further similarity of the two regulatory systems is indicated by 54% amino acid sequence identity in the aligned primary structures of PobR and PcaU . The pob and pca systems were shown to differ, however, in the relative orientations of transcriptional starts with respect to the site where the activator binds to DNA, the size of the intergenic region, and the tightness of transcriptional control . The spontaneous mutation blocking pca gene expression was located in the promoter for the pca operon . The 19-nucleotide residue operator sequences were shown to be parts of a consensus associated with transcriptional activation of genes associated with protocatechuate catabolism . Two different binding sites for Pseudomonas putida PcaR differ from the consensus in only a single nucleotide residue, and DNA directly downstream from Acinetobacter pcaU contains a 19-bp segment differing from the consensus in only two residues . PcaU was shown to bind to DNA containing this segment as well as to the DNA in the pcaU-pcaI intergenic region.

Biol Pharm Bull, 1998 Feb, 21(2), 170 - 3
Two genes involved in the 1,3-diaminopropane production pathway in Haemophilus influenzae; Ikai H et al.; We previously cloned and sequenced the Acinetobacter baumannii dat and ddc genes encoding L-2,4-diaminobutyrate: 2-ketoglutarate 4-aminotransferase (DABA AT) and DABA decarboxylase, respectively, involved in the 1,3-diaminopropane (DAP) production pathway . Homology searches of the gene products provided an indication that a similar gene cluster is present in the genome of Haemophilus influenzae Rd . This was first verified by detection of the corresponding enzyme activities in and the production of DAP by all H . influenzae strains examined . Both of the crude enzymes from the representative strain of H . influenzae showed catalytic properties essentially similar to the A . baumannii DABA AT and DABA DC . An Escherichia coli clone carrying the dat homolog of H . influenzae Rd showed a high level of DABA AT activity, the enzyme protein responsible being detected by immunoblot analysis . These results specify the two H . influenzae genes involved in DAP production.

Polim Med, 1997, 27(3-4), 3 - 9
Release of antibiotics from collagen dressing; Grzybowski J et al.; Our new collagen dressing has been developed recently . Three types (A, B, and C) of the dressing were prepared in this study . Each type contained bacitracin, neomycin or colistin . The antibiotic was input into: i . collagen sponge (CS)--type A, ii . layer of limited hydrophobicity (LLH)--type B, and iii . into both CS and LLH layers--type C . The final concentration of the antibiotic that resulted from the loading level was 2 mg/cm2 for the dressings of type A and B and 4 mg/cm2 for the dressing of type C . The antibiotics were then extracted from the pieces of dressings for two days through dialysis membrane . Susceptibility of 54 bacterial strains (S . aureus, P . aeruginosa, and Acinetobacter) isolated from burn wounds were tested to the three antibiotics used for preparation of the dressings . The results of the study evidenced that efficiency of released of antibiotics into the extracts depended on the kind of antibiotic and on the type of dressing . The concentration of the antibiotics proved to be much higher than MIC90 values of the bacterial isolates tested in respect to their susceptibility . The dressing containing mixture of the three antibiotics in two layers--CS and LLH is now considered as potentially effective for care of infected wounds . It may be useful for the treatment of infected wounds or for profilaxis of contaminated wounds, ensuring: i . sufficient antimicrobial activity in wound, and ii . optimal wound environment for the presence of collagenic biomaterial on the damaged tissue.

Eur J Clin Microbiol Infect Dis, 1998 Jan, 17(1), 37 - 40
Acinetobacter baumannii colonization in ventilated preterm infants; Nagels B et al.; The role of Acinetobacter baumannii in infections in ventilated preterm infants was evaluated in 15 colonized infants (11 male, 4 female) in a pediatric intensive care unit . These cases were randomly matched by birth weight and gestational age with ventilated non-colonized controls (8 male, 7 female) . Case records were reviewed for signs and symptoms of infection . Colonized infants were ventilated significantly longer (p < 0.05) than controls, and had body temperatures of > 37 degrees C for a significantly longer period of time (p < 0.05) . No other parameter of infection differed significantly between the groups . The duration of intensive care treatment did not differ between cases and controls, nor did the weight gain during intensive care treatment . No fatalities occurred in either group.

Mol Cells, 1997 Dec 31, 7(6), 730 - 7
Purification and characterization of a manganese-containing superoxide dismutase from a carboxydobacterium, Pseudomonas carboxydohydrogena; An SS et al.; Superoxide dismutase from Pseudomonas carboxydohydrogena, a carboxydobacterium, grown on carbon monoxide was purified 37.6-fold in seven steps to homogeneity, with a yield of 1.4% . The final specific activity was 2,396 units per mg protein as determined by an assay based on a 50% decrease in the rate of cytochrome c reduction . The molecular weight of the native enzyme was determined to be 42,500 . Sodium dodecyl sulfate gel electrophoresis revealed two identical subunits of molecular weight 21,700 . The optimal pH for enzyme activity was found to be 9.0 . The enzyme was stable to heat treatment . The isoelectric point of the native enzyme was found to be 7.1 . The enzyme showed an absorption peak at 280 nm with a shoulder at around 289 nm . Sodium azide, but not sodium cyanide and hydrogen peroxide, was found to inhibit the enzyme activity . One mol of native enzyme was found to contain 1.09 g-atom of manganese . Analysis of amino acid composition revealed that the enzyme contains cysteine . The superoxide dismutase of P . carboxydohydrogena was found to have antigenic sites identical to those of Oligotropha carboxydovorans . The enzyme showed partial identity to Hydrogenophaga pseudoflava and Escherichia coli enzymes, but no identity to Acinetobacter sp . strain JC1 enzyme.

Appl Environ Microbiol, 1998 Mar, 64(3), 896 - 901
Transcription of ppk from Acinetobacter sp . strain ADP1, encoding a putative polyphosphate kinase, is induced by phosphate starvation; Geissdorfer W et al.; Polyphosphate kinase (Ppk) catalyzes the formation of polyphosphate from ATP . We cloned the ppk gene (2,073 bp) from Acinetobacter sp . strain ADP1; this gene encodes a putative polypeptide of 78.6 kDa with extensive homology to polyphosphate kinase from Escherichia coli and other bacteria . Chromosomal disruption of ppk by inserting a transcriptionally fused lacZ does not affect growth under conditions of phosphate limitation or excess . beta-Galactosidase activity expressed from the single-copy ppk::lacZ fusion is induced 5- to 15-fold by phosphate starvation . An increased amount of ppk transcript (2.2 kb) was detected when cells were grown at a limiting phosphate concentration . Primer extension analysis revealed a regulated promoter located upstream of a second, constitutive promoter . Potential similarities of this regulation with the effects of PhoB and PhoR of E . coli are discussed.

J Fr Ophtalmol, 1997, 20(7), 551 - 3
{Uncommon intra-orbital foreign body . Apropos of a case}; Briat B et al.; We report an unusual case of an acute iatrogenic unilateral exophthalmos in a woman affected by acinetobacter baumanii septicemia . The possible hypothesis of the exophthalmos is discussed.

Ann Acad Med Singapore, 1997 Sep, 26(5), 599 - 603
The pattern of burn infection in the Singapore National Burns Centre; Ang SW et al.; As part of the multi-pronged strategy in the fight against burn infection, we conducted a retrospective study of the pattern of infection in our burn patients for a period of 15 months from January 1993 to March 1994 . We studied culture and sensitivity reports to determine the incidence of each organism, their antibiotic sensitivity patterns and the time interval between the burns injury and the appearance of these organisms . Organisms like methicillin-resistant Staphylococcus aureus (MRSA) and multiply-resistant Acinetobacter baumannii constituted a problem in our patients . Other organisms that were isolated from our patients included Pseudomonas aeruginosa, Enterobacter species and Klebsiella species . The infection control measures in our burns centre are aimed at combating the spread of gram-positive and gram-negative organisms . This study has helped to influence our antibiotic administration policy for treating infection in our centre based on the sensitivity patterns of the prevailing flora.

Ann Acad Med Singapore, 1997 Sep, 26(5), 593 - 8
Bacteraemia in the elderly; Ismail NH et al.; The aims of the study were to describe community-acquired and nosocomial bacteraemia in elderly patients and to determine the factors associated with increased mortality in these patients attending a tertiary hospital in Singapore . A consecutive series of 191 patients aged more than 60 years of age admitted in 1995 was studied retrospectively . All of them had positive blood culture results obtained from the Department of Pathology and the case notes were reviewed and entered into a standard clinical protocol . They were analysed for age, sex, place of origin, race, sites of infection, clinical parameters and bacteriology . The mean age of the study population was 75 years (SD = 8.9 years) . Bacteraemia was acquired from the community in 57.5% of patients, 33% was nosocomial in origin and 9.5% acquired it in chronic long term care facilities . The common organisms cultured in community-acquired infections were Escherichia coli (26.1%), Klebsiella species (25.4%), Streptococcus species (11.1%), methicillin sensitive Staphylococcus aureus (7.6%) and Proteus mirabilis (4.8%) . The common organisms cultured in nosocomial infections were Klebsiella species (19.8%), Enterobacter species (14.6%), E . coli (11.8%), Acinetobacter baumanii (9.2%), methicillin sensitive Staphylococcus aureus (7.9%) and methicillin-resistant Staphylococcus aureus (7.9%) . Whilst most cases of bacteraemia were single organism cultures, 13.5% were polymicrobial . The common sources of bacteraemia were chest (27.5%), urinary tract (24.5%), skin (12.5), hepatic (8.8%), gut (4.3%), cardiovascular system (1%) and others (3.6%) . In 12.5% of cases, the sources were multiple and in 5.3% of cases, the source could not be identified . Twenty-one per cent of patients with bacteraemia died . The following factors were associated with increased mortality rate: older age (median age of those that died was 78.5 years compared to survivors with a median age of 73 years, P = 0.011), patient's place of origin (patients in nursing home at higher risk of death, P = 0.04), patient's mobility status (immobile patients at higher risk, P = 0.00297), source of bacteraemia--respiratory infection at increased risk of death (P = 0.00009) but urinary tract infection had a better survival rate (P = 0.03935) and multiple sites of infection (patients with multiple sites of infection had higher risk, P = 0.00897) . Methicillin-sensitive Staphylococcus aureus bacteraemia was associated with a mortality rate of 35.3%, followed by Klebsiella species 28.6%, Pseudomonas aeruginosa 28.6%, methicillin-resistant Staphylococcus aureus 25%, Proteus mirabilis 25% and E . coli 19.1% . Important clinical parameters which indicated a poor clinical outcome were: high pulse rate, hypotension, increased respiratory rate, low total white cell count, coagulopathy, hypoalbuminaemia and increased creatinine level.

Eur J Biochem, 1998 Jan 15, 251(1-2), 189 - 94
Structural studies of the O-antigen isolated from the phenol-soluble lipopolysaccharide of Acinetobacter baumannii (DNA group 2) strain 9; Haseley SR et al.; A polysaccharide containing D-GalNAc, D-Glc and 4-acetamido-4,6-dideoxy-D-glucose (Qui4NAc) was isolated from the phenol-soluble lipopolysaccharide originating from Acinetobacter baumannii strain 9 . The structure of the repeating unit was shown by means of monosaccharide analyses, Smith-degradation, partial acid hydrolysis, mass spectrometry, and NMR spectroscopy to be a branched pentasaccharide, in which the tetrasaccharide backbone is built from amino sugars only . {structure: see text} The polysaccharide was identified by serological and western blot analyses as the O-antigen of the lipopolysaccharide.

J Chemother, 1997 Dec, 9(6), 394 - 402
In vitro activity of fosfomycin trometamol against pathogens from urinary tract infections: a Spanish multicenter study; Garcia-Rodriguez JA et al.; The in-vitro susceptibilities of a total of 1371 urinary tract pathogens to fosfomycin trometamol were determined . According to the NCCLS breakpoints, Enterobacteriaceae and gram-positive microorganisms were, in general, very sensitive to this antimicrobial . More than 90.0% of the Escherichia coli and Citrobacter spp . and more than 70.0% of the Klebsiella pneumoniae, K . oxytoca, Enterobacter spp., Proteus mirabilis, Staphylococcus aureus, coagulase-negative staphylococci and Enterococcus spp . strains tested were susceptible to fosfomycin trometamol . However, Pseudomonas aeruginosa and Acinetobacter spp . strains were more resistant . In general, recent clinical isolates from urinary tract infections (UTIs) in both community and hospital were also very sensitive (> 80.0%) to fosfomycin, its activity being higher than that of the rest of the antimicrobials commonly used for therapy of uncomplicated UTIs . More than 75.0% of the most frequently isolated pathogens from UTIs, except for P . aeruginosa (31.8%) and Acinetobacter spp . (11.1%), were susceptible to fosfomycin trometamol . The results obtained in this study, together with the infrequency of side effects and its pharmacokinetic properties, indicate that fosfomycin trometamol may be a useful alternative for single-dose therapy of uncomplicated UTIs.

Diagn Microbiol Infect Dis, 1998 Jan, 30(1), 53 - 9
The prevalence and antibiotic susceptibility pattern of gram-negative bacterial isolates in two ICUs in Saudi Arabia and Kuwait; Rotimi VO et al.; In surveys of the prevalence and antibiotic susceptibility pattern of consecutive Gram-negative bacterial isolates in two intensive care units (ICUs) in Saudi Arabia (Jeddah) and Kuwait, 106 and 101 isolates, respectively, were analyzed . The most common bacterial isolates in Jeddah versus Kuwait ICUs were Pseudomonas aeruginosa (26%, 26%), Escherichia coli (23%, 3%), Klebsiella pneumoniae (20%, 17%), inducible Enterobacteraecae group (17%, 14%), and Acinetobacter spp . (9%, 33%) . Overall, about 99% of all isolates were susceptible to ciprofloxacin in both centers, whereas 87 and 96% were susceptible to imipenem, 69 and 64% to ceftazidime, 59 and 52% to cefotaxime, and 25 and 67% to piperacillin, respectively, in Jeddah and Kuwait . Prior antibiotic usage was more common among patients in Jeddah than in Kuwait . Dominant features of the study in Jeddah were the E . coli and Klebsiella spp . demonstrating multiresistance to monobactams, cephems, and all three aminoglycosides, and evidence of two classes of resistance to beta-lactam antibiotics which were not seen among the Kuwaiti isolates . The Kuwaiti Pseudomonas spp . were more sensitive to imipenem than the Jeddah Pseudomonas spp . (100% versus 68%) . The higher number of resistant bacteria seen in Jeddah than Kuwaiti may be a reflection of the higher antibiotic consumption, in particular higher usage of broad spectrum cephalosporins in Jeddah ICU.

Ophthalmologica, 1998, 212(2), 126 - 32
Bacterial corneal ulcer: a multivariate study; Wang AG et al.; A retrospective clinicomicrobiological review of 314 patients with bacterial corneal ulcers from January 1982 to December 1992 was performed . Multivariate statistical analysis was done with multiple logistic regression using PROC LOGIST of SAS statistical software . Positive cultures were grown from 134 (42.7%) of the patients . Pseudomonas aeruginosa, staphylococci, and Acinetobacter spp . were the most frequent pathogens . Significant associations between contact lens use and P . aeruginosa (odds ratio, OR 8.16), between previous herpes simplex keratitis and Streptococcus spp . (OR 18.2) were found . Acinetobacter spp . occurred more frequently in eyes with burn and/or lagophthalmos (OR 13.1/26.2) . Staphylococcus aureus was associated with trauma (OR 6.27) and age under 50 (OR 5.08-13.6) . Nonpseudomonal gram-negative bacilli were associated with age over 50 (OR 3.24) . Drug sensitivity tests for these isolated microorganisms showed that vancomycin and ceftazidime were the most effective agents.

FEMS Microbiol Lett, 1998 Feb 1, 159(1), 121 - 7
Expression of genes from Rahnella aquatilis that are necessary for mineral phosphate solubilization in Escherichia coli; Kim KY et al.; Rahnella aquatilis is a Gram-negative bacterium that can fix atmospheric nitrogen and also has the ability to solubilize mineral phosphate . We have cloned the genes that confer the mineral phosphate solubilizing (Mps) trait from this organism by mobilizing a cosmid library of R . aquatilis into Escherichia coli HB101 . A 7.0-kb EcoRI fragment from a cosmid, when transferred into E . coli strains HB101 and DH5 alpha, conferred the ability to solubilize hydroxyapatite and the production of gluconic acid to E . coli . The relative amounts of soluble phosphate and gluconic acid produced by the cloned 7.0-kb EcoRI fragment in E . coli were significantly higher than those of R . aquatilis . Nucleotide sequence analysis revealed two complete open reading frames (ORF1 and ORF2) and a partial ORF, ORF1 and ORF2 encoded proteins of molecular mass 10 kDa and 44 kDa . The 44-kDa protein showed extensive sequence similarity to pqqE of Erwinia herbicola, Klebsiella pneumoniae and A . Acinetobacter calcoaceticus . The 10-kDa protein revealed strong similarity to the pqqD of K . pneumoniae and A . calcoaceticus.

Antibiot Khimioter, 1997, 42(12), 19 - 24
{Treatment of lower respiratory tract infections in the elderly}; Komarova VP et al.; Sixty outpatients at the age of 65 to 75 years with exacerbated chronic bronchitis were treated with antibiotics: amoxycillin/clavulanic acid (20 patients), cefaclor (20 patients) and ciprofloxacin (20 patients) . The treatment course in all the cases was 5 days . Bacteriological tests of the sputum specimens and estimation of the isolate antibiotic susceptibility by the disk diffusion method were applied to all the patients before and after the treatment . 73 per cent of the patients had mixed infection . The microflora mainly included various species of streptococci highly susceptible to the drugs (54 per cent) as well as highly susceptible strains of pneumococci and hemophilic bacilli (33 and 17 per cent respectively) . Atypical microflora was detected in 10 per cent of the cases . Pseudomonas aeruginosa strains were isolated in 2 cases . Acinetobacter sp . slightly susceptible only to ciprofloxacin was isolated in 1 case . Citrobacter sp . slightly susceptible to cefaclor and moderately susceptible to ciprofloxacin was detected in 1 case . Enterobacter sp . moderately susceptible only to ciprofloxacin was isolated in 1 case . A positive factor was moderate susceptibility of Proteus mirabilis to all the three drugs . In 24 patients (the average age of 54.7 years) the pharmacokinetics of ofloxacin administered under 2 different regimens was studied . The drug was used in a single dose of 400 mg once a day (group 1) or in a dose of 200 mg twice a day (group II) followed by estimation of the drug concentration in the blood and sputum . The pathogen eradication was stated in 61.5 and 72.7 per cent of the patients in groups I and II, respectively . By the results of the treatment with the use of the above mentioned antibiotics in the elderly patients fluoroquinolones should be considered preferable from the clinical and pharmacoeconomic viewpoints.

Am J Respir Crit Care Med, 1998 Feb, 157(2), 531 - 9
Ventilator-associated pneumonia caused by potentially drug-resistant bacteria; Trouillet JL et al.; To determine risk factors for ventilator-associated pneumonia (VAP) caused by potentially drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and/or Stenotrophomonas maltophilia, 135 consecutive episodes of VAP observed in a single ICU over a 25-mo period were prospectively studied . For all patients, VAP was diagnosed based on results of bronchoscopic protected specimen brush (> or = 10(3) cfu/ml) and bronchoalveolar lavage (> or = 10(4) cfu/ml) specimens . Seventy-seven episodes were caused by "potentially resistant" bacteria and 58 episodes were caused by "other" organisms . According to logistic regression analysis, three variables among potential factors remained significant: duration of mechanical ventilation (MV) > or = 7 d (odds ratio {OR} = 6.0), prior antibiotic use (OR = 13.5), and prior use of broad-spectrum drugs (third-generation cephalosporin, fluoroquinolone, and/or imipenem) (OR = 4.1) . Distribution of the 245 causative bacteria was analyzed according to four groups defined by prior duration of MV (< 7 or > or = 7 d) and prior use or lack of use (within 15 d) of antibiotics . Although 22 episodes of early-onset VAP in patients receiving no prior antibiotics were caused by antibiotic-susceptible bacteria, 84 episodes of late-onset VAP in patients receiving prior antibiotics were mainly caused by potentially resistant bacteria . Differences in the potential efficacies (ranging from 100% to 11%) against microorganisms of 15 antimicrobial regimens were studied according to classification into these four groups . These findings may provide a more rational basis for selecting the initial therapy of patients suspected of having VAP.

Am J Respir Crit Care Med, 1998 Feb, 157(2), 371 - 6
Impact of invasive and noninvasive quantitative culture sampling on outcome of ventilator-associated pneumonia: a pilot study; Sanchez-Nieto JM et al.; We performed an open, prospective, randomized clinical trial in 51 patients receiving mechanical ventilation for more than 72 h, in order to evaluate the impact of using either invasive (protected specimen brush {PSB} and bronchoalveolar lavage {BAL} via fiberoptic bronchoscopy) or noninvasive (quantitative endotracheal aspirates {QEA}) diagnostic methods on the morbidity and mortality of ventilator-associated pneumonia (VAP) . Patients were randomly assigned to two groups: Group A patients (n = 24) underwent QEA, PSB, and BAL; Group B patients (n = 27) underwent only QEA cultures . Empiric antibiotic treatment was given according to the attending physician and was modified according to the results of cultures and sensitivity in Group A using PSB and BAL results and in Group B based upon QEA cultures . Bacteriologic cultures were done quantitatively for EA, PSB, and BAL . Thresholds of > or = 10(5), > or = 10(3), and > or = 10(4) CFU/ml were used for QEA, PSB, and BAL, respectively . Microbial cultures from Group A patients were positive in 16 (67%) BAL samples, 14 (58%) PSB samples, and 16 (67%) QEA samples . In Group B patients, QEA microbial cultures yielded positive results in 20 of 27 (74%) samples . In Group A, there was total agreement between culture results of the three techniques on 17 (71%) occasions . In five (21%) cases, QEA coincided with either BAL or PBS . In only two (8%) cases, QEA cultures did not coincide with either PSB or BAL . No cases of positive BAL or PSB cultures had negative QEA cultures . Initial antibiotic treatment was modified in 10 (42%) patients from Group A and in four (16%) patients from Group B (p < 0.05) . The observed crude mortality rate was 11 of 24 (46%) in Group A, and 7 of 27 (26%) in Group B, whereas the adjusted mortality rates (observed crude minus predicted at admission) for Groups A and B were 29 and 10%, respectively . There were no statistically significant differences when comparing crude and adjusted mortality rates of Groups A and B . There were no differences in mortality between both groups when comparing pneumonia, considering together Pseudomonas aeruginosa and Acinetobacter spp . (Group A, 33% versus Group B, 27%) . There were no differences between Groups A and B with regard to ICU stay duration and total duration of mechanical ventilation . In this pilot study, the impact of bronchoscopy was to lead to more frequent antibiotic changes with no change in mortality . Further studies with larger population samples are warranted to confirm these findings.

Can J Microbiol, 1997 Dec, 43(12), 1133 - 46
Occurrence and identification of microorganisms in compacted clay-based buffer material designed for use in a nuclear fuel waste disposal vault; Stroes-Gascoyne S et al.; A full-scale nuclear fuel waste disposal container experiment was carried out 240 m below ground in an underground granitic rock research laboratory in Canada . An electric heater was surrounded by buffer material composed of sand and bentonite clay and provided heat equivalent to what is anticipated in a Canadian nuclear fuel waste repository . During the experiment, the heat caused a mass transport of water and moisture content gradients developed in the buffer ranging from 13% closest to the heater to 23% at the rock wall of the deposition hole . Upon decommissioning after 2.5 years, microorganisms could be cultured from all samples having a moisture content above 15% but not from samples with a moisture content below 15% . Heterotrophic aerobic and anaerobic bacteria were found in numbers ranging from 10(1) to 10(6) cells/g dry weight buffer . Approximately 10(2), or less, sulphate-reducing bacteria and methanogens per gram of dry weight buffer were also found . Identification of buffer population members was performed using Analytical Profile Index (API) strips for isolated bacteria and 16S rRNA gene sequencing for in situ samples . A total of 79 isolates from five buffer layers were identified with API strips as representing the beta, gamma and delta groups of Proteobacteria and Gram-positive bacteria . Sixty-seven 16S rRNA clones that were obtained from three buffer layers were classified into 21 clone groups representing alpha and gamma groups of Proteobacteria, Gram-positive bacteria, and a yeast . Approximately 20% of the population comprised Gram-positive bacteria . Members of the genera Amycolatopsis, Bacillus, and Nocardia predominated . Among Gram-negative bacteria, the genera Acinetobacter and Pseudomonas predominated . Analysis of lipid biomarker signatures and in situ leucine uptake demonstrated that the buffer population was viable . The results suggest that a nuclear fuel waste buffer will be populated by active microorganisms only if the moisture content is above a value where free water is available for active life.

Biochem Biophys Res Commun, 1998 Feb 4, 243(1), 289 - 94
Organization and transcriptional characterization of the cat1 gene cluster in Acinetobacter lwoffi K24; Kim SI et al.; Previously, we have reported that two clustered cat genes from Acenitobacter lwoffi K24 had different arrangements, catB1C1A1 and catB2A2C2 (Kim, S.I., S.-H . Leem, J.-S . Choi, Y.H . Chung, S . Kim, Y.-M . Park, Y.K . Park, Y.N . Lee, and K.-S . Ha . 1997, J . Bacteriol . 179, 5226-5231) . By further analysis of the organization of the cat1 gene cluster, we obtained a complete sequence of the catB1 gene, which encoded 40.8-kDa polypeptide containing 379 amino acids, and found a open reading frame (ORF) coding a putative regulatory protein in upstream region of catB1 on plasmid pCD1-1 . This ORF encoded 34.2-kDa polypeptide containing 379 amino acids and had more than 40% identity with catR, LysR family regulatory protein of Pseudomonas putida . RT-PCR, Northern blot analysis and primer extension assay for transcriptional analysis of the cat1 gene cluster revealed that the catB1C1 genes were cotranscribed and the catA1 gene was independently transcribed.

Gene, 1998 Jan 5, 206(1), 53 - 62
Characterization of a gene cluster from Ralstonia eutropha JMP134 encoding metabolism of 4-methylmuconolactone; Erb RW et al.; A 2,585 bp chromosomal DNA segment of Ralstonia eutropha JMP134 (formerly: Alcaligenes eutrophus JMP134) which contains a gene cluster encoding part of the modified ortho-cleavage pathway encodes a putative transport protein for 4-methylmuconolactone, a novel 4-methylmuconolactone methylisomerase and methylmuconolactone isomerase . The putative 4-methylmuconolactone transporter, a protein with a calculated molecular mass of 45.8 kDa, exhibits sequence homology to other members of the major superfamily of transmembrane facilitators and shows the common structural motif of 12 transmembrane-spanning alpha-helical segments and the hallmark amino acid motif characteristic of the superfamily . Consistent with the novelty of the reaction catalyzed by 4-methylmuconolactone methylisomerase, no primary sequence homologies were found between this enzyme or its gene and other proteins or genes in the data banks, suggesting that this enzyme represents a new type of isomerase . The molecular mass of the native 4-methylmuconolactone methylisomerase was determined by gel filtration analysis to be 25 +/- 2 kDa . From the polynucleotide sequence of the gene, a molecular mass of 12.9 kDa was calculated and hence we predict a homodimeric quaternary structure . The high sensitivity of 4-methylmuconolactone methylisomerase to heavy metals and thiol-modifying reagents implicates the involvement of sulfhydryl groups in the catalytic reaction . The methylmuconolactone isomerase - calculated molecular mass 10.3 kDa - has a primary structure related to the classical muconolactone isomerases (EC 5.3.3.4) of Acinetobacter calcoaceticus, of two Pseudomonas putida strains and of Ralstonia eutropha JMP134, suggesting that these are all isoenzymes . Consistent with this proposal is the finding that the purified protein exhibits muconolactone-isomerizing activity.

J Infect, 1997 Nov, 35(3), 316 - 8
Community-acquired Acinetobacter pneumonia: a case report; Yang CH et al.; A 35-year-old male with glucose-6-phosphate dehydrogenase (G6PD) deficiency was admitted because of right chest (pleuritic) pain, fever, cough with scarce production of blood-tinged sputum, and generalized yellowish discolouration of skin for 2 days . Radiographic examination revealed right lower lobe necrotizing pneumonia . Hypotension, dyspnoea and severe haemolysis was noted the next day . Echo-guided lung aspiration and sputum cultures both grew Acinetobacter baumannii . Antibiotic therapy was started immediately, but fever persisted and abscess formation was noted 1 week later . After aggressive supportive and antibiotic therapy, he made a slow but complete recovery from the pneumonia, and was then discharged in a stable condition . Acinetobacter baumannii is a well-known causative agent of nosocomial infections, particularly in intensive units . Community-acquired pneumonia, however, is quite rare, and usually has a fulminant course and high case fatality rate.

Diagn Microbiol Infect Dis, 1997 Dec, 29(4), 265 - 72
Multicenter evaluation of antimicrobial resistance to six broad-spectrum beta-lactams in Colombia using the Etest method . The Colombian Antimicrobial Resistance Study Group; Jones RN et al.; The need for comprehensive and quantitative accurate antimicrobial resistance surveillance systems has become acute as a guide to problem recognition and to focus local interventions . A multilaboratory (10 medical centers) Colombia surveillance project was initiated in early 1997 to monitor the potency and spectrum of six (cefepime, cefotaxime, ceftazidime, cefoperazone/sulbactam, aztreonam, and imipenem) broad-spectrum antimicrobial agents tested against 100 organisms per participant center (802 strains) . Ten groups of organisms were tested by a reference-quality method (Etest; AB BIODISK, Solna, Sweden) with results validated by concurrent quality control and additional challenge strain analysis . Results from nine qualifying medical centers were tabulated, and 95.7 to 96.8% of quality assurance tests were within expected ranges . Only cefepime (90.1-100.0% susceptible) and imipenem (96.3-100.0%) were active against all Enterobacteriaceae at > 90% of susceptible isolates using the breakpoint concentrations recommended by the National Committee for Clinical Laboratory Standards . Among ceftazidime- (or cefotaxime- or aztreonam-) resistant Enterobacter spp . and Citrobacter freundii, cefepime remained active, but not cefoperazone with sulbactam . Escherichia coli and Klebsiella spp . strains having resistance phenotypes consistent with extended spectrum beta-lactamase production were discovered in approximately 5 to 10% of isolates . All tested drugs except ceftazidime (31.8-57.7% susceptible) were active against > 94% of oxacillin-susceptible staphylococci . Similar rates of resistance (9.1-14.8%) were observed in Pseudomonas aeruginosa for five of six drugs (not cefotaxime; 15.9% of strains were susceptible) . Acinetobacter spp . isolates were most susceptible to imipenem (95.8%), cefepime (86.1%), and cefoperazone/sulbactam (83.3%) . Overall for the 1997 order of antimicrobial spectrums for these tested compounds was: imipenem (96.6%) > cefepime (93.6%) > cefoperazone/sulbactam (90.5%) > cefotaxime (74.9%) > aztreonam (74.3% for Gram-negative bacilli only) > ceftazidime (73.2%) . These data should be used to guide empiric regimens in Colombia, and additionally will provide a resistance statistical baseline to which future studies in this nation can be compared.

Rev Med Chil, 1997 Feb, 125(2), 149 - 60
{E-test to study small inhibitor concentrations, bacterial diversity and to identify presumptively beta-lactamases in strains of Pseudomonas aeruginosa and Acinetobacter baumannii associated with +nosocomial infections}; Triantafilo V et al.; BACKGROUND: Pseudomonas aeruginosa and Acinetobacter baumanii are two important nosocomial agents that require permanent testing of their antimicrobial susceptibility . AIM: To use E-test to determine minimal inhibitory concentrations, estimate bacterial diversity and presumably identify B-lactamases of strains of Pseudomonas aeruginosa and Acinetobacter baumanii isolated from nosocomial infections . MATERIALS AND METHODS: Sixty eight strains of Pseudomonas aeruginosa and Acinetobacter baumanii isolated in a teaching hospital were analyzed with E-test strips to determine their minimal inhibitory concentrations for different antimicrobials . RESULTS: More than 75% of Acinetobacter baumanii were resistant to Piperacillin, Cefpirome, Cefepime, Gentamicin or Amikacin, 40% of strains were resistant to Ceftazidime, 27 and 53% of isolates had a decreased susceptibility to Meropenem and Piperacillin-tazobactam respectively . Twenty eight to 54% of Pseudomonas aeruginosa strains were resistant to Cefepime, Cefpirome, Ciprofloxacin and Gentamicin . Eighteen and 10% of strains were resistant to Meropenem and Imipenem respectively . Less than 10% of strains were resistant to Amikacin, Azireonam, Piperacillin-tazobactam or Ceftazidime . Most of beta-lactam resistance of Pseudomonas aeruginosa was associated to decreased susceptibility or resistance to Cefpirome, Cefepime or to Meropenem-Imipenem and did not match clearly with known beta-lactamase profiles . CONCLUSIONS: The knowledge of susceptibility of these bacteria responsible for nosocomial infections, will help to plan the appropriate use of antimicrobials.

Rev Enferm, 1997 Sep, 20(229), 17 - 21
{Multi-resistant microorganisms: Acinetobacter . Nursing care}; Mila Enrique A et al.; There has recently been an increase in the incidence of bacteria that are resistant to a variety of medications . Acinetobactor, a gram-negative bacillus, is one that appears most often . This microbe, which has two subspecies, can be carried in the blood of one fourth of the healthy population . It manifests itself pathologically in hospital situations in which the patient becomes gravely ill . The principle infections it can provoke are: meningitis, endocarditis, pneumonia, urinary tract infections, bacteriemia, etc . Treatment is dependent upon antibacterial sensibility tests . As in the case of all microorganisms, prevention of infection is absolutely imperative to stop the spread of this very dangerous bacteria.

Gig Sanit, 1997 Jul-Aug, (4), 15 - 6
{Barrier role of water-purifying construction of water pipe in relation to opportunistic microorganisms}; Zhuravlev PV et al.; The investigations have indicated that in the flood period when the water-purifying means of a water pipe bears the maximum load, the existing water-preparing system cannot fully purify and disinfect drinking water from some opportunistic microbes (Klebsiella, Acinetobacter) . The latter were recorded in the pipe water having the MAC of coliform organisms established by the GOST.

Enferm Infecc Microbiol Clin, 1997 Jun-Jul, 15(6), 319 - 22
{In vitro activity of 9 antibiotics and 3 beta-lactamase inhibitors against 107 clinical isolates of Acinetobacter baumanii}; Echeverria MJ et al.; BACKGROUND: Acinetobacter sp . is an important cause of nosocomial infections and it is often resistant to many antibiotics . In our hospital it often causes infections in patients on the intensive care unit . The aim of this study was to know the susceptibility of Acinetobacter sp . strains isolated in our hospital . METHODS: The in vitro activities of nine antimicrobial agents (ticarcillin, piperacillin, ceftazidime, imipenem, meropenem, gentamicin, tobramycin, amikacin and colistin) and three beta-lactamase inhibitors (sulbactam, clavulanate and tazobactam) against 107 clinical isolates of Acinetobacter baumannii were studied . MICs were determined by a dilution agar method, except for colistin, which we used the disk-diffusion agar method . RESULTS: Of the antimicrobial agents tested imipenem and colistin were highly active against all isolates (100% susceptibility), meropenem presented good activity (96.3% susceptibility), ticarcillin presented moderated activity (84.1% susceptibility) . Most of the strains were resistant to ceftazidime (4.7% susceptibility), piperacillin (3.7% susceptibility) and the aminoglycosides (amikacin 21.5% susceptibility, gentamicin 2.8% susceptibility and tobramycin 4.7% susceptibility) . Sulbactam was the most active agent among the beta-lactamase inhibitors studied (CMI90 = 4 micrograms/ml) . CONCLUSIONS: Recent trends indicate increasing antimicrobial resistance of Acinetobacter baumannii, posing a serious threat to hospitalized patients . An strict attention to maintain a good housekeeping and control of the environment and of the antimicrobial usage, appears the measures most likely to control the spread of Acinetobacter baumannii in hospitals.

Environ Health Perspect, 1997 Nov, 105(11), 1172 - 4
Bovine spongiform encephalopathy: is it an autoimmune disease due to bacteria showing molecular mimicry with brain antigens?
Ebringer A, Thorpe C, Pirt J, Wilson C, Cunningham P, Ettelaie C.
Bovine spongiform encephalopathy (BSE) could be an autoimmune disease produced following exposure of cattle to feedstuffs containing bacteria showing molecular mimicry between bacterial components and bovine tissue . Analysis of molecular sequence databases (Genbank and SwissProt) shows that three bacteria (Acinetobacter calcoaceticus,Ruminococcus albus, and Agrobacter tumefaciens) share sequences with the encephalitogenic peptide of bovine myelin, while three molecules in Escherichia coli show molecular mimicry with host-encoded prion protein . Immune responses against these bacteria at both T and B cell levels may cause neurological tissue injury resembling BSE . The role of these bacteria in BSE, if any, merits further investigation.

Liver Transpl Surg, 1998 Jan, 4(1), 51 - 7
The significance of aerobic gram-negative bacilli in clinical specimens following orthotopic liver transplantation; Wade J et al.; In a prospective study of 284 liver transplant patients, we sought associations between aerobic gram-negative bacillus acquisition or infection and 35 preoperative, perioperative, and postoperative variables . Although the 128 (45%) who acquired aerobic gram-negative bacilli had longer admissions (P = 0.0001), no associations were found with pretransplant variables . Fifty-three (41%) of the 128 acquired coliforms (e.g., Escherichia coli, Klebsiella spp., or Enterobacter spp.), 50 (39%) acquired nonfermentative bacilli (e.g., Acinetobacter spp., Pseudomonas spp., or Stenotrophomonas maltophilia), and a further 25 (20%) acquired both . Acquisition progressed to infection in 58% of patients who acquired coliforms but in only 18% of patients who acquired nonfermentative bacilli (P = 0.005) . Acinetobacter spp . were isolated from more patients than other bacilli but rarely caused infection . The positive predictive values for infection of acquiring coliforms or nonfermentative bacilli in clinical material were 42% and 17%, respectively . This study allowed us to determine for each clinical site the positive predictive values for infection of acquisition of different aerobic gram-negative bacilli . Our results should contribute to the rationalization of antimicrobial prescribing for this patient group.

J Hosp Infect, 1997 Dec, 37(4), 287 - 95
Epidemiological significance of cutaneous, pharyngeal, and digestive tract colonization by multiresistant Acinetobacter baumannii in ICU patients; Ayats J et al.; The aim of this prospective study was to assess the relative epidemiological role of digestive tract colonization by Acinetobacter baumannii, in comparison with other body site colonizations, in patients admitted to intensive care units (ICUs) . From January to May 1995, axillary, pharyngeal and rectal swabs were taken together within the first 48 h of admission, and then weekly during ICU stay . Seventy-three patients were included, 48 of them (66%) had axillary, pharyngeal, or rectal colonization with A . baumannii, nine (19%) of these 48 during the first 48 h and the remaining 28 (77%) during the first week . Twenty-one (29%) had clinical samples positive for A . baumannii and axillary, pharyngeal, or rectal colonization . In 15 of these 21 (71%), colonization on body sites occurred prior to isolation from clinical samples (mean seven days, range 1-20) . Throughout admission, rates of detection of A . baumannii were 75% (36/48) for axillary or pharyngeal swabs and 77% (37/48) for rectal swabs . Combination of two body site swabs yielded culture positive rates of 90% (43/48) for axillary-pharyngeal or axillary-rectal sites, and 96% (46/48) for pharyngeal-rectal . Two epidemic clones were defined by antibiotype and pulsed-field gel electrophoresis (PFGE) of SmaI DNA digests in 48 isolates from 11 patients . We conclude that body sites of patients were a major reservoir for A . baumannii infections in the outbreak . This finding cases doubt on the value of selective decontamination of the digestive tract as an additional infection control measure in this kind of outbreak . The weekly performance of pharyngeal and rectal swabs appears to detect A . baumannii colonization early among ICU patients and enables barrier methods to be applied rapidly.

J Hosp Infect, 1997 Dec, 37(4), 281 - 6
Impact of Acinetobacter spp . in intensive care units in Great Britain and Ireland; Humphreys H et al.; Acinetobacter spp . are of increasing importance as hospital pathogens in intensive care units (ICUs) but it is unclear what clinical impact these bacteria have in Great Britain and Ireland . A survey was carried out by questionnaire on the impact of Acinetobacter in ICUs and the laboratory methods used to identify and type isolates . There were 70 respondents, of whom 25 reported that Acinetobacter had not been recovered from ICU patients within the previous 12 months . The remaining 45 respondents reported that the respiratory tract was the most common site from which these bacteria were isolated, but they were currently endemic in one ICU only . There were considerable differences in methods used to identify Gram-negative bacilli recovered from ICU patients, which may partly explain differences in the reported prevalence of isolates between centres, and 12 laboratories attempted to type isolates by a range of techniques . The availability and use of agreed antibiotic policies specific for ICUs may be particularly important in prevention and control where infection with Acinetobacter is prevalent.

Rev Chir Orthop Reparatrice Appar Mot, 1997, 83(4), 313 - 23
{Two stages reimplantation for infection after knee arthroplasty . Apropos of a series of 29 cases}; Gacon G et al.; PURPOSE OF THE STUDY: The purpose of this work was to precise diagnosis and treatment of infected total knee arthroplasty with two stage reimplantation . MATERIAL: 29 infected total knee arthroplasties were operated between 1984 and 1994 and included in this study (mean F.U . 3.5 Y) . There were 20 females and 9 males, mean age 70 (46-83) . The original arthroplasty was done for OA in 28 patients, RA in one . The arthroplasties were: UHK 2, Bicompartmental 2, Tricompartmental 19 . 20 TKA were cementless . 14 patients showed one or several risk factors . Infection was diagnosed in 1 of 2 ways: preoperative aspiration or culture of surgical specimen . There were 12 staphylococcus epidermidis, 8 staphylococcus aureus, streptococcus (n = 2) acinetobacter (n = 2), peptococcus (n = 1) pseudomonas (n = 1), gemella morbidellum (n = 1) . 6 were non identified . METHOD: The protocol for two stage reimplantation began with components and cement removal . A synovectomy was performed . The knee cavity was filled with antibiotic cement spacer and the wound was closed . The leg was placed in a splint . All patients underwend a continued antibiotic therapy, specific in 20 cases with isolated organisms . A total knee arthroplasty was performed, using a total posterior cruciate substituting prosthesis, 6 to 8 weeks after components removal (2-24) . All patients received parenteral antibiotics after reimplantation for not less than 2 months (2-6) . RESULTS: Infection was eradicated in 24 cases, 22 in one time, 2 bad second debridement . At last follow-up the average Hungerford score was 75.6/100, the average Knee society knee score was 80 and the average functional score was 70 . Mean range of flexion was 95 degrees . 6 patients had recurrent infection and poor result . They underwent arthrodesis . 5 of the 6 patients had solid mature fusion at last follow-up . DISCUSSION: The results of two stage reimplantation for infected total knee replacement showed that this is the method of choice for infection treatment and acceptable function restoration . As other authors, we get a good success rate (82 per cent) . Functional result was better with identified microorganisms, but we did not find any correlation with organisms type or infection length . Punction and bone scanning are of great help for diagnosis in difficult chronical cases . Organism identification is fundamental for infection duration . Staphylococcus epidermidis was the most frequent identified organism . New procedures using articulated cement spacer may improve functional results.

Eur J Clin Microbiol Infect Dis, 1997 Nov, 16(11), 834 - 8
Changing trends in frequency and antimicrobial resistance of urinary pathogens in outpatient clinics and a hospital in Southern Israel, 1991-1995; Weber G et al.; In order to monitor changes in the frequency and antimicrobial resistance of urinary pathogens over several years, urinary cultures received from outpatient clinics and from a hospital during a period of one month each in 1991 and 1995 were analyzed at a clinical microbiology laboratory . In 1991 and 1995, 1366 and 1534 significant monomicrobic cultures respectively were reviewed . The frequency of Escherichia coli dropped significantly in the outpatient clinics from 70.5% to 61.2% (p < 0.0001) . The frequency of Proteus mirabilis, Morganella morganii, Pseudomonas aeruginosa and other gram-negative bacteria also decreased, but the frequency of Klebsiella spp . and Enterobacter spp . increased from 2.6% to 5.8% (p < 0.0001) . In the hospital, the frequency of Enterobacter spp . (p < 0.04), Escherichia coli and Morganella morganii declined from 1991 to 1995, whereas the frequency of Pseudomonas aeruginosa (p = 0.001), Acinetobacter spp . (p < 0.05), Klebsiella spp., Proteus mirabilis and other gram-negative rods increased considerably . The frequency of gram-positive aerobic bacteria rose markedly in outpatient specimens from 6.1% to 13.5% (p < 0.0001), while a decline from 14.4% to 9.3% was noted in hospital specimens (p < 0.02) . A significant rise in the resistance of Escherichia coli to gentamicin and ciprofloxacin (p < 0.0001) was detected in outpatient isolates . In the hospital, gram-negative urinary pathogens demonstrated increased resistance to ampicillin (p = 0.042), cefuroxime (p = 0.005), gentamicin (p = 0.002) and ciprofloxacin (p < 0.0001) during the study period . The changing etiology of urinary tract infections and the increasing resistance of organisms indicate that periodic monitoring and possibly also modification of empirical therapy are required.

Antonie Van Leeuwenhoek, 1997 Nov, 72(4), 299 - 315
Phosphate transport in prokaryotes: molecules, mediators and mechanisms; van Veen HW; Bacteria have evolved sophisticated Pi transport systems which combine high affinity with coupling to metabolic energy . This review discusses the current evidence concerning the physiological, biochemical, and molecular properties of these Pi transport systems in prokaryotes . Major developments of the past years will be presented with emphasis on three kinds of issues . First, work on Pi transport in Escherichia coli and the polyphosphate-accumulating Acinetobacter johnsonii has assigned a novel biochemical mechanism and provided additional descriptive information for the transport of Pi and divalent cations . It is therefore appropriate to summarize these new facts and emphasize their general relevance for pro- and eukaryotic cells . Second, recent work on the bioenergetics of Pi transport in A . johnsonii has demonstrated the profound role of the transmembrane Pi gradient in energy transducing processes such as the accumulation of solutes, and the generation of a proton motive force . These findings and their significance for the survival of the cell during metabolic stress conditions will be discussed . Finally, polyphosphate-accumulating microorganisms play a valuable role in biotechnological applications, such as in wastewater treatment . As such organisms are still underrepresented in current molecular microbiological studies, the investigations in A . johnsonii described here may serve as a useful precedent for those to come.

Prikl Biokhim Mikrobiol, 1997 Sep-Oct, 33(5), 556 - 8
{AccBSI - a novel restriction endonuclease from Acinetobacter calcoaceticus BS}; Abdurashitov MA et al.; The recognition site of a new restriction endonuclease from Acinetobacter calcoaceticus BS was determined . This is a nonpalindromic sequence . AccBSI restrictase cleaves DNA chains in the middle of the recognition sequence; therefore, ligation of its digestion fragments restored AccBSI recognition sites and generated palindromic sequences recognized by SacI and SacII restrictases.

Chest, 1998 Jan, 113(1), 77 - 85
Impact of tracheotomy on colonization and infection of lower airways in children requiring long-term ventilation: a prospective observational cohort study; Morar P et al.; STUDY OBJECTIVES: Determination of the following: (1) colonization and infection rates in children requiring long-term ventilation initially via a transtracheal tube and subsequently via a tracheotomy; (2) the number of infection episodes per 1,000 ventilation days, during both types of artificial airways; and (3) routes of colonization/infection of the lower airways, ie, whether the pathogenesis was endogenous (via the oropharynx) or exogenous (via the transtracheal tube or tracheotomy) . DESIGN: Observational, cohort, prospective study over 2 1/2 years . SETTING: Pediatric ICU (PICU), Royal Liverpool Children's National Health Service Trust of Alder Hey, a tertiary referral center . PATIENTS: Twenty-two children requiring long-term mechanical ventilation initially transtracheally and subsequently via a tracheotomy . INTERVENTION: Nil . RESULTS: The lower airways were colonized in 71% of children during transtracheal ventilation; posttracheotomy, this was 95% (p=0.03) . Children developed significantly fewer infections following colonization with a microorganism posttracheotomy (8/15 pretracheotomy vs 6/21 posttracheotomy; p=0.013) . Throughout the study, there were a total of 17 episodes of infection, all of which were preceded by colonization . Haemophilus influenzae, Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa were the same four causative pathogens during mechanical ventilation both transtracheally and via tracheotomy . Forty-nine episodes of colonization were observed, 15 pretracheotomy and 34 posttracheotomy; of these, 12 (80%) and 19 episodes (56%), respectively, were primary endogenous, ie, present in the oropharynx on hospital admission and subsequently at tracheotomy . Only one colonization episode (7%) of exogenous pathogenesis was observed during transtracheal intubation, while 12 (35%) (p=0.02) occurred after tracheotomy . An equal number of secondary endogenous colonization episodes (two and three, ie, acquired in the oropharynx after PICU admission and after tracheotomy, respectively, were recorded . CONCLUSIONS: (1) Despite a high level of hygiene, exogenous colonization without subsequent infection was common . (2) Although all patients were colonized, the infection rate was lower after tracheotomy . This may be due to enhanced immunity (medically stable) and improved tracheobronchial toilet . (3) Microorganisms in children with tracheotomy differ from those in adults.

Gene, 1997 Dec 19, 204(1-2), 259 - 65
Characterization of a bacterial gene encoding an autophosphorylating protein tyrosine kinase; Grangeasse C et al.; Acinetobacter johnsonii harbors a protein tyrosine kinase activity that is able to catalyze autophosphorylation, like a number of eukaryotic tyrosine kinases . A biochemical and genetic analysis of this enzyme was performed . Maximum phosphorylation in vitro was obtained by incubating the kinase for 2 min at pH 7.0 in the presence of 5 mM magnesium chloride . In contrast to eukaryotic enzymes, no inhibitory effect of genistein and no phosphorylation of synthetic substrates such as poly (Glu80 Tyr20) or angiotensin II were observed . The analysis of the bacterial kinase by two-dimensional gel electrophoresis revealed the presence of at least five isoforms, all phosphorylated exclusively at tyrosine, which supports the concept that autophosphorylation occurs at multiple sites within the protein . The cloning and nucleotide sequencing of the gene encoding this kinase were achieved, which represents the first molecular characterization of a gene of this type in bacteria . An open reading frame of 2199 nucleotides encoding a protein of 82,373 Da was detected . The analysis of the deduced amino acid sequence suggested a possible involvement of the enzyme in cell recognition and bacterial pathogenicity . In addition, the cloning and sequencing of the region immediately upstream of the gene encoding the kinase revealed a novel open reading frame of 426 nucleotides encoding a phosphotyrosine protein phosphatase of 16,217 Da, which indicates that autophosphorylation on tyrosine is a physiologically reversible reaction.

Eur J Biochem, 1997 Dec 1, 250(2), 617 - 23
Structural studies of the putative O-specific polysaccharide of Acinetobacter baumannii O24 containing 5,7-diamino-3,5,7,9-tetradeoxy-L-glycero-D-galacto-nonulosonic acid; Haseley SR et al.; A polysaccharide containing D-GlcN, 2-amino-2,6-dideoxy-L-galactose (L-FucN), and 7-acetamido-5-acylamino-3,5,7,9-tetradeoxy-L-glycero-D-galacto-nonulo sonic acid (LegAX), in which the acyl group (X) is either S-3-hydroxybutyryl (50%) or acetyl (50%), was isolated by mild acid hydrolysis treatment, followed by gel-permeation chromatography, of the water-soluble lipopolysaccharide from Acinetobacter baumannii serogroup O24 . The polysaccharide, characterised by means of monosaccharide analyses, partial acid hydrolysis, methylation analysis and NMR studies, was shown to have a linear tetrasaccharide repeating unit, as depicted below . Serological tests indicated that the polymer corresponded to the O24 antigen . -->6)-alpha-D-GlcpNAc-(1-->3)-alpha-L-FucpNAc-(1-->3)-alpha-D-Glcp NAc-(1-->4)-beta-LegpAX-(1-->.

Antimicrob Agents Chemother, 1997 Dec, 41(12), 2757 - 9
Cloning and nucleotide sequence analysis of a gene encoding an OXA-derived beta-lactamase in Acinetobacter baumannii; Vila J et al.; A clinical strain of Acinetobacter baumannii (strain Ab41) that was resistant to all beta-lactam antibiotics tested except ceftazidime, ceftriaxone, ceftizoxime, and imipenem produced three beta-lactamases: a presumptive chromosomal cephalosporinase, a TEM-1-like beta-lactamase (pI 5.4), and a novel OXA-derived beta-lactamase named OXA-21 (pI 7.0) . The gene encoding OXA-21 was located in an integron . The nucleotide sequence showed three mutations compared with the sequence of OXA-3, with two being silent; the nonsilent mutation generated a substitution of Ile-217 to Met.

Antimicrob Agents Chemother, 1997 Dec, 41(12), 2646 - 51
Loss of intrinsic aminoglycoside resistance in Acinetobacter haemolyticus as a result of three distinct types of alterations in the aac(6')-Ig gene, including insertion of IS17; Rudant E et al.; The distribution of the aac(6')-Ig gene, encoding aminoglycoside 6'-N-acetyltransferase-Ig {AAC(6')-Ig}, was studied in 96 Acinetobacter haemolyticus strains and 12 proteolytic Acinetobacter strains, including Acinetobacter genomospecies 6, 13, and 14 and 3 unnamed species assigned to this genomic group by DNA-DNA hybridization . This gene was detected by DNA-DNA hybridization in all 96 A . haemolyticus strains and by PCR in 95 strains but was not detected in strains of other species, indicating that it may be used to identify A . haemolyticus . Three A . haemolyticus strains were susceptible to tobramycin and did not produce an aminoglycoside 6'-N-acetylating activity, although they contained aac(6')-Ig-related sequences . An analysis of three susceptible A . haemolyticus strains indicated that aminoglycoside resistance was abolished by the following three distinct mechanisms: (i) a point mutation in aac(6')-Ig that led to a Met56-->Arg substitution, which was shown by analysis of a revertant to be responsible for the loss of resistance; (ii) a polythymine insertion that altered the reading frame; and (iii) insertion of IS17, a new member of the IS903 family . These observations indicated that AAC(6')-Ig is not essential for the viability of A . haemolyticus, although the aac(6')-Ig gene was detected in all members of this species.

Dermatology, 1997, 195(3), 274 - 5
Severe self-healing nail dystrophy in a patient on peritoneal dialysis; Caputo R et al.; The unusual case of a patient on peritoneal dialysis who progressively developed onychodystrophy of the hands 2 months after Acinetobacter peritonitis had been reported . The nail disease consisted of acute pseudoclubbing, elkonyxis, severe Beau's lines and onychomadesis and showed spontaneous recovery within 4 months . Although reminiscent of severe Beau's lines and reflex sympathetic dystrophy, this observation shows a peculiar nail disorder of unknown cause.

Enferm Infecc Microbiol Clin, 1997 Sep, 15 Suppl 1, 78 - 85
{The role of carbapenems in the treatment of nosocomial infection}; Martinez Lacasa J et al.; Carbapenems are active beta-lactam antibiotics versus most of the gram positive and gram negative microorganisms and anaerobes although their activity is lacking in the case of Staphylococcus sp . resistant to methicillin, Enterococcus faecium and Streptococcus pneumoniae with high resistance to penicillin and some gram negative bacilli which naturally produce an methaloenzyme able to hydrolyze them such as Stenotrophomonas maltophilia . Imipenem, the first synthetized carbapenem requires administration with cilastatin to avoid inactivation by renal dehydropeptidase 1 . Meropenem does not require being taken with the renal enzyme inhibitor, with its activity being similar to that of imipenem . In abdominal infection the carbapenems have shown to be the authentic monotherapy in this type of infections being as effective as the different schedules of antibiotic associations normally used . Treatment with carbapenems in bacterial meningitis should be currently limited to the cases produced by gram negative bacilli producers of wide spectrum beta-lactamases (WSBL), cases of meningitis by Pseudomonas aeruginosa or gram negative bacilli producers of inducible cephalosporinase . Meropenem is the carbapenem of choice probably in these cases because the carbapenems are often the only active antibiotics and meropenem, specifically, does not have the risk of convulsions observed with imipenem-cilastatin . The carbapenems have shown to be useful in skin and soft tissue infections as well as in obstetric and gynecologic infections as monotherapy similar to the schedules of the currently used antibiotic associations . In the case of nosocomial pneumonias, all the studies have evaluated the carbapenems in monotherapy as useful and effective, specially in the case of pneumonia by gram negative bacilli . Finally, in non filiated nosocomial sepsis and specially in the case of neutropenic patients, the use of carbapenems is particularly attractive in gram negative sepsis in intensive care units . The appearance in the last few years of strains of gram negative bacilli, producers of wide spectrum beta-lactamase or stable repressed hyperproducers of class I chromosomic cephalosporinase, as well as other multiresistant gram negative bacilli, such as Acinetobacter baumanii make the carbapenems, in many cases, the only effective antibiotic in this type of infections.

Enferm Infecc Microbiol Clin, 1997 Sep, 15 Suppl 1, 62 - 8
{The role of meropenem in the treatment of pneumonia in the critical patient}; Leon Gil C et al.; Pneumonia in critical ill patients, most of them associated with insaturation of an artificial a way and the use of mechanical ventilation, involves important morbi/mortality in the Intensive Care Units . Knowledge of pathogenesis, risk factors, and implicated microorganisms in developing of this major infectious complication, in the context of infections which rise in the critically ill patients, allow us to apply prophylaxis measures which could decrease its incidence, and establish antimicrobial therapy, which permit us to cover all the etiologic possibilities . Availability in the arsenal of the powerful antimicrobial, of a new carbapenemic, meropenem, and based on the different studies and clinic assays, allow to recommend its use with warranties and efficacy, in the empirical or's in concretely those due to Pseudomonas aeruginosa, enterobacteriaceae, (in general or producers of ample spectrum beta-lactamases), and Acinetobacter spp., in monotherapy or combined therapy, with aminoglycosides.

Enferm Infecc Microbiol Clin, 1997 Sep, 15 Suppl 1, 57 - 61
{The role of meropenem in bacterial meningitis}; Fernandez Viladrich P; Meropenem is a new carbapenem antibiotic of with an antibacterian spectrum similar to that of imipenem, but from which it may mainly be differentiated by the possibility of its administration at high doses and it has no demonstrated proconvulsive effect, properties which make it applicable in the treatment of bacterial meningitis . The clinical and experimental experience in the treatment of bacterial meningitis with this antibiotic is herein reviewed . It has been observed that the efficacy and safety of meropenem in meningitis caused by N . meningitidis, H . influenzae and pneumococci sensitive to penicillin may be similar to that of cefotaxime or ceftriaxone in both the pediatric and adult population . There are very few reports on the treatment of meningitis caused by pneumococci resistant to penicillin . However, given that the activity of meropenem on these pneumococci is similar to that of cefotaxime and that the doses administered are much lower, it does not appear to be recommendable in the treatment of this indication, although it should be tested in all meningeal strain to these characteristics isolated . It may currently be considered that the main indication of meropenem in the infections of the central nervous system is in nosocomial meningitis by multiresistant gram negative bacilli such as those of the Klebsiella-Serratia-Enterobacter and Acinetobacter sp . group . Therefore a limited, albeit favorable, report on the clinical experience with meropenem is herein presented . Meropenem may also be useful in the treatment of meningitis by Pseudomonas aeruginosa in which other treatments have failed.

Biochim Biophys Acta, 1997 Oct 9, 1354(1), 49 - 54
Cloning and sequencing of genes encoding malonate decarboxylase in Acinetobacter calcoaceticus; Koo JH et al.; Malonate decarboxylase from Acinetobacter calcoaceticus was isolated and characterized (Kim, Y.S., Byun, H.S., J . Biol . Chem . 269 (1994) 29636-29641), and its subunits were reanalyzed recently to be alpha, beta, gamma, and delta . The genes for the subunits, MdcA (548 a.a.), B (295 a.a.), C (238 a.a.), and D (102 a.a.), of the enzyme have been cloned by using oligonucleotide primers deduced from amino acid sequences of peptides isolated from the purified enzyme, and sequenced to be clustered in an operon in the order of A-D-B-C . The operon was found to encode more genes than mdcABCD . The Escherichia coli, transformed with the vector containing the insert mdcADBC and about 1.7 kb of an upstream region, expressed the four subunits of the enzyme but the proteins did not show enzyme activity . It indicates that, like the enzymes from Malonomonas rubra and Klebsiella pneumoniae, more genes are needed for the formation of the functional malonate decarboxylase.

Am J Respir Crit Care Med, 1997 Nov, 156(5), 1647 - 55
Oropharyngeal or gastric colonization and nosocomial pneumonia in adult intensive care unit patients . A prospective study based on genomic DNA analysis; Garrouste-Orgeas M et al.; Colonization of the digestive tract has been supposed to be the source of many hospital-acquired infections, especially nosocomial pneumonia . To assess the relationship between oropharyngeal and gastric colonization and subsequent occurrence of nosocomial pneumonia, we prospectively studied 86 ventilated, intensive care unit (ICU) patients . Oropharyngeal or gastric colonizations were detected and quantified on admission and twice weekly during ICU stay . When nosocomial pneumonia was suspected on clinical grounds (new chest X-ray infiltrate and purulent tracheal secretions), diagnosis was assessed on fiberoptic bronchoscopy with quantitative cultures of a protected specimen brush sampling and/or a plugged telescoping catheter sampling yielding > or = 10(3) cfu/ml of at least one microorganism . Bacterial strains responsible for colonization and infection (Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacteriaceae, and Staphylococcus aureus) were compared using pulsed-field electrophoresis . A total of 31 cases (36%) of pneumonia were diagnosed . Oropharyngeal colonization, detected either on admission or from subsequent samples, was a predominant factor of nosocomial pneumonia as compared with gastric colonization . For instance, oropharyngeal colonization with A . baumannii yielded a 7.45-fold estimated increased risk of pneumonia as compared with patients not yet or not identically colonized (p = 0.0004) . DNA genomic analysis demonstrated that an identical strain was isolated from oropharyngeal or gastric samples and bronchial samples in all but three cases of pneumonia, due to S . aureus . These findings provide better knowledge of the pathophysiology of nosocomial pneumonia in mechanically ventilated patients.

Eur J Clin Microbiol Infect Dis, 1997 Oct, 16(10), 740 - 3
Molecular typing of Acinetobacter baumannii from ten different intensive care units of a university hospital; Presterl E et al.; Thirty-one isolates of Acinetobacter baumannii were collected from ten intensive care units of an Austrian university hospital . All isolates were typed by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) . Two strains colonizing 13 infants in the neonatal intensive care unit were identified by ERIC-PCR . All other Acinetobacter baumannii isolates had highly divergent ERIC-PCR patterns, despite having the same antibiogram . Thus, a hospital-wide clonal distribution, as suggested by identical antibiogram patterns, was excluded by ERIC-PCR.

Eur J Clin Microbiol Infect Dis, 1997 Oct, 16(10), 737 - 40
Risk factors, clinical features and outcome of Acinetobacter bacteremia in adults; Poutanen SM et al.; The medical records of 39 patients with Acinetobacter bacteremia identified in the period between 1985 and 1995 were reviewed . In 24 cases (62%) the bacteremia was considered to have been clinically significant . Most of the infections (79%) were nosocomial, and the majority of these were acquired in an intensive care unit . Ten (42%) patients developed septic shock complicating the bacteremia and 13 (54%) died . In most of these cases (85%), Acinetobacter bacteremia was thought to have caused or contributed to death . The following variables were associated with a greater risk of mortality: age > 65 years (OR = 16; p = 0.01); development of septic shock (OR = 22; p = 0.004); and the presence of coagulopathy (OR = 20; p = 0.03).

Diagn Microbiol Infect Dis, 1997 Nov, 29(3), 187 - 92
Antimicrobial activity of 12 broad-spectrum agents tested against 270 nosocomial blood stream infection isolates caused by non-enteric gram-negative bacilli: occurrence of resistance, molecular epidemiology, and screening for metallo-enzymes; Jones RN et al.; A total of 270 recent nosocomial blood stream isolates of non-Enterobacteriaceae Gram-negative bacilli representing nearly 50 U.S . medical centers were characterized . The numbers of isolates of individual organisms were: Pseudomonas aeruginosa (n = 204), Acinetobacter spp . (n = 48), and Stenotrophomonas maltophilia (n = 18) . MICs were determined using the broth microdilution susceptibility method with 12 antimicrobial agents: piperacillin, piperacillin/tazobactam, ceftriaxone, ceftazidime, cefepime, imipenem, ciprofloxacin, ofloxacin, amikacin, gentamicin, tobramycin, and trimethoprim/sulfamethoxazole . Based on current National Committee for Clinical Laboratory Standards breakpoints, rates of resistance to cefepime, ceftazidime, and imipenem were as follows: P . aeruginosa, 3, 9, and 5%; Acinetobacter spp., 2, 37, and 0%; and S . maltophilia, 88.7, 35.3, and 100%, respectively . Trimethoprim/sulfamethoxazole was the most active agent against S . maltophilia (100% susceptible) . Twenty-eight isolates of P . aeruginosa that expressed high levels of resistance to ceftazidime (MIC, > 256 micrograms/mL) and imipenem (MIC, > 32 micrograms/mL) were examined for potential metallo-beta-lactamase production by polymerase chain reaction and were found to be negative . Molecular typing of P . aeruginosa isolates revealed many patient-unique strains, but also noted clustering of infections due to isolates of the same DNA type, suggesting possible nosocomial transmission in 9 of 14 medical centers . Given the resistance profile and pathogenic potential of these non-enteric Gram-negative bacilli, considerable effort should be exerted to develop and enforce infection control and antimicrobial utilization practices that will limit the spread of these organisms in the hospital environment.

J Urol, 1998 Jan, 159(1), 280 - 3
Polymerase chain reaction amplification of bacterial 16S rRNA genes in interstitial cystitis and control patient bladder biopsies; Keay S et al.; PURPOSE: Several characteristics of the chronic bladder disease called interstitial cystitis (IC) suggest an infectious etiology . However, a single causative organism has not been convincingly cultured in vitro, and DNA for a variety of microorganisms has been found inconsistently in bladder biopsies from IC patients . We therefore looked for a possible bacterial cause for IC by using a sensitive nested PCR assay on cystoscopic bladder biopsy specimens obtained from IC patients and controls . MATERIALS AND METHODS: Bladder biopsies were obtained at cystoscopy from 6 IC patients and 6 controls . DNA was extracted from these specimens and PCR with 2-round amplification performed using nested primers from a highly conserved region of the bacterial 16s rRNA gene . Amplified DNA was purified and sequenced using the Sequenase PCR Product Sequencing Kit, and the sequences obtained were compared with bacterial rRNA gene sequences recorded in GenBank . RESULTS: Biopsy specimens from all 6 patients and 6 controls were positive by PCR for DNA encoding bacterial 16s rRNA . Sequence data indicated a predominant microorganism in 10 of the 12 specimens, with > 95% homology to DNA from several different genera of bacteria including Acinetobacter, Propionobacterium, Salmonella, and Escherichia . None of the organisms identified by PCR had been cultured from tissue or urine obtained simultaneously from these persons, using sensitive culture techniques . CONCLUSIONS: These data indicate no difference between IC patients and controls in the proportion of bladder biopsies with PCR positivity or the type(s) of organism present, providing additional evidence that IC is not associated with infection by a particular type of bacterium.

J Clin Microbiol, 1997 Dec, 35(12), 3269 - 73
Evaluation of Vitek GNI+ and Becton Dickinson Microbiology Systems Crystal E/NF identification systems for identification of members of the family Enterobacteriaceae and other gram-negative, glucose-fermenting and non-glucose-fermenting bacilli; O'Hara CM et al.; We evaluated the Vitek GNI+ and Becton Dickinson Crystal E/NF identification systems for their ability to accurately identify 619 and 626 strains, respectively, of members of the family Enterobacteriaceae and other glucose-fermenting and non-glucose-fermenting gram-negative rods . All strains tested were taken from a stock collection and passed three times on 5% sheep blood agar prior to testing . These strains represented a more rigorous challenge to both systems than one resulting from the testing of consecutive clinical isolates . Testing with both systems was done according to the manufacturers' instructions, and tests were repeated in duplicate when errors occurred . Vitek version 5.01 and Crystal version 3.0 softwares were used for identifications . The identification results from each system were compared with identifications previously determined with reference biochemicals . At the completion of the appropriate incubation period, the GNI+ and Crystal systems correctly identified 80.1 and 71.1% of the total isolates, respectively . After additional tests suggested by the software programs were completed, the GNI+ had an accuracy of 87.6% and the Crystal system's accuracy had improved to 87.9% . The error rates for the GNI+ and Crystal systems were 6.5 and 5.3%, respectively . A report of "no identification" was given for 6.0 and 6.9% of the isolates, respectively, and was associated with no particular organism group . One isolate each of Acinetobacter lwoffii and Vibrio alginolyticus would not grow in the Vitek card . The average times to detection for correct enteric identifications in the GNI+ system were 4.1 and 6.8 h for nonenteric identifications, while the Crystal results were routinely read at 18 h . We conclude that there was no significant difference (P > 0.05) between the results of the GNI+ card and those of the Crystal E/NF system after additional testing was performed with the group of organisms tested, but the overall accuracy for both systems in this study was below 90%.

J Clin Microbiol, 1997 Dec, 35(12), 3071 - 7
Multicenter study using standardized protocols and reagents for evaluation of reproducibility of PCR-based fingerprinting of Acinetobacter spp; Grundmann HJ et al.; Seven laboratories in six European countries examined 40 isolates belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex to investigate whether standardized protocols and quality-controlled reagents could produce reliable, discriminatory, and reproducible PCR-based fingerprinting results . Four PCR protocols with different primers (primers DAF4, ERIC-2, M13, and REP1 + REP2) were used . The epidemiological conclusions reached by the participating laboratories were substantially correct, with 96.4% of the total isolate grouping allocations agreeing with the consensus view . All laboratories identified the main epidemiological clusters, and each laboratory also identified two non-outbreak-related isolates . There were no significant differences between the isolate grouping results obtained by the different protocols and with the different primers . Visual comparison indicated that the standardized protocols and reagents yielded reproducible fingerprint patterns, but with some variations in particular band intensities . Minor variations in fingerprint profiles were detected, but computer-assisted analysis of PCR fingerprints obtained on agarose gels demonstrated that 88.3 to 91.6% (depending on the source of DNA) of the patterns clustered correctly, while 96.4 to 98.9% of the patterns clustered correctly following automated high-resolution laser fluorescence analysis . Correlation of the patterns for isogenic isolates ranged from 83.3 to 86.6% but was slightly better (mean correlation, 87.1%) for centrally prepared DNA extracts than for DNA extracts prepared by individual laboratories (mean correlation, 84.7%) . It was concluded that independently produced PCR fingerprint patterns can be obtained reproducibly for Acinetobacter spp . at the practical level if (i) quality-controlled reagents, (ii) standardized extraction of DNA, and (iii) standardized amplification conditions are used.

Mol Cells, 1997 Oct 31, 7(5), 635 - 40
Peptide mapping and amino acid sequencing of two catechol 1,2-dioxygenases (CD I1 and CD I2) from Acinetobacter lwoffii K24; Kim SI et al.; The partial amino acid sequences of two catechol 1,2-dioxygenases (CD I1 and CD I2) from Acinetobacter lwoffii K24 have been determined by analysis of peptides after cleavages with endopeptidase Lys-C, endopeptidase Glu-C, trypsin, and chemicals (cyanogen bromide and BNPS-skatole) . They include 248 amino acid sequences (4 fragments) of CD I1 and 211 amino acid sequences (5 fragments) of CD I2 . Two enzymes have more than 50% sequence homology with type I catechol 1,2-dioxygenases and less than 30% sequence homology with type II catechol 1,2-dioxygenases . Two enzymes have similar hydropathy profiles in the N-terminal region, suggesting that they have similar secondary structures.

J Chemother, 1997 Oct, 9(5), 341 - 6
Comparative in vitro activity of cefepime against nosocomial isolates; Sofianou D et al.; Cefepime, a new parenteral cephalosporin, was evaluated for its in vitro antibacterial activity in comparison with other broad-spectrum antibiotics against a total of 445 recently isolated microorganisms of nosocomial origin . Cefepime was highly active against all species of Enterobacteriaceae with minimum inhibitory concentrations (MIC90S) ranging from 0.25-8 micrograms/ml . Cefepime showed moderate activity against Acinetobacter spp (MIC50 and MIC90, 16 micrograms/ml) but its activity was superior to that of any drug tested, except imipenem . Against Pseudomonas aeruginosa its activity was comparable to that of ceftazidime and was greater than that of cefotaxime, aztreonam, ciprofloxacin and aminoglycosides . Of all the agents tested, imipenem was the most active compound . Cefepime was active against Staphylococcus aureus and coagulase-negative methicillin-susceptible staphylococci but it had no activity against methicillin-resistant staphylococci and enterococci.

J Chemother, 1997 Oct, 9(5), 336 - 40
Comparative in vitro evaluation of piperacillin/tazobactam in a tertiary care hospital; Platsouka E et al.; Bacterial resistance is usually a serious problem in tertiary care hospitals . The aim of this in vitro study was to evaluate the beta-lactamase inhibitor combination piperacillin/tazobactam in a hospital environment with high bacterial resistance rates and compare it with other beta-lactam agents . Three hundred and sixty-two isolates from various clinical materials were studied during the period March-August 1996 . Material for culture was collected from patients of all the wards of our hospital, with the majority being from the Intensive Care Unit (45%) . Pathogenic Gram-positive and Gram-negative bacteria with high resistance rates and beta-lactamase production were studied (staphylococci, enterococci, Enterobacteriaceae, Pseudomonas) . Significant bacterial resistance rates were identified for ceftazidime (50% for Klebsiellae, 60% for Enterobacter spp, 60% for Proteus spp, 33% for Pseudomonas spp, 75% for Acinetobacter spp) and ciprofloxacin (33% for both Klebsiellae and Enterobacter spp, 67% for Pseudomonas spp, 50% Acinetobacter spp) . Fifty percent of Enterococcus isolates were resistance to ciprofloxacin but all of them were susceptible to piperacillin/tazobactam, amoxicillin/clavulanate and imipenem . The antibacterial activity of piperacillin/tazobactam (susceptibility rates 83 to 100% for Enterobacteriaceae, 83% for Pseudomonas spp and 75% for Acinetobacter spp) was higher than that of ceftazidime, piperacillin and ciprofloxacin . Imipenem, being mostly a reserve product, showed higher activity against Acinetobacter, Klebsiella and Enterobacter species.

Antimicrob Agents Chemother, 1997 Nov, 41(11), 2586 - 8
In vitro synergistic activities of tobramycin and selected beta-lactams against 75 gram-negative clinical isolates; Owens RC Jr et al.; The microdilution checkerboard technique was utilized to distinguish synergistic activity between tobramycin and four beta-lactams: piperacillin-tazobactam, ticarcillin-clavulanate, ceftazidime, and ceftriaxone . Beta-lactam-aminoglycoside combinations were tested against 75 clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumanii, Citrobacterfreundii, Serratia marcescens, and Enterobacter cloacae . Despite in vitro susceptibilities, all isolates demonstrated either synergism or indifference; no antagonism was observed . Against pathogenic gram-negative nosocomial isolates, a greater percentage of synergy was consistently observed with combination regimens containing tobramycin and piperacillin-tazobactam or ticarcillin-clavulanate than with the cephalosporin-containing regimens.

FEBS Lett, 1997 Oct 13, 416(1), 61 - 4
Purification, biochemical properties and substrate specificity of a catechol 1,2-dioxygenase from a phenol degrading Acinetobacter radioresistens; Briganti F et al.; A catechol 1,2-dioxygenase (C1,2O) has been purified to homogeneity from Acinetobacter radioresistens grown on phenol as the sole carbon and energy source . The C1,2O appears to be a homodimer, with a molecular mass of 78,000 Da . At relatively high ionic strengths (0.5 M Na2SO4) subunit dissociation occurs and the monomeric unit (38,700 Da) is shown to be active . This phenomenon has never been observed before in dioxygenases . The purified C1,2O contains 0.96 iron(III) ions per unit and spectroscopic measurements suggest the presence of one high-spin iron(III) ion in an environment characteristic of intradiol cleaving enzymes . The NH2-terminal amino acid sequence has been determined and compared to the primary structures of intradiol rings cleaving dioxygenases from other Acinetobacter strains revealing 45% homology with the benzoate-grown A . calcoaceticus ADP-1 and an identity of only one of the 20 amino acids sequenced for the phenol-grown A . calcoaceticus NCIB 8250.

J Hosp Infect, 1997 Oct, 37(2), 125 - 35
Genotypic investigation of multidrug-resistant Acinetobacter baumannii infections in a medical intensive care unit; Marques MB et al.; Multi-resistant Acinetobacter baumannii isolates obtained from 13 hospitalized patients over a six-month period were evaluated . One patient had an isolate susceptible only to imipenem; the next three had isolates susceptible to imipenem and ampicillin/sulbactam; the next six patients had isolates which were susceptible to imipenem, amikacin, and ampicillin/sulbactam; while the final three patients had isolates which were susceptible to imipenem and ampicillin/sulbactam . Ten patients died, five within 10 days of a positive culture . Five of six patients with bacteraemia succumbed to the infection . DNA extracted from all isolates was amplified by polymerase chain reaction using four random primers (RAPD) . The resulting band patterns were compared and strains identified . In addition, all isolates were biotyped . RAPD analysis and biotyping showed that there were two distinct strains involved . The first four patients were infected with one strain (genotype inverted question markA', biotype 9), the subsequent nine patients were infected with a second strain (genotype inverted question markB', biotype 1) . These results suggested that there was patient-to-patient spread of strains . Institution of, and strict adherence to, isolation procedure and other infection control practices controlled the spread of infection . These data emphasize the need for active surveillance for multidrug-resistant organisms in critically ill patients, and the value of molecular typing of strains in a hospital setting to investigate spread of infection.

J Hosp Infect, 1997 Oct, 37(2), 113 - 23
Nosocomial outbreak of multi-resistant Acinetobacter baumannii on a surgical ward: epidemiology and risk factors for acquisition; Koeleman JG et al.; Between December 1994 and April 1995, a nosocomial outbreak caused by a multi-resistant Acinetobacter baumannii, occurred on a surgical ward in our hospital . The organism was isolated from 13 patients, eight of whom were infected whereas the others were colonized . Twelve isolates were compared by cell envelope protein electrophoretic profiles and AFLP, a recently described DNA fingerprinting method . Both methods indicated that this outbreak was caused by spread of a single strain, which was identified as A . baumannii by amplified ribosomal DNA fingerprinting (ARDRA) . A case-control comparison was performed to identify risk factors associated with nosocomial acquisition of A . baumannii . Risk factors for cross-colonization were length of stay, surgery, wounds and treatment with broad-spectrum antibiotics . Cross-infection with A . baumannii among patients occurred despite implementation of stringent infection control measures . The outbreak was controlled after temporary closure of the surgical ward for disinfection purposes . Patients admitted on a general surgical ward colonized or infected with multi-resistant A . baumannii strains should alert the hospital infection control team, and prompt implementation of strict infection prevention measures to prevent further spread is advised.

Appl Environ Microbiol, 1997 Nov, 63(11), 4150 - 7
A novel competence gene, comP, is essential for natural transformation of Acinetobacter sp . strain BD413; Porstendorfer D et al.; Acinetobacter sp . strain BD413 (= ATCC 33305), a nutritionally versatile bacterium, has an extremely efficient natural transformation system . Here we describe the generation of eight transformation-affected mutants of Acinetobacter sp . strain BD413 by insertional mutagenesis . These mutants were found by Southern blot analysis and complementation studies to result from single nptII marker insertions at different chromosomal loci . DNA binding and uptake studies with one mutant, T205, revealed that the transformation deficiency of this mutant results from a complete lack of DNA binding and, therefore, uptake activity . A novel competence gene essential for natural transformation, named comP, was cloned by complementation of mutant T205 . The nucleotide sequence of comP was determined, and its deduced 15-kDa polypeptide displays significant similarities to type IV pilins . Analysis of the ultrastructure of a transformation-deficient comP mutant and the transformation-competent wild-type strain revealed that both are covered with bundle-forming thin fimbriae (3 to 4 nm in diameter) and individual thick fimbriae (6 nm in diameter) . These results provide evidence that the pilinlike ComP is unrelated to the piluslike structures of strain BD413 . Taking all data into account, we propose that ComP functions as a major subunit of an organelle acting as a channel or pore mediating DNA binding and/or uptake in Acinetobacter sp . strain BD413.

Chemosphere, 1997 Oct, 35(8), 1637 - 50
Microbial response to repeated applications of low concentrations of pentachlorophenol in an alfisol under pasture; Martins JM et al.; Columns of an Alfisol under permanent pasture were polluted by repeated additions of pentachlorophenol (PCP) (7 mg l-1) to levels of 102 and 510 mg Kg-1, to simulate a dynamic diffuse pollution . PCP was rapidly sorbed to the soil organic matter, and was only slightly degraded . Measurements of soil microbial biomass-C revealed a 25% decrease in total biomass-C caused by both leaching and PCP toxicity . Microbial biomass-C measurements performed on soil fractions showed that only microorganisms located in the outer compartment of the aggregates were affected . Microorganisms protected by soil micro-aggregates were not affected, suggesting that they were not in contact with PCP, which was thus unavailable for biodegradation . Three gram negative bacterial strains (Si, C3 and C2), able to use PCP as a sole carbon and energy source, were isolated after 0, 1 and 3 months of PCP enrichment respectively, and were identified as Pseudomonas (Si) and Acinetobacter (C3 and C2) . In liquid degradation tests, the strains C2 and C3 degraded 60% of PCP within 26 days whereas the Pseudomonas degraded only 25% . A specific immuno-labeling of the three strains permitted to show that repeated PCP additions to soil had a positive, negative or absence of effect on the populations C2, C3 and Si respectively.

J Clin Microbiol, 1997 Nov, 35(11), 2819 - 25
Distribution of Acinetobacter species on human skin: comparison of phenotypic and genotypic identification methods; Seifert H et al.; At least 19 genomic species are recognized as constituting the genus Acinetobacter . However, little is known about the natural reservoirs of the various members of the genus . An epidemiological study was therefore performed to investigate the colonization with Acinetobacter spp . of the skin and mucous membranes of 40 patients hospitalized in a cardiology ward and 40 healthy controls . Single samples were obtained once from each of nine different body sites, i.e., forehead, ear, nose, throat, axilla, hand, groin, perineum, and toe web . Identification of Acinetobacter isolates was achieved by using phenotypic properties and was compared to identification by amplified ribosomal DNA restriction analysis . Selected isolates were further investigated with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, ribotyping, and DNA-DNA hybridization . Plasmid profile analysis was used for epidemiological typing . Thirty patients (75%) and 17 controls (42.5%) were found to be colonized with Acinetobacter spp., and the colonization rates of patients increased during their hospital stay . The most frequently isolated species were Acinetobacter lwoffii (47%), A . johnsonii (21%), A . radioresistens (12%), and DNA group 3 (11%) . In contrast, A . baumannii and DNA group 13TU, the most important nosocomial Acinetobacter spp., were found only rarely on human skin (0.5 and 1%, respectively) and their natural habitat remains to be defined . A good correlation between phenotypic and genotypic methods for identification of Acinetobacter spp . was observed, and only two isolates could not be assigned to any of the known DNA groups.

Diagn Microbiol Infect Dis, 1997 Sep, 29(1), 19 - 28
Use of different PCR-based DNA fingerprinting techniques and pulsed-field gel electrophoresis to investigate the epidemiology of Acinetobacter calcoaceticus-Acinetobacter baumannii complex; Liu PY et al.; Acinetobacter calcoaceticus-Acinetobacter baumannii complex is an important nosocomial pathogen for which optimal typing methods in epidemiologic investigations have not been defined . We compared DNA macrorestriction analysis by pulsed-field gel electrophoresis (PFGE) with different PCR-based DNA fingerprinting techniques, including enterobacterial repetitive intergenic consensus (ERIC) polymerase chain reaction (PCR), repetitive extragenic palindromic (REP) PCR, arbitrary-primed PCR with primer M13, and multiplex PCR with primers REP-1, REP-2 and M13, for characterization of 98 clinical isolates (including 10 apparent outbreak-related isolates and 68 presumed epidemiologically unrelated isolates) in a tertiary-care hospital over a 4-year period . The PFGE patterns after Smal restriction of the bacterial DNA were analyzed by computer software (Gelcompar) using the unweighted pair group method with arithmetic averages clustering and the Dice coefficient . A cluster of 48 isolates (cluster A), including 9 outbreak isolates, linked at a level of 83.4% similarity was observed . This epidemic strain and its variants were also found among the 68 presumed epidemiologically unrelated isolates, and this may represent ongoing endemic infection in this institution . The discrimination index for the PCR-based DNA fingerprinting techniques was 0.75 for enterobacterial repetitive intergenic consensus 1, 0.71 for M13, 0.77 for REP-1, 0.77 for REP-2, and 0.87 for multiplex PCR . The discriminatory power of PFGE was found to be higher than those of PCR-based techniques . It was concluded that both PFGE and PCR-based fingerprinting are useful for typing of A . calcoaceticus-A . baumannii complex . However, PFGE can detect minor mutations among outbreak strains, and this is important for epidemiological study of this species in a complex endemic setting.

Clin Ther, 1997 Jul-Aug, 19(4), 691 - 700
Antibiotic resistance among gram-negative nosocomial pathogens in the intensive care unit: results of 6-year body-site monitoring; Barsic B et al.; Results of 6-year body-site monitoring in an intensive care unit (ICU) are presented and antimicrobial resistance of gram-negative isolates analyzed . The study included 622 patients . Six hundred thirty-five bacterial isolates-causes of nosocomial sepsis, pneumonia, and urinary tract infections (UTIs)-were tested during the study . Gram-negative bacteria were the predominant isolates, causing 65% of cases of sepsis, 78.7% of pneumonias, and 70.2% of UTIs . Gram-negative isolates (454) were highly resistant to antimicrobials commonly used in the ICU, with the exception of imipenem . Resistance was 1.1% among pathogens responsible for UTIs, 6.7% among those causing sepsis, and 13.6% among those responsible for pneumonia . Klebsiella pneumoniae associated with pneumonia and sepsis was significantly less resistant to ciprofloxacin than were isolates from urine (22.8% and 13.9%, respectively, vs 44.4%) . Pseudomonas aeruginosa strains responsible for pneumonia were less resistant to ceftazidime than were isolates causing sepsis and UTI (35.7% vs 51.3% and 51.5%, respectively) . Acinetobacter calcoaceticus strains associated with UTI were significantly more resistant to netilmicin than were strains responsible for sepsis and pneumonia (83.3% vs 40.3% and 42.6%, respectively) . The study confirmed that in addition to focused microbiologic surveillance, multiple-body-site monitoring can provide unique information about the sensitivity of the pathogens involved . The results suggest that antimicrobial resistance among nosocomial pathogens depends on the site of infection or the type of microbiologic specimen.

FEMS Microbiol Lett, 1997 Oct 1, 155(1), 99 - 105
Cloning and characterization of genes encoding an enzyme which oxidizes dimethyl sulfide in Acinetobacter sp . strain 20B; Horinouchi M et al.; Acinetobacter sp . strain 20B was isolated based on the ability to utilize dimethyl sulfide as the sole sulfur source . Since strain 20B oxidized indole as well as dimethyl sulfide, indigo production by recombinant Escherichia coli clones carrying Acinetobacter DNA was used as a selection for cloning genes encoding dimethyl sulfide oxidation genes . The gene encoding an indole-oxidizing enzyme was also found to oxidize dimethyl sulfide . The dimethyl sulfide-oxidizing enzyme genes consisted of six open reading flames designated dsoABCDEF . The deduced amino acid sequences of dsoABCDEF were homologous with those of the multicomponent phenol hydroxylases . DsoABCDEF oxidized dimethyl sulfide to dimethyl sulfoxide, and dimethyl sulfoxide to dimethyl sulfone.

Appl Environ Microbiol, 1997 Oct, 63(10), 3941 - 5
Effect of fluorochromes on bacterial surface properties and interaction with granular media; Chen J et al.; Simple, efficient, and safe tagging methods are desired in short-term microbial transport studies such as in the study of filtration systems for water and wastewater treatment . Suitability of selected fluorochromes as bacterial tagging agents in transport studies was evaluated on the basis of stability of stained cells and the effect of staining on bacterial surface characteristics and interaction with granular media . Surface properties were characterized by zeta potential and microbial adhesion to hydrocarbons . The effect of staining on interactions between bacteria and porous media was evaluated in terms of removal of bacteria in batch adsorption tests using sand coated with aluminum hydroxide to enhance adsorption . The DNA-specific fluorochrome 4',6-diamidino-2-phenylindole (DAPI) had generally negligible effects on bacterial surface properties and interaction with sand, as indicated in batch adsorption tests using pure cultures (Escherichia coli or Acinetobacter sp.) and wastewater bacteria . Cells stained with DAPI were stable for 48 h at 4 or 20 degrees C . Other nucleic acid fluorochromes tested had different but significant effects on bacterial cells and produced less stable fluorescence . Since transport through porous media is modulated by surface properties, it may be concluded based on these results that the choice of fluorochromes is critical in microbial transport studies . DAPI appeared to be a promising tagging agent . Time dependence of fluorescence of stained cells may limit the use of fluorochrome-tagged cells in long-term transport studies.

Diagn Microbiol Infect Dis, 1997 Aug, 28(4), 183 - 6
Activity of selected beta-lactams, ciprofloxacin, and amikacin against different Acinetobacter baumannii biotypes from Chilean hospitals; Bello H et al.; The activity of some third generation cephalosporins, aztreonam, imipenem, ciprofloxacin, and amikacin against isolates of Acinetobacter baumannii of various biotypes has been studied . The isolates, independently of the biotype, exhibited a broad multiresistance against cephalosporins . Ceftazidime was the most active and cefoperazone the least active compound . Aztreonam also showed low activity and no imipenem-resistant strains were found . Ciprofloxacin and amikacin were somewhat more active than cephalosporins, but resistant isolates were also frequent . Isolates of Biotypes 9 and 8 exhibited broader multiresistance than those of Biotype 6 and "other."

J Bacteriol, 1997 Oct, 179(19), 6041 - 7
Dihydroxyacetone synthase from a methanol-utilizing carboxydobacterium, Acinetobacter sp . strain JC1 DSM 3803; Ro YT et al.; Acinetobacter sp . strain JC1 DSM 3803, a carboxydobacterium, grown on methanol was found to show dihydroxyacetone synthase, dihydroxyacetone kinase, and ribulose 1,5-bisphosphate carboxylase, but no hydroxypyruvate reductase and very low hexulose 6-phosphate synthase, activities . The dihydroxyacetone synthase was found to be expressed earlier than the ribulose 1,5-bisphosphate carboxylase . The dihydroxyacetone synthase was purified 19-fold in eight steps to homogeneity, with a yield of 9% . The final specific activity of the purified enzyme was 1.12 micromol of NADH oxidized per min per mg of protein . The molecular weight of the native enzyme was determined to be 140,000 . Sodium dodecyl sulfate-gel electrophoresis revealed a subunit of molecular weight 73,000 . The optimum temperature and pH were 30 degrees C and 7.0, respectively . The enzyme was inactivated very rapidly at 70 degrees C . The enzyme required Mg2+ and thiamine pyrophosphate for maximal activity . Xylulose 5-phosphate was found to be the best substrate when formaldehyde was used as a glycoaldehyde acceptor . Erythrose 4-phosphate, glycolaldehyde, and formaldehyde were found to act as excellent substrates when xylulose 5-phosphate was used as a glycoaldehyde donor . The Kms for formaldehyde and xylulose 5-phosphate were 1.86 mM and 33.3 microM, respectively . The enzyme produced dihydroxyacetone from formaldehyde and xylulose 5-phosphate . The enzyme was found to be expressed only in cells grown on methanol and shared no immunological properties with the yeast dihydroxyacetone synthase.

Biochem J, 1997 Aug 15, 326 ( Pt 1), 47 - 51
Identification by site-directed mutagenesis of three essential histidine residues in membrane dipeptidase, a novel mammalian zinc peptidase; Keynan S et al.; Membrane dipeptidase (EC 3.4.13.19) is a plasma membrane zinc peptidase that is involved in the renal metabolism of glutathione and its conjugates, such as leukotriene D4 . The enzyme lacks the classical signatures of other zinc-dependent hydrolases and shows no homology with any other mammalian protein . We have used site-directed mutagenesis to explore the roles of five histidine residues in pig membrane dipeptidase that are conserved among mammalian species . When expressed in COS-1 cells, the mutants H49K and H128L exhibited a specific activity and Km for the substrate Gly-D-Phe comparable with those of the wild-type enzyme . However, the mutants H20L, H152L and H198K were inactive, but were expressed at the cell surface at equivalent levels to the wild-type, as assessed by immunoblotting and immunofluorescence . These three mutants were compared with regard to their ability to bind to the competitive inhibitor cilastatin, which binds with equal efficacy to native and EDTA-treated pig kidney membrane dipeptidase . Expressed wild-type enzyme and mutants H20L and H198K were efficiently bound by cilastatin-Sepharose, but H152L failed to bind . Thus His-152 appears to be involved in the binding of substrate or inhibitor, whereas His-20 and His-198 appear to be involved in catalysis . Membrane dipeptidase shares some similarity with a dipeptidase recently cloned from Acinetobacter calcoaceticus . In particular, His-20 and His-198 of membrane dipeptidase are conserved in the bacterial enzyme, as are Glu-125 and His-219, previously shown to be required for catalytic activity.

Chest, 1997 Oct, 112(4), 1050 - 4
Risk factors for infection by Acinetobacter baumannii in intubated patients with nosocomial pneumonia; Baraibar J et al.; STUDY OBJECTIVE: To investigate the epidemiology of infection by Acinetobacter baumannii in patients with ventilator-associated pneumonia (VAP) . DESIGN: Prospective clinical study . SETTING: Three medical-surgical ICUs in teaching hospitals . PATIENTS: We followed up 707 mechanically ventilated patients and 148 episodes of VAP with etiologic diagnosis . RESULTS: A baumannii was isolated in 12 (8.1%) episodes in 148 patients . Five of these episodes were directly responsible for death . Using logistic regression analysis, the risk of VAP due to A baumannii was found to be high in patients with neurosurgery (odds ratio {OR}=10.03; 95% confidence interval {CI}=1.55 to 64.90), ARDS (OR=9.73; 95% CI=1.60 to 59.24), head trauma (OR=5.17; 95% CI=0.88 to 30.34), and large-volume pulmonary aspiration (OR=2.90; 95% CI=0.80 to 10.53) . CONCLUSIONS: Intubated patients who develop pneumonia and have any of the above factors are at an increased risk of Acinetobacter infection.

Crit Care Med, 1997 Oct, 25(10), 1713 - 6
Tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 concentrations in cerebrospinal fluid predict ventriculoperitoneal shunt infection; Asi-Bautista MC et al.; OBJECTIVE: To determine the diagnostic value of cerebrospinal fluid tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta, and IL-6 released into the cerebrospinal fluid of patients with ventriculoperitoneal shunt infection . DESIGN: Prospective, observational study . SETTING: University teaching hospital . PATIENTS: Sixty-four patients requiring cerebrospinal fluid aspiration for suspected ventriculoperitoneal shunt malfunction . INTERVENTIONS: Cerebrospinal fluid samples were obtained by shunt aspiration at the time of patient presentation . MEASUREMENTS AND MAIN RESULTS: TNF-alpha and IL-1 beta concentrations were measured by enzyme-linked immunosorbent assay, and IL-6 activity by bioassay . The sensitivity, specificity, predictive values, and overall efficiency for each cytokine were determined based on the cerebrospinal fluid culture results . Ten patients had positive cerebrospinal fluid cultures, eight of which yielded Staphylococcus species, and one each Acinetobacter and Pseudomonas . Cerebrospinal fluid TNF-alpha, IL-1 beta, IL-6, protein, and leukocyte concentrations were significantly increased in patients with shunt infection . Cerebrospinal fluid IL-6 activity had the highest diagnostic accuracy of the cytokines evaluated, with sensitivity of 80% and specificity of 98% . CONCLUSIONS: The presence of cerebrospinal fluid inflammatory cytokines strongly suggests ventriculoperitoneal shunt infection . Detection of these cytokines in the cerebrospinal fluid could be used for earlier diagnosis of bacterial infection.

Int J Syst Bacteriol, 1997 Oct, 47(4), 1179 - 87
Discrimination of Acinetobacter genomic species by AFLP fingerprinting; Janssen P et al.; AFLP is a novel genomic fingerprinting method based on the selective PCR amplification of restriction fragments . The usability of this method for the differentiation of genomic species in the genus Acinetobacter was investigated . A total of 151 classified strains (representing 18 genomic species, including type, reference, and field strains) and 8 unclassified strains were analyzed . By using a single set of restriction enzymes (HindIII and TaqI) and one particular set of selective PCR primers, all strains could be allocated to the correct genomic species and all groups were properly separated, with minimal intraspecific similarity levels ranging from 29 to 74% . Strains belonging to genomic species 8 (Acinetobacter lwoffii sensu stricto) and 9 grouped together in one cluster . The closely related DNA groups 1 (Acinetobacter calcoaceticus), 2 (Acinetobacter baumannii), 3 and 13TU (sensu Tjernberg & Ursing 1989) were clearly distinguishable, with intraspecific linkage levels above 50% . Strains of the independently described genomic species 13BJ (sensu Bouvet & Jeanjean 1989) and 14TU linked together at a relatively low level (33%) . Although a previous DNA-DNA hybridization study seemed to justify the unification of these genomic species, AFLP analysis actually divides the 13BJ-14TU group into three well-separated subgroups . Finally, four unclassified strains obtained from diverse sources and origins grouped convincingly together, with a similarity linkage level of approximately 50% . These strains showed no similarities in their AFLP patterns with any of the other 155 strains studied and may represent a thus-far-undescribed Acinetobacter species . Based on these results, AFLP should be regarded as an important auxiliary method for the delineation of genomic species . Furthermore, because AFLP provides a detailed insight into the infraspecific structure of Acinetobacter taxa, the method also represents a highly effective means for the confirmation of strain identity in the epidemiology of acinetobacters.

Antimicrob Agents Chemother, 1997 Oct, 41(10), 2265 - 9
Widespread detection of PER-1-type extended-spectrum beta-lactamases among nosocomial Acinetobacter and Pseudomonas aeruginosa isolates in Turkey: a nationwide multicenter study; Vahaboglu H et al.; We studied the prevalence and molecular epidemiology of PER-1-type beta-lactamases among Acinetobacter, Klebsiella, and Pseudomonas aeruginosa strains isolated over a 3-month period in eight university hospitals from distinct regions of Turkey . A total of 72, 92, and 367 Acinetobacter, Klebsiella, and P . aeruginosa isolates were studied, respectively . The presence of blaPER was determined by the colony hybridization method and later confirmed by isoelectric focusing . We detected PER-1-type beta-lactamases in 46% (33/72) of Acinetobacter strains and in 11% (40/367) of P . aeruginosa strains but not in Klebsiella strains . PER-1-type enzyme producers were highly resistant to ceftazidime and gentamicin, intermediately resistant to amikacin, and susceptible or moderately susceptible to imipenem and meropenem . Among PER-1-type-beta-lactamase-positive isolates, five Acinetobacter isolates and six P . aeruginosa isolates from different hospitals were selected for ribosomal DNA fingerprinting with EcoRI and SalI . The EcoRI-digested DNAs were later hybridized with a digoxigenin-labelled PER-1 probe . The ribotypes and the lengths of blaPER-carrying fragments were identical in four Acinetobacter strains . A single isolate (Ac3) harbored a PER gene on a different fragment (approximately 4.2 kbp) than the others (approximately 3.4 kbp) and showed a clearly distinguishable ribotype . Ribotypes of P . aeruginosa strains obtained with EcoRI showed three patterns . Similarly, in Pseudomonas strains two different EcoRI fragments harbored blaPER (approximately 4.2 kbp in five isolates and 3.4 kbp in one isolate) . PER-1-type beta-lactamases appear to be restricted to Turkey . However, their clonal diversity and high prevalence indicate a high spreading potential.

J Clin Microbiol, 1997 Oct, 35(10), 2602 - 5
Molecular epidemiology of acquisition of ceftazidime-resistant gram-negative bacilli in a nonoutbreak setting; D'Agata E et al.; We prospectively studied the acquisition of ceftazidime-resistant gram-negative bacilli (CAZ-RGN) in two surgical intensive care units (SICU) during a nonoutbreak period . Surveillance cultures were obtained from patients at the time of admission and serially thereafter . CAZ-RGN isolates were typed by pulsed-field gel electrophoresis (PFGE) . Three hundred and forty-three patients were enrolled from whom 1,621 baseline and follow-up cultures were obtained . The most common species isolated from patients were Pseudomonas aeruginosa (22), Enterobacter cloacae (21), Acinetobacter spp . (13), Enterobacter aerogenes (11), Citrobacter spp . (10), Pseudomonas spp . (non P . aeruginosa) (9), and Stenotrophomonas spp . (7) . For each species, PFGE strain types were highly diverse; no single type was recovered from more than four patients . Twenty-eight patients acquired a CAZ-RGN during the SICU stay; in six (21%), emergence of resistance from a previously susceptible strain was documented on the basis of matching serial strain types . Transmission of CAZ-RGN between patients occurred but was infrequent, as judged by analyzing strain types of epidemiologically linked patients . In conclusion, colonization with CAZ-RGN in SICU was associated with diverse species and strains, as determined by molecular typing . Emergence of resistance from previously susceptible strains appeared to be more important than horizontal transmission in acquisition of CAZ-RGN in a nonoutbreak period.

J Med Microbiol, 1997 Sep, 46(9), 721 - 46
Clinical importance and antibiotic resistance of Acinetobacter spp . Proceedings of a symposium held on 4-5 November 1996 at Eilat, Israel; Towner KJ; Members of the genus Acinetobacter, particularly multiresistant strains of A . baumannii, are implicated in a wide spectrum of nosocomial infections, including bacteraemia, secondary meningitis and urinary tract infection, but have now assumed a particularly important role as agents of nosocomial pneumonia in intensive care units (ICUs) . Rapid genotyping methods for the identification and typing of these organisms have allowed a better appreciation of the epidemiology and survival of these organisms in the hospital environment . Their emergence as significant pathogens seems to be related partly to their survival ability and partly to their ability to develop resistance rapidly to the major groups of antibiotics, resulting in a considerable selective advantage in environments (such as ICUs) with widespread and heavy uses of antibiotics . Molecular and biochemical mechanisms of resistance to the major beta-lactam, aminoglycoside and quinolone groups of antibiotics have now been elucidated in some detail for these organisms, and experimental models, including a mouse model of A . baumannii pneumonia, have been developed to examine the efficacy of different therapeutic regimens for difficult-to-treat-infections caused by these bacteria . 'Non-classic' antibiotic combinations--such as ticarcillin with clavulanic acid and sulbactam--seem to show promise for treating systemic infections caused by otherwise multiresistant strains, but revised screening procedures in the pharmaceutical industry may be required in the near future to select novel compounds with activity against multiresistant Acinetobacter spp . and other emerging gram-negative, non-fermentative bacilli in general.

FEMS Microbiol Rev, 1997 Jul, 20(3-4), 201 - 16
Phylogenetic characterization of bacteria in the subsurface microbial culture collection; Balkwill DL et al.; The Subsurface Microbial Culture Collection (SMCC) was established by the U.S . Dept . of Energy (DOE) and contains nearly 10,000 strains of microorganisms (mostly bacteria) isolated from terrestrial subsurface environments . Selected groups of bacterial isolates from three sample sites situated above geochemically and hydrologically different subsurface environments have been characterized by phylogenetic analysis of 16S ribosomal RNA (rRNA) gene nucleotide sequences . Among these isolates were members of six major phylogenetic groups of bacteria: the high-G+C and low-G+C Gram-positive bacteria; the alpha-, beta-, and gamma-subdivisions of the Proteobacteria; and the Flexibacter/Cytophaga/Bacteroides group . A small number of the SMCC strains may be members of new bacterial genera, but most of them could be placed with reasonable confidence into more than 35 previously described genera . The majority of the Gram-positive isolates were species of Arthrobacter, Bacillus, or Streptococcus, whereas Acinetobacter, Comamonas, Pseudomonas, Sphingomonas, and Variovorax were among the most frequently encountered Gram-negative genera . A high proportion of the strains were placed in fewer than 10 genera, implying that there is substantial duplication within the SMCC at the genus level . When groups of isolates assigned to Acinetobacter, Arthrobacter, or Sphingomonas were analyzed in more detail, however, it was found that each group consisted of subgroups of strains that probably differed at the species level . Restriction endonuclease analysis (applied to the strains from one sample site) indicated that additional diversity was present at the strain level . Most of the SMCC isolates assigned to some genera (e.g., Acinetobacter) were very closely related to previously described species in those genera, but most of the isolates assigned to other genera (e.g., Arthrobacter and Sphingomonas) appeared (or were shown) to be new species, thereby indicating that a reasonable amount of novelty is present within the SMCC at the species level.

Rev Environ Contam Toxicol, 1997, 152, 57 - 83
Risk assessment of opportunistic bacterial pathogens in drinking water; Rusin PA et al.; This study was undertaken to examine quantitatively the risks to human health posed by heterotrophic plate count (HPC) bacteria found naturally in ambient and potable waters . There is no clear-cut evidence that the HPC bacteria as a whole pose a public health risk . Only certain members are opportunistic pathogens . Using the four-tiered approach for risk assessment from the National Academy of Sciences, hazard identification, dose-response modeling, and exposure through ingestion of drinking water were evaluated to develop a risk characterization, which estimates the probability of infection for individuals consuming various levels of specific HPC bacteria . HPC bacteria in drinking water often include isolates from the following genera: Pseudomonas, Acinetobacter, Moraxella, Aeromonas, and Xanthomonas . Other bacteria that are commonly found are Legionella and Mycobacterium . All these genera contain species that are opportunistic pathogens which may cause serious diseases . For example, the three nonfermentative gram-negative rods most frequently isolated in the clinical laboratory are (1) Pseudomonas aeruginosa, (2) Acinetobacter, and (3) Xanthomonas maltophilia . P . aeruginosa is a major cause of hospital-acquired infections with a high mortality rate . Aeromonas is sometimes associated with wound infections and suspected to be a causative agent of diarrhea . Legionella pneumophila causes 4%-20% of cases of community-acquired pneumonia and has been ranked as the second or third most frequent cause of pneumonia requiring hospitalization . The number of cases of pulmonary disease associated with Mycobacterium avian is rapidly increasing and is approaching the incidence of M . tuberculosis in some areas . Moraxella can cause infections of the eye and upper respiratory tract . The oral infectious doses are as follows in animal and human test subjects: P . aeruginosa, 10(8)-10(9); A, hydrophila, > 10(10); M . avium, 10(4)-10(7); and X . maltophilia, 10(6)-10(9) . The infectious dose for an opportunistic pathogen is lower for immunocompromised subjects or those on antibiotic treatment . These bacteria have been found in drinking water at the following frequencies: P . aeruginosa, < 1%-24%; Acinetobacter, 5%-38%; X . maltophilia, < 1%-2%; Aeromonas, 1%-27%; Moraxella, 10%-80%; M . avium, < 1%-50%; and L . pneumophila, 3%-33% . These data suggest that drinking water could be a source of infection for some of these bacteria . The risk characterization showed that risks of infection from oral ingestion ranged from a low of 7.3 x 10(-9) (7.3/billion) for low exposures to Aeromonas to higher risks predicted at high levels of exposure to Pseudomonas of 9 x 10(-2) (98/100) . This higher risk was only predicted for individuals on antibiotics . Overall, the evidence suggests that specific members of HPC bacteria found in drinking water may be causative agents of both hospital- and community-acquired infections . However, the case numbers may be very low and the risks represent levels generally less than 1/10,000 for a single exposure to the bacterial agent . Future research needs include (1) determining the seasonal concentrations of these bacteria in drinking water, (2) conducting adequate dose-response studies in animal subjects or human volunteers, (3) determining the health risks for an individual with multiple exposures to the opportunistic pathogens, and (4) evaluating the increase in host susceptibility conferred by antibiotic use or immunosuppression.

Pathol Biol (Paris), 1997 May, 45(5), 363 - 70
{Comparative in vitro activity of cefepime: multicenter study in Aquitaine}; Quentin C et al.; Over a 6 month-period (1st January to 30th June 1995), the results of antibiotic susceptibility testing routinely performed for beta-lactams against enterobacteria, Pseudomonas aeruginosa, and Acinetobacter in 7 laboratory hospitals of Aquitaine, have been collected and divided in susceptibility profiles . A total of 9269 strains (7323 enterobacteria, 1667 P . aeruginosa, 279 Acinetobacter) have been examined . On the whole, cefepime (91,5%) and ceftazidime (91,7%) were the most active cephalosporins, followed by cefpirome (87,9%) and cefotaxime (80,4%); imipenem was the most active beta-lactam agent (97,4%) . When the strains were divided according to their susceptibility profiles, the advantage of cefepime was shown to be related to its excellent activity against enterobacteria: all strains susceptible to cefotaxime and ceftazidime (CTX/CAZ-S) were susceptible to cefepime, as were most of the strains with an intermediate susceptibility or resistant to these drugs (CTX/CAZ-I/R, approximately 5% of the enterobacteria) . The latter strains exhibited a phenotype corresponding either to the overproduction of their chromosomal cephalosporinase (approximately 20% of the species belonging to group 3) or to the synthesis of an extended spectrum beta-lactamase (19% of the strains of Klebsiella pneumoniae) . Cefepime was active against 93% of the derepressed mutants of enterobacteria, including 3 imipenem resistant isolates of Enterobacter . CAZ-S strains of P . aeruginosa (84%) were usually susceptible to cefepime (80%), as were 6% of the CAZ-I/R strains . CAZ-S strains of A . baumannii (16.3%) were generally susceptible to cefepime (83%), as were 3.2% of the CAZ-I/R strains.

J Bacteriol, 1997 Sep, 179(18), 5943 - 6
benK encodes a hydrophobic permease-like protein involved in benzoate degradation by Acinetobacter sp . strain ADP1; Collier LS et al.; The chromosomal benK gene was identified within a supraoperonic gene cluster involved in benzoate degradation by Acinetobacter sp . strain ADP1, and benK was expressed in response to a benzoate metabolite, cis,cis-muconate . The disruption of benK reduced benzoate uptake and impaired the use of benzoate or benzaldehyde as the carbon source . BenK was homologous to several aromatic compound transporters.

J Bacteriol, 1997 Sep, 179(18), 5935 - 42
mucK, a gene in Acinetobacter calcoaceticus ADP1 (BD413), encodes the ability to grow on exogenous cis,cis-muconate as the sole carbon source; Williams PA et al.; Benzyl alcohol, benzaldehyde, benzoate, and anthranilate are metabolized via catechol, cis,cis-muconate, and the beta-ketoadipate pathway in Acinetobacter calcoaceticus ADP1 (BD413) . Mutant strain ISA25 with a deletion spanning catBCIJF and unable to metabolize muconate further will not grow in the presence of an aromatic precursor of muconate . Growth on fumarate as the sole carbon source with added benzyl alcohol or benzaldehyde selected spontaneous mutants of ISA25 . After repair of the cat deletion by natural transformation with linearized plasmid pPAN4 (catBCIJF) 10 mutants were unable to grow on benzoate of cis,cis-muconate but could still grow on anthranilate . Transformation with wild-type chromosomal DNA demonstrated the presence of two unlinked mutations in each strain, one in the benABCD region, encoding the conversion of benzoate to catechol, and the other in a gene determining the ability to grow on exogenous cis,cis-muconate . The wild-type gene, named mucK, was cloned into pUC18, and its nucleotide sequence was determined . It encodes a 413-residue protein of M(r) = 45,252 which is a member of a superfamily of membrane transport proteins and which is within a subgroup involved in the uptake of organic acids . Five of the mutant alleles were cloned, and the mutations were determined by nucleotide sequencing . All the mutations were in the mucK coding region and consisted of three deletions, one duplication, and a substitution . Insertional inactivation of mucK resulted in the loss of the ability to utilize exogenous muconate . The location of mucK on the chromosome appeared to be unique for genes associated with the benzoate branch of the beta-ketoadipate pathway in being close to the pca-qui-pob gene cluster (for p-hydroxybenzoate utilization) and distant from the functionally related ben-cat cluster . Downstream of mucK and transcribed in the same direction is an open reading frame encoding a protein of 570 residues (M(r) = 63,002) which shows considerable homology with a mammalian electron transport protein; its insertional inactivation had no detectable phenotypic effect.

Curr Microbiol, 1997 Sep, 35(3), 191 - 3
Bioremediation of crude oil contamination with Acinetobacter sp . A3; Hanson KG et al.; Acinetobacter sp . A3 is able to extensively degrade Bombay High Crude Oil (BHCO) and utilize it as the sole source of carbon . A total degradation of 70% BHCO was noted by the end of 120 h of growth of Acinetobacter sp . A3 under shake flask condition, 60% of which was due to biodegradation . In crude oil-contaminated soil (5%) amended with Acinetobacter sp . A3, there was both an increase in colony-forming units (CFU) and crude oil degradation . This is in contrast to a decrease in CFU of the indigenous microorganisms and lower degradation in unamended soil within the same 30-day period . Also, Acinetobacter sp . A3-treated soil permitted better germination of Mung beans (Phaseolus aureus) and growth as evidenced by better length and weight of the plants and chlorophyll content of its leaves, which was attributed to the reduction in phytotoxicity of the crude oil owing to its degradation . This crude oil degradative capability of Acinetobacter sp . A3 could be exploited for bioremediation purposes.

FEMS Microbiol Lett, 1997 Aug 15, 153(2), 333 - 9
Oxacillin-hydrolyzing beta-lactamase involved in resistance to imipenem in Acinetobacter baumannii; Hornstein M et al.; Acinetobacter baumannii strain A148, a clinical isolate resistant to imipenem (MIC = 32 mg l-1), synthesized two beta-lactamases with pIs 6.3 and > 9.2 . The pI 6.3 enzyme hydrolyzed the penicillins, including isoxazoylpenicillins, first-, second- and, to a lesser extent, third-generation cephalosporins . It was inhibited by chloride ions and by the penem beta-lactamase inhibitor BRL 42715 . Clavulanate was a weak inhibitor and EDTA did not affect the beta-lactamase activity . This enzyme also hydrolyzed imipenem with a catalytic efficiency (Kcat/Km) of 1500 mM-1 s-1 . Moreover, this purified beta-lactamase produced a positive microbiological clover-leaf test with imipenem . Therefore, the pI 6.3 beta-lactamase was considered to be involved in the imipenem resistance of A . baumannii strain A148.

FEMS Microbiol Lett, 1997 Aug 15, 153(2), 321 - 6
Identification and characterization of an aadB gene cassette at a secondary site in a plasmid from Acinetobacter; Segal H et al.; Transformation studies showed that an aminoglycoside resistance gene, aadB, is carried on a 6.0-kb plasmid (pRAY) in a clinical isolate of Acinetobacter (strain SUN) . The gene was cloned and sequenced . An analysis of the DNA sequencing data showed that although the aadB gene is part of cassette, it is not associated with an integron . Rather, the aadB cassette has recombined at a secondary site downstream of putative promoters on pRAY.

Eur J Biochem, 1997 Aug 1, 247(3), 815 - 9
Structural studies of the O-antigenic polysaccharide of the lipopolysaccharide from Acinetobacter (DNA group 11) strain 94 containing 3-amino-3,6-dideoxy-D-galactose substituted by the previously unknown amide-linked L-2-acetoxypropionic acid or L-2-hydroxypropionic acid; Haseley SR et al.; A polysaccharide containing D-Gal, D-GalNAc, 3-(L-2-acetoxypropionamido)-3,6-dideoxy-D-galactose (approximately 80%) and 3-(L-2-hydroxypropionamido)-3,6-dideoxy-D-galactose (approximately 20%) was isolated by mild acid hydrolysis, followed by gel-permeation chromatography, from the phenol-soluble lipopolysaccharide (phenol/water extracted) derived from Acinetobacter strain 94 . The polysaccharide, characterised by means of monosaccharide analyses, partial acid hydrolysis, and NMR studies, consisted of a branched tetrasaccharide repeating unit, as depicted below, in which Fucp3Nacyl represents 3-(L-2-hydroxypropionamido)-3,6-dideoxy-D-galactose, in which approximately 80% of the acyl residues are O-acetylated . These Fucp3N derivatives and an O-acetylated acyl group are therefore constituents of bacterial LPS, but to our knowledge are not present in any other natural carbohydrates . {sturcture: see text}

J Bacteriol, 1997 Aug, 179(16), 5226 - 31
Cloning and characterization of two catA genes in Acinetobacter lwoffii K24; Kim SI et al.; Two novel type I catechol 1,2-dioxygenases inducible on aniline media were isolated from Acinetobacter lwoffii K24 . Although the two purified enzymes, CD I1 and CD I2, had similar intradiol cleavage activities, they showed different substrate specificities for catechol analogs, physicochemical properties, and amino acid sequences . Two catA genes, catA1 and catA2, encoding by CD I1 and CD I2, respectively, were isolated from the A . lwoffii K24 genomic library by using colony hybridization and PCR . Two DNA fragments containing the catA1 and catA2 genes were located on separate regions of the chromosome . They contained open reading frames encoding 33.4- and 30.4-kDa proteins . The amino acid sequences of the two proteins matched well with previously determined sequences . Interestingly, further analysis of the two DNA fragments revealed the locations of the catB and catC genes as well . Moreover, the DNA fragment containing catA1 had a cluster of genes in the order catB1-catC1-catA1 while the catB2-catA2-catC2 arrangement was found in the catA2 DNA fragment . These results may provide an explanation of the different substrate specificities and physicochemical properties of CD I1 and CD I2.

J Bacteriol, 1997 Aug, 179(16), 5118 - 25
Identification and analysis of a gene encoding L-2,4-diaminobutyrate:2-ketoglutarate 4-aminotransferase involved in the 1,3-diaminopropane production pathway in Acinetobacter baumannii; Ikai H et al.; The ca . 2.2-kbp region upstream of the ddc gene encoding L-2,4-diaminobutyrate decarboxylase in Acinetobacter baumannii was sequenced and found to contain another open reading frame of 1,338 nucleotides encoding a protein with a deduced molecular mass of 47,423 Da . Analysis of the homologies observed from the deduced amino acid sequence indicated that the gene product is an enzyme belonging to subgroup II of the aminotransferases . This was first verified when examination of the crude extracts from Escherichia coli transformants led to detection of a novel aminotransferase activity catalyzing the following reversible reactions: L-2,4-diaminobutyric acid + 2-ketoglutaric acid<-->L-glutamic acid + L-aspartic beta-semialdehyde . Further confirmation was obtained when the gene was overexpressed in E . coli and the corresponding protein was purified to homogeneity . It catalyzed the same reactions and its N-terminal amino acid sequence was consistent with that deduced from the nucleotide sequence . Therefore, the gene and its product were named dat and L-2,4-diaminobutyrate:2-ketoglutarate 4-aminotransferase (DABA AT), respectively . Feeding experiments of A . baumannii with L-{U-14C}aspartic acid resulted in the incorporation of the label into 1,3-diaminopropane . Apparent homologs of dat and DABA AT were detected in other Acinetobacter species by PCR amplification and Western blotting . These results indicate that the dat gene (as well as the ddc gene) participates in the synthesis of 1,3-diaminopropane, the only diamine found in this genus . However, the biological role, if one exists, of 1,3-diaminopropane synthesis is unknown.

Eur J Biochem, 1997 Jul 15, 247(2), 659 - 65
Ca2+ and its substitutes have two different binding sites and roles in soluble, quinoprotein (pyrroloquinoline-quinone-containing) glucose dehydrogenase; Olsthoorn AJ et al.; To investigate the mode of binding and the role of Ca2+ in soluble, pyrroloquinoline-quinone (PQQ)-containing glucose dehydrogenase of the bacterium Acinetobacter calcoaceticus (sGDH), the following enzyme species were prepared and their interconversions studied: monomeric apoenzyme (M); monomer with one firmly bound Ca2+ ion (M*); dimer consisting of 2 M* (D); dimer consisting of 2 M and 2 PQQ (Holo-Y); dimer consisting of D with 2 PQQ (Holo-X); fully reconstituted enzyme consisting of Holo-X with two extra Ca2+ ions (Holo) or substitutes for Ca2+ (hybrid Holo-enzymes) . D and Holo are very stable enzyme species regarding monomerization and inactivation by chelator, respectively, the bound Ca2+ being locked up in such a way that it is not accessible to chelator . D can be converted into M* by heat treatment and the tightly bound Ca2+ can be removed from M* with chelator, transforming it into M . Reassociation of M* to D occurs spontaneously at 20 degrees C; reassociation of M to D occurs by adding a stoichiometric amount of Ca2+ . Synergistic effects were exerted by bound Ca2+ and PQQ, each increasing the affinity of the protein for the other component . Dimerization of M to D occurred with Ca2+, Cd2+, Mn2+, and Sr2+ (in decreasing order of effectiveness), but not with Mg2+, Ba2+, Co2+, Ni2+, Zn2+, or monovalent cations . Conversion of inactive Holo-X into active Holo, was achieved with Ca2+ or metal ions effective in dimerization . Although it is likely that activation of Holo-X involves binding of metal ion to PQQ, the spectral and enzymatic activity differences between normal Holo- and hybrid Holo-enzymes are relatively small . Titration experiments revealed that the two Ca2+ ions required for activation of Holo-X are even more firmly bound than the two required for dimerization of M and anchoring of PQQ . Although the two binding sites related with the dual function of Ca2+ show similar metal ion specificity, they are not identical . The presence of two different sites in sGDH appears to be unique because in other PQQ-containing dehydrogenases, the PQQ-containing subunit has only one site . Given the broad spectrum of bivalent metal ions effective in reconstituting quinoprotein dehydrogenase apoenzymes to active holoenzymes, but the limited spectrum for an individual enzyme, the specificity is not so much determined by PQQ but by the variable metal-ion-binding sites.

Biochim Biophys Acta, 1997 Jul 5, 1327(1), 119 - 30
Interactions of an antimicrobial peptide, magainin 2, with outer and inner membranes of Gram-negative bacteria; Matsuzaki K et al.; Magainin peptides, isolated from Xenopus skin, have broad spectra of antimicrobial activity and low toxicities to normal eukaryotic cells, thus being good candidates for therapeutic agents . The mechanism of action is considered to be the permeabilization of bacterial membranes . A number of studies using lipid vesicles have elucidated its molecular detail . However, their interactions with bacteria are not yet well understood . In this paper, we synthesized several magainin analogs with different charges (0 to +6) and hydrophobicities, and systematically studied their interactions with the outer and inner membranes of three species of Gram-negative bacteria (Escherichia coli, Acinetobacter calcoaceticus, Proteus vulgaris) . The treatment of the E . coli cells with native magainin 2 (+4) immediately induced the efflux of the intracellular K+ ions and the cell death . A number of blebs were formed on the bacterial surface and the outer membrane became leaky . An increase in the peptide's positive charge enhanced the outer membrane permeabilization and the bactericidal activity . The cationic peptides also effectively permeabilized the inner membranes rich in acidic phospholipids, indicating the importance of electrostatic interactions . Substitution of Trp for Phe simultaneously increased the bactericidal activity and the hemolytic activity . A strategy to develop potent antimicrobial peptides was discussed on the basis of these results.

Support Care Cancer, 1997 Jul, 5(4), 330 - 3
Analysis of 553 episodes of monomicrobial bacteraemia in cancer patients: any association between risk factors and outcome to particular pathogen?
Spanik S, Kukuckova E, Pichna P, Grausova S, Krupova I, Rusnakova V, Kralovicova K, Krchnakova A, Mrazova M, Lacka J, Koren P, Stopkova K, Nogova J, Demitrovicova A, Helpianska L, Krcmery V Jr.
Relationships between aetiology, various risk factors (such as neutropenia, catheter insertion, endoscopy, therapy with corticosteroids, therapeutic use of antimicrobials, antibiotic prophylaxis, source of infection), symptomatology and outcome were studied in 553 monomicrobial bacteraemic episodes in cancer patients observed within 7 years at the National Cancer Institute of the Slovak Republic . The ratio of gram-positive to gram-negative bacteraemia was 1:1 (43.5% vs 43.8%), and yeasts caused 7.2% of monomicrobial episodes . The highest mortality was associated with Pseudomonas aeruginosa (19.2%), non-albicans Candida yeasts (25%) and Bacteroides fragilis (22.6%) . Independent risk factors for particular pathogens were investigated by a computerized logistic regression model . The only independent risk factor for staphylococcal and enterococcal bacteraemia was vascular catheter insertion (OR = 1.95 and 2.05, CI = 95%, P = 0.035 and 0.044, respectively) . However, there were no independent specific risk significant factors for viridans streptococcal bacteraemia and bacteraemia due to Enterobacteriaceae or Ps . aeruginosa . Neutropenia was found to be an independent predictor for development of Acinetobacter spp . bacteraemia (OR = 3.84, CI = 95%, P = 0.044) . Prior therapy with third-generation cephalosporines was a predictive, independent risk factor for the development of fungaemia (OR = 1.99, CI = 95%, P = 0.028) but not of enterococcal bacteraemia . We also did not observe any association between prior therapy with imipenem and Stenotrophomonas maltophilia bacteraemias . Multivariate analysis confirmed that fungaemia may be independently associated with higher mortality than bacteraemia caused by Enterobacteriaceae and staphylococci . However, the mortality of fungaemia was statistically no different from that of Ps . aeruginosa, Stenotrophomonas spp . and viridans streptococci bacteraemias.

Eur J Biochem, 1997 Jul 1, 247(1), 82 - 90
Structural investigation of the lipopolysaccharide from Acinetobacter haemolyticus strain NCTC 10305 (ATCC 17906, DNA group 4); Vinogradov EV et al.; The structure of the lipopolysaccharide (LPS) from Acinetobacter haemolyticus strain NCTC 10305 (DNA group 4) was elucidated by means of analytical chemistry, NMR spectroscopy and fast-atom-bombardment mass spectrometry . Several oligosaccharides were obtained after deacylation or successive de-O-acylation, dephosphorylation, reduction, and de-N-acylation of LPS . In the major fraction of the LPS, the core is attached to the lipid A through D-glycero-D-talo-2-octulopyranosonic acid (Ko), whereas in a minor fraction (<20%) Ko is replaced by 3-deoxy-D-manno-octulopyranosonic acid (Kdo) . The structures of the phosphorylated carbohydrate backbones of these LPS fractions are {structure: see text} with Dha = 3-deoxy-D-lyxo-2-heptulosaric acid, Sug = sugar and is Ko in a major fraction and Kdo in a minor fraction . All sugar residues have the D-configuration and are present in the pyranose form . Mass spectrometry of de-O-acylated LPS revealed the presence of an additional hexose residue in minor amounts, the position and nature of which could not be identified.

Infect Control Hosp Epidemiol, 1997 Jul, 18(7), 510 - 2
A pseudo-outbreak of respiratory infection with Acinetobacter species; Sule O et al.; We describe an apparent outbreak of respiratory infection with Acinetobacter species involving 14 patients over 8 days . Epidemiological investigation revealed two consecutive pseudo-outbreaks of infection caused by two consecutive, unrelated laboratory errors in the processing of sputum, nasopharyngeal, and endotracheal aspirates.

Infect Control Hosp Epidemiol, 1997 Jul, 18(7), 499 - 503
Association of private isolation rooms with ventilator-associated Acinetobacter baumanii pneumonia in a surgical intensive-care unit; Mulin B et al.; OBJECTIVE: To determine the rates and routes of Acinetobacter baumanii colonization and pneumonia among ventilated patients in a surgical intensive-care unit (SICU) before and after architectural modifications . DESIGN: A nonsequential study comparing two groups of patients . All isolates from systematic and clinical samples were genotyped by pulsed-field gel electrophoresis (PFGE) . Records of patients hospitalized during the first and second periods were reviewed and findings were compared . Between the two periods, the SICU was remodeled from enclosed isolation rooms and open rooms to only enclosed isolation rooms with handwashing facilities in each room . SETTING AND PATIENTS: All patients hospitalized and mechanically ventilated for more than 48 hours in the 15-bed SICU of the University Hospital of Besancon (France) . RESULTS: For the first and second periods, the rates of colonization were, respectively, 28.1% and 5.0% of patients (P < 10(-7); relative risk {RR}, 2.23; 95% confidence interval {CI95}, 1.8-2.75) and the specific rates of bronchopulmonary (BP) colonization were, respectively, 9.1 and 0.5 per 1,000 days of mechanical ventilation (P < 10(-5) . Seven major PFGE isolate types were identified, 4 of which were isolated from 44 of the 47 colonized or infected patients . Logistic regression analysis showed that colonization was not associated with patient characteristics . CONCLUSION: Conversion from open rooms to isolation rooms may help control nosocomial BP tract acquisition of A baumanii in mechanically ventilated patients hospitalized in an SICU.

Am J Trop Med Hyg, 1997 Jul, 57(1), 7 - 15
Bacteriologic studies of skin, tissue fluid, lymph, and lymph nodes in patients with filarial lymphedema; Olszewski WL et al.; Filarial lymphedema is complicated by frequent episodes of dermatolymphangioadenitis (DLA) . It is not certain whether DLA is of filarial or bacterial etiology . The frequency of episodic DLA does not depend on the presence or absence of microfilariae . Antibiotic therapy is effective in prevention and treatment of DLA . These observations point to the bacterial rather than filarial etiology of DLA . Skin and lymph node biopsies, tissue fluid, lymph, and blood from patients with chronic filarial lymphedema, and during acute episodes of DLA, were cultured for detection of bacteria . A high prevalence of bacterial isolates from the tissue fluid (64%), lymph (75%), and inguinal lymph nodes (66%) of limbs with filarial lymphedema was found . Bacillus cereus, Staphylococcus epidermidis, S . hominis, S . capitis, S . xylosus, and Micrococcus spp . were the most common isolates . Bacteria were also isolated from the blood of patients with recent episodes of DLA, with strains of the same phenotype and antibiotic sensitivity in all specimens from patients with DLA . Bacterial strains of the same phenotype and antibiotic sensitivity were documented on the toe web surface and in tissue fluid (25%), lymph (26%), or lymph nodes (41%) . Increasing prevalence of bacterial isolates in tissue fluid, lymph, and lymph nodes was observed in advanced stages of lymphedema . Bacilli and cocci were sensitive to gentamicin, tetracyline, rifampicin, vancomycin, kanamycin and cotrimoxazole, and least sensitive to penicillin . Blood cultures of patients in the periods between DLA attacks were negative . In healthy controls without edema and episodes of DLA, tissue fluid did not contain bacteria . In lymph, only single colonies of Micrococcus and Acinetobacter were cultured in 12% of the cases . Impaired lymph drainage and lack of elimination of penetrating bacteria may be responsible for progression of lymphedema and recurrent attacks of DLA.

Int J Syst Bacteriol, 1997 Jul, 47(3), 837 - 41
Phylogenetic relationship of the twenty-one DNA groups of the genus Acinetobacter as revealed by 16S ribosomal DNA sequence analysis; Ibrahim A et al.; The inter- and intrageneric relationships of members of the genus Acinetobacter were investigated by performing a comparative sequence analysis of PCR-amplified 16S ribosomal DNAs (rDNAs) from 21 strains representing all of the DNA groups that have been described . Phylogenetic treeing confirmed that Acinetobacter spp . form a coherent cluster within the gamma subdivision of the class Proteobacteria that includes strains with overall levels of 16S rDNA sequence similarity of more than 94% . The analysis of intrageneric relationships suggested that the majority of the strains cluster in five clearly distinguishable clusters, and this conclusion was supported by the results obtained with the different methods used for phylogenetic analysis (i.e., the maximum-likelihood, parsimony, and distance matrix methods) . The first cluster contains the representatives of DNA groups 2 (Acinetobacter baumannii) and TU13, whereas the second cluster comprises representatives of DNA groups 3, "Close To TU13," and "between 1 and 3." The representatives of closely related Acinetobacter DNA groups 8 (Acinetobacter twoffii) and 9 belong to the third cluster, which includes the representative of DNA group 6 as well . The fourth cluster is formed by DNA groups BJ15, BJ16, and BJ17, and the fifth cluster comprises DNA groups 1 (Acinetobacter calcoaceticus), BJ14, 10, and 11 . Within the fifth cluster the 16S rDNA sequences of DNA group 10 and 11 strains are nearly identical . The representatives of DNA groups 4 (Acinetobacter haemolyticus), 5 (Acinetobacter junii), 7 (Acinetobacter johnsonii), 12 (Acinetobacter radioresistens), TU14, and TU15 form individual branches that are not significantly affiliated with any of the five clusters identified . Apart from the clustering of the most closely related DNA groups, the general topology of the distance dendrogram revealed some discrepancy with previous DNA-DNA hybridization data, which may point to the inadequacy of comparative 16S rDNA sequence analysis for reflecting true evolutionary relationships of closely related bacterial taxa . Important, however, was the presence of unique sequence motifs in each of the 21 different DNA groups studied, which may be useful for rapid differentiation of DNA groups of the genus Acinetobacter.

J Bacteriol, 1997 Jul, 179(14), 4631 - 4
Identification and characterization of xcpR encoding a subunit of the general secretory pathway necessary for dodecane degradation in Acinetobacter calcoaceticus ADP1; Parche S et al.; A mutant of Acinetobacter calcoaceticus ADP1 unable to grow on alkanes was complemented for growth on hexadecane with a DNA fragment encoding a protein with homology to XcpR, a subunit of the general secretion pathway for exoproteins in Pseudomonas aeruginosa . Insertional inactivation of xcpR in A . calcoaceticus ADP1 by transcriptional fusion to lacZ abolishes secretion of lipase and esterase and leads to lack of growth on dodecane and slower growth on hexadecane . We, therefore, propose the participation of a secreted protein in alkane degradation.

Am J Ophthalmol, 1997 Jul, 124(1), 19 - 23
Infectious crystalline keratopathy caused by gram-negative bacteria; Khater TT et al.; PURPOSE: To identify the characteristics and outcomes of infectious crystalline keratopathy caused by gram-negative bacteria . METHODS: We reviewed all patients treated at a university eye center for infectious crystalline keratopathy from 1978 through 1995 and performed a nested case-comparison study by comparing patients with keratitis caused by gram-negative rods and those with keratitis caused by gram-positive cocci . RESULTS: Eighteen patients (mean age +/- SD, 59 +/- 17 years) displayed unilateral culture-positive infectious crystalline keratopathy . Among 18 eyes with crystalline keratopathy, five occurrences (28%) were caused by gram-negative rods (Acinetobacter lwoffi, Citrobacter koseri, Enterobacter aerogenes, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia), 10 (55%) were caused primarily by gram-positive cocci, and three (17%) were caused primarily by yeasts . Four cases grew two different isolates . No significant difference in predisposing factors, clinical appearance, or visual outcome was found between infections caused by gram-negative bacteria and those caused by gram-positive bacteria . CONCLUSIONS: Gram-negative bacteria can cause infectious crystalline keratopathy but have no distinguishing features from infectious crystalline keratopathy caused by streptococci and other gram-positive bacteria . Appropriate laboratory evaluation is therefore necessary to guide specific antimicrobial therapy.

J Bacteriol, 1997 Jul, 179(13), 4270 - 6
Combining localized PCR mutagenesis and natural transformation in direct genetic analysis of a transcriptional regulator gene, pobR; Kok RG et al.; We present a procedure for efficient random mutagenesis of selected genes in a bacterial chromosome . The method combines PCR replication errors with the uptake of PCR-amplified DNA via natural transformation . Cloning of PCR fragments is not required, since mutations are transferred directly to the chromosome via homologous recombination . Random mutations were introduced into the Acinetobacter chromosomal pobR gene encoding the transcriptional activator of pobA, the structural gene for 4-hydroxybenzoate 3-hydroxylase . Mutant strains with strongly reduced PobR activity were selected by demanding the inability to convert 4-hydroxybenzoate to a toxic metabolite . Of spontaneous pobR mutants, 80% carry the insertion element IS1236, rendering them inappropriate for structure-function studies . Transformation with Taq-amplified pobR DNA increased the mutation frequency 240-fold and reduced the proportion of IS1236 inserts to undetectable levels . The relative fidelity of Pfu polymerase compared with Taq polymerase was illustrated by a reduced effect on the mutation frequency; a procedure for rapid assessment of relative polymerase fidelity in PCR follows from this observation . Over 150 independent mutations were localized by transformation with DNA fragments containing nested deletions of wild-type pobR . Sequence analysis of 89 of the mutant pobR alleles showed that the mutations were predominantly single-nucleotide substitutions broadly distributed within pobR . Promoter mutations were recovered, as were two mutations that are likely to block pobR translation . One-third of the recovered mutations conferred a leaky or temperature-sensitive phenotype, whereas the remaining null mutations completely blocked growth with 4-hydroxybenzoate . Strains containing two different nonsense mutations in pobR were transformed with PCR-amplified DNA to identify permissible codon substitutions . Independently, second-site suppressor mutations were recovered within pcaG, another member of the supraoperonic pca-qui-pob cluster on the Acinetobacter chromosome . This shows that combining PCR mutagenesis with natural transformation is of general utility.

Mol Cells, 1997 Jun 30, 7(3), 380 - 8
Purification and some properties of ribulose 1,5-bisphosphate carboxylases/oxygenases from Acinetobacter sp . strain JC1 and Hydrogenophaga pseudoflava; Kim EY et al.; Ribulose 1,5-bisphosphate carboxylases/oxygenases (RuBisCOs) of two carboxydobacteria, Acinetobacter sp . strain JC1 and Hydrogenophaga pseudoflava, grown on carbon monoxide were purified and partially characterized . RuBisCO of Acinetobacter sp . JC1 was purified 5-fold in eight steps to homogeneity, with a yield of 1.6% . The final specific activity of the purified enzyme was 39.5 nmol CO2 incorporated per min per mg protein . The molecular weight of the native enzyme was determined to be 520,000 . Sodium dodecyl sulfate-gel electrophoresis revealed two nonidentical subunits of molecular weights 53,500 and 15,000 . The Km and Vmax for CO2 were 36.7 microM and 296.1 nmol per min per mg protein, respectively, and those for ribulose 1,5-bisphosphate were 3.7 microM and 770 nmol per min per mg protein, respectively . The enzyme of H . pseudoflava was purified 55-fold in eight steps to homogeneity, with a yield of 3.6% . The final specific activity was 304.3 nmol CO2 incorporated per min per mg protein . The molecular weight of the enzyme was estimated to be 505,000 . The enzyme was found to have two kinds of nonidentical subunits of molecular weights 51,500 and 14,000 . The Km and Vmax for CO2 were found to be 16.4 microM and 777.8 nmol per min per mg protein, respectively, and those for ribulose 1,5-bisphosphate were 0.1 microM and 436.2 nmol per min per mg protein, respectively . The N-terminal amino acid sequences of the large and small subunits of Acinetobacter sp . JC1 enzyme were Ala-Asp-Arg-Trp-Asn-Ala-Gly-Val-IIe-Pro-Tyr-Ala-Glu-Met-Gly and Met-Arg-Ile-Thr-Glu-Gly-Thr-Phe-Ser-Tyr-Leu-Pro-Asp-Phe-Thr, respectively . The sequences of the H . pseudoflava enzyme were Ala-Thr-Lys-Thr-Tyr-Asu-Ala-Gly-Val-Lys-Glu-Tyr-Trp-Ser-Thr and Met-Ser-Met-Gln-Asp-Tyr-His-Ser-Arg-Leu-Ser-Asp-Pro-Ala-Ile, respectively . The peptide map of RuBisCO from Acinetobacter sp . JC1 grown on carbon monoxide was different from that of the bacterium grown on methanol . The two RuBisCOs, however, were found to be identical in N-terminal residue and antigenic property . The RuBisCO of Acinetobacter sp . JC1 was found to share no immunological properties with those of H . pseudoflava, Oligotropha carboxidovorans and Pseudomonas carboxydohydrogena.

Carbohydr Res, 1997 Jun 20, 301(3-4), 187 - 92
Structure of the O18 antigen from Acinetobacter baumannii; Haseley S et al.; The polymeric O antigen was obtained from lipopolysaccharide extracted from isolated, defatted cell walls of the reference strain for Acinetobacter baumannii serogroup O18 . Monosaccharide analyses and NMR spectra established that the polymer had a regular structure with a repeating unit based on residues of D-galactose (2), N-acetyl-D-galactosamine (1), and N-acetyl-D-mannosamine (1) . Further interpretation of the NMR spectra, combined with the results of methylation analysis and a Smith degradation, showed that the repeating unit had the following structure . beta-D-ManpNAc-(1-->4)-alpha-D-Galp 1 decreases 4 -->3)-beta-D-GalpNAc-(1-->3)-beta-D-Galp-(1-->.

Gene, 1997 Jun 11, 192(1), 179 - 90
Uptake and processing of DNA by Acinetobacter calcoaceticus--a review; Palmen R et al.; In natural transformation, DNA in the form of macromolecular fragments can be translocated across the cell envelope of prokaryotic microorganisms . During the past two decades, several, largely mutually contradictory, hypotheses have been forwarded to explain the molecular mechanism and bioenergetics of this translocation process . Other biomacromolecules are translocated across the bacterial cell envelope as well, such as polysaccharides and proteins, the latter for instance in the process of the assembly of type-IV pili . This brings up the question whether or not common components are involved . Here, we review analyses of DNA translocation in Acinetobacter calcoaceticus, a Gram-negative eubacterium that is able to migrate through twitching motility, and also shows a high frequency of natural transformation . DNA uptake in this organism is an energy-dependent process . Upon entry into the cells, the DNA fragments are integrated into the resident chromosome when a sufficiently large region of mutual homology is available (200 to 400 bp) . However, this process is rather inefficient, and on the average 500 bp of each incoming fragment is degraded through exonuclease activity . Upon covalent attachment of a bulky protein molecule to the transforming DNA, the DNA-translocation machinery becomes blocked in further translocation activity . Since A . calcoaceticus is not well suited for transposon mutagenesis, a random mutagenesis procedure has been developed, based on the ligation of an antibiotic-resistance marker to random fragments of chromosomal DNA . This method was used to generate several mutants impaired in the natural transformation process . Three of these have been characterized in detail . No components, common to the translocation of macromolecules through the cell envelope of Acinetobacter, have been detected in this screen.

Diagn Microbiol Infect Dis, 1997 Jun, 28(2), 61 - 4
Verification of a PCR-based typing method for Acinetobacter baumannii in a pseudo-outbreak investigation; Cimolai N et al.; Acinetobacter spp . isolates were increasingly obtained from clinical specimens and sterility samples, and a subsequent epidemiological investigation implicated an intermittently contaminated supply of commercially acquired enrichment broths . Typing was performed with DNA amplification by the polymerase chain reaction (PCR) using enterobacterial repetitive intergenic consensus sequence primers, ERIC2 and reverse ERIC1R . The reliability of this PCR-based typing method was verified by the ability of the technique to demonstrate homology and differences among isolates from an epidemiologically well-defined pseudo-outbreak.

J Antimicrob Chemother, 1997 Jun, 39 Suppl B, 29 - 34
Antibacterial activity of trovafloxacin against nosocomial Gram-positive and Gram-negative isolates; Cunha BA et al.; A total of 1132 clinical isolates from 952 patients with nosocomial infections were tested against the fluoroquinolone trovafloxacin by the agar dilution method . They comprised 285 staphylococci, 111 streptococci, 94 enterococci and 470 isolates of Enterobacteriaceae, 92 Pseudomonas aeruginosa, 27 Stenotrophomonas maltophilia, 28 Haemophilus influenzae and 25 Acinetobacter calcoaceticus . The in-vitro activity of trovafloxacin was compared with that of ciprofloxacin, norfloxacin, beta-lactam and aminoglycoside agents . Over 96% of Enterobacteriaceae were susceptible to trovafloxacin with an MIC of <0.03-4 mg/L . It also inhibited 97% and 100% clinical isolates of P . aeruginosa and S . maltophilia, respectively . All staphylococci, including 51 strains of methicillin-resistant Staphylococcus aureus, were susceptible to trovafloxacin, which also had excellent activity against streptococci and enterococci, inhibiting all 111 strains of the former and 94% of the latter . Trovafloxacin had a greater activity against both Gram-positive and Gram-negative bacteria than ciprofloxacin, norfloxacin, penicillins, cephalosporins and the aminoglycosides tested.

J Antimicrob Chemother, 1997 Jun, 39(6), 757 - 62
Quinolone-resistance mutations in the topoisomerase IV parC gene of Acinetobacter baumannii; Vila J et al.; Mutations in the parC gene, which encodes a subunit of topoisomerase IV, were determined in 21 epidemiologically unrelated clinical isolates of Acinetobacter baumannii . Our studies highlight the conserved sequences in the quinolone-resistance-determining region of the parC gene from A . baumannii and other bacteria . Nine of ten isolates with MICs of ciprofloxacin of > or = 32 mg/L showed a change of Ser80 to Leu and one showed a change of Glu84 to Lys . These results suggest that ParC from A . baumannii is a secondary target for quinolones and that mutations at residues Ser80 and Glu84, when combined with mutations at Ser83 of GyrA, may render A . baumannii highly resistant to quinolones.

J Clin Microbiol, 1997 Jun, 35(6), 1394 - 7
Survival of Acinetobacter baumannii on dry surfaces; Wendt C et al.; Acinetobacter spp . have frequently been reported to be the causative agents of hospital outbreaks . The circumstances of some outbreaks demonstrated the long survival of Acinetobacter in a dry, inanimate environment . In laboratory experiments, we compared the abilities of five Acinetobacter baumannii strains, three Acinetobacter sp . strains from the American Type Culture Collection (ATCC), one Escherichia coli ATCC strain, and one Enterococcus faecium ATCC strain to survive under dry conditions . Bacterial solutions of the 10 strains were inoculated onto four different material samples (ceramic, polyvinyl chloride, rubber, and stainless steel) and stored under defined conditions . We investigated the bacterial counts of the material samples immediately after inoculation, after drying, and after 4 h, 1 day, and 1, 2, 4, 8, and 16 weeks of storage . A statistical model was used to distribute the 40 resulting curves among four types of survival curves . The type of survival curve was significantly associated with the bacterial strain but not with the material . The ability of the A . baumannii strains to survive under dry conditions varied greatly and correlated well with the source of the strain . Strains isolated from dry sources survived better than those isolated from wet sources . An outbreak strain that had caused hospital-acquired respiratory tract infections survived better than the strains from wet sources, but not as well as strains from dry sources . Resistance to dry conditions may promote the transmissibility of a strain, but it is not sufficient to make a strain an epidemic one . However, in the case of an outbreak, sources of Acinetobacter must be expected in the dry environment.

J Med Microbiol, 1997 May, 46(5), 360 - 71
Moraxella (Branhamella) catarrhalis--clinical and molecular aspects of a rediscovered pathogen; Enright MC et al.; Since its discovery at the end of the nineteenth century, Moraxella (Branhamella) catarrhalis has undergone several changes of nomenclature and periodic changes in its perceived status as either a commensal or a pathogen . Molecular analysis based on DNA hybridisation or 16S rDNA sequence comparisons has established its phylogenetic position as a member of the Moraxellaceae and shown that it is related more closely to Acinetobacter spp . than to the genus Neisseria in which it was placed formerly . However, confusion with phenotypically similar Neisseria spp . can occur in the routine diagnostic laboratory if appropriate identification tests are not performed . M . catarrhalis is now accepted as the third commonest pathogen of the respiratory tract after Streptococcus pneumoniae and Haemophilus influenzae . It is a significant cause of otitis media and sinusitis in children and of lower respiratory tract infections in adults, especially those with underlying chest disease . Nosocomial spread of infection, especially within respiratory wards, has been reported . Invasive infection is uncommon, but analysis of reports for England and Wales between 1992 and 1995 revealed 89 cases of M . catarrhalis bacteraemia, with the peak incidence in children aged 1-2 years . Carriage rates of M . catarrhalis are high in children and in the elderly, but its role as a commensal organism has probably been overstated in the past . Approximately 90% of strains are now beta-lactamase positive and, given that the first such strain was reported in 1976, this represents a dramatic increase in frequency over the last 20 years which has not been paralleled in any other species . The BRO-1 and BRO-2 beta-lactamase enzymes of M . catarrhalis are found in other Moraxellaceae, but are not related to beta-lactamases of any other species and their origin is therefore unknown . Molecular and typing studies have shown that the M . catarrhalis species is genetically heterogeneous and these methods have aided epidemiological investigation . Studies of factors that may be related to pathogenicity have shown the existence of three serotypes of lipooligosaccharide and the presence of fimbriae and a possible capsule . Some strains are serum-resistant, probably by virtue of interference with complement action, whilst transferrin- and lactoferrin-binding proteins enable the organism to obtain iron from its environment . An antibody response in humans to various M . catarrhalis antigens, including highly conserved outer-membrane proteins, has been demonstrated . Increased understanding of the organism's pathogenic properties and the host response to it may help to identify suitable vaccine targets or lead to other strategies to prevent infection . Whilst it remains, at present, the third most important respiratory pathogen, the impact of immunisation strategies for other organisms may change this position . The speed with which M . catarrhalis acquired beta-lactamase demonstrates the capacity of this organism to surprise us.

Antimicrob Agents Chemother, 1997 May, 41(5), 1073 - 6
Activities of levofloxacin, ofloxacin, and ciprofloxacin, alone and in combination with amikacin, against acinetobacters as determined by checkerboard and time-kill studies; Bajaksouzian S et al.; A total of 101 Acinetobacter genospecies (77 Acinetobacter baumannii strains and 24 non-A . baumannii strains) were tested for their susceptibilities to levofloxacin, ofloxacin, and ciprofloxacin and for synergy between the quinolones and amikacin by checkerboard titration and time-kill analyses . The MICs at which 50% of the isolates are inhibited (MIC50)/MIC90s for the 101 strains were as follows (in micrograms per milliliter): levofloxacin, 0.25/16.0; ofloxacin, 0.5/32.0; ciprofloxacin, 0.25/> 64.0; and amikacin, 1.0/> 32.0 . At empiric breakpoints of < or = 2.0 microg/ml, 61% of the strains were susceptible to all three quinolones . At a breakpoint of < or = 16.0 microg/ml, 84% of the strains were susceptible to amikacin . Checkerboard titrations yielded synergistic fractional inhibitory concentration (FIC) indices (< or = 0.5) for one strain with levofloxacin and amikacin and for two strains with ofloxacin and amikacin . Indices of > 0.5 to 1.0 were seen for 57, 54, and 55 strains with levofloxacin plus amikacin, ofloxacin plus amikacin, and ciprofloxacin plus amikacin, respectively, and indices of > 1.0 in 43, 45, and 46 strains, respectively, were found with the above three combinations . No strains yielded antagonistic FIC indices (> 4.0) . Most FIC results of > 1.0 occurred in strains for which the quinolone MICs were > 2.0 microg/ml and for which the amikacin MICs were > or = 32.0 microg/ml . By contrast, synergy (defined as > or = 2 log10 decrease compared to the more active compound alone by time-kill analysis) was found in all seven strains tested for which the quinolone MICs were < or = 2.0 microg/ml . For eight other strains for which the quinolone MICs were > 2.0 microg/ml as determined by time-kill analysis, quinolone and amikacin concentrations in combination were usually too high to permit clinical use . Time-kill analysis was found to be more sensitive in detecting synergy than was the checkerboard method.

Antimicrob Agents Chemother, 1997 May, 41(5), 1010 - 6
Antibacterial activity of BMS-180680, a new catechol-containing monobactam; Fung-Tomc J et al.; The in vitro activities of a new catechol-containing monobactam, BMS-180680 (SQ 84,100), were compared to those of aztreonam, ceftazidime, imipenem, piperacillin-tazobactam, ciprofloxacin, amikacin, and trimethoprim-sulfamethoxazole . BMS-180680 was often the most active compound against many species of the family Enterobacteriaceae, with MICs at which 90% of the isolates were inhibited (MIC90s) of < or = 0.5 microg/ml for Escherichia coli, Klebsiella spp., Citrobacter diversus, Enterobacter aerogenes, Serratia marcescens, Proteus spp., and Providencia spp . BMS-180680 had moderate activities (MIC90s of 2 to 8 microg/ml) against Citrobacter freundii, Morganella morganii, Shigella spp., and non-E . aerogenes Enterobacter spp . BMS-180680 was the only antibiotic evaluated that was active against >90% of the Pseudomonas aeruginosa (MIC90, 0.25 microg/ml), Burkholderia cepacia, and Stenotrophomonas maltophilia (MIC90s, 1 microg/ml) strains tested . BMS-180680 was inactive against most strains of Pseudomonas fluorescens, Pseudomonas stutzeri, Pseudomonas diminuta, and Burkholderia pickettii . BMS-180680 was moderately active (MIC90s of 4 to 8 microg/ml) against Alcaligenes spp . and Acinetobacter lwoffii and less active (MIC90, 16 microg/ml) against Acinetobacter calcoaceticus-Acinetobacter baumanii complex . BMS-180680 lacked activity against gram-positive bacteria and anaerobic bacteria . Both tonB and cir fiu double mutants of E . coli had greatly decreased susceptibility to BMS-180680 . Of the TEM, PSE, and chromosomal-encoded beta-lactamases tested, only the K1 enzyme hydrolyzed BMS-180680 to any measurable extent . Like aztreonam, BMS-180680 bound preferentially to penicillin-binding protein 3 . The MICs of BMS-180680 were not influenced by the presence of hematin or 5% sheep blood in the test medium or with incubation in an atmosphere containing 5% CO2 . BMS-180680 MICs obtained under strict anaerobic conditions were significantly higher than those obtained in ambient air.

Antimicrob Agents Chemother, 1997 May, 41(5), 881 - 5
Comparative in vitro antimicrobial susceptibilities of nosocomial isolates of Acinetobacter baumannii and synergistic activities of nine antimicrobial combinations; Marques MB et al.; The in vitro susceptibilities of 69 nosocomial Acinetobacter isolates were determined by the broth microdilution method . Fourteen (20%) isolates were resistant to at least two aminoglycosides and two extended-spectrum penicillins . Nine antimicrobial combinations were then tested for synergy against these 14 isolates by checkerboard titration: imipenem with ciprofloxacin, amikacin, and tobramycin and ampicillin-sulbactam, piperacillin-tazobactam, and ticarcillin-clavulanate with amikacin and tobramycin . Synergy was detected with one or more antimicrobial combinations against 9 of 14 (64%) isolates, partial synergy was detected with one or more combinations against all 14 isolates, and an additive effect alone was observed with two different combinations against two isolates . No antagonism was detected with any combination . Imipenem plus either amikacin or tobramycin resulted in a synergistic or partial synergistic response against all 14 isolates . Specific combinations showing synergy against A . baumannii isolates were imipenem with tobramycin (four isolates), imipenem with amikacin (three isolates), ampicillin-sulbactam with tobramycin (six isolates), ampicillin-sulbactam with amikacin (three isolates), and ticarcillin-clavulanate with tobramycin (one isolate) . Genotyping by randomly amplified polymorphic DNA analysis showed that 9 of the 14 isolates were of one strain, 4 isolates were of a second strain, and the remaining isolate was of a different strain . Eight of 14 (57%) patients infected with resistant A . baumannii isolates died . Only 3 of 14 patients had received a therapeutic regimen which was tested for synergy . Clinical studies are needed to determine the significance of these findings.

Appl Environ Microbiol, 1997 May, 63(5), 1945 - 52
Natural transformation and availability of transforming DNA to Acinetobacter calcoaceticus in soil microcosms; Nielsen KM et al.; A small microcosm, based on optimized in vitro transformation conditions, was used to study the ecological factors affecting the transformation of Acinetobacter calcoaceticus BD413 in soil . The transforming DNA used was A . calcoaceticus homologous chromosomal DNA with an inserted gene cassette containing a kanamycin resistance gene, nptII . The effects of soil type (silt loam or loamy sand), bacterial cell density, time of residence of A . calcoaceticus or of DNA in soil before transformation, transformation period, and nutrient input were investigated . There were clear inhibitory effects of the soil matrix on transformation and DNA availability . A . calcoaceticus cells reached stationary phase and lost the ability to be transformed shortly after introduction into sterile soil . The use of an initially small number of A . calcoaceticus cells and nutrients, resulting in bacterial growth, enhanced transformation frequencies within a limited period . The availability of introduced DNA for transformation of A . calcoaceticus cells disappeared within a few hours in soil . Differences in transformation frequencies between soils were found; A . calcoaceticus cells were transformed at a higher rate and for a longer period in a silt loam than in a loamy sand . Physical separation of DNA and A . calcoaceticus cells had a negative effect on transformation . Transformation was also detected in nonsterile soil microcosms, albeit only in the presence of added nutrients and at a reduced frequency . These results suggest that chromosomal DNA released into soil rapidly becomes unavailable for transformation of A . calcoaceticus . In addition, strain BD413 quickly loses the ability to receive, stabilize, and/or express exogenous DNA after introduction into soil.

Clin Infect Dis, 1997 May, 24(5), 932 - 5
Treatment of multidrug-resistant Acinetobacter baumannii meningitis with ampicillin/sulbactam; Jimenez-Mejias ME et al.; The clinical features and the outcomes of eight cases of nosocomial Acinetobacter baumannii meningitis treated with ampicillin/sulbactam are reported . All the patients had fever, neck stiffness or meningeal signs, and a low consciousness level, and in their cerebrospinal fluid (CSF), pleocytosis, a low glucose level, and an elevated protein level were noted . For all CSF isolates of A . baumannii, the MIC of ampicillin/sulbactam was < or = 8/4 microg/mL . The MICs of sulbactam by microdilution in two cases were 4 microg/mL . All isolates were resistant to cefotaxime, ceftriaxone, ceftazidime, ureidopenicillins, ciprofloxacin, and gentamicin . Seven isolates were resistant to imipenem . A . baumannii was isolated from other samples in seven episodes . All patients were treated with ampicillin/sulbactam (seven with 2 g/l g every 6 hours and one with 2 g/l g every 8 hours) . Six patients were cured and two patients died of meningitis . There were no side effects with the ampicillin/sulbactam treatment . In conclusion, ampicillin/sulbactam may be effective as therapy for meningitis caused by A . baumanii resistant to imipenem and other beta-lactam drugs.

J Bacteriol, 1997 May, 179(9), 2969 - 75
Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase; Reiser S et al.; Acinetobacter calcoaceticus BD413 accumulates wax esters and triacylglycerol under conditions of mineral nutrient limitation . Nitrosoguanidine-induced mutants of strain BD413 were isolated that failed to accumulate wax esters under nitrogen-limited growth conditions . One of the mutants, Wow15 (without wax), accumulated wax when grown in the presence of cis-11-hexadecenal and hexadecanol but not hexadecane or hexadecanoic acid . This suggested that the mutation may have inactivated a gene encoding either an acyl-acyl carrier protein or acyl-coenzyme A (CoA) reductase . The Wow15 mutant was complemented with a cosmid genomic library prepared from wild-type A . calcoaceticus BD413 . The complementary region was localized to a single gene (acr1) encoding a protein of 32,468 Da that is 44% identical over a region of 264 amino acids to a product of unknown function encoded by an open reading frame associated with mycolic acid synthesis in Mycobacterium tuberculosis H37Ra . Extracts of Escherichia coli cells expressing the acr1 gene catalyzed the reduction of acyl-CoA to the corresponding fatty aldehyde, indicating that the gene encodes a novel fatty acyl-CoA reductase.

Eur J Biochem, 1997 Apr 15, 245(2), 477 - 81
Structural and serological characterisation of the O-antigenic polysaccharide of the lipopolysaccharide from Acinetobacter junii strain 65; Haseley SR et al.; A polysaccharide containing rhamnose (Rha) and Gal was isolated by acetic acid hydrolysis, followed by gel-permeation chromatography, from the water-soluble lipopolysaccharide (phenol/water extracted) from Acinetobacter junii strain 65 . The polysaccharide was characterised by means of monosaccharide analyses, Smith degradation, and NMR studies, and was shown to have a linear pentasaccharide repeating unit, as depicted below . This structure was specifically recognised in western blots and enzyme immunoassays by polyclonal rabbit antisera . {structure in text}

Eur J Biochem, 1997 Apr 15, 245(2), 470 - 6
Structural and serological characterisation of the O-antigenic polysaccharide of the lipopolysaccharide from Acinetobacter strain 90 belonging to DNA group 10; Haseley SR et al.; Water-soluble lipopolysaccharide (phenol/water extraction) isolated from Acinetobacter strain 90, which belongs to DNA group 10, was hydrolysed with 1% acetic acid, ultracentrifuged, and water-soluble products finally eluted from a Sephadex G-50 column . The major fraction, a polysaccharide, contained D-Gal, D-GlcNAc, D-GalNAc, and 4,6-dideoxy-4-{(R)-3-hydroxybutyramido}-D-galactose (Fuc4NBuOH) . The polysaccharide was characterised by means of monosaccharide analyses, Smith-degradation, N-deacetylation/deamination, and NMR studies, and was shown to have a branched pentasaccharide repeating unit . {structure in text} This structure was specifically recognised in western blots and enzyme immunoassays by polyclonal rabbit antisera.

Ecotoxicol Environ Saf, 1997 Apr, 36(3), 269 - 74
The toxicity of substituted phenolic compounds to a detoxifying and an acetic acid bacterium; Loffhagen N et al.; In the detoxifying bacterium Acinetobacter calcoaceticus 69-V and in the acetic acid bacterium Acetobacter methanolicus MB 58, glucose and xylose are oxidized, respectively, via PQQ-dependent membrane-bound dehydrogenases, which are linked to the respiratory chain in a manner enabling energy conservation via electron transport phosphorylation (ETP) in the cytoplasmic membrane . Neither the glucose and gluconic acid nor the xylose and xylonic acid are metabolized . Therefore, measurements of sugar oxidation-driven ATP syntheses ought not to be disturbed by ATP drainage caused by anabolic processes . Studying the effect of substituted phenolic compounds on these energization processes reveals that their toxicity increases with an increasing degree of chlorination and that A . calcoaceticus 69-V is more stable than A . methanolicus MB 58 against chlorinated phenols . On the other hand, A . methanolicus MB 58 is more stable against 2,4-dinitrophenol (2,4-DNP) and 2,4-dichlorophenoxyacetic acid (2,4-D), especially in the acidic pH range, in which the sensitivity of ATP synthesis to the uncouplers is higher than that of respiration . The toxicity caused by protonophoric activities ought to be barely detectable by respiratory and dehydrogenase tests . The luminescence system of Photobacterium phosphoreum tested in the luminescent bacteria test was much more sensitive . This test system should be used as a screening tool and the effects measured must be confirmed by toxicity tests evaluating the stability of bacteria themselves involved in processes of detoxification as well as the production of toxic metabolites, monitored with respect to their velocity and efficiency.

Microbiology, 1997 Apr, 143 ( Pt 4), 1345 - 57
Directed introduction of DNA cleavage sites to produce a high-resolution genetic and physical map of the Acinetobacter sp . strain ADP1 (BD413UE) chromosome; Gralton EM et al.; The natural transformability of the soil bacterium Acinetobacter sp . ADP1 (BD413UE), formerly classified as A . calcoaceticus, has facilitated previous physiological and biochemical investigations . In the present studies, the natural transformation system was exploited to generated a physical and genetic map of this strain's 3780 +/- 191 kbp circular chromosome . Previously isolated Acinetobacter genes were modified in vitro to incorporate a recognition sequence for the restriction endonuclease NotI . Following transformation of the wild-type strain by the modified DNA, homologous recombination placed each engineered NotI cleavage site at the chromosomal location of the corresponding gene . This allowed precise gene localization and orientation of more than 40 genes relative to a physical map which was constructed with transverse alternating field electrophoresis (TAFE) and Southern hybridization methods . The positions of NotI, AscI and I-CeuI recognition sites were determined, and the latter enzyme identified the presence of seven ribosomal RNA operons . Multiple chromosomal copies of insertion sequence IS1236 were indicated by hybridization . Several of these copies were concentrated in one region of the chromosome in which a spontaneous deletion of approximately 100 kbp occurred . Moreover, contrary to previous reports, ColE1-based plasmids appeared to replicate autonomously in Acinetobacter sp . ADP1.

J Med Microbiol, 1997 Apr, 46(4), 314 - 20
Direct comparison of two commercially available computer programs for analysing DNA fingerprinting gels; Seward RJ et al.; Randomly amplified polymorphic DNA (RAPD) fingerprints were generated with M13 and DAF4 primers for 25 isolates of Acinetobacter spp . obtained from 16 different hospitals situated in 12 countries . The overall robustness of the algorithms and the reproducibility of the cluster analysis results generated by two commercially available computer programs (GelCompar and DENDRON) for analysing DNA fingerprinting gels were tested by examining the same set of fingerprinting data independently in two laboratories with the different software packages . Both programs were efficient at recognising and grouping strains with closely similar RAPD fingerprints, i.e., strains which might be expected to have a close epidemiological or evolutionary relationship . However, the relationships suggested for less closely related strains showed considerable variation in terms of the overall similarity or percentage correlation values suggested by the programs . It was concluded that both programs were useful tools for indicating close genotypic relationships between individual strains, but that epidemiological conclusions based on the similarity or correlation values (or the dendrograms derived from them) obtained for less closely related strains should be treated with considerable caution.

Can J Microbiol, 1997 Apr, 43(4), 384 - 90
Bioengineering of emulsifier structure: emulsan analogs; Gorkovenko A et al.; Strategies were investigated to modulate the side chain structure of emulsans formed by Acinetobacter calcoaceticus RAG-1 . Analysis of emulsan fatty acid side chain groups by gas chromatography--mass spectrometry (GC-MS) revealed that by provoking the exogenous n-alkanoic fatty acids 15:0, 16:0, and 17:0, emulsan analogs were formed with 53, 46, and 44 mol%, respectively, of fatty acid substituents with chain lengths equal to that of the carbon source . In contrast, the increase in emulsan fatty acids of chain lengths less than 15 or greater than 17 by providing corresponding shorter and longer chain length fatty acids as carbon sources was not substantial . When {1-13C}-labeled (99% enriched) palmitic acid was used as a carbon source along with acetate, analysis of M/z 75/74 and 87/88 isotopomer ratios by GC-MS indicated that 84 and 86% of the 16:0 (9-cis) side groups, respectively, were incorporated intact from the 16:0 carbon source . The percentage of 14- 15-, 16-, 17-, and 18-carbon chain length fatty acid esters that were monounsaturated were 11, 26, 50, 70, and 85% respectively . Based on the observed percentage of unsaturated chain length dependence and almost identical enrichment at C-1 of 16:0 and 16:1 (9-cis) side groups from {1-13 C}-labeled experiments, it was concluded that desaturation of preformed n-alkanoic acids was the predominant mechanism of their formation . Further work established correlations between side chain structure and product emulsification specificity/activity, so that bioengineered emulsans with improved selectivity can now be formed.

Antimicrob Agents Chemother, 1997 Apr, 41(4), 767 - 70
Activities of beta-lactams against Acinetobacter genospecies as determined by agar dilution and E-test MIC methods; Visalli MA et al.; The agar dilution MIC method was used to test activities of ticarcillin, ticarcillin-clavulanate, amoxicillin, amoxicillin-clavulanate, ampicillin, ampicillin-sulbactam, piperacillin, piperacillin-tazobactam, inhibitors alone, ceftazidime, and imipenem against 237 Acinetobacter genospecies . A total of 93.2% of strains were beta-lactamase positive by the chromogenic cephalosporin method . Overall, ampicillin-sulbactam was the most active combination against all strains (MIC at which 50% of the isolates are inhibited {MIC50} and MIC90, 4.0 and 32.0 microg/ml; 86.9% susceptible at < or = 16 microg/ml), followed by ticarcillin-clavulanate (16.0 and 128.0 microg/ml; 85.7% susceptible at < or = 64 microg/ml), piperacillin-tazobactam (16.0 and 128.0 microg/ml; 84.8% susceptible at < or = 64 microg/ml), and amoxicillin-clavulanate (16.0 and 64.0 microg/ml; 54.4% susceptible at < or =16 microg/ml) . Ceftazidime and imipenem yielded MIC50s and MIC90s of 8.0 and 64.0 microg/ml (ceftazidime) and 0.5 and 1.0 microg/ml (imipenem), respectively; 71.3% of strains were susceptible to ceftazidime at < or = 16 microg/ml, and 99.2% were susceptible to imipenem at < or = 8 microg/ml . Sulbactam was the most active beta-lactamase inhibitor alone (MIC50 and MIC90, 2.0 and 16.0 microg/ml); clavulanate and tazobactam were less active (16.0 and 32.0 microg/ml for both compounds) . Enhancement of beta-lactams by beta-lactamase inhibitors was not always seen in beta-lactamase-positive strains, and activity of combinations such as ampicillin-sulbactam was due to the inhibitor alone . Acinetobacter baumannii was the most resistant genospecies . By contrast, Acinetobacter haemolyticus, Acinetobacter calcoaceticus, Acinetobacter johnsonii, Acinetobacter junii, Acinetobacter radioresistens, and other non-Acinetobacter baumannii strains were more susceptible to all compounds tested . E-test MICs were within 1 dilution of agar dilution MICs in 38.4 to 89.6% of cases and within 2 dilutions in 61.6 to 98.6% of cases.

Eur J Biochem, 1997 Mar 15, 244(3), 761 - 6
Structural and serological characterisation of the O-antigenic polysaccharide of the lipopolysaccharide from Acinetobacter haemolyticus strain ATCC 17906; Haseley SR et al.; A polysaccharide containing 2-acetamido-2-deoxy-D-galacturonic acid (GalNAcA), 2.4-diacetamido-2,4,6-trideoxy-D-glucose (QuiNAc4NAc), and D-alanine (Ala) was isolated from the water-soluble lipopolysaccharide (LPS) originating from the reference strain for Acinetobacter haemolyticus (DNA group 4) strain ATCC 17906 . The polysaccharide, characterised by means of monosaccharide analyses and NMR studies, was shown to be based on a linear trisaccharide repeating unit, as shown below, with the alanine group amide-bound to position 6 of one GalNAcA residue . It was specifically recognised in western blots by polyclonal rabbit antisera . {structure: see text}

Cas Lek Cesk, 1997 Mar 12, 136(5), 154 - 6
{The effect of cefepime on ceftazidime, cefotaxime and imipenem resistant strains of Acinetobacter, Xanthomonas, Pseudomonas, Flavobacterium, Sphingobacterium and on producers of extended spectrum beta-lactamases (ESBL) with resistance transfer}; Blahova J et al.; BACKGROUND: The new cephalosporins with heterocyclic positively charged substituent at position C3 belong to the 4th generation cephalosporins . It is not evident, whereas these antibiotics are effective against cefotaxime-ceftazidime-resistant bacteria . We investigated the efficiency of the cefepime (Maxipime, BMS) against Acinetobacter sp., X . maltophilia, Pseudomonas sp., Flavobacterium sp., Sphingobacterium sp . and against strains with production of ESBL (Extended Spectrum beta-Lactamases) (Enterobacter sp., Citrobacter sp., Klebsiella sp.) . METHODS AND RESULTS: We determined the susceptibility of the 54 strains resistant to 50 mg/l and more of ceftazidime . The majority of the strains (35) are susceptible to cefepime and MIC is the range 1.65-3.15 mg/l of cefepime . 17 strains have MIC = 6.25 mg/l . Two strains (one strain P . aeruginosa a one strain K . pneumoniae) were resistant to cefepime and MIC = 12.5 mg/l . The activity of beta-lactamases was determined by quantitative macroiodometric method in one strain of P . cepacia and two strains of Sphingobacterium multivorum . They hydrolyse actively imipenem (they produce metallo-beta-lactamase) and ceftazidime (they are highly resistant to this antibiotic), but cefepime is more slowly hydrolysed than ceftazidime . CONCLUSIONS: At the present time cefepime is effective against ceftazidime-resistant strains in so-called "problematic" species of bacteria . However, it is important to protect its efficiency in the future, this requires its rational use.

Enferm Infecc Microbiol Clin, 1997 Mar, 15(3), 140 - 3
{Selection of resistance mutants and bacteriostatic and bactericidal activity of meropenem and imipenem against Acinetobacter spp.}; Villar HE et al.; BACKGROUND: To evaluate the inhibitory and bactericidal activity of meropenem and imipenem against multiresistant isolates of Acinetobacter spp and to compare the frequency of mutation for both antibiotics . METHODS: Minimum inhibitory concentrations were determined by the agar dilution method . Bactericidal activities were evaluated by killing curves method employing 8 times the MIC . One-step resistant mutant selection was performed by spreading more than 5 x 10(8) ufc/ml on agar Mueller Hinton plates containing 2, 4 and 8 times the MIC of meropenem or imipenem . RESULTS: In the group of sensitive strains (MIC < 4 mg/l for imipenem and meropenem) we detected lower MIC for imipenem than meropenem (61.5% of the strains) . Strains with reduced susceptibility to imipenem (MIC = 4 mg/l) were more sensitive to meropenem with MICs equivalents to the sensitive group . Bactericidal activity was detected in 6 hs for imipenem and in 24 hs for meropenem . Meropenem was bactericidal in 4 clinical isolates with MICs = 4 mg/l for imipenem and imipenem was bactericidal in laboratory mutants resistant to meropenem . It was no possible to select mutants resistant to imipenem but for meropenem the rate of mutation was 1.4 x 10(-9) to 1.0 x 10(-8) . Mutants resistant to meropenem were susceptible to imipenem and 57% of them were stable . CONCLUSIONS: From the laboratory point of view we consider that imipenem is more active than meropenem because it presents lower MICs, better bactericidal activity, and no risk to select resistance . However meropenem could be useful in some strains resistant to imipenem (MIC = 4 mg/l) . Cross-resistance was no detected so we consider that both antibiotics should be tested against Acinetobacter spp . because they are not equivalents.

Arch Bronconeumol, 1997 Mar, 33(3), 133 - 5
{Peracetic acid: alternative to the sterilization of bronchofibroscopes}; Villate JI et al.; The Steris system for cold sterilization with peracetic acid was evaluated by effecting a series of contaminations of a fiberoptic bronchoscope (FB) with specimens of Pseudomonas aeruginosa, Acinetobacter baumanii and Mycobacterium kansasi . The FB was contaminated 24 times, 8 times by each microorganism, using specimens containing more than 10(8) cfu/ml . After fixing the secretions on the FB and washing it with enzyme soap, the BF was sterilized . Specimens were taken for culturing after contamination of the FB, after washing, immediately after sterilization and 1 hour after sterilization . No microorganism growth of any of the samples was detected either immediately after sterilization or one hour later . Microbiological data confirmed contamination of the FB after aspiration and fixation of the inoculate . Chemical and biological tests with B . stearothermophilus spores as specified by the manufacturer were correct in all cases: 24 contaminations and 52 processes of prior training . The efficacy of washing with enzyme soap before sterilization stands out . In 14 of the 24 samples, culture was negative after washing and in 7 the concentration of microorganisms was less than 500 cfu/ml, which confirms the need for appropriate washing before any disinfection or sterilization process is begun . In conclusion, the Steris system based on peracetic acid is an alternative to other systems for cold sterilization or high level disinfection.

Clin Infect Dis, 1997 Mar, 24(3), 494 - 7
beta-Lactamase inhibition and in vitro activity of sulbactam and sulbactam/cefoperazone; Williams JD; beta-Lactamase inhibitors such as sulbactam are beta-lactam compounds that have low antimicrobial activity but are able to inhibit enzymes (beta-lactamases) that destroy beta-lactam antibiotics like penicillins and cephalosporins . The main activity of beta-lactamase inhibitors is directed against plasmid-mediated transferable enzymes and various extended-spectrum enzymes . Sulbactam is also active against some of the fixed chromosomally mediated enzymes produced by gram-negative bacteria and is active against Bacteroides and Acinetobacter species . Cefoperazone, a third-generation cephalosporin, is active against a wide range of gram-positive and gram-negative bacteria, including Enterobacteriaceae and Pseudomonas species . However, transferable beta-lactamases are now produced by numerous gram-negative organisms, mitigating the effectiveness of therapy with this agent . Chromosomally mediated enzymes are less common but can be induced in some strains of Klebsiella, Enterobacter, and Serratia species . The full potential of cefoperazone against Enterobacteriaceae and Pseudomonas species is restored by the addition of sulbactam; this addition extends cefoperazone's spectrum of activity to include Bacteroides and Acinetobacter species.

J Antimicrob Chemother, 1997 Mar, 39(3), 419 - 22
Antimicrobial susceptibilities of blood culture isolates obtained before and after the introduction of ciprofloxacin; Pieroni P et al.; The in-vitro susceptibilities of 1658 blood culture isolates to ciprofloxacin and 13 other antimicrobial agents were determined, and compared with the results for isolates obtained before and after the availability of ciprofloxacin in 1989 . Only six (0.6%) of 995 Enterobacteriaceae were resistant to the fluoroquinolones tested; all of the ciprofloxacin-resistant strains were isolated after 1989 (P = 0.04) . No significant increase in ciprofloxacin resistance was found in Pseudomonas aeruginosa or Acinetobacter spp . No resistance to ciprofloxacin was found in 124 Staphylococcus aureus isolates prior to 1989, but five (2.4%) of 208 S . aureus strains recovered after 1989 were ciprofloxacin-resistant (P = 0.16) . Rates of resistance to ciprofloxacin and other antimicrobial agents commonly used to treat bacteraemic infections have remained relatively low in this Canadian teaching hospital over the past 16 years.

Gene, 1997 Feb 28, 186(2), 305 - 8
Nucleotide sequence of a putative periplasmic Mn superoxide dismutase from Acinetobacter calcoaceticus ADP1; Geissdorfer W et al.; We determined 5.8 kilobases of nucleotide sequence upstream of the rubredoxin encoding rubA gene of Acinetobacter calcoaceticus (Ac) ADP1 . Sequence analysis revealed four open reading frames named cysD', cobQ, sodA and lysS, coding for proteins with high similarity to known sulfate adenylate transferases (partial), cobyric acid synthases, superoxide dismutases (Sod) and lysyl tRNA synthetases, respectively . Out of a large number of bacterial Sod sequences SodA of Ac ADP1 is the first member of the Fe/Mn Sod family apparently located in the periplasmic space.

Eur J Biochem, 1997 Feb 15, 244(1), 147 - 54
Structures of polymeric products isolated from the lipopolysaccharides of reference strains for Acinetobacter baumannii O23 and O12; Haseley SR et al.; A polysaccharide containing D-galactose (Gal), 2-acetamido-2-deoxy-D-galactose (GalNAc), 2-acetamido-2-deoxy-D-glucose (GlcNAc), and 3-deoxy-3-(D-3-hydroxybutyramido)-D-quinovose (Qui3NR) was isolated from lipopolysaccharide (LPS) obtained from cells walls of the reference strain for Acinetobacter baumannii O23 . By means of NMR studies, methylation analysis, and chemical degradations, the repeating unit of the polymer was identified as a branched pentasaccharide with the structure 1 . The same polymer was apparently also present in LPS of the reference strain for serogroup O12, together with a second polymer based on a branched tetrasaccharide with the structure 2 . This second polymer has previously been isolated as the O16 antigen of A . baumannii {Haseley, S.R., Diggle, H.J . & Wilkinson, S . G . (1996) Carbohydr . Res . 293, 259-265} and is probably present as a minor component of the LPS of A . baumannii O11 {Haseley, S.R . & Wilkinson, S.G . (1996) Eur . J . Biochem . 237, 266-271} . {Sequence: see text}

APMIS, 1997 Feb, 105(2), 131 - 8
Epidemiological study of Acinetobacter species isolated from an intensive care unit; Garcia-Arata MI et al.; An epidemiological survey of the increase in Acinetobacter species isolates occurring in the intensive care unit of a Spanish teaching hospital during 1993 and 1994 was carried out . Different laboratory methods were used to find out, whether there was a genetic linkage . The isolates were divided into three main groups according to the resistance patterns to 11 drugs . Using API 20NE biotyping, eight different types were found . The two most common contained 20 and 11 isolates, respectively . Five different plasmid profile types were observed, although plasmids were only demonstrated in 40% of the isolates . Ribotyping with EcoRI, SalI and ClaI enzymes revealed 10, 9, and 8 different patterns, respectively . In total, 15 different ribotypes were identified using these three enzymes . Twenty-one isolates belonged to exactly the same ribotype, and 13 were associated with two highly related ribotypes . In the first ribotype, only five isolates harboured plasmids . The ribotyping method produced 100% typability and ribotypes were easy to compare; it also had taxonomic value . Ribotyping allowed us to determine the genetic linkage between Acinetobacter isolates recovered from ICU patients.

Int J Biol Macromol, 1997 Feb, 20(1), 9 - 21
Incorporation of 2-hydroxyl fatty acids by Acinetobacter calcoaceticus RAG-1 to tailor emulsan structure; Zhang J et al.; Acinetobacter calcoaceticus RAG-1 was cultured on different chain length saturated 2-hydroxyl fatty acid (2-HOFA) carbon sources as follows: C12:0 (2-OH), C14:0 (2-OH), C16:0 (2-OH) and C18:0 (2-OH) . These 2-HOFAs were used as either sole carbon sources or cosubstrates with C14:0 (total 1% w/v) to form new emulsans (EMs) having controlled side chain FA structure and, therefore, unique emulsifier characteristics . EM yields and cell dry weights ranged from 0.6 to 1.8 g/l and 0.9 to 3.9 g/l, respectively, depending on the carbon source(s) and the cultivation conditions . The content of C12:0 (2-OH) EM substituents reached high levels (306 nmol/mg-EM, 64.4 mol% of total FAs) by selectively feeding this FA . Substantial quantities of 2-HOFAs with chain lengths > or = C14-up to 96 nmo1/mg-EM or 15.2 mol% for C16:0 (2-OH)-were also incorporated in EMs by providing the corresponding 2-HOFA carbon source in the medium . By increasing the medium 2-HOFA concentration large increases in EM total FA contents resulted . The EM FA content was as high as 955 nmol/mg-EM or 23 wt% for a culture containing 0.75 g/100 ml C18:0 (2-OH) . An important metabolic pathway involved in EM side chain formation from C16:0 (2-OH) and C18:0 (2-OH) involves decarboxylation, oxidation of the alkanol to the corresponding n-1 FA-CoA intermediate and formation of odd chain length substituent side chain linkages by an EM acyl transferase . Addition of the enzyme alkylating agent iodoacetamide to cultures was used to: (i) enhance the incorporation into EMs of both C12:0 (2-OH) and C16:0 (2-OH) substituents; and (ii) increase by 1.3 to 1.8 fold (by wt.) the total EM FA content . Finally, it was concluded that enhanced emulsification activity of EMs is not necessarily achieved by forming products with relatively high 2- and 3-hydroxydodecanoic acid contents.

J Chemother, 1997 Feb, 9(1), 9 - 16
Antibacterial activities of grepafloxacin, ciprofloxacin, ofloxacin and fleroxacin; Barry AL et al.; Grepafloxacin (OPC-17116) and three other fluoroquinolones were tested against 461 bacterial isolates representing 44 species . Grepafloxacin was superior to ciprofloxacin, ofloxacin and fleroxacin in its activity against the Gram-positive cocci, including staphylococci, pneumococci and hemolytic streptococci . Attempts to select grepafloxacin-resistant mutants from a methicillin-resistant Staphylococcus aureus strain were unsuccessful, although ciprofloxacin readily selected quinolone-resistant mutants of that strain . Among Gram-negative bacilli other than Escherichia coli, mutants were readily selected by in vitro exposure to either grepafloxacin or ciprofloxacin . All such mutants showed complete cross resistance to six other quinolones . The four study drugs were active against nalidixic acid-susceptible strains belonging to 13 species of the Enterobacteriaceae, but ciprofloxacin was the most potent drug studied . Against Acinetobacter spp . and Stenotrophomonas maltophilia, grepafloxacin was two- to four-times more active than ciprofloxacin . However, against Pseudomonas aeruginosa, ciprofloxacin was two- to four-times more potent than grepafloxacin . Grepafloxacin and ciprofloxacin were both found to be bactericidal agents.

J Chemother, 1997 Feb, 9(1), 5 - 8
Effect of vancomycin and teicoplanin alone or in combination with fusidic acid or amikacin against methicillin-resistant staphylococci; Roussel-Delvallez M et al.; The action of two glycopeptides (vancomycin and teicoplanin) alone or in combination with amikacin or fusidic acid has been studied against 10 non-repetitive strains of methicillin-resistant Staphylococcus . The plotted killing curves show that the combination of vancomycin or teicoplanin plus fusidic acid always exhibited an antagonist effect at 24 h for the 10 strains . The combination vancomycin or teicoplanin plus amikacin shows the same effect at 24 h as vancomycin or teicoplanin alone . Thus, the combination glycopeptide plus amikacin does not alter the activity of the glycopeptide but does increase the spectrum of activity of the combination versus Gram-negative nosocomial bacteria (Pseudomonas aeruginosa, Acinetobacter sp) . The vancomycin or teicoplanin plus fusidic acid combination may be responsible for bacteriological failure against methicillin-resistant Staphylococcus.

Zentralbl Bakteriol, 1997 Feb, 285(3), 403 - 12
Macrorestriction analysis (PFGE) of serologically cross-reactive serovars of Acinetobacter baumannii and genospecies 3; Traub WH et al.; Forty-two serovar reference strains of Acinetobacter baumannii and genospecies 3, which yielded major or minor, one-way or two-way (reciprocal) serological cross-reactions, were subjected to macrorestriction (SmaI, ApaI) analysis with the aid of pulsed-field gel electrophoresis (PFGE) . The PFGE patterns of serovars 3 and 21 of genospecies 3 differed by 3 (SmaI) and 2-4 (ApaI) DNA fragments and thus were closely/possibly related in their genotype . Serovars 13 and 26 of genospecies 3 differed by only 2 DNA fragments (SmaI), suggesting close genetic relatedness; however, these two particular serovars of genospecies 3 appeared to be genotypically indistinguishable following restriction with ApaI . Serovars 2, 4, and 12 of genospecies 3 appeared to be unrelated to serovar 13 of genospecies 3 (SmaI); however, restriction with ApaI indicated a possible relatedness . Genospecies 3 serovars 2 and 26 differed by 5 DNA fragments (SmaI and ApaI), implying a possible relatedness . All other cross-reactive serovars examined proved to be genotypically unrelated, i.e., differed by > or = 7 DNA fragments (SmaI restriction).

Lett Appl Microbiol, 1997 Feb, 24(2), 105 - 8
Production of amylase by the intestinal microflora in cultured freshwater fish; Sugita H et al.; The amylase-producing ability of the intestinal microflora in cultured specimens of ayu, carp, channel catfish, Japanese eel and tilapia was determined . Mean viable counts of aerobes and anaerobes ranged from 1.1 x 10(6) to 3.7 x 10(8) cfu g-1 and from 1.3 x 10(3) to 1.6 x 10(8) cfu g-1, respectively . Aeromonas spp . and Bacteroidaceae were predominant in four to five fish species . Of 206 strains examined, 65 (31.6%) produced > or = 0.01 U amylase ml-1 . The percentage of producers differed among families and genera of bacteria and fish species . While 56% of the anaerobes produced amylase, only 20% of the aerobes did . More than 50% of Aeromonas, Bacteroidaceae and Clostridium strains produced amylase efficiently while Acinetobacter, coryneforms, Enterobacteriaceae, Moraxella, Plesiomonas and Streptococcus strains did not . High amylase production (> or = 0.05 U ml-1) was found in 12 strains, 11 from Aeromonas and one Pseudomonas . The percentage of high amylase producers in Japanese eel was lower than the other four fish (2-30%) . These results strongly suggest that the amylase produced by the intestinal microflora play an important role in the digestion of starch in freshwater fish to some extent.

J Antimicrob Chemother, 1997 Feb, 39(2), 255 - 60
A reassessment of the in-vitro activity of colistin sulphomethate sodium; Catchpole CR et al.; The in-vitro activity of colistin sulphomethate sodium was compared with that of other commonly used antimicrobial agents against 377 recent clinical isolates of Gram-negative bacteria (including 94 strains of Pseudomonas aeruginosa from patients with cystic fibrosis) and 16 organisms with defined resistance patterns . Colistin was active against most strains of P . aeruginosa (MIC90 4 mg/L), Shigella spp . (MIC90 0.5 mg/L), Salmonella spp . (MIC90 1 mg/L), Acinetobacter spp . (MIC90 2 mg/L), Citrobacter spp . (MIC90 1 mg/L), Escherichia coli (MIC90 1 mg/L), Klebsiella spp . (MIC90 8 mg/L) and Enterobacter spp . (MIC50 1 mg/L) . No useful activity was demonstrated against Providentia spp . or Serratia spp . The results show that colistin remains a useful antimicrobial agent against Gram-negative bacteria, particularly those strains which are resistant to more commonly used antibiotics.

J Antimicrob Chemother, 1997 Feb, 39(2), 235 - 40
Oral treatment of Staphylococcus spp . infected orthopaedic implants with fusidic acid or ofloxacin in combination with rifampicin; Drancourt M et al.; Oral therapy of staphylococcal infection of orthopaedic implants with 900 mg/day rifampicin combined with either 1.5 g/day fusidic acid for 5 days followed by 1 g/day thereafter, or 600 mg/day ofloxacin was compared . Patients with an infected hip were treated for 6 months, with removal of any unstable prosthesis after 5 months' treatment and those with an infected knee prosthesis were treated for 9 months, with removal of the prosthesis after 6 months of treatment . Patients with infections of other type of bone implants were treated for 6 months with removal of the implant after 3 months of treatment, if necessary . Cure was defined as the absence of clinical, microbiological and radiological evidence of infection 12 months after completion of treatment . The treatment of 46 of the 52 included in the study was evaluated for safety and that of 42 was assessed for efficacy . Overall treatment was successful for 11 (55%) of 20 patients treated with rifampicin and fusidic acid group and for 11 (50%) of the 22 treated with rifampicin and ofloxacin . Treatment failed in four cases in each treatment group because of persistent infection . One patient given rifampicin and fusidic acid and three patients given rifampicin and ofloxacin failed treatment because of relapse . Superinfection led to failure in the remainder and was due to staphylococci in all but one case in which Acinetobacter calcoaceticus var . anitratus was isolated . There were no side effects related to study treatment . Oral treatment with rifampicin combined with fusidic acid may be a suitable alternative to the combination of rifampicin and ofloxacin for treating implant infections due to Staphylococcus spp . either when the patient is intolerant to quinolones or when the infecting organism is resistant to these drugs.

J Hosp Infect, 1997 Feb, 35(2), 129 - 40
Outbreak of septicaemia in neonates caused by Acinetobacter junii investigated by amplified ribosomal DNA restriction analysis (ARDRA) and four typing methods; Bernards AT et al.; Septicaemia caused by Acinetobacter occurred in six infants in the neonatal unit . A total of 18 acinetobacters were isolated from blood cultures, cultures of intravascular catheters, and surveillance cultures . Twelve isolates from the six affected infants were identified as Acinetobacter junii by the use of a novel method, amplified ribosomal DNA restriction analysis (ARDRA) . Typing of the organisms using the biochemical profiles of the API 20NE system, antibiogram typing, cell envelope protein electrophoresis, and PCR fingerprinting with two primer sets, ERIC1/ERIC2 and ERIC2/ 1026, showed that these 12 isolates were indistinguishable, whereas the remaining six isolates were different . The six infants recovered after therapy with ciprofloxacin alone in five cases and with a combination of ciprofloxacin and gentamicin in one case . This study showed that A . junii is capable of causing a serious, though non-fatal infection in neonates . The combined use of genotypic and phenotypic methods allowed the rapid separation of epidemic from non-epidemic isolates . It is concluded that for a better understanding of the role of the various Acinetobacter genomic species in human pathology, identification of acinetobacters according to the recent taxonomy is imperative.

Microbiology, 1997 Feb, 143 ( Pt 2), 595 - 602
Sequence analysis of pqq genes required for biosynthesis of pyrroloquinoline quinone in Methylobacterium extorquens AM1 and the purification of a biosynthetic intermediate; Toyama H et al.; Methylobacterium extorquens AM1 produces pyrroloquinoline quinone (PQQ), the prosthetic group of methanol dehydrogenase . Two genes clusters have been shown to be required for PQQ biosynthesis in this micro-organism and complementation analysis has identified seven pqq genes, pqqDGCBA and pqqEF . The DNA sequence of pqqDGC' was reported previously . This paper reports the sequence of the genomic region corresponding to pqqC'BA . For consistency, the nomenclature of pqq genes in Klebsiella pneumoniae will be followed . The new nomenclature for pqq genes of M . extorquens AM1 is pqqABCDE and pqqFG . In the genomic region sequenced in this study, two open reading frames were found . One of these encodes pqqE, which showed high identity to analogous pqq genes in other bacteria . PqqE also showed identity to MoaA and NifB in the N-terminal region, where a conserved CxxxCxYC sequence was identified . The sequence of the second open reading frame covered both the pqqC and pqqD regions, suggesting that both functions were encoded by this gene . It is proposed to designate this gene pqqC/D . The deduced amino acid sequence of the pqqC/D products showed identity to PqqC of K . pneumoniae and Pqql of Acinetobacter calcoaceticus in the N-terminal region, and to PqqD of K . pneumoniae and Pqql of A . calcoaceticus in the C-terminal region . A fragment of M . extorquens AM1 DNA containing only pqqC/D produced a protein of 42 kDa in Escherichia coli, which corresponds to the size of the deduced amino acid sequence of PqqC/D, confirming the absence of a separate pqqD . This genomic region complemented the growth of pqqC mutants of M . extorquens AM1 and Methylobacterium organophilum DSM 760 on methanol . As previously reported for pqq genes of K . pneumoniae, a pqqC mutant of M . extorquens AM1 produced an intermediate of PQQ biosynthesis, which was converted to PQQ by incubation with a crude extract from E.coli cells expressing PqqC/D . The intermediate was found in both crude extract and culture supernatant, and it was purified from the crude extract . The PqqC/D enzyme reaction appeared to require molecular oxygen and reduced nicotinamide adenine dinucleotides.

FEMS Microbiol Lett, 1997 Feb 1, 147(1), 1 - 9
Bacterial carnitine metabolism; Kleber HP; L-(-)-Carnitine is a ubiquitously occurring substance, essential for the transport of long-chain fatty acids through the inner mitochondrial membrane . Bacteria are able to metabolize this trimethylammonium compound in three different ways . Some, especially Pseudomonas species, assimilate L-(-)-carnitine as sole source of carbon and nitrogen . The first catabolic step is catalysed by the L-(-)-carnitine dehydrogenase . Others, for instance, Acinetobacter species, degrade only the carbon backbone, with formation of trimethylamine . Finally, various members of the Enterobacteriaceae are able to convert carnitine, via crotonobetaine, to gamma-butyrobetaine in the presence of C and N sources and under anaerobic conditions . This two-step pathway, including a L-(-)-carnitine dehydratase and the crotonobetaine reductase, was demonstrated in Escherichia coli . The DNA sequence encompassing the cai genes of E . coli, which encode the carnitine pathway, has been determined . Some bacteria are also able to metabolize the non-physiological D-(+)-carnitine, which results as a waste product in some chemical procedures for L-(-)-carnitine production based on the resolution of racemic carnitine.

J Bacteriol, 1997 Feb, 179(4), 1329 - 36
Expression, inducer spectrum, domain structure, and function of MopR, the regulator of phenol degradation in Acinetobacter calcoaceticus NCIB8250; Schirmer F et al.; Degradation of phenol by Acinetobacter calcoaceticus NCIB8250 involves (sigma54-dependent expression of a multicomponent phenol hydroxylase and catechol 1,2-dioxygenase encoded by the mop operon . Complementation of a new mutant deficient in phenol utilization yielded the regulatory locus mopR . It is located in divergent orientation next to the mop operon . MopR is constitutively expressed at a low level from a sigma70-type promoter and belongs to the NtrC family of regulators . The amino acid sequence is similar to that of XylR regulating xylene degradation and to that of DmpR regulating dimethylphenol degradation in Pseudomonas spp . However, it shows a different effector profile for substituted phenols than DmpR . MopR activates phenol hydroxylase expression in the presence of phenol in Escherichia coli, indicating that it binds the effector . The phenol binding A domains of MopR and DmpR have fewer identical residues than the A domains of DmpR and XylR, despite the fact that XylR recognizes different effectors . This suggests that sequence conservation in the A domain does not reflect the potential to bind the respective effectors . Overexpression of the MopR A domain in the presence of wild-type MopR causes loss of mop inducibility by phenol, establishing its negative transdominance over MopR . Deletion of 110 residues from the N terminus did not affect transdominance of the truncated domain, whereas deletion of 150 residues abolished it completely . This result establishes the distinction of two subdomains, A(N) and A(C), which together constitute the A domain . The C-terminal portion of the A domain, A(C), shows considerable affinity for the C domain, even in the presence of the trigger phenol.

Antimicrob Agents Chemother, 1997 Feb, 41(2), 345 - 51
Use of a new mouse model of Acinetobacter baumannii pneumonia to evaluate the postantibiotic effect of imipenem; Joly-Guillou ML et al.; Acinetobacter baumannii is responsible for severe nosocomial pneumonia . To evaluate new therapeutic regimens for infections due to multiresistant strains and to study the pharmacodynamic properties of various antibiotics, we developed an experimental mouse model of acute A . baumannii pneumonia . C3H/HeN mice rendered transiently neutropenic were infected intratracheally with 5 x 10(6) CFU of A . baumannii . The mean log10 CFU/g of lung homogenate (+/- the standard deviation) were 9 +/- 0.9, 9.4 +/- 0.8, 8.6 +/- 1.2, and 7.7 +/- 1.4 on days 1, 2, 3, and 4 postinoculation . The lung pathology was characterized by pneumonitis with edema and a patchy distribution of hemorrhages in the peribronchovascular spaces of both lungs . Abscesses formed on days 3 and 4 . Four days after inoculation, subacute pneumonitis characterized by alveolar macrophage proliferation and areas of fibrosis was observed . The cumulative mortality on day 4 was 85% . This new model was used to study the effects of 1, 2, or 3 50-mg/kg doses of imipenem . Imipenem concentrations in lungs were above the MIC for 2 h after the last dose . The in vivo postantibiotic effect (PAE) was determined during the 9-h period following the last dose; it decreased in duration with the number of doses: 9.6, 6.4, and 4 h after 1, 2, and 3 50-mg/kg doses, respectively . In contrast, no in vitro PAE was observed . This model offers a reproducible acute course of A . baumannii pneumonia . The presence of a prolonged in vivo PAE supports the currently recommended dosing intervals of imipenem for the treatment of human infections due to A . baumannii, i.e., 15 mg/kg three times a day.

Eur J Biochem, 1997 Jan 15, 243(1-2), 167 - 73
Structural and serological characterisation of the O-specific polysaccharide from lipopolysaccharide of Acinetobacter calcoaceticus strain 7 (DNA group 1); Vinogradov EV et al.; S-form lipopolysaccharide was isolated by phenol/water extraction from a strain of Acinetobacter calcoaceticus (DNA group 1 ) . The structure of the O-antigenic polysaccharide was determined by compositional analysis and NMR spectroscopy of the de-O-acylated lipopolysaccharide . The isolated polysaccharide obtained after hydrolysis of lipopolysaccharide in 0.01 M trifluoroacetic acid has the following structure: {STRUCTURE IN TEXT} in which Pyr is pyruvate . The O-acetyl substitution of D-Gal was non-stoichiometric . The O-antigen was specifically recognised in western blots by polyclonal rabbit antisera.

Eur J Biochem, 1997 Jan 15, 243(1-2), 122 - 7
The structure of the carbohydrate backbone of the lipopolysaccharide from Acinetobacter strain ATCC 17905; Vinogradov EV et al.; The structure of the carbohydrate backbone of the lipopolysaccharide from Acinetobacter strain ATCC 17905 was studied . After deacylation of the lipopolysaccharide, a mixture of two compounds (ratio approximately 2:1) was isolated by high-performance anion-exchange chromatography, the structures of which were determined by NMR spectroscopy and electrospray-mass spectrometry as {STRUCUTRE IN TEXT} {Sug, 3-deoxy-D-manno-2-octulopyranosonic acid (Kdo) in oligosaccharide 1 (major portion) and D-glycero-D-talo-2-octulopyranosonic acid (Ko) in oligosaccharide 2 (minor portion)} . All monosaccharide residues also possess the D-configuration and are present in the pyranose form.

J Basic Microbiol, 1997, 37(3), 167 - 74
Chemicals and heat generate different protein patterns in Acinetobacter calcoaceticus; Benndorf D et al.; The effect of exposing Acinetobacter calcoaceticus 69-V to DNP-stress and heat shock was examined by two-dimensional gel electrophoresis of proteins, which were detected either by autoradiography or by silver staining . Both DNP stress and heat shock led to altered patterns of protein synthesis or concentration . About 10% of the proteins which were synthesized newly or at an increased rate and about 25% of those which were found newly or with an increased concentration after DNP treatment were identified after heat shock, too.

Lupus, 1997, 6(5), 480 - 3
Acinetobacter pericarditis with tamponade in a patient with systemic lupus erythematosus; Lam SM et al.; We describe a case of active systemic lupus erythematosus (SLE) complicated with a large amount of pericardial effusion with diastolic collapse of right ventricle suggestive of tamponade . Isolates from surgical drainage of pericardial fluid showed Acinetobacter baumannii exhibiting multiple antibiotics resistance . Despite the high frequency of both pericardial involvement and of infection complications in SLE, septic pericarditis and tamponade is considered rare . Most of the reported cases of septic pericarditis in SLE were due to Staphylococcal aureus, and Acinetobacter baumannii has never been reported beforePublication Types:

	Case Reports
	Review
	Review of Reported Cases

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