Respir Med, 1993 Oct, 87(7), 535 - 9 Cystic fibrosis: antibiotic prescribing practices in the United Kingdom and Eire; Taylor RF et al.; The antimicrobial prescribing practices of 26 physicians from the U.K . and Eire who care for patients with cystic fibrosis (CF) were assessed by postal questionnaire . Our main aim was to delineate divergent practices which may reveal a need for controlled prospective studies . For first-line intravenous (i.v.) therapy of acute exacerbations associated with Pseudomonas aeruginosa, 20 physicians (76.9%) combine a penicillin derivative with an aminoglycoside, in contrast to five (19.2%) who regularly use i.v . monotherapy with ceftazidime and one who combines i.v . ceftazidime with an aminoglycoside . When i.v . therapy is considered inappropriate, oral ciprofloxacin is sometimes used by all clinicians and oral broad spectrum agents are used in addition by 13, chloramphenicol being prescribed most often . Excluding allergy, the most important factor influencing choice of agents by 19 (73.1%) physicians is the most recent sputum susceptibility results . For maintenance therapy, 21 prescribe oral anti-staphylococcal agents if Staphylococcus aureus is isolated; of these, eight do so only if lung function deteriorates, nine after repeated isolation and four after first isolation of S . aureus . The remaining five physicians give anti-staphylococcal drugs to all patients once the diagnosis of CF is made . For maintenance of lung function in patients with persistent P . aeruginosa, all physicians used nebulized antibiotics, the indications for which vary between units . There was general concordance in the therapy of exacerbations associated with P . aeruginosa, whereas the use of agents to maintain lung function is more varied . We suggest that prospective studies address practices which vary greatly, such as the route, the duration and the timing of initiating antibiotic therapy given to maintain lung function. Br J Theatre Nurs, 1993 Oct, 3(7), 5 - 6, 9 Theatre footwear: a health hazard? Thomas JA, Fligelstone LJ, Jerwood TE, Rees RW. Theatre footwear frequently appears to be contaminated with blood . We assessed objectively the nature and degree of contamination of theatre shoes after cleaning . Two hundred pairs of theatre shoes were randomly selected from three hospitals in South East Wales . Hospital 1 (H1), 100 pairs of shoes, Hospital 2 (H2), 40, Hospital 3 (H3), 60 . They were examined for general appearance, the presence of bacterial pathogens and blood, using a leuchomalachite green assay . The majority of shoes were dirty, 63% in H1, 80% in H2, and 95% in H3 . Six per cent of shoes in H1, 2.5% in H2 and 0% in H3 were contaminated with staphylococcus aureus . No shoes were contaminated with pseudomonas aeruginosa . Thirty six per cent of shoes in H1, 40% in H2 and 57% in H3 were contaminated with blood . In H1 it was possible to determine the grade of staff to whom the shoes belonged . Fifty eight per cent of consultant surgeons' shoes tested positive for blood, 50% of junior surgeons, 16% of operating department assistants and none of nurses' theatre shoes . The high level of blood contamination following cleaning may pose a potential HIV or hepatitis B risk to patients, manual shoe cleaner and surgeons . We have demonstrated that current shoe cleaning practices are ineffective . We propose methods that should eliminate this risk . Procedures will need to be defined. Thorax, 1993 Oct, 48(10), 1002 - 5 Adult cystic fibrosis: association of acute pulmonary exacerbations and increasing severity of lung disease with auxotrophic mutants of Pseudomonas aeruginosa; Taylor RF et al.; BACKGROUND--Pseudomonas aeruginosa has been located in the endobronchiolar spaces of patients with cystic fibrosis where nutrients may be limited . In these sites it is thought that adaptation of the pathogen might occur and growth factors, present in relative excess, may thus promote survival of the organism . Auxotrophy of pulmonary isolates of P aeruginosa has previously been shown to be a feature of cystic fibrosis and chronic lung sepsis; auxotrophic isolates have additional nutritional requirements to the prototrophic "wild types" of the species . A study was therefore carried out to determine whether the proportion of auxotrophs differs between stable and acutely ill patients, or correlates with the extent of underlying disease . METHODS--Sputum samples were cultured for P aeruginosa and tested for auxotrophy by spreading serial dilutions of homogenised sputum on to a minimal medium which supports only prototrophs, and a complete medium which supports both nutritional types . The proportion of auxotrophs to prototrophs was determined and growth factors of confirmed auxotrophs were identified . RESULTS--Thirty two (86%) of 37 adults with cystic fibrosis infected with P aeruginosa harboured auxotrophs; methionine dependent mutants were isolated from seven of 16 patients tested (44%) . More than 50% of the total number of colonies were auxotrophic in 19 of 26 samples (73%) from patients with acute exacerbations and in only six of 15 samples (40%) from clinically stable patients . In four patients from whom samples in both the acute and stable states were available, the proportion of auxotrophs fell in the sample taken when stable . Auxotrophs predominated in all samples from 11 of those patients with very severe underlying lung disease, in contrast to 13 of 30 samples from patients with less severe disease . There was no association between the percentage of auxotrophs and the presence of other respiratory pathogens . CONCLUSIONS--The majority of adults with cystic fibrosis infected with P aeruginosa harbour auxotrophs in the sputum . A significant proportion of acutely ill patients and those with severe underlying disease have a preponderance of auxotrophs in the sputum compared with stable patients and those with less severe disease. Int J Biol Macromol, 1993 Oct, 15(5), 287 - 92 Biosynthesis of poly(3-hydroxy-alkanoates) in Pseudomonas aeruginosa AO-232 from 13C-labelled acetate and propionate; Saito Y et al.; Pseudomonas aeruginosa AO-232 produced poly(3-hydroxyalkanoates) (P(3HA)) containing monomer units of even carbon numbers C6, C8, C10 and C12, when sodium acetate was fed as the sole carbon source . In contrast, the P(3HA) produced from sodium propionate was composed of seven different 3HA units ranging from C6 to C12 . The pathways of P(3HA) synthesis were investigated by using 13C-labelled acetate and propionate as the carbon sources . The 13C-labelled carbonyl carbon of {1-13C} acetate was selectively incorporated into the odd-numbered carbon atoms of 3HA units, while the methyl carbon of {2-13C} acetate was introduced into the even-numbered carbon atoms of 3HA units . The 13C-labelled carbonyl carbon of {1-13C} propionate was selectively incorporated into the third carbon atoms from methyl carbons in the 3HA units of C7, C9 and C11 . The synthesis of P(3HA) from acetate or propionate was related to de novo fatty acid biosynthesis. Arerugi, 1993 Oct, 42(10), 1616 - 22 {Experimental acute lung injury in guinea pigs after aerosol challenge with sonicated Pseudomonas aeruginosa whole cells}; Kasamatsu Y et al.; Acute hemorrhagic alveolitis was elicited in the lungs of guinea pigs by aerosol challenge with sonicated P . aeruginosa whole cells . Histological findings showed the severe inflammatory changes, which were characterized by the inflammatory infiltration of alveolar macrophages (AM), polymorphonuclear leukocytes (PMN) and eosinophils in the peribronchial and the alveolar space at 8 hours after the challenge . A marked increase of PMN as well as AM was noted in the bronchial alveolar lavage fluid (BALF) at 8 hours after the challenge and the increase of the numbers of AM and PMN in the BALF remained until 24 hours after challenge . The complement titer (CH50) and C3 component in the serum decreased at the early stage, and CH50 maintained low level and C3 component increased gradually . Polyethyleneglycol precipitation-complement consumption test (PEG-CC) of the BALF showed the existence of immune complexes formed in the airway after aerosol inhalation . These data suggest that the immune complexes of P . aeruginosa activate the complement system in the lungs, which is followed by the infiltration of inflammatory cells . Guinea pigs which were pretreated with cobra venom factor significantly reduced the extent of the inflammatory changes in the lungs . The results suggests that the complement system might act as an important factor of the acute lung injury in this model. Pediatr Emerg Care, 1993 Oct, 9(5), 289 - 91 Soaring suppurative sea shells from the sea shore: Pseudomonas aeruginosa and Klebsiella pneumoniae septic arthritis after a marine sea shell injury; Ritter MS et al.; Septic arthritis is the most important diagnosis to consider in patients presenting with acute monarticular arthritis . We present the case of an eight-year-old girl who developed a Pseudomonas aeruginosa and Klebsiella pneumoniae septic arthritis of her knee following an injury with a marine sea shell . After treatment with antibiotics and arthroscopic irrigation, she had good functional recovery . We could find no previously reported cases of Pseudomonas aeruginosa or Klebsiella pneumoniae septic arthritis resulting from an injury in a marine environment . The pathogenesis and treatment of septic arthritis and infection following marine injuries are discussed. FEMS Microbiol Lett, 1993 Oct 1, 113(1), 63 - 6 Chemotaxis away from thiocyanic and isothiocyanic esters in Pseudomonas aeruginosa; Ohga T et al.; Negative chemotaxis, the movement of organisms away from chemicals, was investigated in Pseudomonas aeruginosa using a rapid videotape method . Digital image processing was used to detect changes in bacterial numbers near the mouth of a capillary containing a test chemical . P . aeruginosa was found to be repelled by thiocyanic and isothiocyanic esters including allyl isothiocyanate, ethyl thiocyanate, methyl isothiocyanate and methyl thiocyanate . Particularly, the movement of bacteria away from methyl thiocyanate was so drastic that bacterial numbers near the mouth of the capillary decreased by approximately 80% within 30 s after the start of observation . Mutant strains, fully motile but lacking positive chemotaxis, did not escape away from the esters, suggesting a common mechanism between positive and negative chemotaxes in this organism. Am Rev Respir Dis, 1993 Oct, 148(4 Pt 1), 992 - 6 Pseudomonas aeruginosa bronchopulmonary infection in late human immunodeficiency virus disease; Baron AD et al.; Pseudomonas aeruginosa infection is unusual in individuals with human immunodeficiency virus infection, and it most often occurs in the setting of other risk factors, such as neutropenia or cytotoxic drug use . We noted an increasing number of pulmonary isolates of this organism in our clinic population and sought to describe the clinical correlates of this finding . Our study consisted of a retrospective review of the microbiology, radiology, and clinical records of 1,852 HIV-seropositive adults seen at a university-based outpatient AIDS clinic . We identified 16 individuals with Pseudomonas bronchopulmonary infection . All subjects had advanced HIV disease with prior AIDS diagnoses, and mean CD4 counts of 25/mm3 (0.025 x 10(9)/L) . Pseudomonas was the sole pulmonary pathogen in 14 of 16 patients and was associated with new chest X-ray abnormalities in 14 cases . Four individuals had acute pseudomonal pneumonia with sepsis; this presentation was associated with hospitalization and other known risk factors for Pseudomonas infection . In contrast, 12 patients had more indolent, community-acquired infection, which had a low mortality rate and occurred in the absence of other risk factors . Survivors of the initial bout of Pseudomonas infection had an 86% relapse rate despite a median survival of only 4.5 months . This pattern of pseudomonal disease is reminiscent of cystic fibrosis and suggests a role for maintenance therapy. Am Rev Respir Dis, 1993 Oct, 148(4 Pt 1), 1061 - 5 Erythromycin inhibits the production of elastase by Pseudomonas aeruginosa without affecting its proliferation in vitro; Sakata K et al.; Extracellular proteases from Pseudomonas aeruginosa play important roles in infections in the respiratory tract . The effect of erythromycin (EM), a macrolide antibiotic, on the production of elastase by P . aeruginosa was investigated in vitro and compared with the effect of other antibiotics . Thirty-four (94.4%) of thirty-six different strains produced detectable amounts of elastase determined by the gel diffusion method . The elastase production was inhibited completely by EM in 27 (79.4%) of 34 strains at some concentrations between 0.125 and 64 micrograms/ml . At 4 micrograms/ml or less, the elastase production was inhibited completely in four (11.8%) strains and more than 50% in the other 10 (29.4%) . At 8 micrograms/ml or less, the elastase production was inhibited completely in 11 (32.4%) strains and more than 50% in the other nine (26.5%) . The proliferation was partially inhibited at 32 and 64 micrograms/ml . Roxithromycin inhibited the elastase production at higher concentrations than EM without inhibiting the proliferation . Midecamycin and ampicillin did not inhibit the elastase production or the proliferation . Doxycycline and ticarcillin inhibited the elastase production and/or the proliferation at concentrations greater than 16 micrograms/ml . Although ofloxacin (OFLX) inhibited both the proliferation and the elastase production in parallel at low concentrations, there were six (16.7%) strains resistant to OFLX . Among them the elastase production was inhibited in five strains by EM . These results suggest that EM acts on P . aeruginosa to inhibit extracellular production of elastase without affecting the proliferation of the bacteria. Zhonghua Liu Xing Bing Xue Za Zhi, 1993 Oct, 14(5), 304 - 6 {Plasmid profiles of 120 strains of Pseudomonas aeruginosa}; Wu T; The plasmid profiles of 120 clinical isolates of Pseudomonas Aeruginosa (PA) from Nanjing City were determined by the Kado and Liu method and the technique was compared with other epidemiological typing schemes based on serotype . Only 24.2% of these strains harbored plasmids . A total of 13 different plasmid profiles were observed . Plasmids varied in size from 1.91 to 45.14 MDa . The serotypability was 95.00% . A comparison between the plasmid profiles and the serotypes might be of value in the epidemiologic fingerprinting of clinical isolates of PA. J Bioenerg Biomembr, 1993 Oct, 25(5), 547 - 56 Biophysical characterization of OprB, a glucose-inducible porin of Pseudomonas aeruginosa; Wylie JL et al.; OprB, a glucose-inducible porin of P . aeruginosa, was characterized by black lipid bilayer analysis and circular dichroism spectroscopy . Black lipid bilayer analysis of OprB revealed a single-channel conductance of 25 pS, the presence of a glucose binding site with a Ks for glucose of 380 +/- 40 mM, and the formation of channels with a strong selection for anions . Analysis of P . aeruginosa OprB circular dichroism spectra revealed a high beta sheet content (40%) which is within the range of that determined for other porins . Values obtained from black lipid bilayer analysis were compared to those previously obtained for OprB of P . putida {Saravolac et al . (1991) . J . Bacteriol . 173, 4970-4976} and indicated extensive similarities in the single-channel conductance and glucose-binding properties of these two porins . Immunological and amino terminal sequence analysis revealed a high degree of homology . Of the first 14 amino terminal residues, 12 were identical . A major difference between the two porins was found in their ion selectivity . Whereas P . aeruginosa OprB is anion selective, P . putida OprB and other carbohydrate selective porins are known to be cation selective. Biull Eksp Biol Med, 1993 Oct, 116(10), 421 - 4 {The cause of benign and malignant courses of infection due to different strains of Pseudomonas aeruginosa}; Pal'tsyn AA et al.; Two groups of rats with experimental wound infection caused by various Ps . aeruginosa strains were investigated . The development of the disease was characterized as benign in the group infected by the first strain . Infection was presented as local inflammation . As for the second strain, the infection having features of malignancy was often presented in the form of septicopyemia . It appeared that the difference between the clinical course of the two compared groups correlated with those in humoral immunity status . The animal reaction to administration of both strains was agglutinative antibody formation . Besides agglutination, antibodies formed against the first strain caused the expressed complement-dependent lysis of bacterial cells . No lysis of bacteria of the second strain was observed. Acta Ophthalmol (Copenh), 1993 Oct, 71(5), 666 - 70 Application of topical lomefloxacin against experimental Pseudomonas endophthalmitis in rabbits; Hatano H et al.; Lomefloxacin is a new quinolone compound with a broad antibacterial spectrum and excellent penetration into the aqueous humor by topical application . Therefore, an experimental study was done to evaluate the efficacy of topical lomefloxacin against experimental endophthalmitis with Pseudomonas aeruginosa . Lomefloxacin eye drops were instilled six times a day onto infected rabbit eyes and gentamicin, sulbenicillin and saline were also tested comparatively in the same manner as lomefloxacin . Clinical observation for 1 week and counting viable pseudomonas cell numbers in the anterior chamber were done . Among all topical eye drops tested, lomefloxacin was shown to be most effective in lowering clinical scores and viable cell numbers in the anterior chamber . In conclusion, lomefloxacin is expected to be a useful ophthalmic solution in the treatment of pseudomonal endophthalmitis. J Clin Invest, 1993 Oct, 92(4), 1875 - 80 Pseudomonas aeruginosa pili bind to asialoGM1 which is increased on the surface of cystic fibrosis epithelial cells; Saiman L et al.; The basis for the unique association of Pseudomonas aeruginosa and the cystic fibrosis (CF) lung has remained obscure despite major advances in the understanding of the molecular genetic cause of this disease . There is evidence to suggest that abnormalities in CF transmembrane conductance regulator function result in alterations in the glycosylation of epithelial components . The number of asialoGM1 residues, as representative of a class of glycolipids which contain a GalNAc beta 1-4Gal sequence for P . aeruginosa attachment, was quantified by flow cytometric studies of respiratory epithelial cells in primary culture from both CF patients and normal subjects . Superficial asialoGM1 was detected on 12% of the CF cells as compared with 2.9% of the cells from normal control subjects (P = 0.03, chi 2 = 4.73), and more asialoGM1 residues were exposed on CF cells after modification by P . aeruginosa exoproducts . AsialoGM1, but not the sialylated glycolipid GM1, was demonstrated to be a receptor for 125I-labeled P . aeruginosa pilin, a major adhesin for this organism, and exogenous asialoGM1 was found to competitively inhibit P . aeruginosa adherence to epithelial cells, thus, confirming the biological role of the asialoGM1 receptor . Quantitative and qualitative differences in the sialylation of superficial glycolipids in CF epithelial cells may directly contribute to the colonization of the CF lung by P . aeruginosa. Antibiot Khimioter, 1993 Oct-Nov, 38(10-11), 35 - 9 {Piperacillin in the treatment of suppurative inflammatory complications in cancer patients}; Dmitrieva NV et al.; Piperacillin (Pipril, Lederle, USA) is semisynthetic penicillin highly active against aerobic and anaerobic organisms . Its high activity was demonstrated with respect to 289 strains of aerobes, 82.7 per cent of the Pseudomonas aeruginosa strains being susceptible to Pipril . Diverse purulent inflammatory complications were treated with Pipril in doses of 8 to 24 g a day in 27 patients with malignant tumors . The clinical effect in 84.6 per cent of the cases was recorded . Complete elimination of the pathogens was observed in 73.5 per cent of the patients . Therefore, Pipril should be considered as one of the most active antibiotics for the treatment of purulent inflammatory complications in oncological patients. Bratisl Lek Listy, 1993 Oct, 94(10), 555 - 8 {The effect of antibiotics and their combinations on Pseudomonas aeruginosa in vitro}; Milosovic P et al.; During the ten year period (1981-1990) of detection of Pseudomonas aeruginosa susceptibility towards anti-Pseudomonas antibiotics a decrease in susceptibility towards GEN took place, namely from 91.7% to 80.0% . Susceptibility towards STR, COL and POL has not altered . During the course of five years we recorded a remarkable augmentation in resistance towards the group of 10 new antibiotics NET-by 24.3%, TIC-by 20.6% and AZL-by 18.5% . The most effective antibiotics of this group were CIP (100%), AMI (98.6%), OFL (99.3%), and CTZ (100%) . Eight combinations of antibiotics were tested on 100 strains and CTX+GEN was proved to be the most effective combination-synergistic effect on 92.0 strains . The comparison of the effect of CTX+GEN combination on 12 strains implies identical results gained by both, the plate dilution method and the method of detection of lethal effect rate . For the purpose of routinized examinations the dilution micromethod is the most suitable . (Tab . 4, Ref . 19.). Mol Microbiol, 1993 Oct, 10(2), 431 - 43 Xcp-mediated protein secretion in Pseudomonas aeruginosa: identification of two additional genes and evidence for regulation of xcp gene expression; Akrim M et al.; In Pseudomonas aeruginosa, several exoproteins synthesized with a signal sequence (elastase, lipase, phospholipases, alkaline phosphatase and exotoxin A) are secreted by a two-step mechanism . They first cross the inner membrane in a signal sequence-dependent way, and are further translocated across the outer membrane in a second step requiring secretion functions encoded by several xcp genes . Ten xcp genes have already been characterized (Bally et al., 1992a) . In this study, two additional xcp genes, xcpP and xcpQ, are described . They are located in the 40 min region of the chromosome where they probably define an operon, divergent from the xcpR-Z operon previously characterized in this region . These two genes encode two proteins, XcpP and XcpQ, similar to PulC and PulD of the pul system of Klebsiella oxytoca . Moreover, the two divergent operons share a common regulation which is growth-phase dependent. Mol Microbiol, 1993 Oct, 10(2), 283 - 92 Linker-insertion mutagenesis of Pseudomonas aeruginosa outer membrane protein OprF; Wong RS et al.; The oprF gene, expressing Pseudomonas aeruginosa major outer membrane protein OprF, was subjected to semi-random linker mutagenesis by insertion of a 1.3 kb HincII kanamycin-resistance fragment from plasmid pUC4KAPA into multiple blunt-ended restriction sites in the oprF gene . The kanamycin-resistance gene was then removed by PstI digestion, which left a 12 nucleotide pair linker residue . Nine unique clones were identified that contained such linkers at different locations within the oprF gene and were permissive for the production of full-length OprF variants . In addition, one permissive site-directed insertion, one non-permissive insertion and one carboxyterminal insertion leading to proteolytic truncation were also identified . These mutants were characterized by DNA sequencing and reactivity of the OprF variants with a bank of 10 OprF-specific monoclonal antibodies . Permissive clones produced OprF variants that were shown to be reactive with the majority of these monoclonal antibodies, except where the insertion was suspected of interrupting the epitope for the specific monoclonal antibody . In addition, these variants were shown to be 2-mercaptoethanol modifiable, to be resistant to trypsin cleavage in intact cells and partly cleaved to a high-molecular-weight core fragment in outer membranes and , where studied, to be accessible to indirect immunofluorescence labelling in intact cells by monoclonal antibodies specific for surface epitopes . Based on these data, a revised structural model for OprF is proposed. Mol Microbiol, 1993 Oct, 10(2), 233 - 43 Common components in the assembly of type 4 fimbriae, DNA transfer systems, filamentous phage and protein-secretion apparatus: a general system for the formation of surface-associated protein complexes; Hobbs M et al.; The Pseudomonas aeruginosa genes pilB-D and pilQ are necessary for the assembly of type 4 fimbriae . Homologues of these genes and of the subunit (pilin) gene have been described in various different bacterial species, but not always in association with type 4 fimbrial biosynthesis and function . Pil-like proteins are also involved in protein secretion, DNA transfer by conjugation and transformation, and morphogensis of filamentous bacteriophages . It seems likely that the Pil homologues function in the processing and export of proteins resembling type 4 fimbrial subunits, and in their organization into fimbrial-like structures . These may either be true type 4 fimbriae, or components of protein complexes which act in the transport of macromolecules (DNA or protein) into or out of the cell . Some PilB-like and PilQ-like proteins are apparently also involved in the assembly of non-type 4 polymeric structures (filamentous phage virions and conjugative pili) . The diverse studies summarized in this review are providing insight into an extensive infrastructural system which appears to be utilized in the formation of a variety of cell surface-associated complexes. Biotechnology (N Y), 1993 Oct, 11(10), 1133 - 6 Conversion to mucoidy in Pseudomonas aeruginosa; Deretic V et al.; Chronic respiratory complications in cystic fibrosis, compounded by recurring infections with mucoid Pseudomonas aeruginosa and the associated inflammation, are the primary cause of high mortality in this inheritable disease . Since the conversion of P . aeruginosa into the exopolysaccharide alginate overproducing strains plays a critical role in the establishment of chronic infection, studies are directed towards understanding the processes underlying this phenomenon . The genes (algU, mucA, and mucB) and genetic alterations responsible for conversion to mucoidy have been recently characterized . The mutations leading to the emergence of mucoid strains are superimposed on a regulatory system with elements that resemble those controlling other aspects of bacterial developmental physiology. FEMS Immunol Med Microbiol, 1993 Oct, 7(3), 251 - 6 Immunological studies of an artificial antigen with specificity of a common polysaccharide antigen of Pseudomonas aeruginosa; Makarenko TA et al.; Synthetic D-rhamnan, with the structure of Pseudomonas aeruginosa common polysaccharide antigen (CPA), was conjugated with BSA . The artificial antigen obtained, and the natural antigens, lipopolysaccharides (LPS) of P . aeruginosa and Pseudomonas cerasi with rhamnan chains of the same structure, were studied by ELISA with rabbit antibodies to the D-rhamnan-BSA conjugate and to the P . cerasi O-antigen . Immunological relations between the LPS of P . aeruginosa and P . cerasi determined by CPA as well as between these LPS and D-rhamnan-BSA were revealed by ELISA . O-antiserum to P . cerasi possesses protective activity in the mouse passive protection test when mice are challenged with some P . aeruginosa strains; the antiserum to the D-rhamnan-BSA does not possess protective activity in mice. Proc Natl Acad Sci U S A, 1993 Sep 15, 90(18), 8377 - 81 Mechanism of conversion to mucoidy in Pseudomonas aeruginosa infecting cystic fibrosis patients; Martin DW et al.; Chronic respiratory infections with mucoid Pseudomonas aeruginosa are the leading cause of high mortality and morbidity in cystic fibrosis (CF) . The initially colonizing strains are nonmucoid, but in the CF lung they invariably convert into the mucoid, exopolysaccharide alginate-overproducing form causing further deterioration and poor prognosis . Here we report the molecular basis of conversion to mucoidy . The algU gene is required for expression of the key alginate biosynthetic gene algD and encodes a protein homologous to sigma H, an alternative sigma factor regulating sporulation and other post-exponential-phase processes in Bacillus . The algU gene and the negative regulators mucA and mucB constitute the gene cluster controlling conversion to mucoidy . We demonstrate a critical role of mucA in this process based on (i) the presence of frameshift mutations disrupting the mucA coding region in mucoid cells that were absent in nonmucoid parental strains, (ii) genetic complementation of mucA mutations with the mucA+ gene, (iii) allelic replacements with specific mutant mucA genes causing conversion to mucoidy in previously nonmucoid cells, and (iv) detection of identical and additional mucA mutations in clinical mucoid strains isolated from the lungs of CF patients . These results suggest that the switch from the nonmucoid to mucoid state can be caused by inactivation of mucA, resulting in constitutive expression of alginate biosynthetic genes dependent on algU for transcription and that such mutants may be selected in vivo during chronic infections in CF. FEMS Microbiol Lett, 1993 Sep 15, 112(3), 255 - 9 Mapping of ben genes of Pseudomonas aeruginosa; Zhang C et al.; Four ben genes responsible for the conversion of benzoate to catechol in Pseudomonas aeruginosa PAO have been mapped to a 4.6 kb KpnI fragment, ben-1 and ben-4 were known to be separate genes but now ben-1508 has been found to be different from ben-2 . The two genes were distinguished by Tn5 mutagenesis of a cosmid clone and deletion mapping . It is likely that the four genes mapped (ben-4, ben-2, ben-1508 and ben-1) correspond to the previously characterized benR (regulatory gene) and benABC (benzoate dioxygenase) respectively. Gene, 1993 Sep 6, 131(1), 103 - 6 Characterization of the bstVIRM genes encoding the Bacillus stearothermophilus V restriction-modification system; Gonzalez E et al.; The nucleotide (nt) sequence of a 2.7-kb HindIII-EcoRI DNA fragment encoding the bstVIR and bstVIM genes has been determined . The sequence predicts a restriction endonuclease of 224 amino acids (aa), M(r) 25,104, and a methyl-transferase of 561 aa, M(r0 65,702 . Both genes are aligned in the same orientation and are separated by a 102-nt intergenic region . No homology was found between R.BstVI and M.BstVI when their deduced aa sequences were compared . Significant similarity at the aa level was found, however, when both enzymes were compared to their equivalents in the paeR7IRM system of Pseudomonas aeruginosa PAO303. Gene, 1993 Sep 6, 131(1), 1 - 8 Sequence of the algL gene of Pseudomonas aeruginosa and purification of its alginate lyase product; Boyd A et al.; The alginate lyase-encoding gene (algL) of Pseudomonas aeruginosa was localized to a 1.7-kb EcoRI-XbaI fragment within the alginate biosynthetic gene cluster at 34 minutes on the chromosome . The nucleotide sequence of this DNA fragment revealed an ORF encoding a protein of M(r) 40,885 which is transcribed in the same orientation as the other alg genes within the biosynthetic gene cluster . The predicted protein has a potential N-terminal signal peptide which is consistent with its proposed periplasmic location . The AlgL protein was overproduced in Escherichia coli and purified . The purified protein was shown to have alginate lyase activity . In addition, an algL insertion mutant of the mucoid P . aeruginosa 8830 was constructed . This mutant (alm1) had a nonmucoid phenotype due to a polar effect on the transcription of an essential alg gene, algA . Thus, the algL gene is located within a region of the alginate biosynthetic gene cluster that appears to be non-essential for alginate production. J Clin Microbiol, 1993 Sep, 31(9), 2366 - 70 Influence of zinc on Pseudomonas aeruginosa susceptibilities to imipenem; Cooper GL et al.; Serial dilution susceptibility testing of imipenem against 59 clinical isolates of Pseudomonas aeruginosa, conducted simultaneously on single lots of Difco and BBL Mueller-Hinton agar (MHA), resulted in MICs for 90% of strains tested of 8 and 16 micrograms/ml, respectively . MICs for Escherichia coli, Klebsiella pneumoniae, and Pseudomonas spp . were also higher on BBL MHA . Quantification of the cation content of the two MHAs by atomic absorption spectroscopy demonstrated that the zinc concentration in BBL MHA was 15 times greater than that measured in Difco MHA (2.61 and 0.17 micrograms/ml, respectively) . Concentrations of calcium, magnesium, iron, manganese, and copper in the two agars were similar . Addition of zinc to Difco MHA resulted in increases in MICs of imipenem for P . aeruginosa but not in the MICs of ceftazidime or cefpirome for P . aeruginosa (P < 0.01) . A lesser zinc effect was seen on the activity of imipenem against E . coli, K . pneumoniae, and Pseudomonas spp . The activities of ceftazidime and cefpirome were similar on both MHAs when tested against all gram-negative organisms in this study . Thus, the effect of zinc in MHA was clearly demonstrated by a significant increase in the MICs of imipenem for P . aeruginosa, and, to a lesser extent, for other gram-negative bacilli. J Clin Microbiol, 1993 Sep, 31(9), 2320 - 6 Genome macrorestriction analysis of diversity and variability of Pseudomonas aeruginosa strains infecting cystic fibrosis patients; Struelens MJ et al.; Genome macrorestriction fingerprinting with XbaI and DraI was used to analyze the relatedness of 166 Pseudomonas aeruginosa isolates collected from 31 cystic fibrosis patients over a 1- to 20-month period and to correlate their genotype with patterns of resistance to 14 antimicrobial agents . Quantitative comparison of intra- and interpatient similarities of P . aeruginosa macrorestriction patterns disclosed two discrete ranges that clearly discriminated subclonal variation (> 80% relatedness) and clonal diversity (10 to 70% relatedness) . Cloning-derived mutants exhibited up to 20% divergence of genomic macrorestriction patterns during the course of chronic colonization of individual patients . Change of susceptibility to multiple antimicrobial agents developed in 50% of sequential pairs of isolates from individual patients . Only 19% of these susceptibility changes were attributable to strain substitution, while the majority (56%) of resistance changes were associated with minor genomic variations of a persistent strain . Sixty-six percent of patients harbored one strain, and 33% carried two strains . Three common strains colonized 5 (28%) of 18 patients attending a cystic fibrosis clinic, and another two strains colonized two patient pairs (31%) of 13 patients staying at a rehabilitation center, suggesting potential cross-infection in these settings . By indexing regional polymorphisms throughout the chromosome structure, macrorestriction analysis can monitor subclonal evolution of P . aeruginosa and identify isogenic resistance mutants . Quantitative macrorestriction fingerprinting enables discrimination between clonal variants and clones of distinct origins and should therefore provide a reliable tool for investigating the mode of acquisition of P . aeruginosa in cystic fibrosis patients. Am J Respir Cell Mol Biol, 1993 Sep, 9(3), 323 - 34 Altered carbohydrate composition of salivary mucins from patients with cystic fibrosis and the adhesion of Pseudomonas aeruginosa; Carnoy C et al.; We compared the chemical composition of salivary mucin glycopeptides from cystic fibrosis (CF) and from non-CF subjects and the adhesion of Pseudomonas aeruginosa to these different salivary glycopeptides . Three pools of CF saliva, four pools of non-CF saliva, one individual CF saliva, and one individual non-CF saliva were studied . The soluble fraction of the saliva was treated with pronase, and gel filtration was performed to obtain high and low molecular mass salivary mucin glycopeptides . The yield of total glycopeptides was significantly higher from CF than from non-CF saliva . Furthermore, the chemical composition revealed a significantly higher sialic acid content in CF than in non-CF mucin glycopeptides, and higher sulfate and fucose content in CF than in non-CF high molecular mass glycopeptides . We studied the adhesion of a nonmucoid strain of P . aeruginosa (1244), its nonpiliated isogenic derivative, and a mucoid strain (M35) to salivary mucin glycopeptides from patients with CF and from non-CF subjects . The three strains bound significantly more to the CF salivary glycopeptides than to the corresponding non-CF salivary glycopeptides . The nonpiliated isogenic mutant of P . aeruginosa 1244 also bound to CF salivary glycopeptides, suggesting that the adhesion of P . aeruginosa could involve nonpilus adhesions . Furthermore, neuraminidase treatment of CF glycopeptides decreased the adhesion of P . aeruginosa 1244 . Altogether these results suggested that differences in mucins may in part explain the specificity of P . aeruginosa for CF. J Clin Invest, 1993 Sep, 92(3), 1221 - 8 Pseudomonas aeruginosa-induced lung and pleural injury in sheep . Differential protective effect of circulating versus alveolar immunoglobulin G antibody; Pittet JF et al.; The overall objective of these studies was to determine whether IgG antibody to Pseudomonas aeruginosa would modify the acute lung and pleural injury that developed over 24 h after the instillation of 10(10) live P . aeruginosa into the distal airspaces of one lung in unanesthetized sheep . Using a quantitative experimental model to measure protein permeability across the alveolar epithelial, lung endothelial, and pleural mesothelial barriers, the effect of IgG antibody to P . aeruginosa was examined under four different experimental conditions . First, the effect of IgG antibody to P . aeruginosa in the circulation was examined by instilling 10(10) live P . aeruginosa in 5% ovine albumin in sheep that had been vaccinated . Under these conditions, the presence of circulating IgG antibody to P . aeruginosa reduced lung endothelial injury but did not modify the lung epithelial or pleural injury caused by intraalveolar P . aeruginosa . Therefore, the second experimental protocol determined the effect of instilling immune serum from a sheep that had been vaccinated so that IgG antibody to P . aeruginosa was present in both the circulation and in the airspaces along with instillation of live bacteria . Under these conditions, injury to the lung endothelium, alveolar epithelium, and pleural space was completely prevented . Therefore, the third protocol examined the protective effect of instillation of IgG antibody to P . aeruginosa in the airspaces concurrent with the live bacteria . Interestingly, intraalveolar IgG antibody to P . aeruginosa prevented all evidence of lung epithelial and pleural injury, and this effect was associated with a marked decrease in the number of viable bacteria in the lung after 24 h . Therefore, the fourth protocol examined the prophylactic effect of instillation of the specific IgG antibody to P . aeruginosa 24 h before instillation of the bacteria . With this prophylactic regimen, epithelial, endothelial, and pleural injury were prevented, and there was a significant decrease in the number of bacteria recovered from the lung . Thus, delivery of IgG antibody to P . aeruginosa the distal airspaces of the lung alone may provide a novel therapeutic approach to preventing acute pulmonary infection caused by P . aeruginosa. J Bacteriol, 1993 Sep, 175(18), 5798 - 805 Surface action of gentamicin on Pseudomonas aeruginosa; Kadurugamuwa JL et al.; The mode of action of gentamicin has traditionally been considered to be at the 30S ribosomal level . However, the inhibition of bacterial protein synthesis alone appears to be insufficient to entirely explain the bactericidal effects . Bacteriolysis is also mediated through perturbation of the cell surface by gentamicin (J.L . Kadurugamuwa, J.S . Lam, and T.J . Beveridge, Antimicrob . Agents Chemother . 37:715-721, 1993) . In order to separate the surface effect from protein synthesis in Pseudomonas aeruginosa PAO1, we chemically conjugated bovine serum albumin (BSA) to gentamicin, making the antibiotic too large to penetrate through the cell envelope to interact with the ribosomes of the cytoplasm . Furthermore, this BSA-gentamicin conjugate was also used to coat colloidal gold particles as a probe for electron microscopy to study the surface effect during antibiotic exposure . High-performance liquid chromatography confirmed the conjugation of the protein to the antibiotic . The conjugated gentamicin and BSA retained bactericidal activity and inhibited protein synthesis on isolated ribosomes in vitro but not on intact cells in vivo because of its exclusion from the cytoplasm . When reacted against the bacteria, numerous gentamicin-BSA-gold particles were clearly seen on the cell surfaces of whole mounts and thin sections of cells, while the cytoplasm was devoid of such particles . Disruption of the cell envelope was also observed since gentamicin-BSA and gentamicin-BSA-gold destabilized the outer membrane, evolved outer membrane blebs and vesicles, and formed holes in the cell surface . The morphological evidence suggests that the initial binding of the antibiotic disrupts the packing order of lipopolysaccharide of the outer membrane, which ultimately forms holes in the cell envelope and can lead to cell lysis . It is apparent that gentamicin has two potentially lethal effects on gram-negative cells, that resulting from inhibition of protein synthesis and that resulting from surface perturbation; the two effects in concert make aminoglycoside drugs particularly effective antibiotics. Exp Parasitol, 1993 Sep, 77(2), 195 - 9 Plasmodium falciparum: inhibition of sporogonic development in Anopheles stephensi by gram-negative bacteria; Pumpuni CB et al.; We investigated the effects of bacteria on Plasmodium falciparum sporogonic development in Anopheles stephensi . Four gram-negative (Escherichia coli H243, E . coli HB101, Pseudomonas aeruginosa, and Ewingella americana) and two gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) bacterial strains were used in the study . Tenfold dilutions of bacteria suspended in phosphate-buffered saline were mixed with an infectious meal of gametocyte-enriched cultures and fed to adult mosquitoes . All gram-negative bacteria strains partially or completely inhibited oocyst formation at different concentrations . Additionally, geometric mean number of oocysts showed a correspondingly significant decrease with increasing bacterial concentration (P < 0.001) . In contrast, gram-positive bacteria strains did not have any inhibitory effects on oocyst formation even at very high concentrations . Oocyst development was not affected by: (i) culture supernatants of E . americana, (ii) formalin-treated E . coli H243, (iii) lipopolysaccharide of E . coli J5 (mutant of 0111:B4) . These studies show that gram-negative but not gram-positive bacteria affect sporogonic-stage development of P . falciparum in A . stephensi . Inhibition of parasite acquisition may be an attribute of specific or nonspecific cytoadherence properties of gram-negative bacteria to the parasites. J Bacteriol, 1993 Sep, 175(17), 5452 - 9 Enhancer-like activity of A1gR1-binding site in alginate gene activation: positional, orientational, and sequence specificity; Fujiwara S et al.; Significant activation of promoters of alginate genes such as algD or algC occurs in mucoid Pseudomonas aeruginosa during its proliferation in the lungs of cystic fibrosis patients . These promoters have been shown to be responsive to environmental signals such as high osmolarity . The signaling is mediated by a so-called two-component signal transduction system, in which a soluble protein, AlgR2, undergoes autophosphorylation and transfers the phosphate to a DNA-binding response regulator protein, AlgR1 . The phosphorylated form of AlgR1 has a high affinity for binding at upstream sequences of both the algC and algD promoters . Two AlgR1-binding sites (ABS) have been reported upstream of the algC gene . One of the two ABSs (algC-ABS1, located at -94 to -81) is critical for the algC activation process, while the second ABS (algC-ABS2, located at +161 to +174) is only weakly active . We now report the presence of a third ABS within the structural gene of algC, and this ABS (algC-ABS3) is also important for algC promoter activation . algC-ABS1 can be replaced functionally by algC-ABS2, algD-ABS1, or algD-ABS2 and somewhat weakly by algD-ABS3 . Introduction of a half-integral turn in the DNA helix between the algC site of transcription initiation and algC-ABS1 allowed only slight reduction of promoter activity, suggesting that the binding site could be appreciably functional even when present in the opposite face of the helix . Activation of the algC promoter is independent of the relative location (upstream or downstream of the mRNA start site), the number of copies, or the orientation of algC-ABS1, suggesting that it behaves like a eukaryotic enhancer element in promoting transcription from the algC promoter. Exp Cell Res, 1993 Sep, 208(1), 296 - 302 DNA fragmentation and cytolysis in U937 cells treated with diphtheria toxin or other inhibitors of protein synthesis; Kochi SK et al.; We treated the human monoblastoid cell line, U937, with various cytotoxic proteins or drugs that specifically inhibit protein synthesis and monitored the cells for degradation of chromosomal DNA and other changes . In cells treated with diphtheria toxin (DT), Pseudomonas aeruginosa exotoxin A, ricin toxin, and abrin toxin the chromosomal DNA was degraded into oligonucleosome-sized fragments, the chromatin became condensed, and the cell nuclei fragmented . All of these changes are characteristic of cells undergoing apoptosis, or programmed cell death . Various drugs, including puromycin, cycloheximide, emetine, and anisomycin produced similar changes . An enzymically attenuated mutant of DT, DT-E148S, produced effects identical to those produced by the native toxin, except that a higher concentration of toxin was required, corresponding to the reduction in ADP-ribosylation activity . In all cases, DNA degradation and other changes were observed only after the rate of protein synthesis was reduced to low levels, approximately 10% or less of normal levels . These results imply that inhibition of protein synthesis in U937 cells induces apoptosis, regardless of the mechanism of action of the inhibitor . Differences in the kinetics of induction of apoptosis by the various inhibitors may reflect secondary effects on other aspects of cellular physiology. Clin Pharm, 1993 Sep, 12(9), 657 - 74; quiz 700-1 Pharmacologic management of cystic fibrosis; Wallace CS et al.; Standard pharmacologic management of cystic fibrosis is discussed and the role of new agents in the treatment of this disease is explored . Cystic fibrosis is a recessive, fatal genetic disease involving multiple organ systems, in which patients develop pancreatic insufficiency, malabsorption, and repeated pulmonary infections . Pharmacotherapy to date has included broad-spectrum antimicrobials and aggressive nutritional management with microencapsulated pancreatic enzymes . Acute pulmonary exacerbations, caused by Pseudomonas aeruginosa, require combination i.v . antimicrobial therapy for 14 to 21 days . With the recent discovery of the genetic defect responsible for cystic fibrosis, as well as the cellular mechanism, new pharmacologic approaches are being explored to improve treatment . Aerosolized amiloride is being tested to modify the basic defect in the chloride channel . Dornase, a new mucolytic, is used to decrease sputum viscosity and increase mucociliary clearance . Leukoprotease inhibitors are currently being evaluated for decreasing the acute inflammatory reaction in the lung . Gene therapy has been promising, but its role in the management of cystic fibrosis is many years away . Drug therapy for cystic fibrosis has been primarily directed at treating infections with antibiotics and supplementing digestive enzymes and vitamins . New agents and gene therapy may substantially change the morbidity and mortality of this disease. Mikrobiologiia, 1993 Sep-Oct, 62(5), 887 - 96 {Oxidative dehalogenation of 2-chloro- and 2,4-dichlorobenzoates by Pseudomonas aeruginosa}; Romanov VL et al.; The strain Pseudomonas aeruginosa 142 isolated from the utilising PSBs bacterial association was capable of growth on 2-chloro- and 2,4-dichlorobenzoates as sole carbon sources, but it did not utilize 3-Cl, 4-Cl, 3,5-diCl- and 2,6-dichlorobenzoates . P . aeruginosa 142 dehalogenated 2-Cl-, 2,4-diCl- and 2,5-dichlorobenzoates in aerobic conditions . The release of chloride was not observed in microaerophilic and anaerobic conditions . The activities of catechol-1,2-dioxygenase and 4-chlorocatechol-1,2-dioxygenase were found in cell extracts after growth of this strain on 2,4-dichlorobenzoate . The presented results suggested that oxidative release of chloride in ortho-position is the first step of metabolism of 2-Cl-, 2,4-diCl- and 2,5-dichlorobenzoates . The further splitting of corresponding catechols is carried out by ortho-pathway. Infection, 1993 Sep-Oct, 21(5), 297 - 302 Specific IgG2 antibodies to Pseudomonas aeruginosa lipid A and lipopolysaccharide are early markers of chronic infection in patients with cystic fibrosis; Kronborg G et al.; The IgG subclass antibody response to the two parts of Pseudomonas aeruginosa lipopolysaccharide; endotoxic lipid A and the O-polysaccharide, were investigated in a retrospective longitudinal study involving 16 patients with cystic fibrosis and chronic P . aeruginosa lung infection . The purpose of the study was to see if any of the IgG subclasses of either specificity could be used as prognostic markers in the development and subsequent course of the lung disease . IgG2 anti-lipid A, IgG3 anti-lipid A, and IgG2 anti-polysaccharide showed a significant positive correlation with deteriorating pulmonary function already before chronic P . aeruginosa lung infection was diagnosed as well as in subsequent years . The findings suggest antigenic exposure of the patient before chronic infection is detected by routine sputum examinations, and further support our previous findings of a critical role of the IgG subclass response in modulating the course of inflammatory lung damage in these patients. EMBO J, 1993 Sep, 12(9), 3637 - 42 Antitermination of amidase expression in Pseudomonas aeruginosa is controlled by a novel cytoplasmic amide-binding protein; Wilson SA et al.; Amide-inducible expression of the aliphatic amidase system of Pseudomonas aeruginosa can be reconstituted in Escherichia coli with only the amidase structural gene amiE, the negative regulator amiC and the positive regulator amiR, a transcription antitermination factor . Complementation experiments in E . coli suggest that negative control of amidase expression by AmiC is mediated by a protein-protein interaction with AmiR . Purified AmiC binds acetamide with a KD of 3.7 microM in equilibrium dialysis studies, and therefore AmiC appears to be the sensory partner of the AmiC/AmiR pair of regulatory proteins, responding to the presence of amides . Sequence analysis techniques suggest that AmiC is a member of the structural family of periplasmic binding proteins, but has a distinct and novel cytoplasmic role. EMBO J, 1993 Sep, 12(9), 3357 - 64 Three-dimensional structure of the alkaline protease of Pseudomonas aeruginosa: a two-domain protein with a calcium binding parallel beta roll motif; Baumann U et al.; The three-dimensional structure of the alkaline protease of Pseudomonas aeruginosa, a zinc metalloprotease, has been solved to a resolution of 1.64 A by multiple isomorphous replacement and non-crystallographic symmetry averaging between different crystal forms . The molecule is elongated with overall dimensions of 90 x 35 x 25 A; it has two distinct structural domains . The N-terminal domain is the proteolytic domain; it has an overall tertiary fold and active site zinc ligation similar to that of astacin, a metalloprotease isolated from a European freshwater crayfish . The C-terminal domain consists of a 21-strand beta sandwich . Within this domain is a novel 'parallel beta roll' structure in which successive beta strands are wound in a right-handed spiral, and in which Ca2+ ions are bound within the turns between strands by a repeated GGXGXD sequence motif, a motif that is found in a diverse group of proteins secreted by Gram-negative bacteria. APMIS, 1993 Sep, 101(9), 732 - 4 Pseudomonas aeruginosa bacteraemia detected with a new blood culture system Colorbact: a note of caution; Schonheyder HC et al.; Detection of Pseudomonas aeruginosa bacteraemia by the newly introduced Colorbact blood culture system (Statens Seruminstitut, Copenhagen) was ascertained in a Danish regional department of clinical microbiology . Ten of sixteen bacteraemias (63%, 95% CL: 35-85%) were detected within 24 h; the 48 h figure was 81% (95% CL: 54-96%) . The initial bacteriological diagnosis was confounded, however, by the observation of non-motile rods or atypical motility in 8 episodes, including 4 of the 10 episodes with a positive direct microscopy during the first 24 h . This may be an untoward effect of vigorous agitation . In two episodes P . aeruginosa was isolated only from the anaerobic culture bottle, whilst in two other episodes P . aeruginosa grew in aerobic and anaerobic bottles . This observation may reflect a chance distribution of viable bacteria among the bottles in the Colorbact set. Antimicrob Agents Chemother, 1993 Sep, 37(9), 1931 - 7 Pharmacodynamic effects of extended dosing intervals of imipenem alone and in combination with amikacin against Pseudomonas aeruginosa in an in vitro model; McGrath BJ et al.; The pharmacodynamic effects of extended imipenem dosing intervals were studied against two strains of Pseudomonas aeruginosa (ATCC 27853 and an imipenem-resistant mutant, 27853R) in an in vitro model of infection . Imipenem was administered as monotherapy (simulated 1-g bolus every 8 or every 12 h) and in combination with amikacin (7.5-mg/kg bolus every 12 h or a 15-mg/kg bolus once) . Monotherapy with imipenem administered every 8 h was equally bactericidal at 24 h compared with regimens combined with amikacin for ATCC 27853 . Imipenem administered every 12 h against the sensitive strain and both imipenem monotherapy regimens against the resistant strain demonstrated regrowth at 24 h . Although both amikacin regimens administered as monotherapy resulted in rapid bacterial killing activity with respect to time to a 99.9% reduction in log10 CFU/milliliter, regrowth at 24 h was observed at levels reaching or exceeding the initial inoculum . All combination regimens resulted in no detectable growth by 24 h regardless of dosing interval for either drug or initial susceptibility to imipenem . Results from this study indicate the potential for several novel dosing regimens against P . aeruginosa . Monotherapy with imipenem, 1 g every 8 h, was effective against a sensitive strain of P . aeruginosa . Combination therapy with imipenem and once-daily or twice-daily amikacin resulted in increased killing activity against imipenem-resistant P . aeruginosa . Once-daily or twice-daily amikacin in combination therapy, regardless of P . aeruginosa susceptibility, allowed for extension of imipenem dosing intervals. Antimicrob Agents Chemother, 1993 Sep, 37(9), 1927 - 30 Therapy with cefoperazone plus sulbactam against disseminated infection due to cefoperazone-resistant Pseudomonas aeruginosa and Escherichia coli in granulocytopenic mice; Chandrasekar PH et al.; Using a granulocytopenic murine model, we evaluated the efficacy of cefoperazone plus sulbactam against disseminated infection due to isolates of beta-lactamase-producing, cefoperazone-resistant (MIC, > or = 50 micrograms/ml) Escherichia coli and Pseudomonas aeruginosa . Both isolates were susceptible in vitro to cefoperazone plus sulbactam (MIC, < or = 6.3 micrograms/ml) . Mice rendered granulocytopenic with cyclophosphamide were divided into three groups: group A--infected, untreated mice (controls); group B--infected, cefoperazone-treated mice (700 mg/kg of body weight); and group C--infected, cefoperazone-plus-sulbactam-treated mice (700 mg plus 350 mg) . In the E . coli experiment, survival rates in groups A, B, and C were 25, 46, and 73%, respectively . In the experiment with P . aeruginosa, survival rates in groups A, B, and C were 0, 10, and 50%, respectively (P < 0.001) . Highly significant differences also were noted for colony counts in the blood, liver, and spleen of group C mice versus group A or B mice in both experiments . Thus, cefoperazone plus sulbactam appears to be a promising combination for the treatment of infections due to certain cefoperazone-resistant gram-negative bacilli, including P . aeruginosa. Antimicrob Agents Chemother, 1993 Sep, 37(9), 1856 - 9 Age and therapeutic outcome of experimental Pseudomonas aeruginosa keratitis treated with ciprofloxacin, prednisolone, and flurbiprofen; Hobden JA et al.; This study was conducted to determine whether the age of the host influences the pathogenesis and therapeutic outcome of drug-treated Pseudomonas aeruginosa keratitis . Young (3- to 5-month-old) and old (1.5- to 3-year-old) rabbits were intrastromally infected with P . aeruginosa ATCC 27853 . Sixteen hours later, rabbits in both age subpopulations were divided into three groups and treated topically as follows: group 1, phosphate-buffered saline; group 2, 0.3% ciprofloxacin; and group 3, 0.3% ciprofloxacin, 1.0% prednisolone, and 0.03% flurbiprofen . Drops were given every 15 min for 1 h and then every 30 min for 9 h . At 27 h postinfection, ocular pathology was graded with a slit lamp examination (SLE) scoring system . Aqueous humor was collected for ciprofloxacin quantitation, and corneas were harvested for bacterial enumeration and estimation of polymorphonuclear leukocytes . Young rabbits had more severe inflammation and pathology than old rabbits . At 27 h postinfection, SLE scores and polymorphonuclear leukocyte numbers were significantly higher for young rabbits than old rabbits (P < 0.02), regardless of treatment . Prednisolone and flurbiprofen significantly reduced SLE scores in both age groups (P < 0.03) without affecting the antimicrobial efficacy of ciprofloxacin. Antimicrob Agents Chemother, 1993 Sep, 37(9), 1756 - 63 Dose ranging and fractionation of intravenous ciprofloxacin against Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro model of infection; Marchbanks CR et al.; The effect of dose or dose interval on the pharmacodynamics of simulated high-dose intravenous ciprofloxacin therapy on infection due to Pseudomonas aeruginosa and Staphylococcus aureus was studied in an in vitro hollow-fiber model of infection . Simulated doses of 1,200 mg of ciprofloxacin per day as either 400 mg every 8 h or 600 mg every 12 h against P . aeruginosa resulted in selection of ciprofloxacin-resistant bacteria . The results with one test strain that was isolated from a patient prior to administration of intravenous ciprofloxacin demonstrated selection of a gyrA mutant in the model, as had occurred in vivo . A single 1,200-mg dose every 24 h did not select for bacterial resistance; however, breakthrough regrowth of ciprofloxacin-susceptible bacteria occurred . Dosages of 400 or 600 mg of ciprofloxacin every 12 h effectively reduced bacterial counts of one strain each of methicillin-susceptible or -resistant S . aureus, with no bacterial resistance detected at the end of experiment; in contrast, 200 mg every 12 h resulted in bacterial regrowth due to the selection of drug-resistant bacteria . These data show the need for high-dose intravenous ciprofloxacin, particularly with regimens producing high peak levels, for treatment of infections where selection for bacterial resistance is a clinical problem. J Antibiot (Tokyo), 1993 Sep, 46(9), 1458 - 70 Synthesis and biological activity of C-3' ortho dihydroxyphthalimido cephalosporins; Baudart MG et al.; A series of C-3' ortho dihydroxyphthalimido cephalosporins 3-7 has been prepared by reaction of C-3' aminomethyl cephalosporin 41 with the corresponding N-carboethoxyphthalimides 23-25, 37, 38 . These new cephalosporins exhibit excellent in vitro Gram-negative activities, including Pseudomonas aeruginosa, excellent beta-lactamases stability and pharmacokinetics equivalent or better than ceftriaxone. Graefes Arch Clin Exp Ophthalmol, 1993 Sep, 231(9), 521 - 8 The role of Pseudomonas aeruginosa elastase in corneal ring abscess formation in pseudomonal keratitis; Ijiri Y et al.; In order to identify the causative factors of ring abscess, which is the characteristic feature of pseudomonal keratitis, pseudomonal endotoxin, exotoxin A, and elastase were each separately injected into guinea pig cornea . There was no formation of ring abscess . Injection of living Pseudomonas aeruginosa strains IFO3455 and Takamatsu which produce all three molecules, clearly induced ring abscess . In contrast, when heat-killed bacteria strain IFO3455 or living bacteria of the non-elastase-producing strain PA103 were injected, ring abscess was not induced . Furthermore, when living bacteria strain IFO3455 were injected with anti-elastase antibody or a protease inhibitor, ovomacroglobulin, ring abscess formation was significantly inhibited . Histological examination demonstrated that the ring abscess was a dense accumulation and aggregation of polymorphonuclear leukocytes (PMN) with debris of cells and lamellae in the deep stroma at the corneal margins, suggesting prevention of PMN migration to the central lesion . The presence of anti-elastase antibody or a specific elastase inhibitor facilitated PMN migration towards living bacteria strain IFO3455 in an in vitro model . These results indicate that pseudomonal elastase is a necessary but not sufficient factor in the formation of ring abscess in pseudomonal keratitis. Changgeng Yi Xue Za Zhi, 1993 Sep, 16(3), 154 - 63 The antimicrobial activity of imipenem/cilastatin and its treatment in critical ill patients with polymicrobial and mixed infection; Leu HS et al.; The antimicrobial activity of imipenem/cilastatin (IPM/CS) was determined for a broad spectrum of 7,157 organisms isolated from the Clinical Microbiology Laboratory of Chang Gung Memorial Hospital, Linkou Medical Center, between April 1 and June 30, 1988 . Ninety eight point one percent of 4,389 gram negative aerobes, 95.8% of 2391 gram positive rods, and 95.9% of 507 anaerobes, were shown to be sensitive to IPM/CS . Ninety nine point two percent of 837 Pseudomonas aeruginosa isolates were sensitive to this antibiotic . This study also disclosed that this agent was much more active against Pseudomonas aeruginosa than any other tested aminoglycosides (gentamicin, amikacin, netilmicin) or third generation cephalosporins (cefotaxime, latamoxef, ceftazidime) . Twelve critically ill patients with polymicrobial and mixed infection were recruited into this trial . All patients received IPM/CS 500 mg intravenously every six hours except one patient with poor renal function had 250 mg every six hours . The average duration of therapy was 12.5 days . All patients were evaluated according to the selection criteria . IPM/CS achieved favorable clinical response in 83.7 percent . The antibiotic was well tolerated . One patient discontinued treatment because of jaundice . One patient had superinfection of fungemia . The results suggested that IPM/CS is very useful in the treatment of patients with mixed infections due to gram positive, gram negative, and anaerobic bacteriae, even when empirical therapy with other antibiotics fails. Agents Actions, 1993 Sep, 40(1-2), 106 - 9 The effect of a cyclooxygenase inhibitor on the in vivo polymorphonuclear leukocyte migration to Pseudomonas aeruginosa peptide chemotactins; Fontan PA et al.; Pseudomonas aeruginosa chemotactic peptides (PAPCs) induced migration of polymorphonuclear leukocytes (PMNL) into the lungs when administered by the aerosol route . Migration of PMNL into the lungs and total protein content of lung lavage fluids in response to PAPCs aerosol challenge, and mortality from lethal challenge with P . aeruginosa were decreased by piroxicam treatment. Trends Microbiol, 1993 Sep, 1(6), 217 - 21 Phagocytosis of Pseudomonas aeruginosa by macrophages: receptor-ligand interactions; Speert DP; Phagocytic cells play a critically important role in host defense against infection with Pseudomonas aeruginosa . Recent observations on the receptors and ligands that mediate ingestion of this bacterium by phagocytic cells and the factors that modulate phagocytosis have provided the theoretical underpinning for novel therapeutic strategies. Pediatr Res, 1993 Sep, 34(3), 345 - 8 Association between protective efficacy of antibodies to tumor necrosis factor and suppression of nitric oxide production in neonatal rats with fatal infection; Shi Y et al.; In a rat model of fatal infection caused by Pseudomonas aeruginosa, the circulating level of nitrite/nitrate (NO2-/NO3-), a good indicator for nitric oxide production, was remarkably increased after elevation of circulatory tumor necrosis factor (TNF) . Anti-TNF MAb cotreatment was shown to blunt hypoglycemia and hyperlacticemia and was associated with decreased mortality of septic animals . Moreover, anti-TNF MAb significantly reduced not only plasma TNF but also plasma NO2-/NO3- levels . Dexamethasone had a similar effects, and when anti-TNF MAb was used in combination with dexamethasone, the suppression of nitric oxide production and the protective efficacy were more remarkable compared with therapy with either anti-TNF MAb or dexamethasone alone . Our present data suggested that the protective efficacy of anti-TNF MAb may correlate with the suppression of nitric oxide production and also with a modulation in metabolic abnormalities in the septic newborn rats. J Bacteriol, 1993 Sep, 175(18), 5934 - 44 The pilG gene product, required for Pseudomonas aeruginosa pilus production and twitching motility, is homologous to the enteric, single-domain response regulator CheY; Darzins A; The Pseudomonas aeruginosa pilG gene, encoding a protein which is involved in pilus production, was cloned by phenotypic complementation of a unique, pilus-defective mutant of strain PAO1 . This mutant, designated FA2, although resistant to the pilus-specific phage D3112 was sensitive to the pilus-specific phages B3 and F116L . In spite of the unusual phage sensitivity pattern, FA2 lacked the ability to produce functional polar pili (pil) and was incapable of twitching motility (twt) . Genetic analysis revealed that the FA2 pil mutation, designated pilG1, mapped near the met-28 marker located at 20 min and was distinct from the previously described pilT mutation . This map location was confirmed by localization of a 6.2-kb EcoRI fragment that complemented FA2 on the SpeI and DpnI physical map of the P . aeruginosa PAO1 chromosome . A 700-bp region encompassing the pilG gene was sequenced, and a 405-bp open reading frame, with characteristic P . aeruginosa codon bias, was identified . The molecular weight of the protein predicted from the amino acid sequence of PilG, which was determined to be 14,717, corresponded very closely to that of a polypeptide with the apparent molecular weight of 15,000 detected after expression of pilG from the T7 promoter in Escherichia coli . Moreover, the predicted amino acid sequence of PilG showed significant homology to that of the enteric CheY protein, a single-domain response regulator . A chromosomal pilG insertion mutant, constructed by allele replacement of the wild-type gene, was not capable of pilus production or twitching motility but displayed normal flagellum-mediated motility . These results, therefore, suggest that PilG may be an important part of the signal transduction system involved in the elaboration of P . aeruginosa pili. Zh Mikrobiol Epidemiol Immunobiol, 1993 Sep-Oct, (5), 32 - 5 {The variability of a Pseudomonas aeruginosa population in the phase of parasitism on Tetrahymena pyriformis}; Riapis LA et al.; Types of interaction between P . aeruginosa and T . pyriformis have been studied . The study has revealed that phagocytizing protozoa are killed by P . aeruginosa in the process of their joint cultivation . The data obtained in this study indicate that in the process of interaction of these species phagocytosis-resistant cells are selected from heterogeneous microbial population . The use of this model is believed to be promising in the study of the fate of P . aeruginosa in abiotic and biotic environment. Igaku Kenkyu, 1993 Sep, 63(3), 95 - 100 {A report on the therapeutical experiences of which have successfully made several antibiotics-resistant bacteria (MRSA etc) negative on bedsores and respiratory organs}; Nakanishi T; Scattering Vitamin C of a small dose on a bedsore, enhances remarkably bactericidal effect of antibiotics . With scattering of it, 1% cream of Sulfadiazine made antibiotics-resistant bacteria (Methicillin-resistant Staphylococcus aureus = MRSA, Pseudomonas aeruginosa etc.) negative on a bedsore . Also in MRSA-infection of respiratory organs, combined administration of Vitamin C gives more effective bactericidal efficacy to some antibiotics . In a case infected with MRSA, of which the Minocycline-therapy had been ineffective, the combined administration of Vitamin C with Minocycline led him successfully to the negativeness of MRSA. Mol Microbiol, 1993 Sep, 9(5), 1027 - 35 Nucleotide sequence and expression of the Pseudomonas aeruginosa algF gene controlling acetylation of alginate; Shinabarger D et al.; Colonization of the cystic fibrosis lung by Pseudomonas aeruginosa is greatly facilitated by the production of an exopolysaccharide called alginate . In this study we determined the nucleotide sequence of an alginate modification gene, algF, which controls the addition of acetyl groups to alginate . Expression of algF using a T7 promoter-expression system showed that algF codes for a 24.5 kDa polypeptide (predicted size 22,832 Da) that is processed to 19.5 kDa . The N-terminus of the processed polypeptide matched the predicted amino acid sequence of AlgF starting at Asp-29 . An algF mutant failed to produce alginate owing to a polar effect on the downstream algA gene . Although the algA gene, provided in trans, restored synthesis of alginate, the alginate was non-acetylated . We show that a plasmid containing both the algF and algA gene complements the alginate acetylation defect of the algF mutant strain. Reg Immunol, 1993 Sep-Oct, 5(5), 245 - 52 Immunization with homologous Pseudomonas aeruginosa pili protects against ocular disease; Rudner XL et al.; The prophylactic effect of pili in prevention or amelioration of Pseudomonas aeruginosa ocular disease was examined in mice, using both systemic and topical protection approaches . At 30 days postinfection, a significant number of animals actively or passively immunized with pili homologous to pseudomonal strain American Type Culture Collection 19660 were protected from ocular disease when compared with similarly infected phosphate-buffered saline controls . Although exogenously mixing strain 19660 with either homologous or heterologous (PAK/PR1) pili before topical application of the inoculum significantly inhibited bacterial adhesion in vitro, in similarly designed in vivo studies, animals were not protected from corneal disease . Neither was significant ocular protection conferred using pili (PAK/PR1) heterologous to the infecting strain (19660) for active or passive immunization of mice, nor in studies involving exogenous mixing of PAK/PR1 pili or its pili-specific monoclonal antibody with strain 19660 prior to topical application of the latter . These results provide evidence that significant ocular protection is achieved by either active or passive, but not topical, immunization with pili homologous to the infecting bacterial strain and that immunization with pili heterologous to the infecting bacterial strain fails to provide protection against ocular disease, despite the fact that heterologous pili are highly effective at decreasing bacterial binding to cornea in vitro. J Gen Microbiol, 1993 Sep, 139 ( Pt 9), 2215 - 23 Detection of the outer membrane lipoprotein I and its gene in fluorescent and non-fluorescent pseudomonads: implications for taxonomy and diagnosis; De Vos D et al.; The open reading frame of the OprI lipoprotein gene from Pseudomonas aeruginosa was amplified by polymerase chain reaction (PCR) starting from purified DNA or colony lysates . A fragment of the expected size (249 bp) was detected in all P . aeruginosa strains from various clinical and geographical origins . The gene could only be amplified in pseudomonads of rRNA group I which are considered to be the authentic genus Pseudomonas . Digestions with HaeIII, PvuII and SphI of the amplified fragments demonstrated a sequence variation in the oprI gene . Colony, dot and Western blots with two monoclonal antibodies (mAbs) against the lipoprotein I confirmed our PCR results . These findings open interesting perspectives for the molecular taxonomy of the genus Pseudomonas and the development of diagnostic tools. J Hosp Infect, 1993 Sep, 25(1), 53 - 6 Phenoxyethanol is effective topical therapy of gram-negative cellulitis in neutropenic patients; Mitchell P et al.; In neutropenic patients cellulitis caused by Gram-negative organisms may prove difficult to control and cause considerable tissue damage . Phenoxyethanol has activity against a range of bacteria, including Pseudomonas aeruginosa, and is absorbed by intact skin . Three severely neutropenic patients are described in whom cellulitis failed to respond to appropriate intravenous antibiotics . However the topical application of phenoxyethanol solution gave prompt local control . This cheap and nontoxic agent may give dramatic improvement in this difficult clinical situation. J Immunol Methods, 1993 Aug 26, 164(1), 27 - 32 Direct double antibody sandwich immunoassay for Pseudomonas aeruginosa elastase; Jaffar-Bandjee MC et al.; A direct sandwich enzyme immunoassay was developed in order to quantify Pseudomonas aeruginosa elastase . As a solid phase the wells of a microtitre plate were coated with specific IgG and horseradish peroxidase labelled IgG was used as the second antibody . The detection limit of the assay was 0.26 ng/ml and a good agreement was found with elastolytic activity determined using elastin-Congo red . This assay was simple, specific, sensitive and reproducible, and permits the determination of low levels of elastase. Lancet, 1993 Aug 21, 342(8869), 465 - 9 Eicosapentaenoic acid in cystic fibrosis: evidence of a pathogenetic role for leukotriene B4; Lawrence R et al.; Much of the lung damage that limits the life of young adults with cystic fibrosis is due to proteases and oxygen metabolites generated by neutrophils, which are recruited into the airway by the interaction between Pseudomonas aeruginosa and pulmonary macrophages . Leukotriene B4 (LTB4) has been proposed as a local mediator of this process; its production is susceptible to specific modulation with dietary eicosapentaenoic acid (EPA) . We carried out a placebo-controlled trial of EPA (2.7 g daily for 6 weeks) to assess its effects on markers of clinical state, peripheral neutrophil function, and lung inflammation in sixteen patients with cystic fibrosis colonised with P aeruginosa . EPA was well tolerated and resulted in a significant reduction in sputum volume (median change with EPA -10 mL/day, placebo 0; p = 0.015), and improvements in Schwachman score (EPA 5%, placebo 0; p = 0.034), forced expiratory volume in 1 s (EPA 0.25 L, placebo -0.1 L; p = 0.006), and vital capacity (EPA 0.6 L, placebo 0; p = 0.011) . Relative chemotaxis of circulating neutrophils to LTB4 increased from a subnormal baseline of 4 (median; range 0-10) microns/30 min before treatment, to a near normal value of 11 (5-18) microns/30 min after EPA . Relative chemotaxis to LTB4 of patients taking placebo did not change: the difference in response was highly significant (p = 0.001) . Specific reduction of neutrophil chemotaxis to LTB4 is a sensitive assay of chronic in-vivo exposure to LTB4 . Our results suggest that LTB4 has a pathogenetic role in the lung damage of cystic fibrosis . Longer-term clinical trials of EPA are warranted in a larger number of cystic fibrosis patients. J Mol Biol, 1993 Aug 20, 232(4), 1208 - 10 Crystallization and preliminary X-ray analysis of the di-haem cytochrome c peroxidase from Pseudomonas aeruginosa; Fulop V et al.; Cytochrome c551 peroxidase is a periplasmic enzyme expressed in Pseudomonas aeruginosa at low oxygen tensions . The glycosylated enzyme has been purified to homogeneity and crystallized by vapour diffusion techniques using polyethylene glycol 2000 as the precipitant in the presence of isopropanol . The crystals belong to the trigonal space group P3(1)21 or P3(2)21 with unit cell dimensions of a = b = 113.8 A, c = 72.0 A . They are suitable for X-ray analysis and diffract to dmin = 2.5 A . There is one peroxidase molecule in the crystallographic asymmetric unit. Biochem Biophys Res Commun, 1993 Aug 16, 194(3), 1460 - 5 Calcium ion-mediated opening of the channel gate in the Pseudomonas aeruginosa porin; Yoshihara E et al.; The gate-forming domain of protein D2 (OprD2) in the outer membrane of Pseudomonas aeruginosa contains an amino acid sequence homologous to the calcium-binding site of the myosin light chain . This observation lets us to test the effect of Ca2+ on the channel function of OprD2 . The diffusion rate of p-nitrophenyl phosphate (PNPP) through OprD2 was 2.3 times higher in the presence of mM order of Ca2+, but not Mg2+ or Mn2+ . Concomitantly, the intrinsic fluorescence emission of OprD2 became about 10% lower in the presence of Ca2+ . As the proteolytic cleavage of the gate-forming domain of OprD2 results the channel activity about 7 times higher, we tested the effect of Ca2+ on the solute permeability through the trypsin-treated OprD2 . The diffusion rate of PNPP in the trypsin-treated OprD2 appeared to be nearly identical in the presence and absence of Ca2+ . The result suggests that Ca2+ activates the OprD2 channel exerting its effect on the gate-forming domain. Schweiz Med Wochenschr, 1993 Aug 10, 123(31-32), 1520 - 5 {Spontaneous pubic osteomyelitis caused by Pseudomonas aeruginosa}; Groeneweg CE et al.; A 53-year-old woman was admitted because of a two weeks' history of progressive perineal pain, low-grade fever, a high erythrocyte sedimentation rate, and tenderness over the inferior rami of the pubic bone . Osteomyelitis was suspected . However, bone scanning, computed tomography, and magnetic resonance imaging of the pelvis showed no evidence of intraosseous disease, but revealed signs of inflammation in the surrounding soft tissue . Conventional antimicrobial therapy was unsuccessful . Biopsy of the bone demonstrated active osteomyelitis and the cultures grew Pseudomonas aeruginosa . Osteomyelitis of the pubic bone and symphysis is most often a sequel to pelvic surgery but has also been observed in i.v . drug abusers . In both circumstances Pseudomonas aeruginosa has frequently been identified as the causative agent . Pelvic osteomyelitis is extremely rare in patients without predisposing factors . Osteomyelitis can only be differentiated from osteitis pubis, a non-infectious inflammatory disease, by bone biopsy . The treatment of choice for osteomyelitis is a beta-lactam antibiotic effective against pseudomonas in combination with an aminoglycoside for 4-6 weeks . Recent studies have demonstrated that new generation quinolones are also effective. J Mol Biol, 1993 Aug 5, 232(3), 992 - 4 Preliminary crystallographic study of cyclohexadienyl dehydratase from Pseudomonas aeruginosa; Obmolova G et al.; Single crystals of cyclohexadienyl dehydratase from Pseudomonas aeruginosa have been obtained by vapour diffusion from ammonium sulphate solution (pH 6.0) at 4 degrees C . The crystals belong to the tetragonal space group P4(3)2(1)2 or P4(1)2(1)2 with a = b = 105.5 A and c = 165.0 A . The asymmetric unit contains at least one dimeric protein molecule with M(r) = 72 kDa . The crystals diffract to 3 A resolution and are suitable for an X-ray analysis. Biochim Biophys Acta, 1993 Aug 4, 1182(1), 83 - 93 Pseudomonal elastase injection causes low vascular resistant shock in guinea pigs; Khan MM et al.; An intravenous injection of culture supernatants obtained from an elastase producing strain (IFO-3455) of Pseudomonas aeruginosa exhibited immediate fall of mean arterial blood pressure from 63.8 +/- 1.62 to 35.6 +/- 2.31 mmHg (P < 0.001), increased heart rate from 249.6 +/- 3.86 to 272.6 +/- 2.18 beats/min (P < 0.05), and increased respiratory rate from 44.8 +/- 2.33 to 68.6 +/- 1.60/min (P < 0.01) within 5 min in the anesthetized guinea pigs . In contrast, culture supernatants obtained from an elastase non-producing strain (PA-103) did not cause the cardio-respiratory alterations, even though the same dose of endotoxin was contained in the supernatants . Intravenous or intracardiac injection of purified Pseudomonas aeruginosa elastase (1.2 mg/kg) but not endotoxin (up to 2.0 mg/kg) reproduced the immediate shock followed by death within 45 min in anesthetized or in conscious guinea pigs . Consistently, the shock-inducing ability of pseudomonal elastase was prevented by pretreatment with anti-pseudomonal elastase rabbit F(ab')2 antibodies or with a synthetic inhibitor of pseudomonal elastase . Furthermore, intravenous injection of a non-lethal dose of pseudomonal elastase (0.8 mg/kg) immediately decreased peripheral vascular resistance when estimated from a change of perfusion pressure at hindquarter circulation from 74.0 +/- 1.00 to 52.6 +/- 1.76 mmHg (P < 0.05) in association with fall of arterial blood pressure and of cardiac output which was estimated from a change of regional aortic flow . The same low-resistant shock was also observed in rats . We speculate, therefore, that bacterial proteinases may play an important role in human septic shock. Biochemistry, 1993 Aug 3, 32(30), 7698 - 702 Site saturation of the histidine-46 position in Pseudomonas aeruginosa azurin: characterization of the His46Asp copper and cobalt proteins; Germanas JP et al.; Cassette mutagenesis has been used to replace the copper ligand His46 of Pseudomonas aeruginosa azurin with 19 other amino acids and a stop codon . Several mutant proteins were expressed in Escherichia coli and isolated; however, only the variant in which His was replaced by Asp exhibited the spectral characteristics of a blue (type 1) center . The spectroscopic and electrochemical properties of this mutant protein show that the copper site is perturbed relative to wild-type azurin . The absorption spectrum of Cu(II)(His46Asp) azurin exhibits a S(Cys)-->Cu(II) band at 612 nm, as well as weaker features at approximately 300, 454, and approximately 850 nm; its EPR spectrum is rhombic (g parallel = 2.327(1), gx approximately 2.03, and gy approximately 2.07; A parallel = 22(2) x 10(-4), Ax approximately 46 x 10(-4), and Ay approximately 22 x 10(-4) cm-1) . The reduction potential of the mutant (260 mV vs NHE at pH 8.5; 297 mV at pH 5.0) is lower than that of wild-type azurin (288 mV at pH 8.5; 349 mV at pH 5.0) . The S(Cys)-->Co(II) absorption bands (approximately 300 and 362 nm) in Co(II)(His46Asp) azurin are strongly blue-shifted relative to those (330 and 375 nm) in the spectrum of the Co(II) (His46) protein, whereas the intensities of the ligand-field bands in the 500-650-nm region (epsilon approximately 100 M-1 cm-1) indicate a five-coordinate Co(II) environment. Mol Microbiol, 1993 Aug, 9(3), 591 - 9 Role of the lipB gene product in the folding of the secreted lipase of Pseudomonas glumae; Frenken LG et al.; The LipB protein of Pseudomonas glumae is essential for the production of active extracellular lipase encoded by the lipA gene . When lipase is overproduced in P . glumae in the absence of a functional lipB gene, the enzyme accumulates intracellularly in an inactive conformation . Heterologous expression of the lipase in Pseudomonas aeruginosa, Bacillus subtilis and Escherichia coli indicated that LipB is not directly involved in the translocation of the lipase across the inner or outer membrane . However, the presence of LipB was essential for obtaining active lipase and had a profound influence on the stability of the protein to proteolytic degradation . Inactive lipase, produced in the absence of LipB could be activated in vitro by unfolding and refolding, which demonstrates that LipB activity is not responsible for an essential covalent modification of the enzyme . We propose that LipB is a lipase-specific foldase . Furthermore, proper folding of the lipase in the periplasm appears to be essential for Xcp-mediated translocation across the outer membrane. Mol Microbiol, 1993 Aug, 9(3), 497 - 506 Differentiation of Pseudomonas aeruginosa into the alginate-producing form: inactivation of mucB causes conversion to mucoidy; Martin DW et al.; Mucoidy in Pseudomonas aeruginosa is a critical virulence factor associated with chronic respiratory infections in cystic fibrosis . A cluster of three tightly linked genes, algU, mucA and mucB located at 67.5 min, controls development of mucoid phenotype . This locus is allelic with a group of mutations (muc) associated with conversion into constitutively mucoid forms . One of the genes previously characterized in this region, algU, is absolutely required for the transcriptional activation of algD, a critical event in the establishment of mucoidy . AlgU is homologous to the alternative sigma factor sigma H (Spo0H) controlling sporulation and competence in Bacillus . Two genes downstream of algU, mucA and mucB were further characterized in this study . Previous complementation studies have demonstrated that mucA is required for suppression of mucoidy in the muc-2 strain PAO568 . In this work, complementation analysis indicated that, in addition, mucB was required for suppression of mucoidy in the muc-25 strain PAO581, and for enhanced complementation of the muc-2 mutation in PAO568 . The complete nucleotide sequence of mucA and mucB was determined . Insertional inactivation of mucB on the chromosome of the standard genetic strain PAO resulted in mucoid phenotype, and in a strong transcriptional activation of algD . Thus, a loss of mucB function is sufficient to cause conversion of P . aeruginosa into the mucoid phenotype . Since the algU-mucA-mucB region is a general site where muc mutations have been mapped, it is likely that mucB participates in the emergence of mucoid forms . Both mucA and mucB play a regulatory role in concert with the sigma-like factor AlgU; all three genes, along with signal transduction and histone-like elements, control differentiation of P . aeruginosa into the mucoid phenotype. J Antibiot (Tokyo), 1993 Aug, 46(8), 1289 - 99 Synthesis and biological properties of some 3-{(N-substituted-amino)pyridinium-4-thiomethyl}-7-{2-(2-amino-thiazol- 4-yl)-2-(Z)-(methoxyimino)acetamido}ceph-3-em-4-carboxylates; Branch CL et al.; The synthesis and antibacterial activity of a series of beta-lactamase stable, broad spectrum 7-{2-(2-amino-thiazol-4-yl)-2-(Z)-(methoxyimino)acetamido}-cephalo sporins, characterised by a C-3-{N-(substituted-amino)pyridinium-4-thiomethyl} group, is described . Gram-positive and Gram-negative bacteria including extended spectrum beta-lactamase-producing strains were most susceptible to the N-amino- and N-methylamino derivatives (3a) and (3b); with the exception of Pseudomonas aeruginosa, (3b) was more active in vitro and in vivo than cefpirome or ceftazidime. Genetika, 1993 Aug, 29(8), 1288 - 94 {The effect of certain Escherichia coli genes on the appearance of the TCS phenotype, conferred by plasmid RP4 with an integrated genome of the D3112 Pseudomonas aeruginosa phage}; Kaplan AM et al.; The possibility of the SOS system activation caused by introduction of a hybrid plasmid RP4::D3112 (where D3112 is a genome of the transposable phage of Pseudomonas aeruginosa) into Escherichia coli was examined . It has been shown previously that the presence of this plasmid confers to E . coli a so called TCS phenotype: E . coli (RP4::D3112) forms normal colonies and grows at 42 degrees C but does not divide and becomes filamentous at 30 degrees C, probably because of E . coli DNA damages generated in the course of D3112 replication-transposition . It was shown that the level of prophage lambda induction is not elevated during the growth of E . coli (lambda) (RP4::D3112) cells at 30 degrees C . The character of the TCS phenotype was not affected by lex A3 or lex A51 mutations (which cause correspondingly non-inducibility or constitutive expression of the SOS regulon) . It was concluded therefore that the TCS phenotype is not related to induction of the SOS response . It was found also that the mutation to heat shock gene dnaJ (dnaJ259) is a cause for significant decrease in phage D3112 production in E . coli dnaJ259 (RP4::D3112) cells . The DNA hybridization data of labelled RP4 and D3112 DNA with total E . coli dnaJ259 (RP4::D3112) DNA suggest that the dnaJ259 probably affected the late D3112 functions. FEMS Microbiol Lett, 1993 Aug 1, 111(2-3), 315 - 20 Investigation of the Pseudomonas aeruginosa ampR gene and its role at the chromosomal ampC beta-lactamase promoter; Lodge J et al.; The complete sequence of the Pseudomonas aeruginosa beta-lactamase regulator gene ampR has been determined . The amino acid sequence encoded by this gene is compared with other members of the LysR family of transcription factors . The P . aeruginosa ampC promoter was subcloned and gel mobility shift assays were used to demonstrate specific binding of AmpR to the ampC promoter region. FEMS Microbiol Lett, 1993 Aug 1, 111(2-3), 251 - 4 An inexpensive infrared growth sensor array for detection of bacterial antibiotic susceptibility; Mason DJ et al.; An inexpensive infrared sensor was constructed and used for the rapid testing of bacterial antibiotic susceptibility by detection of changes in absorbance at 950 nm . By comparing cultures of clinical isolates together with control strains (Escherichia coli NCTC 10418, Staphylococcus aureus NCTC 6571 or Pseudomonas aeruginosa NCTC 10662) after addition of an antibiotic, results on susceptibility were obtained within 3-5 h from the original plate culture . Representative strains of E . coli, P . aeruginosa, and S . aureus were tested successfully against ampicillin, penicillin, gentamicin or ciprofloxacin. Chronobiol Int, 1993 Aug, 10(4), 259 - 70 Circadian variation in amikacin clearance and its effects on efficacy and toxicity in mice with and without immunosuppression; Hosokawa H et al.; A once-daily dosage regimen has been recently recommended in the use of aminoglycoside antibiotics since they induce a postantibiotic effect . In choosing this regimen, one must determine the most appropriate time of day for administration of the drug . We investigated the effects of the timing of amikacin (AMK) administration on the kinetics, the efficacy against intraperitoneal infection with Pseudomonas aeruginosa, and the toxicity of AMK in mice with and without immunosuppression . We found circadian variations in the kinetics, efficacy, and toxicity of the drug in mice . Male and female ICR mice, which were housed under a light-dark (12:12 h) cycle with free food and water intake, were injected subcutaneously with AMK sulfate 50 mg/kg body wt . There was a circadian variation in AMK clearance for both sexes with the maximum value in the dark phase and the minimum in the light phase after a single administration . When AMK 500 mg/kg/day was repeatedly administered once daily for 30 days, higher toxicity was demonstrated in mice injected with the drug at the time of day with lower AMK clearance, although no difference was demonstrated in the toxicity between the two time points with different AMK clearance when AMK 1,500 mg/kg was administered in a single dose . The ED50 of AMK to cure the infected mice in the midlight phase (13:00 h) with lower clearance was significantly lower than that in the middark phase (01:00 h) with higher clearance . In contrast, the ED50 in the early light phase (09:00 h) was significantly lower than that in the early dark phase (21:00 h), although AMK clearance was no different between these two different time points . In mice premedicated with cyclophosphamide to suppress immune functions, the difference in the ED50 of AMK was still demonstrated between 13:00 and 01:00 h, but not between 09:00 and 21:00 h . The present study shows not only that there were circadian variations in both AMK clearance and toxicity after repeated administration, but also that there was a circadian variation in the efficacy of AMK in mice infected with P . aeruginosa . These results suggest that the timing of drug administration should be considered in pharmacotherapy with AMK and that the most appropriate time of administration in mice and nocturnal animals may be in the midlight (resting) phase . They also suggest that the ED50 of AMK against P . aeruginosa infection may be influenced not only by the circadian variation in pharmacokinetics but also by the variations in immune systems suppressed by cyclophosphamide. Eur J Biochem, 1993 Aug 1, 215(3), 841 - 4 Stereochemistry of the reaction catalysed by 2-aminoethylphosphonate aminotransferase . A 1H-NMR study; Lacoste AM et al.; (R)- and (S)-2-amino{2-D1}ethylphosphonic acids ({2-D1}AEP) were synthesised to investigate the stereochemistry of the reaction catalysed by 2-aminoethlphosphonate aminotransferase from Pseudomonas aeruginosa . This enzyme catalyses the transfer of the amino group of AEP to pyruvate to produce 2-phosphonoacetaldehyde and alanine . The enzymic reaction proceeding through the abstraction of a proton from the Schiff-base complex formed between the enzyme-bound pyridoxal 5'-phosphate, and the substrate, was carried out in an aqueous buffer at pH 8.5; it was followed by high-field 1H-NMR measurements (500 MHz, H2O) on an AMX 500 Bruker spectrometer . The spectra, recorded with chiral (R)- or (S)-{2-D1}AEP, both showed the methylenic signal (3.0 ppm), whereas (S)-{2-D1}AEP gave the additional aldehydic signal (CHO, 9.6 ppm) . These data clearly show that AEP-aminotransferase catalyses the abstraction of the pro-S hydrogen atom at the prochiral C2 carbon of AEP . Furthermore, careful timing of NMR measurements over a 2-hour period allows us to show the occurrence of an isotopic effect. J Bacteriol, 1993 Aug, 175(16), 5057 - 65 Identification of algF in the alginate biosynthetic gene cluster of Pseudomonas aeruginosa which is required for alginate acetylation; Franklin MJ et al.; Mucoid strains of Pseudomonas aeruginosa produce a high-molecular-weight exopolysaccharide called alginate that is modified by the addition of O-acetyl groups . To better understand the acetylation process, a gene involved in alginate acetylation called algF was identified in this study . We hypothesized that a gene involved in alginate acetylation would be located within the alginate biosynthetic gene cluster at 34 min on the P . aeruginosa chromosome . To isolate algF mutants, a procedure for localized mutagenesis was developed to introduce random chemical mutations into the P . aeruginosa alginate biosynthetic operon on the chromosome . For this, a DNA fragment containing the alginate biosynthetic operon and adjacent argF gene in a gene replacement cosmid vector was utilized . The plasmid was packaged in vivo into lambda phage particles, mutagenized in vitro with hydroxylamine, transduced into Escherichia coli, and mobilized to an argF auxotroph of P . aeruginosa FRD . Arg+ recombinants coinherited the mutagenized alginate gene cluster and were screened for defects in alginate acetylation by testing for increased sensitivity to an alginate lyase produced by Klebsiella aerogenes . Alginates from recombinants which showed increased sensitivity to alginate lyase were tested for acetylation by a colorimetric assay and infrared spectroscopy . Two algF mutants that produced alginates reduced more than sixfold in acetyl groups were obtained . The acetylation defect was complemented in trans by a 3.8-kb XbaI-BamHI fragment from the alginate gene cluster when placed in the correct orientation under a trc promoter . By a merodiploid analysis, the algF gene was further mapped to a region directly upstream of algA by examining the polar effect of Tn501 insertions . By gene replacement, DNA with a Tn501 insertion directly upstream of algA was recombined with the chromosome of mucoid strain FRD1 . The resulting strain, FRD1003, was nonmucoid because of the polar effect of the transposon on the downstream algA gene . By providing algA in trans under the tac promoter, FRD1003 produced nonacetylated alginate, indicating that the transposon was within or just upstream of algF . These results demonstrated that algF, a gene involved in alginate acetylation, is located directly upstream of algA. Clin Exp Immunol, 1993 Aug, 93(2), 165 - 71 Treatment of murine macrophages with murine interferon-gamma and tumour necrosis factor-alpha enhances uptake and intracellular killing of Pseudomonas aeruginosa; Pierangeli SS et al.; Murine interferon-gamma (MuIFN-gamma) and murine tumour necrosis-alpha (MuTNF-alpha) are known to be potent immunomodulators of several aspects of the immune response, and they have been shown to exert profound effects on macrophages and monocytes . The purpose of this study was to determine the effects of MuIFN-gamma and MuTNF-alpha on the phagocytosis (uptake and intracellular killing) of opsonized Pseudomonas aeruginosa . Unstimulated peritoneal macrophages obtained from CBA/c mice were exposed to different concentrations of recombinant forms of the cytokines (rMuIFN-gamma and rMuTNF-alpha) for different periods of time . Phagocytosis was assayed using different concentrations of opsonized Ps . aeruginosa . In all cases the pretreatment of the cells with the cytokines increased significantly the uptake and the intracellular killing of bacteria in a dose-dependent manner . rMuTNF-alpha was effective only at 1000 U/ml . Combined treatment with the cytokines showed a less than additive effect with rMuIFN-gamma and rMuTNF-alpha at concentrations of 10 U/ml and 100 U/ml . In the in vivo experiments, peritoneal macrophages obtained from rMuIFN-gamma- or rMuTNF-alpha-treated mice showed enhancement of the intracellular killing of opsonized bacteria in a dose-dependent manner. J Med Microbiol, 1993 Aug, 39(2), 141 - 6 Mortality rates amongst mice with endogenous septicaemia caused by Pseudomonas aeruginosa isolates from various clinical sources; Furuya N et al.; Mice that had been treated with cyclophosphamide and ampicillin were fed with Pseudomonas aeruginosa . These procedures induced an endogenous septicaemia under conditions mimicking the pathophysiology of the disease in man . This model was used to compare the mortality rates in mice infected with P . aeruginosa isolates from various clinical sources . Mortality rates in mice given isolates from blood cultures had a broad range (0-100%), but the mean rate was significantly higher than with isolates from other infection sites . Moreover, blood isolates persisted in the intestines of mice after oral inoculation, whereas most isolates from other sources were gradually eliminated . Most P . aeruginosa isolates from blood culture produced significantly higher levels of exotoxin A and total proteases than isolates from other infection sites . Amongst the blood isolates, all but one of the lethal strains produced large quantities of exotoxin A or total proteases or both . Taken together, the results suggest that the ability of P . aeruginosa to adhere to the intestinal tract and to produce high levels of exo-enzymes may contribute to the development of fatal septicaemia. Invest Ophthalmol Vis Sci, 1993 Aug, 34(9), 2699 - 712 Effect of Pseudomonas aeruginosa elastase, alkaline protease, and exotoxin A on corneal proteinases and proteins; Twining SS et al.; PURPOSE . To determine the effects of exoproducts from the corneal pathogen Pseudomonas aeruginosa on corneal proteinases and proteins . METHODS . Whole rabbit corneas were cultured in the presence or absence of broths conditioned with Pseudomonas aeruginosa, elastase, alkaline protease, and exotoxin A . Protein synthesis was assayed by adding 35S-methionine during the last 6 hours of culture . Caseinolytic assays and zymography on sodium dodecyl sulfate polyacrylamide gels containing casein and gelatin were used in the presence and absence of inhibitors to quantify and identify corneal proteinases . RESULTS . The major proteinases released by the corneas were 92/89 kD (MMP9) and 65 kD (72 kD gelatinase, MMP2) gelatinases and a 97 kD caseinase . Minor proteinases observed included 184, 166, 156, 153, 126, 111, 102, 60, 57, and 43 kD gelatinases and 170, 136, 85, and 54 kD caseinases . P . aeruginosa elastase at 1 microgram/ml cleaved the 92 kD gelatinase to yield a 77 kD active form and cleaved the 65 kD gelatinase to yield a 57 kD active form . At 25 micrograms/ml elastase, the gelatinases were degraded . P . aeruginosa alkaline protease had no effect on the 92 or 65 kD gelatinases . Both elastase and alkaline protease degraded the 97 kD caseinase . Proteinases other than elastase and alkaline protease in P . aeruginosa103- and P . aeruginosa01-conditioned broths also activated and/or degraded corneal proteinases . Exotoxin A inhibited the synthesis of the 92 kD gelatinase and most other proteins . The 72 kD gelatinase and the 97 kD caseinase were released in the presence of exotoxin A . CONCLUSIONS . Pseudomonas aeruginosa exoproducts can contribute directly to keratitis caused by Pseudomonas organisms through toxic effects on corneal cells and degradation of corneal proteins and indirectly through the activation of corneal proteinases. Am Rev Respir Dis, 1993 Aug, 148(2), 467 - 76 Immunofluorescent analysis of plasma fibronectin incorporation into the lung during acute inflammatory vascular injury; Charash WE et al.; Incorporation of plasma fibronectin into tissues is believed to influence endothelial cell-cell interaction, as well as endothelial cell adhesion to matrix . We used immunofluorescent microscopy coupled with tissue extraction of noncovalently incorporated fibronectin to delineate the time course for matrix incorporation of soluble plasma-derived fibronectin into the lung of sheep during postoperative bacteremia . Adult sheep were surgically prepared with both lung and peripheral lymph fistulas . Sheep were anesthetized 2 days following surgery and injected intravenously with a sublethal dose of live Pseudomonas aeruginosa, which consisted of 5 x 10(8) live organisms suspended in 0.9% saline . Bacterial infusion elicited a 300% increase in lung transvascular protein clearance but no increase in peripheral transvascular protein clearance . Purified dimeric human plasma fibronectin (hFn), used as an "immunologic marker," was then infused intravenously (100 mg/sheep) into two additional groups of sheep (nonbacteremic control group and bacteremic experimental group) and allowed to mix with the plasma pool of endogenous soluble sheep fibronectin (sFn) . Incorporation of the plasma-derived hFn into the lung matrix and its distribution in relation to endogenous sheep fibronectin in the matrix was assessed by dual-label immunofluorescence using antibodies specific to either sFn or hFn . Human fibronectin from the vascular compartment codistributed with endogenous sheep fibronectin in the lung matrix . Moreover, its deposition into the lung was markedly increased in postoperative bacteremic sheep compared with nonbacteremic control sheep . Increased hFn deposition in the lung with bacteremia was clearly apparent within 2 h . The hFn deposited in the lung was nonextractable using a heparin-urea tissue extraction buffer, suggesting its rapid covalent cross-linking and incorporation into the lung matrix . Microscopic analysis of serial lung biopsies revealed focal areas of inflammation with an intense mononuclear infiltrate into the lungs by 2 h in the bacteremic sheep . Interstitial edema and vascular endothelial injury were observed by 4 h, with alveolar edema apparent over 6 to 8 h . Thus, postoperative bacteremia results in a rapid incorporation of plasma fibronectin into the lung matrix . This may be a physiologic mechanisms to stabilize the integrity of the lung vascular barrier. J Bacteriol, 1993 Aug, 175(15), 4780 - 9 Characterization of the Pseudomonas aeruginosa alginate lyase gene (algL): cloning, sequencing, and expression in Escherichia coli; Schiller NL et al.; Mucoid strains of Pseudomonas aeruginosa produce a viscous exopolysaccharide called alginate and also express alginate lyase activity which can degrade this polymer . By transposon mutagenesis and gene replacement techniques, the algL gene encoding a P . aeruginosa alginate lyase enzyme was found to reside between algG and algA within the alginate biosynthetic gene cluster at 35 min on the P . aeruginosa chromosome . DNA sequencing data for algL predicted a protein product of ca . 41 kDa, including a 27-amino-acid signal sequence, which would be consistent with its possible localization in the periplasmic space . Expression of the algL gene in Escherichia coli cells resulted in the expression of alginate lyase activity and the appearance of a new protein of ca . 39 kDa detected on sodium dodecyl sulfate-polyacrylamide gels . In mucoid P . aeruginosa strains, expression of algL was regulated by AlgB, which also controls expression of other genes within the alginate gene cluster . Since alginate lyase activity is associated with the ability to produce and secrete alginate polymers, alginate lyase may play a role in alginate production. Infect Immun, 1993 Aug, 61(8), 3287 - 93 Mechanisms of nonopsonic phagocytosis of Pseudomonas aeruginosa; Mork T et al.; The interaction of the macrophage cell line P388D1 with Pseudomonas aeruginosa in the absence of stimulators or opsonins led to substantial association of bacteria, as judged by visual counting and FACScan assays . This association was observable within 5 min of addition of bacteria, could not be disturbed by exhaustive washing, and occurred with pilus- or flagellum-deficient mutants but not with rpoN mutants, which have been proposed to lack a secondary adhesin . In contrast, specific antibody was capable of causing similar enhancement of bacterial uptake regardless of the rpoN phenotype . Fibronectin stimulated uptake of bacteria with the pilus as an adhesin, and stimulation was observable within 5 min . Both fibronectin-enhanced and antibody-opsonized uptake were susceptible to inhibition by pertussis toxin but not by cholera toxin . The influence of fibronectin on P388D1 cells was distinguishable from that of lipopolysaccharide, which caused substantial morphological changes in cells . Although lipopolysaccharide stimulated bacterial uptake, it actually suppressed fibronectin-mediated enhancement of uptake at high concentrations. Clin Invest Med, 1993 Aug, 16(4), 306 - 13 Canadian Bacterial Diseases Network: a new approach to university-industry relationships; Hancock RE et al.; Bacterial diseases are a substantial problem worldwide . Their diagnosis and therapy form the basis of a multibillion dollar industry . This industry is dynamic and is continuously revitalized by research . The Canadian Bacterial Diseases Network (CBDN) was established to capitalize on the enhanced opportunities that now exist for the rapid progression of an idea from conceptualization to implementation and, ultimately, commercialization . CBDN is one of 15 Networks of Centres of Excellence, a Federal Government initiative whose intention is to improve Canada's economic competitiveness in the global market . CBDN research involves fundamental science, is broadly-based, and encompasses all aspects of bacterial diseases . Current projects include the investigations of strategies to block Pseudomonas aeruginosa binding to epithelial cells and a novel anti-toxin approach for Escherichia coli . Also CBDN is investigating the basis for antibiotic resistance in Gram-negative bacteria, and is devising improved procedures for overcoming such resistance mechanisms . CBDN is only 28 months into its first 4-year mandate; however, considerable successes have been enjoyed to date. Int J Pediatr Otorhinolaryngol, 1993 Aug, 27(2), 147 - 57 Airway endoscopy in the diagnosis and treatment of bacterial tracheitis in children; Eckel HE et al.; Children with bacterial tracheitis present with the symptoms of viral laryngotracheobronchitis or epiglottitis, but do not respond to appropriate therapy for these diseases and frequently develop acute respiratory decompensation . Since the treatment and outcome of bacterial tracheitis differ so much from those of viral laryngotracheobronchitis and epiglottitis, prompt and accurate diagnosis is essential . The aim of this study was to evaluate the significance of different diagnostic characteristics in a group of eleven patients and to compare the results to those recently reported in the pediatric and otorhinolaryngologic literature . The present study suggests that reliable predictive factors do not exist for bacterial tracheitis . No single clinical, radiological or laboratory feature was a reliable diagnostic predictor for bacterial tracheitis, nor was it any combination of these features . The only diagnostic procedure to distinguish bacterial tracheitis accurately and promptly from other forms of acute obstructive upper airway diseases was direct laryngo-tracheo-bronchoscopy . Following endoscopic removal of all tracheal secretions and pulmonary toilet, nasotracheal intubation provides sufficient airway maintenance and obviates the need for tracheostomy . Endoscopy is thus diagnostic and therapeutic at the same time . If bacterial tracheitis is suspected a direct laryngoscopy and rigid tracheobronchoscopy should be performed under general anesthesia, as prompt diagnosis and adequate treatment are essential to survival . The cultures of the purulent tracheal secretions frequently revealed Staphylococcus aureus in combination with various pathogens, particularly the involvement of Pseudomonas aeruginosa was noted in two patients . Our data imply a susceptibility of children with Down's syndrome or immunodeficiency to bacterial tracheitis. Int J Pediatr Otorhinolaryngol, 1993 Aug, 27(2), 137 - 45 Opsonization and phagocytosis of bacteria during various middle ear infections; Stenfors LE et al.; Samples of middle ear effusions (MEE) obtained from 50 ch