Enterococci

Clin Infect Dis, 2001 May 1, 32(9), 1373 - 5 Epub 2001 Apr 09.
Successful treatment of vancomycin-resistant Enterococcus endocarditis with oral linezolid; Babcock HM et al.; We report a case of vancomycin-resistant Enterococcus faecium endocarditis that failed to respond to sequential monotherapy with chloramphenicol and quinupristin/dalfopristin but was successfully treated with oral linezolid.

Antimicrob Agents Chemother, 2001 May, 45(5), 1480 - 6
Penicillin-binding protein 5 and expression of ampicillin resistance in Enterococcus faecium; Rice LB et al.; We report a structural and transcriptional analysis of the pbp5 region of Enterococcus faecium C68 . pbp5 exists within a larger operon that includes upstream open reading frames (ORFs) corresponding to previously reported psr (penicillin-binding protein synthesis repressor) and ftsW (whose product is a transmembrane protein that interacts with PBP3 in Escherichia coli septum formation) genes . Hybridization of mRNA from C68, CV133, and four ampicillin-resistant CV133 mutants revealed four distinct transcripts from this region, consisting of (i) E . faecium ftsW (ftsW(Efm)) alone; (ii) psr and pbp5; (iii) pbp5 alone; and (iv) ftsW(Efm), psr, and pbp5 . Quantities of the different transcripts varied between strains and did not always correlate with quantities of PBP5 or levels of ampicillin resistance . Since the psr of C68 is presumably nonfunctional due to an insertion of an extra nucleotide in the codon for the 44th amino acid, the region extending from the ftsW(Efm) promoter through the pbp5 gene of C68 was cloned in E . coli to facilitate mutagenesis . The psr ORF was regenerated using site-directed mutagenesis and introduced into E . faecium D344-SRF on conjugative shuttle vector pTCV-lac (pCWR558 {psr ORF interrupted}; pCWR583 {psr ORF intact}) . Ampicillin MICs for both D344-SRF(pCWR558) and D344-SRF(pCWR583) were 64 microg/ml . Quantities of pbp5 transcript and protein were similar in strains containing either construct regardless of whether they were grown in the presence or absence of ampicillin, arguing against a role for PSR as a repressor of pbp5 transcription . However, quantities of psr transcript were increased in D344-SRF(pCWR583) compared to D344-SRF(pCWR558), especially after growth in ampicillin; suggesting that PSR acts in some manner to activate its own transcription.

Antimicrob Agents Chemother, 2001 May, 45(5), 1394 - 401
In vivo efficacy of trovafloxacin against Bacteroides fragilis in mixed infection with either Escherichia coli or a vancomycin-resistant strain of Enterococcus faecium in an established-abscess murine model; Stearne LE et al.; The pharmacodynamic and pharmacokinetic properties of trovafloxacin were studied in a standardized murine model of established subcutaneous abscesses . Daily dosing regimens of 37.5 to 300 mg/kg every 8 h (q8h) or every 24 h (q24h) were started 3 days after inoculation with mixtures containing either Bacteroides fragilis-Escherichia coli-autoclaved cecal contents (ACC) or B . fragilis-vancomycin-resistant Enterococcus faecium (VREF)-ACC . Treatment was continued for 3 or 5 days . The efficacy of treatment was determined by the decrease in abscess bacterial counts and abscess weights, as well as by the reduction in inflammation (biodistribution of (99m)Tc-HYNIC immunoglobulin G) compared to saline-treated controls . Trovafloxacin showed a significant dose-response effect on the bacterial counts, weight, and inflammation of B . fragilis-E . coli abscesses after 3 and/or 5 days of treatment . A maximum 3.4 and 3.1 log(10) reduction in CFU/abscess in the respective B . fragilis and E . coli bacterial counts was attained after 5 days of treatment with daily doses of 300 mg/kg . The peak serum concentration was more predictive for effect than the area under the concentration-time curve . The C(max) was the pharmacodynamic index most predictive for success, and the efficacy of the q24h regimens was significantly better than the q8h regimens . The antibiotic was ineffective against the VREF in mixed infection with B . fragilis, while the killing of the anaerobe in the same combination was significantly less than in the E . coli combination (P < 0.05) . We conclude that this is a useful model for studying the activity of antimicrobials for the treatment of small (<1-cm), undrainable, mixed-infection abscesses . In addition, we have shown for the first time that a decrease in bacterial numbers also leads to a reduction in both abscess weight and inflammation.

Emerg Infect Dis, 2001 Mar-Apr, 7(2), 183 - 7
Emergence of vancomycin-resistant enterococci; Rice LB; Vancomycin and ampicillin resistance in clinical Enterococcus faecium strains has developed in the past decade . Failure to adhere to strict infection control to prevent the spread of these pathogens has been well established . New data implicate the use of specific classes of antimicrobial agents in the spread of vancomycin-resistant enterococci (VRE) . Extended-spectrum cephalosporins and drugs with potent activity against anaerobic bacteria may promote infection and colonization with VRE and may exert different effects on the initial establishment and persistence of high-density colonization . Control of VRE will require better understanding of the mechanisms by which different classes of drugs promote gastrointestinal colonization.

Clin Microbiol Infect, 2001 Jan, 7(1), 17 - 21
Chloramphenicol treatment for vancomycin-resistant Enterococcus faecium bacteremia; Ricaurte JC et al.; OBJECTIVE: To evaluate the results of treating vancomycin-resistant Enterococcus faecium (VREF) bacteremia with chloramphenicol . METHODS: We retrospectively reviewed the charts of all adult patients with VREF bacteremia treated with chloramphenicol during the calendar year 1998 at a 522-bed tertiary referral center in New York City . Patients were identified by reviewing microbiology laboratory records . Patients with clinically significant VREF bacteremia who received chloramphenicol for at least 48 h were included in the study . Clinical and microbiological outcomes were determined . Microbiological and molecular tests were performed on a small representative sample of isolates to identify the presence of resistance mechanisms and to look for similarity among the isolates . RESULTS: Seven episodes of significant VREF bacteremia occurred in six patients . Mean age was 54 years . All patients had cancer and three had severe neutropenia . Five of seven episodes were associated with chronic indwelling devices, but in only one of these cases was the device removed . All isolates were susceptible to chloramphenicol in vitro . All six microbiologically evaluable episodes had a favorable response to chloramphenicol treatment, and four of seven (57%) clinically evaluable episodes had favorable outcomes . Only one death may have been due to VREF bacteremia, so the maximal attributable mortality was 14% . The three representative samples that were tested further were indistinguishable from one another and they displayed no evidence of resistance mechanisms . CONCLUSIONS: In a cohort of severely ill cancer patients, chloramphenicol was effective in treating VREF bacteremia . The use of chloramphenicol should be considered in treating infections with this highly resistant organism, where therapeutic options are limited.

South Med J, 2001 Mar, 94(3), 353 - 5
Vancomycin-resistant Enterococcus faecium osteomyelitis: successful treatment with quinupristin-dalfopristin; Summers M et al.; Vancomycin-resistant enterococci (VRE) have recently emerged as an increasing concern in the management of severe infections . Treatment of these life-threatening infections has been limited to quinupristin-dalfopristin and, more recently, linezolid therapy . We report the first case, to our knowledge, of vancomycin-resistant Enterococcus faecium vertebral osteomyelitis treated successfully with quinupristin-dalfopristin . We review the recent epidemiology of VRE and briefly outline the pharmacology and pharmacokinetics of quinupristin-dalfopristin.

J Clin Microbiol, 2001 Apr, 39(4), 1678 - 9
Vertebral osteomyelitis caused by Enterococcus raffinosus; Sandoe JA et al.; Enterococcus raffinosus is a rare isolate in clinical specimens . A case of vertebral osteomyelitis caused by E . raffinosus in an elderly patient is described and confirms this organism to be an opportunistic human pathogen.

Protein Sci, 2001 Apr, 10(4), 836 - 44
Sequencing of the ddl gene and modeling of the mutated D-alanine:D-alanine ligase in glycopeptide-dependent strains of Enterococcus faecium; Gholizadeh Y et al.; Glycopeptide dependence for growth in enterococci results from mutations in the ddl gene that inactivate the host D-Ala:D-Ala ligase . The strains require glycopeptides as inducers for synthesis of resistance proteins, which allows for the production of peptidoglycan precursors ending in D-Ala-D-Lac instead of D-Ala-D-Ala . The sequences of the ddl gene from nine glycopeptide-dependent Enterococcus faecium clinical isolates were determined . Each one had a mutation consisting either in a 5-bp insertion at position 41 leading to an early stop codon, an in-frame 6-bp deletion causing the loss of two residues (KDVA243-246 to KA), or single base-pair changes resulting in an amino acid substitution (E13 --> G, G99 --> R, V241 --> D, D295 --> G, P313 --> L) . The potential consequences of the deletion and point mutations on the 3-D structure of the enzyme were evaluated by comparative molecular modeling of the E . faecium enzyme, using the X-ray structure of the homologous Escherichia coli D-Ala:D-Ala ligase DdlB as a template . All mutated residues were found either to interact directly with one of the substrates of the enzymatic reaction (E13 and D295) or to stabilize the position of critical residues in the active site . Maintenance of the 3-D structure in the vicinity of these mutations in the active site appears critical for D-Ala:D-Ala ligase activity.

Microb Drug Resist, 2000 Winter, 6(4), 327 - 30
Effectiveness of a vancomycin restriction policy in changing the prescribing patterns of house staff; Richardson LP et al.; After noting a rise in vancomycin-resistant enterococci (VRE) infections, we initiated a program to decrease inappropriate vancomycin use that focused on improvement of house staff prescribing practices . The initial intervention in June, 1995, encouraging house staff to follow hospital guidelines for vancomycin use and eliciting support from service chiefs in this effort, had little impact . A more intensive educational intervention, beginning in January, 1996, involved concurrent review of all vancomycin orders and one-on-one discussion with the house staff regarding the rationale for the order by an infectious diseases clinical pharmacist . When usage was deemed inappropriate, the pharmacist asked that vancomycin be discontinued, but no automatic stop orders were issued . During the next two and one-half years, this second intervention proved effective at decreasing inappropriate use from 39% to 16.8% +/- 2.4% (p = 0.005) . This change was primarily due to a decrease in appropriate vancomycin prophylaxis by cardiothoracic surgery . VRE infections decreased from 0.29/100 patients discharged prior to initiating the program to 0.13/100 patients discharged after the second intervention (p = 0.01) . This educational program, although labor-intensive, preserved house staff decision-making skills related to antibiotic prescribing at the same time that it decreased inappropriate vancomycin use.

Microb Drug Resist, 2000 Winter, 6(4), 305 - 11
Streptogramin resistance and shared pulsed-field gel electrophoresis patterns in vanA-containing Enterococcus faecium and Enterococcus hirae isolated from humans and animals in Spain; Robredo B et al.; The present study was performed to determine if any of the 45 vanA-containing Enterococcus faecium or 18 vanA-containing E . hirae strains were shared by chickens (32 E . faecium/l7 E . hirae) and humans (13 E . faecium/1 E . hirae) using pulsed field gel electrophoresis (PFGE) and to study quinupristin-dalfopristin (Q-D) resistance . Seven of the 45 E . faecium isolates (from 2 outpatients and from 5 poultry products) were resistant to Q-D (MIC > or = 16 microg/ml); one strain was shown to have satA by PCR and sequencing and, in the other six isolates, the recently described satG gene was demonstrated . Six different PFGE patterns were detected among the 7 Q-D E . faecium-resistant isolates . None of the E . hirae isolates showed Q-D resistance . Among the 45 vanA -containing E . faecium strains, 25 unrelated clones were found by PFGE with highly diverse patterns and an indistinguishable PFGE pattern was observed in vanA-containing E . faecium strains from two humans and two poultry products . A single PFGE pattern was detected in 17 of 18 vanA-containing E . hirae isolates, obtained from one human and 16 chicken samples . Based on the presence of indistinguishable PFGE patterns among VR E . faecium and E . hirae from humans and chickens, we conclude that horizontal transfer of these strains could occur between both groups.

Fish Shellfish Immunol, 2001 Jan, 11(1), 53 - 63
Effects of intrinsic and extrinsic factors on the haemocyte profile of the prawn, Macrobrachium rosenbergii; Cheng W et al.; The giant freshwater prawn Macrobrachium rosenbergii was investigated for its total haemocyte count (THC) based on season, sex, size and feeding rate . The THC, when the prawns were subjected to injections of foreign materials was also investigated . The prawns displayed the highest and lowest THC in autumn and winter respectively, with no significant difference between male and female, or among animals with a body weight range of 7-115 g . The prawns displayed the lowest THC at D3 stage, and the highest in C stage . The prawns displayed the lowest THC when they were fed at 0.1% feeding rate among feeding rates of 0.1%, 0.5%, 1.0% and 1.5% body weight x day(-1) . Prawns injected with carbon powder and Enterococcus showed increased THC during the first 6 h . Prawns injected with saline and carbon powder had the lowest THC after 30 h, and recovered to the normal value after 54 h . Prawns injected with Enterococcus showed the lowest THC after 42 h, and showed delayed recovery.

Arch Microbiol, 2001 Jan, 175(1), 41 - 5
Potassium uptake with low affinity and high rate in Enterococcus hirae at alkaline pH; Kawano M et al.; Two high-affinity K+ uptake systems, KtrI and KtrII, have been reported in Enterococcus hirae . A mutant, JEMK1, defective in these two systems did not grow at pH 10 in low-K+ medium (less than 1 mM K+), but grew well when supplemented with 10 mM KCl . In this mutant, we found an energy-dependent K+ uptake at pH 10 with a low affinity for K+ (Km of approximately 20 mM) and an extremely high rate {Vmax of 1.6 micromol x min(-1) (mg protein)(-1)} . Rb+ uptake {Km of approximately 40 mM and Vmax of 0.5 micromol x min(-1) (mg protein)(-1)}, which was inhibited competitively by K+ and less prominently by Cs+, was also observed . The specificity of this transport is likely to be K+>Rb+>Cs+ . This peculiar K+ transport plays a role as a salvage mechanism against defects in high-affinity systems in the K+ homeostasis of this bacterium.

Lancet, 2001 Mar 17, 357(9259), 853 - 5
Variant esp gene as a marker of a distinct genetic lineage of vancomycin-resistant Enterococcus faecium spreading in hospitals; Willems RJ et al.; In the USA, vancomycin-resistant Enterococcus faecium (VREF) is endemic in hospitals, despite lack of carriage among healthy individuals . In Europe, however, hospital outbreaks are rare, but VREF carriage among healthy individuals and livestock is common . We used amplified fragment-length polymorphism analysis to genotype 120 VREF isolates associated with hospital outbreaks and 45 non-epidemic isolates from the USA, Europe, and Australia . We also looked for the esp virulence gene in these isolates and in 98 VREF from animals . A specific E . faecium subpopulation genetically distinct from non-epidemic VREF isolates was found to be the cause of the hospital epidemics in all three continents . This subpopulation contained a variant of the esp gene that was absent in all non-epidemic and animal isolates . Identification of the variant esp gene will be important in guiding infection-control strategies, and the Esp protein could be a new target for antibacterial therapy.

Pathol Biol (Paris), 2001 Feb, 49(1), 23 - 32
{Evaluation of 7 endoscope washer-disinfectors: bactericidal activity of the disinfectants, antibacterial efficacity of paired washer-disinfector products}; Dusseau JY et al.; The authors studied seven automatic washer disinfectors for flexible endoscopes with two methods . The first method, a microdilution method, studied the bactericidal activity of the seven disinfectants against 21 strains: four reference strains, 14 hospital strains reported in the literature as nosocomial strains responsible for infections transmitted by flexible endoscopes and three vancomycin-resistant Enterococci . The ability of the seven automatic washer disinfectors to decontaminate flexible endoscopes following inoculation with four reference strains was studied with the second method . There were three kinds of results: the results of three automatic washer disinfectors in conformity with both methods; the results of three automatic washer disinfectors conformity with 1 method only; the results of one automatic washer disinfector without conformity with any methods . Both methods should be used for evaluation of automatic washer disinfector . Then, these results emphasize the necessity to modify the use of disinfectants and/or the systems of some automatic washer disinfectors.

Rev Esp Cardiol, 2001 Mar, 54(3), 402 - 4
{Isolated pulmonary endocarditis on native valve in elderly patient without predisposing factors}; Perez-Paredes M et al.; Isolated infective endocarditis in the native pulmonary valve is an unusual clinical entity in patients without predisposing factors and in non-intravenous drugs users . We present the case of a 75-year-old patient, with a subacute clinical picture of fever and pulmonary cavity nodules, admitted to our hospital with an initial suspected diagnosis of pulmonary tuberculosis . The presence of Enterococcal bacteremia in hemocultive and the documentation of a large vegetation in pulmonary valve by transtoracic and transesophageal echocardiography were key factors for final diagnosis.

Antimicrob Agents Chemother, 2001 Apr, 45(4), 1309 - 11
Diversity of Tn1546 elements in clinical isolates of glycopeptide-resistant enterococci from Scottish hospitals; Brown AR et al.; The Tn1546-related elements of 48 Van glycopetide-resistant enterococci were compared . Ten distinct Tn1546 types were identified with variation primarily due to IS1542 and IS1216V-like insertions . Clonal isolates frequently differed in their Tn1546 type, indicating instability of Tn1546-related elements . A putative hybrid promoter was identified, generated upstream of vanR by the insertion of IS1542 . The presence of this hybrid promoter was associated with constitutive expression of the van genes and elevated teicoplanin resistance.

J Antimicrob Chemother, 1999 Feb, 43(2), 261 - 6
The control of hyperendemic glycopeptide-resistant Enterococcus spp . on a haematology unit by changing antibiotic usage; Bradley SJ et al.; The rectal carriage of glycopeptide-resistant Enterococcus spp . (GRE) had been established at approximately 50% in a series of prevalence studies on a busy haematological malignancy unit . The aim of this study was to reduce the chance of patients acquiring GRE . A prospective three-phase sequential study was performed . In Phase 1, the acquisition rate of GRE detectable by rectal swab was measured without any intervention for a period of 4 months . For the following 8 months (Phase 2), the first-line treatment for febrile neutropenic episodes was changed from monotherapy with ceftazidime to piperacillin/tazobactam . In addition, an intense education programme was introduced to improve hygiene to reduce the risk of case-to-case spread . In the final 4 months (Phase 3), ceftazidime was again used as the first-line antimicrobial, while continuing the same level of training in relation to hygiene . The carriage of GRE was measured from rectal swabs done weekly . During the initial 4 months, at any time, 40-50% of patients in the unit were colonized with GRE, and 43 of 75 (57%) new patients initially negative for GRE acquired it within 6 weeks of their admission . In Phase 2, 25 patients out of 129 (19%) acquired GRE, with the acquisition rate falling progressively so that in the last 3 months, only one new patient acquired GRE (logrank comparison of probabilities for cohort 1 vs cohort 2b: P < 0.0001) . A return to ceftazidime in Phase 3 was associated with a return of the risk of acquiring detectable GRE colonization, despite continued hygiene teaching and surveillance, with 21 out of 58 patients (36%) acquiring GRE (cohort 1 vs cohort 3: P = 0.08) . Glycopeptide usage was not reduced during the period of the study . Clinical cases were seen only in Phases 1 and 3 . Although the reduction in the risk of acquiring GRE may have been due in part to hygiene practices as well as to the change in antimicrobial usage, or may have occurred spontaneously for other reasons, the return of the problem with the reintroduction of ceftazidime strongly suggests that this antibiotic was responsible for encouraging the acquisition of detectable GRE.

Mol Microbiol, 2001 Mar, 39(5), 1307 - 20
Dominant-negative mutants of prgX: evidence for a role for PrgX dimerization in negative regulation of pheromone-inducible conjugation; Bae T et al.; PrgX negatively regulates prgQ transcriptional readthrough in the pheromone-inducible enterococcal conjugative plasmid pCF10 . We isolated and characterized 13 dominant-negative prgX mutants, all of which mapped in either the N- or the C-terminus of PrgX . In all mutants, the in vivo level of Qa RNA, an antisense RNA to prgQ RNA, was greatly reduced . When oligomerization of PrgX was tested with a phage lambda cI repressor fusion system, the oligomerization domain was found to be between amino acid residues 78 and 280 . When histidine-tagged PrgX (His-PrgX) was purified by nickel column chromatography from a strain also expressing PrgX, PrgX was co-purified with His-PrgX . Although PrgX was expressed at a much higher level than His-PrgX, an approximately equal amount of PrgX was co-purified . Pheromone induction greatly decreased the co-purification of PrgX . Based on these data, we propose that both the N- and the C-terminal domains of PrgX are required for PrgX positive autoregulation and for the repression of prgQ transcription readthrough . In vivo, PrgX exists as a dimer, and dimerization is mediated by the central region of PrgX.

Curr Opin Investig Drugs, 2000 Oct, 1(2), 173 - 80
Synercid Aventis; Pavan B; Rhone-Poulenc Rorer (RPR) developed Synercid (RP-59500), an injectable synergistic combination of quinupristin and dalfopristin as a treatment for a variety of infections caused by Gram-positive anaerobic bacteria . The treatment was approved in the UK in July 1999, for use in patients with nosocomial pneumonia, skin and soft tissue infections and clinically significant infections due to Enterococcus faecium when there is no other active antibacterial agent {337556,335257} . It was launched in the UK and the US in September 1999 {342899} . In December 1999, Synercid successfully completed the Mutual Recognition Procedure in the EU under Aventis Pharma for use in patients with these infections {351525} . In September 2000, Merrill Lynch predicted first-year sales in 1999 of Euro 15 million, rising to Euro 171 million in 2004 {384874} . In January 1999, BT Alex Brown predicted sales of US $88 million in 1999 rising to US $450 million in 2002 {318220} . In April 1999, ABN Amro predicted annual sales of DM 30 million in 1999, rising to DM 150 million in 2002 {328676}.

Biochim Biophys Acta, 2001 May 1, 1505(1), 75 - 81
Catalytic properties of Na(+)-translocating V-ATPase in Enterococcus hirae; Murata T et al.; V-ATPases make up a family of proton pumps distributed widely from bacteria to higher organisms . We found a variant of this family, a Na(+)-translocating ATPase, in a Gram-positive bacterium, Enterococcus hirae . The Na(+)-ATPase was encoded by nine ntp genes from F to D in an ntp operon (ntpFIKECGABDHJ): the ntpJ gene encoded a K(+) transporter independent of the Na(+)-ATPase . Expression of this operon, encoding two transport systems for Na(+) and K(+) ions, was regulated at the transcriptional level by intracellular Na(+) as the signal . Structural aspects and catalytic properties of purified Na(+)-ATPase closely resembled those of other V-type H(+)-ATPases . Interestingly, the E . hirae enzyme showed a very high affinity for Na(+) at catalytic reaction . This property enabled the measurement of ion binding to this ATPase for the first time in the study of V- and F-ATPases . Properties of Na(+) binding to V-ATPase were consistent with the model that V-ATPase proteolipids form a rotor ring consisting of hexamers, each having one cation binding site . We propose here a structure model of Na(+) binding sites of the enzyme.

Infect Control Hosp Epidemiol, 2001 Feb, 22(2), 116 - 9
Reality check: should we try to detect and isolate vancomycin-resistant enterococci patients?
Ostrowsky B, Steinberg JT, Farr B, Sohn AH, Sinkowitz-Cochran RL, Jarvis WR.
Antimicrobial resistance, including vancomycin resistance in enterococci (VRE), is a growing problem in healthcare facilities . This "Reality Check" session focused on the question of whether we should try to detect and isolate patients colonized or infected with VRE.

J Clin Microbiol, 2001 Mar, 39(3), 1165 - 8
Possible horizontal transfer of the vanB2 gene among genetically diverse strains of vancomycin-resistant Enterococcus faecium in a Korean hospital; Lee WG et al.; A total of 25 isolates of vanB-containing Enterococcus faecium were recovered from patients in a single Korean hospital over a 20-month period . There were two distinct vanB2 patterns among the 11 pulsed-field gel electrophoresis types; 17 contained the prototype vanB2 and 8 contained a novel vanB2 with a 177-bp deletion in vanY(B) . Both vanB2 genes were transmissible in vitro at a mean frequency of 1.1 x 10(-8) transconjugants/donor . These results suggest the horizontal spread of vanB2 is occurring among genetically diverse strains of E . faecium in Korean hospitals.

Clin Infect Dis, 2001 Mar 1, 32(5), 826 - 9 Epub 2001 Feb 23.
Effectiveness of gloves in the prevention of hand carriage of vancomycin-resistant enterococcus species by health care workers after patient care; Tenorio AR et al.; Gloving reduces acquisition of vancomycin-resistant Enterococcus species (VRE) on the hands, and it should be considered for routine inpatient care, even for contact with the intact skin of patients who may be colonized with VRE . However, gloving does not completely prevent contamination of the hands, and hand washing is necessary after glove removal.

Semin Respir Infect, 2000 Dec, 15(4), 314 - 26
Vancomycin-resistant enterococci; McGeer AJ et al.; Over the last 2 decades, enterococci, formerly viewed as organisms of minimal clinical impact, have emerged as important hospital-acquired pathogens in immunosuppressed patients and intensive care units (ICUs) . Vancomycin resistance in enterococci is increasing steadily . Vancomycin-resistant enterococci (VRE) composed 26% of nosocomial enterococci in 1999, a 47% increase from 1994 to 1998 . More that 25% of ICU enterococci are resistant to vancomycin . Antimicrobial therapy is problematic for all VRE, but particularly when bactericidal activity is necessary . Quinipristin-dalfopristin and linezolid are 2 new approved antimicrobials for the treatment of recalcitrant infections caused byVRE . Control of the transmission of VRE, although successful in preventing infections, is neither simple nor inexpensive, and VRE has become endemic in many hospitals . However, endemicity poses serious risks to the health of current and future patients, and of itself, is expensive . Data on the cost-effectiveness of VRE prevention programs are currently lacking and urgently needed; however, because the added cost of a single VRE infection far exceeds those of gowns, gloves, and screening, it seems likely that such control programs represent significant cost savings for those hospitals willing to undertake them.

Anal Chem, 2001 Feb 1, 73(3), 444 - 52
Chromatographic interactions between proteins and sulfoalkylbetaine-based zwitterionic copolymers in fully aqueous low-salt buffers; Viklund C et al.; Macroporous monoliths containing N,N-dimethyl-N-methacryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine (SPE) have been synthesized via in situ photopolymerization, yielding a stoichiometric balance between sulfur and nitrogen in the final polymer, which is indicative of a genuine strong/strong zwitterionic character . The chromatographic properties of these zwitterionic resins were evaluated with respect to the retention behavior of inorganic ions and proteins . The weak electrostatic nature of the interaction between the sulfobetaine monoliths and proteins provided a high selectivity between basic proteins and peptides . Elution was accomplished with low-ionic-strength fully aqueous mobile phases, whereby high recovery was obtained, even for hydrophobic proteins . Chaotropic ions such as perchlorate or thiocyanate were used as mobile phase modifiers to modulate the apparent ion exchange group density, thus introducing a route for the modulation of the ionic strength that is required to competitively elute the protein . The promising features of polymeric sulfoalkylbetaine interaction layers for separation and analysis of biological extracts was also manifested in an application involving purification of biologically active peptide-pheromone obtained from Enterococcus faecium.

Dig Dis Sci, 2000 Nov, 45(11), 2183 - 6
Enterococcal bactibilia in patients with malignant biliary obstruction; Nomura T et al.; Biliary obstruction due to pancreaticobiliary malignancy is often accompanied by bactibilia . The aims of this study were to clarify the impact of preoperative antibiotic use on bile bacterial flora and to identify the bile bacteria responsible for postoperative septic complications in patients with malignant biliary obstruction . Eighty-four patients with malignant biliary obstruction underwent a biliary decompression procedure before definitive surgery . In 63 patients (75%), preoperative bile culture was positive, with nine species being detected . Only the incidence of enterococcal bactibilia increased after antibiotic use (P = 0.0009), with a 16% incidence before and 63% after antibiotic use . When analyzing the correlation between preoperative bile bacteria and postoperative complications, only the Enterococcus species was associated with the occurrence of complications (P = 0.037) . In conclusion, bile bacterial flora changes after preoperative antibiotic use, with a significant increase in the incidence of enterococcal bactibilia . The Enterococcus species is most responsible for postoperative septic complications in patients with malignant biliary obstruction.

J Basic Microbiol, 2000, 40(5-6), 303 - 10
Isolation of an 1,3-1,4-beta-glucan degrading Enterococcus faecium strain from the intestinal tract of chicken and partial characterization of its novel 1,3-1,4-beta-glucanase; Beckmann L et al.; An Enterococcus faecium strain with a novel endo 1,3-1,4-endo-beta-glucanase (lichenase, E.C . 3.2.1.73) was isolated from the intestinal tract of broiler chicken . The enzyme was secreted into the culture medium and acted exclusively on mixed linked 1,3-1,4-beta-glucans as determined with a reducing sugar assay . The purified enzyme has its isoelectric point at pI 4.8, maximum activity was determined at pH 6.5 and 40 degrees C . Thermal stability of the enzyme was low, but high pH stability and high residual activity was observed after incubation in digesta samples from the chicken intestine . Multiple lichenase activities were obtained from culture supernatants on SDS/PAGE and native zymograms, but it is concluded that the lichenase consists of one active protein at 30.5 kD and additional polypeptides of unknown function.

Ned Tijdschr Geneeskd, 2000 Dec 30, 144(53), 2572 - 6
{Epidemiologic increase of various genotypes of vancomycin-resistant Enterococcus faecium in a university hospital}; Mascini EM et al.; After a report of a possible relationship between an outbreak of vancomycin-resistant enterococci (VRE) in a nearby hospital and earlier admission of two of the patients with this VRE in the University Medical Centre of Utrecht (UMCU), the Netherlands, an extensive search for VRE carriers was started in the UMCU . In the study period of two months, VRE carriership was diagnosed in 51 patients in nine of the 11 wards investigated . Twenty-six patients in eight wards were colonized with the same VRE genotype as in the nearby hospital; spread was demonstrated in three wards . In addition, six patients of one ward were colonized with a second genotype and seven other patients with a third genotype, while 12 patients were carriers of a unique genotype . Most carriers were found in the internal medicine/nephrology and dialysis ward . Far-reaching measures (such as cohort nursing, admission stops, use of gowns and gloves, disinfection and restriction of use of vancomycin) taken in the four wards where spread was demonstrated, appeared effective but in three wards, spread was again demonstrated later . Frequent readmissions and transfers of patients appear to play an important part in this matter . None of the 51 colonized patients developed a serious VRE infection.

Ned Tijdschr Geneeskd, 2000 Dec 30, 144(53), 2568 - 72
{Vancomycin-resistant Enterococcus faecium outbreak in a nephrology ward}; van der Steen LF et al.; In April 2000, an outbreak of vancomycin-resistant Enterococcus faecium (VRE) was discovered in an internal medicine/nephrology and dialysis ward of the Eemland Hospital, Amersfoort, the Netherlands . Although enterococci are considered relatively non-virulent, VRE are resistant to almost all commercially available antibiotics . Surveillance cultures were obtained from all patients at the ward, all patients visiting the dialysis ward and the environment of patients . VRE were determined and clustering of strains was analysed using molecular genotyping . In all, 12 patients were colonized with the outbreak strain . Transmission of VRE usually occurs via the hands of health care workers . The ward was closed for new admissions, patients were divided in cohorts of colonized and non-colonized patients, and rooms were disinfected after patient discharge . Infection control measures (such as handwashing and use of gloves and gowns) were enforced and prescriptions of vancomycin and cephalosporins were reduced . With these measures the outbreak could be controlled . Epidemiological analysis demonstrated that earlier admission and previous use of ciprofloxacin, amoxicillin and amoxicillin-clavulanic acid were risk factors for colonization . A nearby hospital was a possible source of this outbreak.

Antimicrob Agents Chemother, 2001 Mar, 45(3), 986 - 9
Molecular analysis of Tn1546-like elements in vancomycin-resistant enterococci isolated from patients in Europe shows geographic transposon type clustering; Schouten MA et al.; Resistance mechanism relatedness was studied in 18 clinical, European vanA vancomycin-resistant enterococci . Molecular analysis revealed 10 Tn1546-like elements, suggesting two evolutionary lineages . Lineage I dominated the European mainland, and lineage II dominated the United Kingdom and Israel . Geographic clustering reflected different types of meat consumption between countries, since each lineage is associated with colonization of different animals.

Antimicrob Agents Chemother, 2001 Mar, 45(3), 901 - 4
Enterocin P causes potassium ion efflux from Enterococcus faecium T136 cells; Herranz C et al.; Enterocin P is a bacteriocin produced by Enterococcus faecium P13 . We studied the mechanism of its bactericidal action using enterocin-P-sensitive E . faecium T136 cells . The bacteriocin is incapable of dissipating the transmembrane pH gradient . On the other hand, depending on the buffer used, enterocin P dissipates the transmembrane potential . Enterocin P efficiently elicits efflux of potassium ions, but not of intracellularly accumulated anions like phosphate and glutamate . Taken together, these data demonstrate that enterocin P forms specific, potassium ion-conducting pores in the cytoplasmic membrane of target cells.

Clin Infect Dis, 2001 Feb 15, 32(4), 587 - 94 Epub 2001 Feb 07.
Attributable mortality rate and duration of hospital stay associated with enterococcal bacteremia; Caballero-Granado FJ et al.; The mortality rate of patients with cases of enterococcal bacteremia is high, although it has often been related to the patients' underlying conditions rather than to the infection itself . To analyze the attributable prognosis of enterococcal bacteremia (assessed by its attributable mortality rate and duration of hospital stay), a prospective, matched case-control study was done . All adults with an episode of enterococcal bacteremia without endocarditis were included . A control patient was randomly selected for every case patient and matched by sex, age and hospital ward . Univariate and multivariate analyses were performed . A total of 122 pairs were included, and incidence of enterococcal bacteremia was 2.3 episodes/1000 discharges . Crude 30-day mortality rates for case patients and control patients were 23% and 17%, respectively (P=.29); thus, the estimated attributable mortality rate was 6% (95% confidence interval, -4% to 16%) . The mean duration of hospital stay of case patients and control patients were 38 and 17 days, respectively (P<.001); thus, the estimated attributable duration of hospital stay was 21 days (95% CI, 7-32 days) . Enterococcal bacteremia without endocarditis does not increase risk of death by itself but extends the duration of hospital stay of patients who develop it.

Am J Infect Control, 2001 Feb, 29(1), 53 - 7
Evaluation of a successful vancomycin-resistant Enterococcus prevention intervention in a community of health care facilities; Sohn AH et al.; BACKGROUND: In April 1997, vancomycin-resistant enterococci (VRE) emerged in several health care facilities in the Siouxland region and a VRE Task Force was formed . From 1997 through 1999, an evaluation of VRE prevalence at 30 facilities was performed . METHODS: In 1999, we conducted a survey and focus groups of health care workers to address initial reactions to VRE, feasibility of the Task Force recommendations, and lessons learned . RESULTS: Personnel at 29 (97%) facilities surveyed completed the questionnaire, and 15 health care workers from 11 facilities participated in 5 focus groups . The outcomes of expanded education and improved awareness of VRE for patients and health care workers were ranked the No . 1 priority overall and by long-term care facility personnel . Respondents agreed that Task Force recommendation adherence had significantly improved infection control (83%) and that the Task Force was an appropriate mechanism to coordinate infection control efforts (90%) . Focus groups commented that it was most difficult to educate family members about VRE; they expressed concern about variation between VRE policies, especially between acute care and long-term care facilities, and about the quality of life of isolated patients . CONCLUSIONS: Our data illustrate that this intervention has been far-reaching and include the development of a health care infrastructure that may be used as a model to address additional health care issues (eg, emerging pathogens or biological threats).

Chest, 2001 Feb, 119(2 Suppl), 426S - 30S
Antibiotic utilization: is there an effect on antimicrobial resistance?
Patterson JE.
The antimicrobial resistance problem in hospitals continues to worsen . In particular, extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KP) and vancomycin-resistant enterococci (VRE) are significant causes of morbidity and mortality among critically ill patients . Treating infections caused by these pathogens presents therapeutic dilemmas . The association between broad-spectrum beta-lactam overutilization and selection for ESBL-KP has been appreciated for some time; several institutions have reported a decrease in the prevalence of ESBL-KP with a shift in antibiotic utilization from third-generation cephalosporins to other broad-spectrum drugs . Currently, optimal treatment of ESBL-KP includes the carbapenems, but widespread use of these drugs is expensive and may be associated with further selection of antibiotic resistance and/or superinfection with other inherently resistant pathogens . VRE are especially difficult organisms to treat because of their inherent and acquired resistance to most currently available antibiotics . The prevalence of VRE has also been documented to decrease upon a shift in antibiotic use from third-generation cephalosporins to broad-spectrum antibiotics of other classes . Thus, antibiotic utilization measures appear to contribute to the control of the emergence of multidrug-resistant pathogens such as ESBL-KP and VRE.

Chest, 2001 Feb, 119(2 Suppl), 405S - 411S
Implementation of strategies to control antimicrobial resistance; Murthy R; Antimicrobial resistance has emerged as a major public health issue in recent years . A steady increase in resistance continues despite the introduction of new antibiotics, and resistant bacteria have been associated with increased patient morbidity and mortality as well as with increased costs . Addressing the problem of antimicrobial resistance requires both infection control and regulation of antibiotic use; addressing either alone is insufficient . Mounting evidence shows that control of the use of broad-spectrum antibiotics (especially vancomycin and third-generation cephalosporins) and implementation of infection control measures can result in decreased incidence of antibiotic-resistant bacteria such as vancomycin-resistant enterococci and extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella . Recent reports from professional organizations and a consensus of experts have outlined strategies for the control of resistance in hospitals, with specific measures identified for antibiotic control and infection control . These reports have emphasized the importance of a multidisciplinary approach in tackling this problem in hospitals and have suggested that a quality-improvement model be used to address antimicrobial resistance . A close collaboration among the disciplines of infectious diseases, microbiology, hospital epidemiology, pharmacy, and nursing, with particular emphasis in ICUs, and with strong support from hospital leadership, can result in an effective program that can be readily incorporated into the quality-improvement goals of any health-care organization.

Biochem J, 2001 Feb 15, 354(Pt 1), 115 - 22
Bioactivity of {6R}-5-formyltetrahydrofolate, an unusual isomer, in humans and Enterococcus hirae, and cytochrome c oxidation of 10-formytetrahydrofolate to 10-formyldihydrofolate; Baggott JE et al.; The bio-inactive C-6 isomer, {6R}-5-formyl-tetrahydrofolate (5-HCO-H(4)F), is not found in Nature . An oral dose of 13.5 micromol of {6R}-5-HCO-H(4)F in humans results in the appearance of the naturally occurring {6S}-5-methyl-tetrahydrofolate and relatively large amounts of other bioactive folates in plasma . The removal of the asymmetry at C-6 could account for these results . Two oxidized cytochrome c {cyt c (Fe3+)} molecules oxidize one 10-formyl-tetrahydrofolate (10-HCO-H(4)F) with second-order kinetics and a rate constant of 1.3 x 10(4) M(-1) x s(-1) . The folate product of this oxidation reaction is 10-formyl-dihydrofolate (10-HCO-H(2)F), which has no C-6 asymmetric centre and is therefore bioactive . The folate-requiring bacterium, Enterococcus hirae, does not normally biosynthesize cytochromes but does so when given an exogenous source of haem (e.g . haemin) . E . hirae grown in haemin-supplemented media for 3 days utilizes both {6R}- and {6S}-5-HCO-H(4)F in contrast to that grown in control medium, which utilizes only the {6S} isomer . Since known chemical reactions form 10-HCO-H(4)F from 5-HCO-H(4)F, the unusually large rate constant for the oxidation of 10-HCO-H(4)F by cyt c (Fe3+) may account for the unexpected bioactivity of {6R}-5-HCO-H(4)F in humans and in E . hirae grown in haemin-containing media . We used an unnatural C-6 folate isomer as a tool to reveal the possible in vivo oxidation of 10-HCO-H(4)F to 10-HCO-H(2)F; however, nothing precludes this oxidation from occurring in vivo with the natural C-6 isomer.

Kidney Int, 2001 Feb, 59(2), 718 - 24
Outpatient vancomycin use and vancomycin-resistant enterococcal colonization in maintenance dialysis patients; Atta MG et al.; BACKGROUND: Although outpatient vancomycin is widely used as empiric therapy for dialysis-associated infections, its relationship with vancomycin-resistant enterococcal (VRE) colonization is not established . METHODS: During a two-year prospective cohort study, rectal swabs obtained from patients at the start and finish of the study period and during interim hospitalizations were cultured for VRE . RESULTS: Ten of 124 patients initially grew VRE . Twenty-four of the remaining patients had no follow-up cultures because of patient death (62%), transfer to another dialysis facility (17%), patient's refusal (7%), and transplantation (4%), and were thus excluded . The remaining patients (N = 90) had a median age of 54.3 years and were 92% African American and 50% male . Fifty-eight percent were treated by hemodialysis . They received 403 g of intravenous vancomycin over 157.2 patient-years of follow-up, 73% as outpatients . Sixteen of 90 patients (17.8%) became colonized with VRE, an incidence rate of one case per 9.8 patient-years of follow-up . None of the 29 patients who did not receive vancomycin developed VRE compared with 26% of those treated with vancomycin (P = 0.001) . The odds ratio (95% CI) for the association of outpatient vancomycin (g per year) with VRE colonization was 1.23 (1.05, 1.44, P = 0.008) . The association remained significant following adjustment in separate logistic regression analyses for relevant demographic, clinical, antimicrobial (inpatient vancomycin, oral or intravenous cephalosprins, aminoglycosides, quinalones, or antianaerobics), and hospitalization exposures . The unadjusted relative risk of death in patients growing VRE was significantly higher than in those not colonized with VRE (P = 0.005) . CONCLUSIONS: VRE colonization is a relatively common and under recognized problem among chronic dialysis patients . It is strongly and independently associated with the outpatient use of vancomycin, which should be avoided whenever possible.

Clin Microbiol Infect, 2000 Nov, 6(11), 585 - 92
National guidelines for the judicious use of glycopeptides in Belgium; Gordts B et al.; OBJECTIVE: The 'HICPAC guidelines', published in the USA in 1995 stressed the crucial role of restrictive usage of glycopeptides in the strategy to limit the emergence and spread of resistant enterococci . Because controversy still remains in Belgium on the necessity and feasability of restricting glycopeptide usage, the infectious diseases advisory board (IDAB) developed a consensus statement on the judicious use of glycopeptides in Belgium . METHODS: The literature on the indications for glycopeptide treatment was reviewed, categorized and discussed by a working party of the IDAB.Consequently, the IDAB reached consensus on the warranted indications for glycopeptide use in Belgium . RESULTS: The opinion of the IDAB-members is reported in a consensus statement specifying the indications for treatment and for prophylaxis with glycopeptide antimicrobials, as well as the situations where glycopeptides should not be used, taking into account the specific epidemiology of bacterial resistance, the availability of antibiotics and the common prescribing practices in Belgium . CONCLUSIONS: The IDAB concludes that restrictive usage of glycopeptides must also be a priority in Belgium . Guidelines on the judicious use of these antibiotics adapted to the national situations must contribute to this objective.

Biochem Biophys Res Commun, 2001 Jan 26, 280(3), 713 - 9
Purification and functional analysis of the copper ATPase CopA of Enterococcus hirae; Wunderli-Ye H et al.; The Enterococcus hirae ATPase CopA is a member of the recently discovered heavy metal ATPases and shares 43% sequence identity with the human Menkes and Wilson copper ATPases . To study CopA biochemically, it was overexpressed in E . coli with an N-terminal histidine tag and purified to homogeneity by nickel affinity chromatography . The purified CopA catalyzed ATP hydrolysis with a V(max) of 0.15 micromol/min/mg and a K(m) for ATP of 0.2 mM and had an optimum pH of 6.25 . The activity was 3- to 4-fold stimulated by reconstitution into proteoliposomes . The enzyme formed an acylphosphate intermediate . Its kinetics of formation and the effects of inhibitors and metal ions upon it support a function of CopA in copper transport . Purification and functional reconstitution of CopA provides the basis to study copper transport in vitro .

Antimicrob Agents Chemother, 2001 Feb, 45(2), 621 - 3
Linezolid therapy of vancomycin-resistant Enterococcus faecium experimental endocarditis; Patel R et al.; We compared the activities of linezolid (25 mg/kg of body weight, administered intraperitoneally every 8 h) and of vancomycin (25 mg/kg of body weight, administered intraperitoneally every 8 h) in a rat model of vanA vancomycin-resistant Enterococcus faecium experimental endocarditis . Results were expressed as median log(10) CFU per gram of vegetation after 3 days of treatment . The median log(10) CFU per gram of vegetation was 10.1 among 7 untreated control animals, 10.2 among 9 vancomycin-treated animals, and 7.9 among 10 linezolid-treated animals . Linezolid treatment was more active (P < 0.05) than vancomycin treatment or no treatment.

J Clin Microbiol, 2001 Feb, 39(2), 820 - 2
Infection of central nervous system by motile Enterococcus: first case report; Kurup A et al.; A 66-year-old man with four indwelling ventriculoperitoneal shunts for multiloculated hydrocephalus from a complicated case of meningitis a year before developed shunt infection based on a syndrome of fever, drowsiness, and cerebrospinal fluid neutrophil pleocytosis in the background of repeated surgical manipulation to relieve successive shunt blockages . The cerebrospinal fluid culture, which yielded a motile Enterococcus species, was believed to originate from the gut . This isolate was lost in storage and could not be characterized further . The patient improved with vancomycin and high-dose ampicillin therapy . He relapsed a month later with Enterococcus gallinarum shunt infection, which responded to high-dose ampicillin and gentamicin therapy . This is probably the first case report of motile Enterococcus infection of the central nervous system.

J Clin Microbiol, 2001 Feb, 39(2), 811 - 5
Vancomycin-resistant Enterococcus faecium strain carrying the vanB2 gene variant in a Polish hospital; Kawalec M et al.; About 2.5 years after the first isolation of the VanA phenotype of vancomycin-resistant Enterococcus faecium (VREM) in Poland, the first VREM strains with the VanB phenotype have emerged independently in two different Warsaw hospitals . In one of these the VREM strain was selected during the long-term antimicrobial treatment of a patient with a wide variety of infection risk factors who died after 3 months of hospitalization . The strain was found to contain the transferable vanB2 gene cluster variant of the polymorphic type that was identified earlier in vancomycin-resistant enterococci from several different countries . In the course of infection the strain underwent genetic diversification due to DNA recombination.

Med Clin North Am, 2000 Nov, 84(6), 1471 - 95
Antienterococcal antibiotics; Lefort A et al.; The treatment of severe enterococcal infections based on the currently available antibacterial agents is difficult . The help of the microbiology laboratory for determining MICs, MBCs, and most effective synergistic combinations is crucial . There is a need for good prospective multicenter clinical trials to improve the prognosis of such infections by defining therapeutic strategies better . Such a requirement is highly suitable for the treatment of infections caused by enterococci exhibiting acquired resistance mechanisms to the available agents . The current clinical development of new compounds looks promising in these persistently life-threatening infections mostly occurring in deficient hosts.

Tunis Med, 2000 Nov, 78(11), 667 - 70
{Infectious endocarditis caused by a glycopeptide-resistant enterococus}; Jouaihia W et al.; Enterococci are an important cause of infective endocarditis . Their resistance to most of the antibiotics involve real therapeutic problems . We report the first clinical isolate of glycopeptide resistant enterococcus from blood culture of patient with a prosthetic valve endocarditis . The strain is an E . faecium with a high level of resistance to vancomycin and teicoplanin (MIC > 256 mg/l), a low level of resistance to gentamycin (MIC = 6 mg/l) and susceptible to ampicillin (MIC = 1.5 mg/l) . Therapeutic failure was observed leading to a surgical treatment . Therapy of such infection caused by multiresistant Enterococcus must be based on the study of bactericidal activity of antibiotic associations . In order to control the spread of this emerging resistance, the implementation of control measures is necessary.

J Antimicrob Chemother, 2001 Jan, 47(1), 105 - 8
Glycopeptide-resistant Enterococcus faecium infections in paediatric liver transplant recipients: safety and clinical efficacy of quinupristin/dalfopristin; Verma A et al.; We describe our experience of quinupristin/dalfopristin for glycopeptide-resistant Enterococcus faecium (GREF) infections in 19 paediatric liver transplant recipients . The median patient age was 2 years and all were receiving immunosuppressive regimens . Quinupristin/dalfopristin was well tolerated and complete resolution of infection was seen in 74% of patients . Side-effects included reversible elevation of serum alkaline phosphatase, skin rash, itching, diarrhoea and vomiting, but therapy was not withdrawn from any patient . Quinupristin/dalfopristin appears safe and efficacious in critically ill immunocompromised children with renal or hepatic impairment.

Eur J Clin Microbiol Infect Dis, 2000 Nov, 19(11), 816 - 22
Prevalence of vancomycin-resistant enterococci in Europe; Schouten MA et al.; The aim of the present study was to determine the prevalence of vancomycin-resistant enterococci (VRE) in Europe . Overall, 49 laboratories in 27 countries collected 4,208 clinical isolates of enterococci . Species identification, susceptibility testing, and van gene determination by polymerase chain reaction were performed in a central laboratory . Overall, 18 vanA and 5 vanB isolates of VRE were found . The prevalence of vanA VRE was highest in the UK (2.7%), while the prevalence of vanB VRE was highest in Slovenia (2%) . Most vanA and vanB VRE were identified as Enterococcus faecium . Most VRE isolates originated from the patient's urogenital tract, skin, or digestive tract . VRE were equally distributed among clinical departments, with no clear preponderance in any single patient group . A total of 71 isolates containing the vanC gene were identified . The prevalence of vanC VRE was highest in Latvia and Turkey, where rates were 14.3 and 11.7%, respectively . Two-thirds of these isolates were identified as Enterococcus gallinarum and one-third as Enterococcus casseliflavus; the majority of these isolates were cultured from feces . Almost all isolates were obtained from hospitalized patients, mostly children . The highest prevalence of high-level gentamicin-resistant enterococci was seen in Turkey and Greece . In general, the distribution of this resistance type seemed unrelated to the occurrence of VRE . The prevalence of vanA/ vanB VRE in Europe is still low; the majority of the VRE isolates exhibit the vanC genotype and colonize the gastrointestinal tract of hospitalized children.

Liver Transpl, 2001 Jan, 7(1), 27 - 31
Natural history of vancomycin-resistant enterococcal colonization in liver and kidney transplant recipients; Patel R et al.; At Mayo Medical Center (Rochester, MN), surveillance rectal (and other-site) cultures have been routinely collected from liver transplant recipients as part of a selective bowel decontamination program . Beginning in 1995, vancomycin-resistant enterococcus (VRE) colonization and infection were identified in Mayo Clinic liver and kidney transplant patients through our surveillance cultures . The purpose of this study is to describe the natural history of VRE colonization in this patient population . Fifty-two patients with VRE colonization (predominantly with a single vanB clone) were identified from September 1995 through December 1997 . Five hundred ninety cultures were reviewed for this study (mean, 11.3 cultures/patient) . The median time from initial VRE colonization to the last surveillance culture obtained was 306 days (range, 1 to 1,393 days) . VRE infection was documented in 6 patients (11.3%) . Eighteen patients (35%) met the criteria for clearance of VRE colonization, defined as VRE-negative rectal culture results on at least 3 consecutive occasions greater than 1 week apart . However, VRE was detected on subsequent surveillance cultures from 2 of these patients (11% relapse rate) . Of the remaining 34 patients, 16 remained colonized with VRE and 18 did not meet the definition for clearance of VRE colonization because of incomplete follow-up . This study documents that VRE colonization usually persists for months to years in liver and kidney transplant patients.

Infect Control Hosp Epidemiol, 2000 Dec, 21(12), 789 - 91
Choice of antibiotic and risk of colonization with vancomycin-resistant Enterococcus among patients admitted for treatment of community-acquired pneumonia; Manzella J et al.; A time-series prospective study of patients admitted to the hospital for treatment of community-acquired pneumonia was undertaken to determine vancomycin-resistant enterococcal perianal colonization rates among patients who received ceftriaxone with or without erythromycin versus those who received levofloxacin . A colonization rate of 16% (8/51) was found in the ceftriaxone-erythromycin group versus 0% (0/52) in the levofloxacin group .

Int J Antimicrob Agents, 2000 Nov, 16 Suppl 1, S19 - 24
Selective pressure by antibiotic use in livestock; Witte W; Selective pressure exerted by the use of antibiotics as growth promoters in food animals appears to have created large reservoirs of transferable antibiotic resistance in these ecosystems . This first became evident for oxytetracycline and later for the streptothricin antibiotic nurseothricin, for which a transfer of relevant resistance determinants (sat genes) to bacterial pathogens of humans was demonstrated . With the emergence of glycopeptide resistance in Enterococcus faecium outside hospitals, a large reservoir of transferable resistance (vanA gene cluster) was identified in animal husbandry due to the use of avoparcin as feed additive . The spread of resistance, which reaches the human enterococcal flora via meat products, is probably due to the dissemination of the vanA gene cluster integrated into different conjugative plasmids among a variety of different strains . Streptogramin resistance associated with the resistance genes vatA and vatG has been found in E . faecium of animal and of clinical origin . Because virginiamycin has been used as growth promoter in animals but streptogramins have been used infrequently in human medicine, this again suggests an animal origin of resistance . Since the use of avoparcin ended, a decline in the rates of glycopeptide-resistant E . faecium (GREF) from animals and humans in the community has been recorded . This supports the ban of antibacterial growth promoters that might interfere with human chemotherapy that has been introduced in European Union countries.

Int J Antimicrob Agents, 2000 Nov, 16 Suppl 1, S11 - 7
Acquired and intrinsic glycopeptide resistance in enterococci; Gholizadeh Y et al.; Enterococci are Gram-positive cocci responsible for severe human infections, such as endocarditis, meningitis, and septicemia and constitute an increasingly frequent cause of nosocomial infections . Enterococci are resistant to nearly all classes of drugs including, since 1986, glycopeptides . Vancomycin and teicoplanin act by blocking cell wall formation and resistance is due to synthesis of modified late peptidoglycan precursors . Glycopeptide resistance can be intrinsic or acquired and strains may be resistant to vancomycin and teicoplanin, or to vancomycin only . Five types of glycopeptide resistance and their biochemical mechanisms have been described in enterococci . Clinical isolates that are dependent on vancomycin for growth have been isolated . Data suggest a dual origin for resistance: glycopeptide-producing organisms or enterococcal species intrinsically resistant to these drugs.

J Clin Microbiol, 2001 Jan, 39(1), 351 - 3
Accuracy of the VITEK 2 system to detect glycopeptide resistance in enterococci; van Den Braak N et al.; We evaluated the accuracy of the VITEK 2 fully automated system to detect and identify glycopeptide-resistant enterococci (GRE) compared to a reference agar dilution method . The sensitivity of vancomycin susceptibility testing with VITEK 2 for the detection of vanA, vanB, and vanC1 strains was 100% . The sensitivity of vancomycin susceptibility testing of vanC2 strains was 77% . The sensitivity of teicoplanin susceptibility testing of vanA strains was 90% . Of 80 vanC enterococci, 78 (98%) were correctly identified by VITEK 2 as Enterococcus gallinarum/Enterococcus casseliflavus . Since the identification and susceptibility data are produced within 3 and 8 h, respectively, VITEK 2 appears a fast and reliable method for detection of GRE in microbiology laboratories.

N Engl J Med, 2000 Dec 28, 343(26), 1925 - 32
Effect of antibiotic therapy on the density of vancomycin-resistant enterococci in the stool of colonized patients; Donskey CJ et al.; BACKGROUND: Colonization and infection with vancomycin-resistant enterococci have been associated with exposure to antibiotics that are active against anaerobes . In mice that have intestinal colonization with vancomycin-resistant enterococci, these agents promote high-density colonization, whereas antibiotics with minimal antianaerobic activity do not . METHODS: We conducted a seven-month prospective study of 51 patients who were colonized with vancomycin-resistant enterococci, as evidenced by the presence of the bacteria in stool . We examined the density of vancomycin-resistant enterococci in stool during and after therapy with antibiotic regimens and compared the effect on this density of antianaerobic agents and agents with minimal antianaerobic activity . In a subgroup of 10 patients, cultures of environmental specimens (e.g., from bedding and clothing) were obtained . RESULTS: During treatment with 40 of 42 antianaerobic-antibiotic regimens (95 percent), high-density colonization with vancomycin-resistant enterococci was maintained (mean {+/-SD} number of organisms, 7.8+/-1.5 log per gram of stool) . The density of colonization decreased after these regimens were discontinued . Among patients who had not received antianaerobic antibiotics for at least one week, 10 of 13 patients who began such regimens had an increase in the number of organisms of more than 1.0 log per gram (mean increase, 2.2 log per gram), whereas among 10 patients who began regimens of antibiotics with minimal antianaerobic activity, there was a mean decrease in the number of enterococci of 0.6 log per gram (P=0.006 for the difference between groups) . When the density of vancomycin-resistant enterococci in stool was at least 4 log per gram, 10 of 12 sets of cultures of environmental specimens had at least one positive sample, as compared with 1 of 9 sets from patients with a mean number of organisms in stool of less than 4 log per gram (P=0.002) . CONCLUSIONS: For patients with vancomycin-resistant enterococci in stool, treatment with antianaerobic antibiotics promotes high-density colonization . Limiting the use of such agents in these patients may help decrease the spread of vancomycin-resistant enterococci.

Rinsho Byori, 2000 Nov, 48(11), 1036 - 43
{Vancomycin-resistant enterococci (VRE)}; Fujita N; Vancomycin-resistant enterococci is a worldwide threat not only in hospitals, but also in communities . Community-acquired infections play an important role in spreading VRE because the use of avoparcin, an antimicrobial growth promoter in food animals, is strongly suggested to cause the emergence of VRE . In particular, chickens imported into Japan have been reported to be highly contaminated with VRE, and this may be a key issue in the prevalence of VRE . Nosocomial VRE infections have become a serious problem in immuno-compromised patients throughout the world, and many VREs have been isolated in Japan in the last few years; however, fortunately, nosocomial outbreaks are still rare . VRE can survive for weeks in hospital environments, which makes infection control difficult and complicated, and strains of VRE resistant to almost all antimicrobial agents are a real threat . In outbreaks of VRE, prudent antimicrobial use and prompt effective infection control are important.

Antimicrob Agents Chemother, 2001 Jan, 45(1), 243 - 51
In vitro activity of trovafloxacin against Bacteroides fragilis in mixed culture with either Escherichia coli or a vancomycin- resistant strain of Enterococcus faecium determined by an anaerobic time-kill technique; Stearne LE et al.; To determine the efficacy of trovafloxacin as a possible treatment for intra-abdominal abscesses, we have developed an anaerobic time-kill technique using different inocula to study the in vitro killing of Bacteroides fragilis in pure culture or in mixed culture with either Escherichia coli or a vancomycin-resistant strain of Enterococcus faecium (VREF) . With inocula of 5 x 10(5) CFU/ml and trovafloxacin concentrations of </=2 microg/ml, a maximum observed effect (E(max)) of >/=6.1 (log(10) CFU/ml) was attained with all pure and mixed cultures within 24 h . With inocula of 10(8) CFU/ml, a similar E(max) and a similar concentration to produce 50% of E(max) (EC(50)) for B . fragilis were found in both pure cultures and mixed cultures with E . coli . However, to produce a similar killing of B . fragilis in the mixed cultures with VREF, a 14-fold increase in the concentration of trovafloxacin was required . A vancomycin-susceptible strain of E . faecium and a trovafloxacin-resistant strain of E . coli were also found to confer a similar "protective" effect on B . fragilis against the activity of trovafloxacin . Using inocula of 10(9) CFU/ml, the activity of trovafloxacin was retained for E . coli and B . fragilis and was negligible against VREF . We conclude that this is a useful technique to study the anaerobic killing of mixed cultures in vitro and may be of value in predicting the killing of mixed infections in vivo . The importance of using mixed cultures and not pure cultures is clearly shown by the difference in the killing of B . fragilis in the mixed cultures tested . Trovafloxacin will probably be ineffective in the treatment of infections involving large numbers of enterococci . However, due to its ability to retain activity against large cultures of B . fragilis and E . coli, trovafloxacin could be beneficial in the treatment of intra-abdominal abscesses.

J Microbiol Methods, 2001 Jan, 43(3), 233 - 9
Development of the Specific and Random Amplification (SARA)-PCR for both species identification of enterococci and detection of the vanA gene; Knijff E et al.; A rapid and reliable polymerase chain reaction (Specific and Random Amplification (SARA)-PCR) has been developed to identify enterococcal species and to detect the vanA gene in one single reaction . This technique was based on the use of the primer set previously designed to amplify a part of the vanA gene (Dutka-Malen et al., J . Clin . Microbiol., 33 (1995) 24-27) . In the chosen low stringency conditions complex patterns were obtained, with a sharp band of approximately 700 bp in cases where the vanA gene was present . Discrimination at the species and strain level was achieved by applying the SARA-PCR assay to a collection of 55 enterococcal isolates and type strains . Simultaneously the vanA gene was detected in all strains showing high resistance to vancomycin.

Clin Infect Dis, 2001 Jan, 32(1), 23 - 9 Epub 2000 Dec 08.
Vancomycin-resistant enterococci among chronic hemodialysis patients: a prospective study of acquisition; D'Agata EM et al.; To determine the prevalence and rate of acquisition of vancomycin-resistant enterococci (VRE) among patients undergoing chronic (i.e., long-term) hemodialysis who were admitted to a tertiary care center, serial rectal cultures for VRE were performed at hospital admission and every 5 days until hospital discharge . A total of 7 (6%) of the 119 patients were colonized with VRE at admission . Six (19%) of the 32 patients who remained in the hospital > or =4 days acquired VRE . A nonambulatory status was significantly associated with colonization at admission (OR, 9.7; 95% CI, 1.8-53; P=.01), and vancomycin exposure was significantly associated with VRE acquisition (relative risk, 1.8; 95% CI, 1.1-2.9; P=.02) . All patients acquired VRE from epidemiologically linked dialysis patients colonized with similar VRE genotypes . Hospital acquisition of VRE contributes substantially to the increasing prevalence of VRE in the chronic hemodialysis patient population.

Int J Hyg Environ Health, 2000 Oct, 203(2), 147 - 52
Nosocomial outbreak of vancomycin-resistant Enterococcus faecium at a German university pediatric hospital; Elsner HA et al.; Nosocomial Infections caused by vancomycin-resistant enterococci (VRE) are an emerging threat to critically ill patients . At the University Hospital Eppendorf, VRE were isolated from 38 patients between August 1993 and April 1997, of whom 32 were hospitalized at the Department of Pediatrics . Pulsed-field gel electrophoresis revealed that 26 Enterococcus faecium isolates from patients of the Department of Pediatrics were identical or closely related, and that isolates from three additional patients of the same department were possibly related . All of these isolates were of vanA genotype . They were resistant to glycopeptides, ampicillin, ciprofloxacin, clindamycin, and erythromycin . Most isolates displayed high-level resistance to gentamicin, but all remained susceptible to quinupristin/dalfopristin . Implementation of stringent hand disinfection and environmental disinfection policies, as well as measures for patient isolation contained this first outbreak of VRE at a German Children's hospital, which emphasizes the importance of hygienic measures for the control of nosocomial spread of these organisms.

Braz J Infect Dis, 1998 Jun, 2(3), 160 - 163
Vancomycin-Resistant Enterococcus faecium: First Case in Brazil; Dalla Costa LM et al.; We report a fatal case of septicemia due to a vancomycin-resistant Enterococcus faecium in a 9 year old girl with aplastic anemia . The isolate was also resistant to ampicillin, teicoplanin, gentamicin (high level), and streptomycin (high level) . We believe that this is the first case of vancomycin-resistant Enterococcus (VRE) reported from a clinical specimen in Brazil.

Microbiology, 2000 Dec, 146 Pt 12, 3129 - 40
Antibacterial activity of synthetic analogues based on the disaccharide structure of moenomycin, an inhibitor of bacterial transglycosylase; Baizman ER et al.; Moenomycin is a natural product glycolipid that inhibits the growth of a broad spectrum of Gram-positive bacteria . In Escherichia coli, moenomycin inhibits peptidoglycan synthesis at the transglycosylation stage, causes accumulation of cell-wall intermediates, and leads to lysis and cell death . However, unlike Esc . coli, where 5-6 log units of killing are observed, 0-2 log units of killing occurred when Gram-positive bacteria were treated with similar multiples of the MIC . In addition, bulk peptidoglycan synthesis in intact Gram-positive cells was resistant to the effects of moenomycin . In contrast, synthetic disaccharides based on the moenomycin disaccharide core structure were identified that were bactericidal to Gram-positive bacteria, inhibited cell-wall synthesis in intact cells, and were active on both sensitive and vancomycin-resistant enterococci . These disaccharide analogues do not inhibit the formation of N:-acetylglucosamine-ss-1, 4-MurNAc-pentapeptide-pyrophosphoryl-undecaprenol (lipid II), but do inhibit the polymerization of lipid II into peptidoglycan in Esc . coli . In addition, cell growth was required for bactericidal activity . The data indicate that synthetic disaccharide analogues of moenomycin inhibit cell-wall synthesis at the transglycosylation stage, and that their activity on Gram-positive bacteria differs from moenomycin due to differential targeting of the transglycosylation process . Inhibition of the transglycosylation process represents a promising approach to the design of new antibacterial agents active on drug-resistant bacteria.

Curr Infect Dis Rep, 1999 Oct, 1(4), 319 - 327
An Update on the Emergence of Glycopeptide Resistance in Enterococci; Gardam MA et al.; Glycopeptide resistance may be either constitutive or transferable (on plasmids or as a transposon), and four phenotypes (van A, B, C, D) have been described to date . Recent data suggest solid media screening protocols appear to be insensitive at detecting low levels of carriage, and up to 40% of colonized patients may be falsely glycopeptide-resistant enterococci (GRE) negative . Managing GRE-colonized or -infected patients using contact precautions appears to be useful in controlling clonal outbreaks, but may be of limited utility once GRE is endemic . Alternate strategies to manage GRE-colonized patients with prolonged carriage and in outpatient or home health settings include using risk-based transmission assessment to limit the logistic and psychosocial difficulties associated with the use of continuous contact precautions . The therapeutic options for treating GRE infection remain limited . Attempts to decolonize GRE-colonized patients with bacitracin appear to be of limited utility.

Curr Infect Dis Rep, 1999 Jun, 1(2), 148 - 152
Vancomycin-Resistant Enterococcus: Infectious Endocarditis Treatment; Rybak MJ et al.; Vancomycin-resistant Enterococcus species represent serious gram-positive pathogens for which there is currently no recommended therapy . There are a number of new antibiotics with activity against these pathogens in development . Although there is a great deal of experience with some of these agents for skin and soft tissue infections, bacteremia, pneumonia, and intra-abdominal infections, there is currently little information available for the treatment of endocarditis . Animal and limited human data thus far suggest that new agents such as quinuprisitin-dalfopristin, LY333328 (a new glycopeptide antibiotic), and daptomycin (a lipopeptide antibiotic) may prove useful for this indication . Additional information, and especially combination treatment, are warranted to improve success and limit the emergence of resistance to these new antibiotics.

Rev Esp Cardiol, 2000 Nov, 53(11), 1437 - 42
{Clinical features and prognosis of infective endocarditis in the elderly}; Castillo Dominguez JC et al.; INTRODUCTION AND OBJECTIVES: In recent decades the mean age of patients with infective endocarditis has progressively increased . The objective of the present study was to describe the clinical features and prognoses of infective endocarditis in the elderly . METHODS: A prospective study was performed of 125 non drug abuser patients over the age of 14 years and admitted from 1987 until 1997 in a single institution . Twenty-one patients were older than 65 years . RESULTS: No significant differences were observed among the age groups with respect to delay in diagnosis, clinical signs, site of the infection and the rate of negative blood cultures . Prosthetic valve endocarditis was more frequent in elderly than in younger adults (41 and 33%, respectively) . S . viridans and enterococcus were more frequent (47 compared with 29% in younger adults, p < 0.05) . Elderly patients underwent surgery less frequently (46 versus 56%) and most surgery was performed on an emergency basis . The in hospital mortality was higher in the elderly (50 versus 15%), p < 0.05 . CONCLUSIONS: Prosthetic valve endocarditis and severe complications during the active phase are more frequent in the elderly and this is related to a worse prognosis in the short and intermediate term . A higher rate of elective surgery during the active phase could improve the prognosis of infective endocarditis in the elderly.

Antimicrob Agents Chemother, 2000 Dec, 44(12), 3444 - 6
Characterization of a divergent vanD-type resistance element from the first glycopeptide-resistant strain of Enterococcus faecium isolated in Brazil; Dalla Costa LM et al.; Enterococcus faecium 10/96A from Brazil was resistant to vancomycin (MIC, 256 microg/ml) but gave no amplification products with primers specific for known van genotypes . A 2,368-bp fragment of a van cluster contained one open reading frame encoding a peptide with 83% amino acid identity to VanH(D), and a second encoding a D-alanine-D-lactate ligase with 83 to 85% identity to VanD . The divergent glycopeptide resistance phenotype was designated VanD4.

J Bacteriol, 2000 Dec, 182(23), 6806 - 14
Biochemical and genetic evidence that Enterococcus faecium L50 produces enterocins L50A and L50B, the sec-dependent enterocin P, and a novel bacteriocin secreted without an N-terminal extension termed enterocin Q; Cintas LM et al.; Enterococcus faecium L50 grown at 16 to 32 degrees C produces enterocin L50 (EntL50), consisting of EntL50A and EntL50B, two unmodified non-pediocin-like peptides synthesized without an N-terminal leader sequence or signal peptide . However, the bacteriocin activity found in the cell-free culture supernatants following growth at higher temperatures (37 to 47 degrees C) is not due to EntL50 . A purification procedure including cation-exchange, hydrophobic interaction, and reverse-phase liquid chromatography has shown that the antimicrobial activity is due to two different bacteriocins . Amino acid sequences obtained by Edman degradation and DNA sequencing analyses revealed that one is identical to the sec-dependent pediocin-like enterocin P produced by E . faecium P13 (L . M . Cintas, P . Casaus, L . S . Havarstein, P . E . Hernandez, and I . F . Nes, Appl . Environ . Microbiol . 63:4321-4330, 1997) and the other is a novel unmodified non-pediocin-like bacteriocin termed enterocin Q (EntQ), with a molecular mass of 3,980 . DNA sequencing analysis of a 963-bp region of E . faecium L50 containing the enterocin P structural gene (entP) and the putative immunity protein gene (entiP) reveals a genetic organization identical to that previously found in E . faecium P13 . DNA sequencing analysis of a 1,448-bp region identified two consecutive but diverging open reading frames (ORFs) of which one, termed entQ, encodes a 34-amino-acid protein whose deduced amino acid sequence was identical to that obtained for EntQ by amino acid sequencing, showing that EntQ, similarly to EntL50A and EntL50B, is synthesized without an N-terminal leader sequence or signal peptide . The second ORF, termed orf2, was located immediately upstream of and in opposite orientation to entQ and encodes a putative immunity protein composed of 221 amino acids . Bacteriocin production by E . faecium L50 showed that EntP and EntQ are produced in the temperature range from 16 to 47 degrees C and maximally detected at 47 and 37 to 47 degrees C, respectively, while EntL50A and EntL50B are maximally synthesized at 16 to 25 degrees C and are not detected at 37 degrees C or above.

Haematologica, 2000 Nov, 85(11), 1158 - 64
Vancomycin-resistant Enterococcus faecium infection in three children given allogeneic hematopoietic stem cell transplantation: clinical and microbiologic features; Carretto E et al.; BACKGROUND AND OBJECTIVES: The emergence of vancomycin-resistant enterococci (VRE) as nosocomial pathogens is a major problem in the US; in Europe, VRE nosocomial infections are uncommon and only rarely have been reported in Pediatric or Neonatal Units . The aim of this study is to report on the clinical and microbiological features of VRE infections in 3 children given hematopoietic stem cell transplantation (HSCT) . PATIENTS AND METHODS: Five episodes of vancomycin-resistant Enterococcus faecium (VREF) infection were diagnosed in 3 children given an allogeneic HSCT . Molecular methods, such as random amplification of polymorphic DNA (RAPD) fingerprinting and automated ribotyping, were used in order to define the circulation of strains . RESULTS: All the isolates were resistant to all commercially available agents and showed the VanA genotypic profile . All children were successfully treated with the combination of quinupristin/dalfopristin (QD) plus teicoplanin (TEC), although treatment was not sufficient to eradicate the micro-organism promptly from the gastrointestinal tract . All our children are still alive . After the first isolation of VRE, a surveillance protocol was started and we documented that the rate of colonization in children and their mothers was less than 1.5% . The RAPD method demonstrated the possible nosocomial transmission of one strain . INTERPRETATION AND CONCLUSIONS: Our experience demonstrates that VRE infection is a life-threatening complication in children given HSCT . Prompt diagnosis of this infection and its treatment with the combination of QD and TEC can successfully manage this severe infection in profoundly immunocompromised patients.

Cardiovasc Pathol, 2000 Sep-Oct, 9(5), 293 - 6
Active infective endocarditis involving all four cardiac valves; Steiner I et al.; A case is presented of a 70-year-old man treated for 3 months for necrotizing pancreatitis with multiorgan failure . The autopsy revealed enterococcal endocarditis affecting all eleven valvular cusps of the four heart valves.

J Antimicrob Chemother, 2000 Nov, 46(5), 823 - 6
Impact of a new quinolone, DU-6859a, and two oral carbapenems, CS-834 and L-084, on the rat and mouse caecal microflora; Liu CX et al.; We determined the influence of a new quinolone, DU-6859a, and two oral carbapenems, CS-834 and L-084, on the rat and mouse caecal microflora . The caecum-skin fistula-implanted rats and conventional mice were given oral antimicrobials at doses of 30 mg/kg bid for 5 days . DU-6859a generated a marked decrease in the numbers of caecal flora except for enterococci . CS-834 and L-084 had little impact on the rat caecal flora . CS-834 caused a great decrease in the numbers of mouse caecal flora but L-084 did not . In vitro studies suggest that the difference is due to the extension of inactivation of antimicrobials by caecum contents.

J Antimicrob Chemother, 2000 Nov, 46(5), 713 - 6
Influence of different medium components on the in vitro activity of the growth-promoting antibiotic flavomycin against enterococci; Butaye P et al.; The growth-promoting antibiotic flavomycin (also called bambermycin, flavophospholipol and moenomycin) has a complex spectrum of activity against enterococci, with some species being naturally resistant and others susceptible . In this study, proteins added to Mueller-Hinton II medium had a strong deleterious effect on the activity of flavomycin, glucose had no effect and starch decreased the activity of flavomycin . The fatty substances Tween 80 and tributyrin increased the activity of flavomycin for several enterococcal species . Slight differences in the composition of the susceptibility test medium affected the MIC results obtained, indicating that strict standardization of the test medium is necessary.

J Clin Microbiol, 2000 Nov, 38(11), 4242 - 5
Improved pulsed-field gel electrophoresis for typing vancomycin-resistant enterococci; Turabelidze D et al.; A rapid protocol for subtyping vancomycin-resistant enterococci by pulsed-field gel electrophoresis is reported . The procedure is simple and potentially cost-effective and allows reproducible subtyping of the strains in approximately 1 day.

J Clin Microbiol, 2000 Nov, 38(11), 4201 - 7
Application of tRNA intergenic spacer PCR for identification of Enterococcus species; Baele M et al.; tRNA intergenic spacer PCR (tDNA-PCR) was evaluated for its usefulness in the differentiation of enterococcal species of human and animal origin . This technique was carried out for 124 strains belonging to 17 enterococcal species and generated DNA fragments, which were separated by capillary electrophoresis . tDNA-PCR enabled us to discriminate for all species tested . Enterococcus faecium showed minor but reproducible differences with Enterococcus durans, while Enterococcus hirae was easily distinguishable . Enterococcus avium, Enterococcus malodoratus, and Enterococcus raffinosus generated highly similar though distinctive patterns.

J Clin Microbiol, 2000 Nov, 38(11), 4058 - 65
Evaluation of fluorescence-based amplified fragment length polymorphism analysis for molecular typing in hospital epidemiology: comparison with pulsed-field gel electrophoresis for typing strains of vancomycin-resistant Enterococcus faecium; Antonishyn NA et al.; Fluorescence-based amplified fragment length polymorphism (fbAFLP) is a novel assay based on the fluorescent analysis of an amplified subset of restriction fragments . The fbAFLP assay involves the selective PCR amplification of restriction fragments from a total digest of genomic DNA . The ligation of adapters with primer-specific sites coupled with primers containing selective nucleotides allowed the full potential of PCR to be realized while maintaining the advantages of restriction endonuclease analysis . Fluorescence-based fragment analysis with polyacrylamide gel electrophoresis provides the accurate band sizing required for homology assessment . The large number of phylogenetically informative characters obtained by fbAFLP is well suited for cluster analysis and database development . The method demonstrated excellent reproducibility and ease of performance and interpretation . We typed 30 epidemiologically well-characterized isolates of vancomycin-resistant enterococci from an outbreak in a university hospital by fbAFLP . Clustering of fbAFLP data matched epidemiological, microbiological, and pulsed-field gel electrophoresis data . This study demonstrates the unprecedented utility of fbAFLP for epidemiological investigation . Future developments in standardization and automation will set fbAFLP as the "gold standard" for molecular typing in epidemiology.

Braz J Med Biol Res, 2000 Nov, 33(11), 1269 - 74
Typing of Enterococcus faecium by polymerase chain reaction and pulsed field gel electrophoresis; Bedendo J et al.; Polymerase chain reaction (PCR) with JB1 or REP consensus oligonucleotides and pulsed field gel electrophoresis (PFGE) were used to study genomic DNA extracted from 31 strains of enterococci . Eleven ATCC strains, representative of 11 species of Enterococcus, were initially tested by JB1-PCR, revealing that Enterococcus malodoratus and Enterococcus hirae presented identical banding patterns . Eight Enterococcus faecium isolates from Stanford University and 12 from Sao Paulo Hospital were studied by JB1-PCR, REP-PCR (1/2)R and PFGE . Among the isolates from Stanford University, 5 genotypes were defined by JB1-PCR, 7 by REP-PCR (1/2)R and 4 by PFGE . Among the isolates from Sao Paulo Hospital, 9 genotypes were identified by JB1-PCR, 6 by REP-PCR and 5 by PFGE . The three methods identified identical genotypes, but there was not complete agreement among them.

Clin Infect Dis, 2000 Oct, 31(4), 1058 - 65 Epub 2000 Oct 25.
Insights into the epidemiology and control of infection with vancomycin-resistant enterococci; Hayden MK; Despite control efforts, the incidence of nosocomial infections due to vancomycin-resistant enterococci (VRE) continues to increase in the United States . VRE are thought to spread primarily by cross-contamination . Recent molecular epidemiologic studies have refined our understanding of this phenomenon . If VRE are not controlled soon after introduction into a hospital, sporadic cases may evolve into a monoclonal outbreak, which may then evolve to polyclonal endemicity . An intervention that is effective in containing VRE in one setting may be ineffective in another . Control of VRE where they are endemic is particularly challenging . Although eradication of endemic VRE may not be possible, aggressive, multifaceted programs have been successful in diminishing the problem . A mathematical model of transmission of VRE and the effect of infection control measures in settings where they are endemic has been reported . The use of such a model may allow more precise determination of the impact of control strategies in the future.

Protein Expr Purif, 2000 Nov, 20(2), 300 - 7
Analysis of three overexpression systems for VanX, the Zinc(II) dipeptidase required for high-level vancomycin resistance in bacteria; Brandt JJ et al.; The gene from Enterococcus faecilis encoding the dipeptidase VanX was subcloned into overexpression vectors pET-5b, pET-27b, and IMPACT-T7, and VanX was overexpressed in BL21(DE3) pLysS Escherichia coli . The pET-5b-vanx overexpression plasmid produces VanX at approximately 12 mg/L under optimum conditions . VanX produced from this overexpression system exists primarily as a dimer in solution, binds ca . 1 Zn(II) ion per monomer, and exhibits K(m) and k(cat) values of 500 +/- 40 microM and 0.074 +/- 0.001 s(-1), respectively, when l-alanine-p-nitroanilide is used as substrate . The IMPACT-T7-vanx overexpression plasmid produces a VanX-fusion protein with a chitin-binding domain that allows for purification of the fusion construct with a chitin column . Cleavage of the fusion protein is completed by an on-column chemical cleavage, resulting in approximately 10 mg/L of purified VanX . VanX produced from this system is identical to that produced from the pET-5b system, except the CD spectrum of the IMPACT-T7-produced VanX suggests a small change in secondary structure . This change in secondary structure does not affect any of the kinetic or metal-binding properties of the enzyme . The pET-27b-vanx overexpression plasmid produces and secretes VanX into the growth medium; this system allows for 20 mg of VanX to be isolated per liter of growth medium . The pET-27b-produced VanX is identical to that produced from pET-5b .

J Infect, 2000 Jul, 41(1), 95 - 7
Treatment of a vancomycin-resistant Enterococcus faecium ventricular drain infection with quinupristin/dalfopristin and review of the literature; Tan TY et al.; Central nervous system infections involving vancomycin-resistant Enterococcus faecium (VREF) are infrequently described and pose significant therapeutic difficulties, because these organisms are intrinsically resistant to many antibiotics . We describe the use of intrathecal quinupristin/dalfopristin to treat a VREF-associated infection in a neuro--surgical patient.

Antimicrob Agents Chemother, 2000 Nov, 44(11), 3189 - 92
Impact of flavophospholipol and vancomycin on conjugational transfer of vancomycin resistance plasmids; Riedl S et al.; The influence of vancomycin and flavophospholipol (FPL) on the transfer rate of conjugative plasmids harboring the vancomycin resistance operon vanA was determined in several clinical and animal isolates of Enterococcus faecium . FPL significantly inhibited the frequency of transfer of conjugative VanA plasmids up to 70-fold . Vancomycin had no significant effect on the transfer rate of VanA plasmids.

Int J Syst Evol Microbiol, 2000 Sep, 50 Pt 5, 1755 - 60
Atopobacter phocae gen . nov., sp . nov., a novel bacterium isolated from common seals; Lawson PA et al.; Two strains of a Gram-positive, catalase-negative, facultatively anaerobic, rod-shaped bacterium isolated from common seals were characterized using phenotypic and molecular taxonomic methods . The two strains closely resembled each other based on their biochemical characteristics, and PAGE analysis of whole-cell protein patterns confirmed their close phenotypic affinity . 16S rRNA gene sequencing showed that the two strains were genetically highly related (99.8% sequence similarity) and that they constitute a new line of descent within the lactic acid group of bacteria . The nearest phylogenetic neighbours of the unknown bacterium were Granulicatella spp., with related taxa such as enterococci, carnobacteria, Desemzia incerta, Lactosphaera pasteurii, Melissococcus plutonius, tetragenococci and vagococci more distantly related . Based on phylogenetic and phenotypic evidence it is proposed that the unknown bacterium from seals be classified in a new genus as Atopobacter phocae gen . nov., sp . nov . The type strain of Atopobacter phocae is CCUG 42358T (= CIP 106392T).

J Bacteriol, 2000 Nov, 182(21), 6228 - 32
Vancomycin resistance is associated with serine-containing peptidoglycan in Enterococcus gallinarum; Grohs P et al.; In Enterococcus gallinarum SC1, a low-level vancomycin-resistant strain, only monomeric muropentapeptides with a C-terminal D-alanine were detected after growth without vancomycin . In contrast, in SC1 induced by vancomycin, as well as in AIB39, a constitutive vancomycin-resistant strain, monomeric and dimeric muropentapeptides with a C-terminal D-serine were detected.

Shock, 2000 Sep, 14(3), 343 - 6
Selective digestive tract decontamination and vancomycin-resistant enterococcus isolation in the surgical intensive care unit; Dahms R et al.; Vancomycin-resistant Enterococcus (VRE) has emerged as a significant nosocomial pathogen in the surgical intensive care unit (SICU) . We wished to test the hypothesis that the use of selective digestive tract decontamination (SDD) in the SICU affects the frequency of VRE isolation . A retrospective review of hospital records and the SICU database was performed using patients admitted to the SICU service for three or more days from January 1, 1996 to December 31, 1999 at our large tertiary-care teaching hospital . During this time use of SDD in selected patient populations decreased due to physician preference . Information gathered included length of SICU stay, presence of VRE infection or colonization, and use and duration of SDD protocol, vancomycin, and ceftazidime . There were 110 newly diagnosed VRE cases in the SICU during this time period . During the same time period 54 patients received SDD . Eight patients who received SDD had positive VRE cultures and seven had the initial positive culture after receiving SDD . Overall, 9.1% of eligible SICU patients received SDD, 18.5% of patients in the SICU for over 3 days had VRE, 7.3% of VRE patients received SDD, and 13.0% of the SICU patients who received SDD subsequently developed VRE . SDD use was not associated with VRE in univariate analysis . Logistic regression analysis showed higher odds ratios for SDD use in combination with vancomycin than for vancomycin use alone (OR=4.3 vs . 10.9) . Odds ratios were over three times higher for SDD plus vancomycin plus ceftazidime use when compared to vancomycin plus ceftazidime use alone (OR=70.5 vs . 19.8) . We conclude that administration of SDD alone did not correlate with increased VRE isolation, but that SDD use in conjunction with vancomycin and ceftazidime was associated with VRE isolation.

Shock, 2000 Sep, 14(3), 259 - 64
Reduction of vancomycin-resistant enterococcal infections by limitation of broad-spectrum cephalosporin use in a trauma and burn intensive care unit; May AK et al.; Both vancomycin and third-generation cephalosporin use are believed to contribute to a rise in vancomycin-resistant enterococci (VRE) infections . In 1998, the largest number of VRE infections in our hospital occurred in the trauma/burn intensive care unit (TBICU), accounting for nearly 20% of hospital infections . In an attempt to control the VRE infection rate, antibiotic protocols for prophylaxis, empiric, and definitive therapy were initiated during the final quarter of 1998 to minimize cephalosporin use by the introduction of piperacillin/tazobactam . Therefore, we undertook a study of the VRE infection rate for the TBICU in relation to vancomycin, piperacillin/tazobactam, piperacillin, third-generation cephalosporin, and total cephalosporin use before and after efforts to limit cephalosporins . These data were compared to those in the medical and surgical intensive care units . During 1998, seven VRE infections occurred in the TBICU . Following initiation of antibiotic protocols, one case of VRE infection occurred in the subsequent month and no cases in the 17 months since . The decrease in the VRE infection rate corresponded with a significant increase in the use of piperacillin/tazobactam and a reduction in third-generation and total cephalosporin use . In contrast, cephalosporin use in the medical and surgical intensive care units remains significantly higher than in the TBICU, and neither unit has had a reduction in their VRE infection rates.

Clin Microbiol Rev, 2000 Oct, 13(4), 513 - 22
Relationships between enterococcal virulence and antimicrobial resistance; Mundy LM et al.; Enterococci have become a vexing problem in clinical medicine because of their ability to infect patients who are typically receiving antibiotic therapy for unrelated underlying illness . Moreover, the infections have become extremely difficult to manage because of the accumulation of antibiotic resistances among enterococci . The ability of enterococci to cause disease is an intrinsic property of the organism or possibly subpopulations within enterococcal species . The probability of an infection's becoming established, however, is almost certainly in part a function of the enterococcal burden . By altering endogenous bacterial flora, antibiotic therapy promotes increased colonization by antibiotic-resistant organisms . Therefore, antibiotic resistance and intrinsic virulence both contribute to disease, but in separate and complementary ways . We review the virulence of enterococci, as distinct from the acquisition of antimicrobial resistance genes, and identify current gaps in our understanding of enterococcal virulence and the basis for disease.

Int J Food Microbiol, 2000 Sep 25, 60(2-3), 185 - 94
Occurrence of the vancomycin-resistant genes vanA, vanB, vanCl, vanC2 and vanC3 in Enterococcus strains isolated from poultry and pork; Lemcke R et al.; It is suspected that the use of avoparcin as a feeding antibiotic for the fat stock contributes to development of cross-resistance against vancomycin and teicoplanin . After isolating enterococci strains from poultry and pork meat by cultivation on citrate azide Tween carbonate agar (CATC) and screening the vancomycin resistance on Columbia colistin nalidixic acid agar (CNA, supplemented with 5% sheepblood and 5 mg vancomycin/l) the polymerase chain reaction (PCR) was used for the detection of the vancomycin resistance genes vanA ('high level'), vanB ('moderate high level'), vanC1, vanC2 and vanC3 ('low level') . Out of 1643 E.-isolates from 115 poultry and 50 pork samples, 420 isolates could be identified as vancomycin resistant, 202 isolates of which carry the vanA, one isolate both the vanA and the vanC1, 38 isolates the vanC1, 14 isolates the vanC2, nine isolates both the vanC1 and the vanC3 gene and 156 isolates carry no gene . The vanB gene was not found in these isolates . Comparing vanA-positive food isolates with those from different human sources by means of the pulsed field gel electrophoresis (PFGE) it could clearly be demonstrated that they do not show homological fingerprints according to the source of origin . It is therefore unlikely that there is a close genetic relationship between isolates from animal foodstuff and humans.

Appl Environ Microbiol, 2000 Oct, 66(10), 4200 - 4
A strain of Enterococcus faecium (18C23) inhibits adhesion of enterotoxigenic Escherichia coli K88 to porcine small intestine mucus; Jin LZ et al.; Few studies, if any, have addressed the adhesion of enterococci to the intestinal mucosa and their interference with the adhesion of pathogens, although more than 60% of probiotic preparations in the market contain strains of enterococci . The objective of this study was to investigate if Enterococcus faecium 18C23 has the ability to inhibit the adhesion of Escherichia coli K88ac and K88MB to the small intestine mucus of piglets . Approximately 9% of E . faecium 18C23 organisms adhered to the small intestine mucus, and the adhesion was found to be specific . Living E . faecium 18C23 culture efficiently inhibited the adhesion of E . coli K88ac and K88MB to the piglet intestine mucus . Inhibition of the adhesion of E . coli K88ac to the small intestine mucus was found to be dose dependent . Inhibition of >90% was observed when 10(9) CFU or more of living E . faecium 18C23 culture per ml was added simultaneously with E . coli to immobilized mucus . The substances from both the 18C23 cells and the spent culture supernatant contributed to the inhibition of adhesion of E . coli K88 to the small intestine mucus receptors . The inhibiting effect was not solely a pH effect since considerable inhibitory action was demonstrated after neutralizing the mixture or spent culture supernatant to pH 7.0 . Part of the inhibition of adhesion of E . coli K88ac by E . faecium 18C23 or its supernatant might occur through steric hindrance.

Pharmacotherapy, 2000 Sep, 20(9 Pt 2), 203S - 212S; discussion 224S-228S
Control of glycopeptide-resistant enterococci in an oncology unit; Bradley SJ; Enterococci are responsible for 10-12% of nosocomial infections . Since 1987 the incidence of glycopeptide-resistant enterococci (GRE; termed vancomycin-resistant enterococci in the United States) has increased dramatically . The mechanism of GRE is well understood and involves mutation of a single terminal amino acid in a peptidoglycan precursor leading to reduced vancomycin affinity . Studies implicated antibiotic selection pressure as a major risk factor for GRE infection and colonization . In the hematology unit of a London hospital, GRE emerged in December 1993, with 38% of patients positive in a point prevalence study . Between December 1993 and June 1995, 13 patients acquired GRE bacteremia, five of whom died . Between 1995 and 1996 a prospective sequential study was undertaken to determine the effect of changing antibiotic treatment of febrile neutropenia (FN) . All patients admitted to the hematology unit were enrolled in the study . In phase 1, treatment continued with ceftazidime monotherapy . In phase 2, piperacillin-tazobactam replaced ceftazidime, and enhanced infection control measures were encouraged . In phase 3, therapy returned to ceftazidime . In phase 1, 57% of patients became colonized or infected with GRE . Phase 2, which was divided into two 4-month cohorts, showed a significant reduction in GRE acquisition, falling to 8% colonization and no clinical infections in the second 4 months . In phase 3, despite heightened infection control procedures, the acquisition rate rose to 36%.

Infect Control Hosp Epidemiol, 2000 Sep, 21(9), 575 - 82
Outbreak of vancomycin-resistant enterococci in a burn unit; Falk PS et al.; OBJECTIVE: To investigate and control an outbreak of colonization and infection caused by vancomycin-resistant enterococci (VRE) in a burn intensive care unit (BICU) . DESIGN: Epidemiological investigation, including multiple point-prevalence culture surveys of patients and environment, cultures from hands of healthcare workers (HCWs), pulsed-field gel electrophoresis (PFGE) typing of patient and environmental isolates, case-control study, and institution and monitoring of control measures . SETTING: BICU in an 800-bed university medical center in Galveston, Texas . RESULTS: Between June 6, 1996, and July 14, 1997, 21 patients were colonized by VRE, and 4 of these patients developed bacteremia . Of 2,844 environmental cultures, 338 (11.9%) were positive, but all hand cultures from HCWs were negative . PFGE typing indicated that the outbreak was clonal, with VRE isolates from patients differing by < or =4 bands from the index case . Thirteen of 14 environmental isolates varied by < or =4 bands from the pattern of the index case . A case-control study analyzed by exact logistic regression identified diarrhea (odds ratio {OR}, 43.9; 95% confidence interval {CI95}, 5.5-infinity; P=.0001) and administration of an antacid (OR, 24.2; CI95, 2.9-infinity; P=.002) as independent risk factors for acquisition of VRE . During a 5-week period in October and November 1996, all patient and 317 environmental cultures were negative for VRE . The outbreak recurred from a contaminated electrocardiogram lead that had not been identified during the prior 5 weeks . VRE were finally eradicated from the BICU in July 1997, using barrier isolation and a very aggressive environmental decontamination program . CONCLUSIONS: A VRE outbreak in a BICU over 13 months was caused by a single clone . After apparent eradication of VRE from a BICU, recrudescence of the outbreak occurred, evidently from a small inapparent source of environmental contamination . Changes in gastrointestinal (GI) tract function (motility) and administration of medications, other than antibiotics, that have an effect on the GI tract may increase the risk of GI tract colonization by VRE in burn patients . Application of barrier isolation and an aggressive environmental decontamination program can eradicate VRE from a burn population.

Antimicrob Agents Chemother, 2000 Oct, 44(10), 2876 - 9
Detection of the high-level aminoglycoside resistance gene aph(2")-Ib in Enterococcus faecium; Kao SJ et al.; A new high-level gentamicin resistance gene, designated aph(2")-Ib, was cloned from Enterococcus faecium SF11770 . The deduced amino acid sequence of the 897-bp open reading frame of aph(2")-Ib shares homology with the aminoglycoside-modifying enzymes AAC(6')-APH(2"), APH(2")-Ic, and APH(2")-Id . The observed phosphotransferase activity is designated APH(2")-Ib.

Oncology (Huntingt), 2000 Aug, 14(8 Suppl 6), 31 - 4
Current treatments for infection in neutropenic patients with hematologic malignancy; Greene JN et al.; Neutropenic patients with cancer are a heterogeneous group of patients who carry a variable risk for infection . When such patients present with fever, appropriate empiric antibiotic therapy is initiated and continued until clinical improvement or clinical or microbiologic data direct a modification in treatment . As the duration of neutropenia increases, so does the need for antimicrobial modifications . Changes in therapy may include antimicrobials directed against gram-positive bacteria, resistant gram-negative bacteria, or fungi . Because of the high risk for colonization by vancomycin-resistant enterococci, vancomycin use is restricted as first-line empiric therapy unless the patient is at a high risk for serious gram-positive infection . Usually in the setting of neutropenia, gram-positive infections are of low virulence . Prophylactic antibiotic therapy may increase the selection of resistant strains and should be avoided . Antibiotic therapy should always be combined with prudent infection-control measures, such as aseptic practices, barrier isolation, handwashing, removal of infected catheters, and infection monitoring . In the immunocompromised patient with cancer and neutropenia, all infections should be treated, with the extent, duration, and site of treatment being directed by risk stratification and specific pathogen identification . Patients with neutropenia are at risk for severe morbidity and mortality related to infection.

Clin Infect Dis, 2000 Aug, 31(2), 586 - 9 Epub 2000 Sep 07.
Aminoglycoside resistance in enterococci; Chow JW; High-level aminoglycoside resistance in enterococci is mediated generally by aminoglycoside-modifying enzymes, which eliminate the synergistic bactericidal effect usually seen when a cell wall-active agent is combined with an aminoglycoside . Clinical microbiology laboratories currently screen for aminoglycoside resistance in enterococci by testing gentamicin and streptomycin susceptibility . If the recently detected aminoglycoside resistance genes, aph(2")-Ib, aph(2")-Ic, and aph(2")-Id, become more prevalent among clinical isolates, the approach for detecting susceptibility to aminoglycoside synergism in enterococci will require modification . More potent aminoglycosides need to be developed that will be resistant to modification by a broad spectrum of aminoglycoside-modifying enzymes present in enterococci.

Biochemistry, 2000 Sep 19, 39(37), 11417 - 24
Peptide analogues of the VanS catalytic center inhibit VanR binding to its cognate promoter; Ulijasz AT et al.; The dodecamer peptide SLCHDSVIGWEC, named E12, was selected from a combinatorial peptide library on the basis of its ability to bind to VanR, the two-component signal transduction response regulator which controls expression of vancomycin resistance in Enterococcus faecium . The binding of E12 was localized to the N-terminal, regulatory domain of VanR which contains Asp-55, the residue which accepts the phosphoryl group from His-164 in the activated VanS sensor kinase . E12, along with a related sequence SLAHDSIIGYLS, named E12.1, was found to inhibit the binding of VanR approximately P to a DNA segment which corresponds to its cognate promoter PvanH . With a single gap, both E12 and E12.1 could be aligned with the octadecamer sequence YLAHDIKTPLTSIIGYLS, comprising Tyr-161 through Ser-178, of the catalytic center dimerization domain of VanS, a sequence with which VanR also normally interacts . Alanine substitution analysis of E12.1 identified six amino acids as indispensable for its ability to inhibit VanR approximately P-PvanH DNA complex formation . A similar analysis of the corresponding amino acids in VanS showed a parallel dependence except for the substitutions Leu-162 --> Ala and Gly-175 --> Ala which interfered with the ability of E12.1 to compete with protein-DNA complex formation, but did not inhibit the ability of VanS to bind VanR . Our findings support a model in which E12 mimics the VanS phosphorylatable sequence with which the regulatory domain of VanR interacts, and thus functions as a "minimalist" analogue of VanS . Our results also indicate the usefulness of phage-displayed peptides as a general tool for mimicking the interacting faces of interacting proteins.

Nutrition, 2000 Sep, 16(9), 729 - 33
Microbiological quality of reconstituted enteral formulations used in hospitals; Oliviera MH et al.; Contamination of enteral feeds may occur during preparation, storage, decanting, and administration to patients . The aim of this study was to investigate the microbiological quality of reconstituted enteral feeds, residual feeds from feed delivery systems, and the water used to reconstitute powdered feeds in hospital . Hazard Analysis Critical Control Points (HACCP) system was implemented to control microbiological contamination of the enteral feeding formulations . Before the implementation of the HACCP system microbiological analyses of feeds showed the presence of indicator organisms such as coliforms and Enterococcus spp . and unacceptably high levels of mesophilic aerobic microorganisms (>10(4) cfu/mL) . After the implementation of the HACCP, the microbial quality of the feeds improved significantly, with counts of <10(1) cfu/mL . Blenders used in reconstituting feeds were found to be the main source of bacterial contamination.

Diagn Microbiol Infect Dis, 2000 Aug, 37(4), 297 - 9
In-vitro synergistic activity of the combination of ampicillin and arbekacin against vancomycin-and high-level gentamicin-resistant Enterococcus faecium with the aph(2")-Id gene; Kak V et al.; The combination of ampicillin plus arbekacin produced synergistic killing against 8 of 13 vancomycin-, ampicillin-, gentamicin-, and streptomycin-resistant Enterococcus faecium isolates that possess the high-level gentamicin resistance gene, aph(2")-Id . This combination may prove useful in treating infections caused by multiresistant enterococci.

J Appl Microbiol, 2000 Aug, 89(2), 349 - 60
The fate of stormwater-associated bacteria in constructed wetland and water pollution control pond systems; Davies CM et al.; The performances of a constructed wetland and a water pollution control pond were compared in terms of their abilities to reduce stormwater bacterial loads to recreational waters . Concentrations of thermotolerant coliforms, enterococci and heterotrophic bacteria were determined in inflow and outflow samples collected from each system over a 6-month period . Bacterial removal was significantly less effective in the water pollution control pond than in the constructed wetland . This was attributed to the inability of the pond system to retain the fine clay particles (< 2 microm) to which the bacteria were predominantly adsorbed . Sediment microcosm survival studies showed that the persistence of thermotolerant coliforms was greater in the pond sediments than in the wetland sediments, and that predation was a major factor influencing bacterial survival . The key to greater bacterial longevity in the pond sediments appeared to be the adsorption of bacteria to fine particles, which protected them from predators . These observations may significantly affect the choice of treatment system for effective stormwater management.

J Clin Microbiol, 2000 Sep, 38(9), 3511 - 2
Continuous ambulatory peritoneal dialysis peritonitis due to Enterococcus cecorum; De Baere T et al.; Enterococcus cecorum was isolated as the etiologic agent of a continuous ambulatory peritoneal dialysis peritonitis episode in an alcoholic patient . To date, this is only the third infection due to this bacterium, found in the intestinal tract of many domestic animals, that has been reported in humans.

J Med Microbiol, 2000 Sep, 49(9), 793 - 9
Genotypic characterisation of endemic VanA Enterococcus faecium strains isolated in a paediatric hospital; Barnaud G et al.; A total of 36 vancomycin-resistant Enterococcus faecium isolates obtained from 30 patients during a 28-month period in a paediatric university hospital was analysed by pulsed-field gel electrophoresis (PFGE) combined with Southern hybridisation of a vanA-specific DNA probe . All the isolates hybridised with the vanA probe . Seventeen different PFGE patterns and 11 PFGE subtypes were identified among the 36 clinical isolates, and the size of probe-positive bands ranged from c . 30 to 300 kb . These data are consistent with an increase in the overall genomic diversity of vancomycin-resistant E . faecium isolates during the study period . Two periods were distinguished . The prevalence of a single clone in the initial period suggested transmission between patients in three wards . During the following period, multiple genotypes of vancomycin-resistant E . faecium were identified, indicative of multiple introductions or the dissemination of resistance genes by recombinant transposition.

Braz J Infect Dis, 2000 Feb, 4(1), 9 - 14
Problems and perils of vancomycin resistant enterococci; Murray BE; Enterococci have been a therapeutic challenge for haIfa century; first in the management of endocarditis, then associated with the emergence of resistance to streptomycin and later to all aminoglycosides, and now with the increasing levels of resistance to penicillins . A major leap in the problem of antimicrobial resistance occurred more than a decade ago when vancomycin resistant enterococci (VRE) were first identified . This resulted from the acquisition by Enterococcus faecium of vancomycin resistant genes . Five types of vancomycin resistance have since been described (VanA-VanE) and others also appear to exist . VanA and VanB are caused by complex gene clusters that may be plasmid and/or transposon encoded . As a result of the gene cluster, cell wall precursors in the bacteria are formed that do not allow effective vancomycin binding, thus the action of vancomycin to inhibit cell wall synthesis is prevented . Therapy of infections caused by VRE is difficult, but a number of potentially effective antibiotics are now being tested in humans, including quinupristin/dalfopristin, linezolid, evernimomycin, daptomycin and LY333328 . Combinations of antibiotics such as ampicillin with quinupristin/dalfopristin or with imipenem, and newer fluoroquinolones are also being evaluated . Until the time when these drugs become available, we must rely on careful monitoring of microbial transmission in hospitals, and we must utilize multi-faceted approaches to prevent the increase in the number and spread of VRE.

New Microbiol, 2000 Jul, 23(3), 305 - 17
Purification of daptomycin binding proteins (DBPs) from the membrane of Enterococcus hirae; Boaretti M et al.; Daptomycin binding proteins (DBPs) are membrane proteins which act as daptomycin targets . Daptomycin is a cyclic lipopeptide antibiotic which is active against Gram-positive bacteria and was shown to be the first inhibitor of lipoteichoic acid (LTA) synthesis . It was found that the antibiotic did not penetrate the bacterial cytoplasm but bound membranes with a non-covalent bond and in particular some proteins which were called DBPs . DBPs were indicated as enzymes involved in LTA synthesis whose binding and inhibition by daptomycin is responsible for the observed effect on bacterial LTA synthesis . The purification of DBPs will make it possible not only to shed light on the biosynthesis of the cell wall polymer but will also provide innovative targets for selection of new antibacterial compounds . In this study, the purification of DBPs is described . Affinity chromatography was used with daptomycin as the ligand . Final elution of DBPs from daptomycin-coupled resin was performed using either 0.1% SDS or 3 M NaCl . Polyacrylamide gel electrophoresis of the eluted protein fractions consistently showed four protein bands (ranging from 55 to 66 kDa) in denaturating conditions and two protein bands (60 and 66 kDa) in non-denaturating conditions . Isoelectrofocusing analysis of the same sample consistently revealed two bands with pIs around 5 . That these purified proteins were really the desired DBPs is demonstrated by the retention of daptomycin-binding capability they displayed.

J Burn Care Rehabil, 2000 Jul-Aug, 21(4), 300 - 3
A cost-benefit analysis of initial burn cultures in the management of acute burns; Miller PL et al.; It is common practice to obtain cultures in the first 24 hours after burn injuries . However, little evidence exists that these tests change clinical practice or clinical outcome . We conducted a retrospective chart review to determine how often the results of wound and other cultures lead to changes in the clinical treatment of patients . A total of 598 charts were reviewed . Four hundred forty-seven patients had a length of stay in the hospital of 1 day or less and were primarily treated in the emergency department and then discharged from the hospital . Wound cultures were obtained for 42 (10%) of these patients . Thirty cultures (71%) had no significant growth . Twelve cultures (29%) grew mixed common skin flora . No patients in this group were "pan-cultured." No patients in this group required antibiotic treatment on the basis of culture results . A total of 151 patients were admitted to the burn center, with an average length of stay of 3.9 days (range, 2-125 days) . In this group, 45 patients (30%) had wound cultures and 24 patients (16%) were pan-cultured in the first 24 hours after admission to the hospital . Enterococcus species grew in the initial wound culture of 1 patient, and the patient was treated with antibiotics . Antibiotics were not ordered for any other patients on the basis of cultures . The collection of routine cultures during the first 24 hours after admission to the hospital is not cost-effective and rarely alters or provides therapeutic direction . An estimated $14,000 per year decrease in charges could be achieved by the elimination of cultures taken during the first 24 hours of admission to the hospital.

Salud Publica Mex, 2000 May-Jun, 42(3), 181 - 7
{Trends of hospital infections at an oncology center, 1986-1996}; Volkow P et al.; OBJECTIVE: To describe the results of ten years of nosocomial infection (NI) surveillance in an oncology center . MATERIAL AND METHODS: This is a descriptive study of the Infection Control and Surveillance Program Committee at the Instituto Nacional de Cancerologia, conducted in 1997 . From June 1986 to December 1996, we surveyed 62,733 hospital discharge records . Criteria used to classify nosocomial infections were those outlined in 1972 by the Centers for Disease Control and Prevention, Atlanta (GA) . Survey data were collected through review of microbiology chart records and of hospital chart records of febrile patients, patients receiving antibiotics, and patients visited after surgery . We calculated the rates of NI as the number of infections/100 discharges . RESULTS: The rate of NI per 100 discharges was 4.4 in 1986, 7.7 in 1987, 8.1 in 1988, 5.9 in 1989, 4.6 in 1990, 5.1 in 1991, 4.3 in 1992, 5.4 in 1993, 7.6 in 1994, 7.1 in 1995 and 8.5 in 1996 . Escherichia coli was the microorganism most frequently isolated . From 1987, an increase of almost seven times in fungi isolations as well as enterococci was observed . CONCLUSIONS: An increasing trend in NI rates was observed in the last four years, probably related to multiple factors such as improved surveillance (better reporting) and a real increase in the frequency of NI.

Am J Infect Control, 2000 Aug, 28(4), 311 - 3
Persistent contamination of fabric-covered furniture by vancomycin-resistant enterococci: implications for upholstery selection in hospitals; Noskin GA et al.; Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens in hospitals throughout the United States . An increasing concern with respect to VRE dissemination is survival on, and potential transmission from, environmental surfaces within health care institutions . Therefore, we assessed survival of VRE on fabric chairs in an attempt to determine the optimal upholstery for the health care setting . VRE was identified on 3 of 10 seat cushions sampled, including 2 chairs in a room of a patient with known VRE . After performing simulated contamination experiments, all samples were positive at 72 hours and 1 week after inoculation . Contamination of the upholstery could be prevented by placing a sheet folded 4 times or a bath blanket folded in half on the seat cushion . In conclusion, VRE are capable of prolonged survival on fabric seat cushions and can be transferred to hands . Environmental surfaces such as chairs may serve as a potential reservoir for nosocomial transmission of VRE, and an easily cleanable, nonporous material is the preferred upholstery in hospitals.

Am J Infect Control, 2000 Aug, 28(4), 298 - 301
Bacteriology and antimicrobial choice in hepatolithiasis; Sheen-Chen S et al.; BACKGROUND AND AIMS: Hepatolithiasis is prevalent in southeast Asia and presents a difficult management problem . Acute repeated episodes of cholangitis are frequently manifested in patients with hepatolithiasis . Without proper treatment, such infection can lead to liver abscess, secondary biliary cirrhosis, portal hypertension, and death from sepsis or hepatic failure . In addition to clearance of the stones and relief of bile stasis either by surgery or by interventional radiologic manipulation, effective antimicrobial therapy also plays a crucial role in the treatment of patients with hepatolithiasis . The aim of this study is to clarify the bacteriology in hepatolithiasis and to provide the information for an appropriate antimicrobial choice . METHODS: From July 1993 to June 1996, 150 patients with hepatolithiasis underwent surgical intervention . Bile specimens were routinely obtained by syringe aspiration from common bile duct . The syringe was immediately capped, and the bile was subsequently cultured for both aerobes and anaerobes . RESULTS: Bacteria were present in the bile of all patients . The bacteria most frequently found were gram-negative bacteria such as Klebsiella sp, Escherichia coli, and Pseudomonas sp, and the gram-positive Enterococcus sp . Bacteroides sp were the most frequently found anaerobes . CONCLUSIONS: This study demonstrated the close relationship between acute cholangitis in hepatolithiasis and enteric bacteria and also displayed the detailed antibiotic sensitivity results . Armed with this fruitful information, we believe the antibiotic treatment for acute cholangitis in hepatolithiasis should first aim at enteric bacteria and be adjusted later according to the results of bacteriologic cultures and clinical situation to achieve an effective microbial control.

Am J Infect Control, 2000 Aug, 28(4), 282 - 5
Risk factors for acquisition of vancomycin-resistant enterococci among patients on a renal ward during a community hospital outbreak; Beltrami EM et al.; BACKGROUND: During an outbreak of vancomycin-resistant enterococcal (VRE) infection and colonization at a community hospital in Indianapolis, Indiana, we performed a case-control study of patients on the hospital's renal unit to determine risk factors for acquisition of VRE among this potentially high-risk patient population . METHODS: Twenty-four renal patients with VRE colonization/infection (ie, case-patients) were compared by univariate and multivariate analyses with 29 renal patients with nosocomially acquired vancomycin-susceptible enterococcal infection and colonization (ie, controls) . RESULTS: Age and length of hospitalization were similar between the VRE case-patients and the vancomycin-susceptible enterococcal control-patients, but case-patients had higher Acute Physiology and Chronic Health Evaluation II scores and received significantly greater numbers of antimicrobials and significantly more days of antimicrobials during the 60 days preceding the first positive enterococcal culture . In an assessment of the appropriateness of vancomycin use, one third of vancomycin orders were found to be inappropriate in both patient groups . CONCLUSIONS: Our data show that among renal patients, those who are severely ill and receive multiple and prolonged courses of antimicrobials are at greatest risk for acquiring VRE infection or colonization . The Centers for Disease Control and Prevention recommends that hospitals develop a comprehensive plan to prevent and control infection and colonization of patients with VRE . This plan should include prompt identification of affected patients, initiation of isolation precautions to prevent patient-to-patient transmission of VRE, and prudent use of antimicrobials, including vancomycin.

J Clin Microbiol, 2000 Aug, 38(8), 2885 - 8
PCR fragment length polymorphism analysis of vancomycin-resistant Enterococcus faecium; Donabedian S et al.; In this study, the glycopeptide resistance element, Tn1546, in 124 VanA Enterococcus faecium clinical isolates from 13 Michigan hospitals was evaluated using PCR fragment length polymorphism . There were 26 pulsed-field gel electrophoresis (PFGE) types, which consisted of epidemiologically related and unrelated isolates from separate patients (1992 to 1996) . Previously published oligonucleotides specific for regions in the vanA gene cluster of Tn1546 were used to amplify vanRS, vanSH, vanHAX, vanXY, and vanYZ . The glycopeptide resistance element, Tn1546, of E . faecium 228 was used as the basis of comparison for all the isolates in this study . Five PCR fragment length patterns were found, as follows . (i) PCR amplicons were the same size as those of EF228 for all genes in the vanA cluster in 19.4% of isolates . (ii) The PCR amplicon for vanSH was larger than that of EF228 (3.7 versus 2.3 kb) due to an insertion between the vanS and vanH genes (79.2% of isolates) . (iii) One isolate in a unique PFGE group had a vanSH amplicon larger than that of EF228 (5.7 versus 2.3 kb) due to an insertion in the vanS gene and an insertion between the vanS and vanH genes . (iv) One isolate did not produce a vanSH amplicon, but when vanS and vanH were amplified separately, both amplicons were the same size as those as EF228 . (v) One isolate had a vanYZ PCR product larger than that of EF228 (2.8 versus 1.6 kb) . This study shows that in a majority of the VanA E . faecium isolates, Tn1546 is altered compared to that of EF228 . A total of 79.2% of the study isolates had the same-size insertion between the vanS and vanH genes . The results of this study show dissemination of an altered Tn1546 in heterologous VanA E . faecium in Michigan hospitals.

Int J Clin Pract, 2000 May, 54(4), 250 - 4
Update on vancomycin resistance; Perichon B et al.; Enterococci can be responsible for severe infections such as endocarditis, meningitis and septicaemia and are one of the most important causes of nosocomial infections . Resistance in enterococci concerns many classes of antibiotics including, since 1986, glycopeptides . These antibiotics act by blocking cell wall formation, and resistance is due to synthesis of modified peptidoglycan precursors . Resistance can be acquired or intrinsic and strains may be resistant to vancomycin and teicoplanin, or to vancomycin only . Five types of glycopeptide resistance and their biochemical mechanisms have been described . Furthermore, strains that are dependent on vancomycin for growth have been isolated from clinical samples . Data suggest that resistance could originate in glycopeptide-producing organisms or in enterococcal species intrinsically resistant to these antibiotics.

Proc Natl Acad Sci U S A, 2000 Aug 1, 97(16), 8921 - 5
The molecular basis of vancomycin resistance in clinically relevant Enterococci: crystal structure of D-alanyl-D-lactate ligase (VanA); Roper DI et al.; d-alanine-d-lactate ligase from Enterococcus faecium BM4147 is directly responsible for the biosynthesis of alternate cell-wall precursors in bacteria, which are resistant to the glycopeptide antibiotic vancomycin . The crystal structure has been determined with data extending to 2.5-A resolution . This structure shows that the active site has unexpected interactions and is distinct from previous models for d-alanyl-d-lactate ligase mechanistic studies . It appears that the preference of the enzyme for lactate as a ligand over d-alanine could be mediated by electrostatic effects and/or a hydrogen-bonding network, which principally involve His-244 . The structure of d-alanyl-d-lactate ligase provides a revised interpretation of the molecular events that lead to vancomycin resistance.

Chem Biol, 2000 Jul, 7(7), 505 - 14
D-Ala-D-X ligases: evaluation of D-alanyl phosphate intermediate by MIX, PIX and rapid quench studies; Healy VL et al.; BACKGROUND: The D-alanyl-D-lactate (D-Ala-D-Lac) ligase is required for synthesis of altered peptidoglycan (PG) termini in the VanA phenotype of vancomycin-resistant enterococci (VRE), and the D-alanyl-D-serine (D-Ala-D-Ser) ligase is required for the VanC phenotype of VRE . Here we have compared these with the Escherichia coli D-Ala-D-Ala ligase DdlB for formation of the enzyme-bound D-alanyl phosphate, D-Ala(1)-PO(3)(2-) (D-Ala(1)-P), intermediate . RESULTS: The VanC2 ligase catalyzes a molecular isotope exchange (MIX) partial reaction, incorporating radioactivity from (14)C-D-Ser into D-Ala-(14)C-D-Ser at a rate of 0.7 min(-1), which approaches kinetic competence for the reversible D-Ala(1)-P formation from the back direction . A positional isotope exchange (PIX) study with the VanC2 and VanA ligases displayed a D-Ala(1)-dependent bridge to nonbridge exchange of the oxygen-18 label of {gamma-(18)O(4)}-ATP at rates of up to 0.6 min(-1); this exchange was completely suppressed by the addition of the second substrate D-Ser or D-Lac, respectively, as the D-Ala(1)-P intermediate was swept in the forward direction . As a third criterion for formation of bound D-Ala(1)-P, we conducted rapid quench studies to detect bursts of ADP formation in the first turnover of DdlB and VanA . With E . coli DdlB, there was a burst amplitude of ADP corresponding to 26-30% of the DdlB active sites, followed by the expected steady-state rate of 620-650 min(-1) . For D-Ala-D-Lac and D-Ala-D-Ala synthesis by VanA, we measured a burst of 25-30% or 51% of active enzyme, respectively . CONCLUSIONS: These three approaches support the rapid (more than 1000 min(-1)), reversible formation of the enzyme intermediate D-Ala(1)-P by members of the D-Ala-D-X (where X is Ala, Ser or Lac) ligase superfamily.

Tunis Med, 2000 Jan, 78(1), 66 - 9
{Infectious enterococcal endocarditis associated with Laubry and Pezzi syndrome}; Kraiem S et al.; Laubry and Pezzi syndrome is a rare but serious complication of ventricular septal defect that increase the infectious endocarditis risk . Authors report a case of an 18 years old young girl presenting an enterococcus infectious endocarditis associated to Laubry and Pezzi syndrome . Initial course is not favourable requiring a surgical treatment in the acute stage . Bacterial endocarditis combined with Laubry and Pezzi syndrome have a poor prognosis needing observation and strict preventive precautions when a favoring factor is present.

FEMS Immunol Med Microbiol, 2000 Aug, 28(4), 291 - 9
Specific antibody promotes opsonization and PMN-mediated killing of phagocytosis-resistant Enterococcus faecium; Rakita RM et al.; Many clinical isolates of Enterococcus faecium are resistant to neutrophil (PMN)-mediated phagocytosis and killing in the presence of normal human serum . We have now examined the ability of specific polyclonal rabbit antibodies to promote opsonization and killing of phagocytosis-resistant E . faecium . Immune rabbit serum generated against formalin-killed E . faecium TX0016, a phagocytosis-resistant strain, markedly promoted binding of TX0016 organisms to PMNs and PMN-mediated killing . These effects were dramatically reduced by (a) adsorption of immune serum with E . faecium TX0016, but not by adsorption with a strain of E . faecium susceptible to phagocytosis, and (b) incubation of immune serum with carbohydrate purified from TX0016, but not by incubation with a surface protein extract from TX0016 . IgG purified from immune serum was unable by itself to promote bacterial binding to PMNs . However, specific IgG was able to promote binding to PMNs and PMN-mediated killing in the presence of normal human serum as a complement source, as were F(ab')(2) and Fab fragments produced from it, and the alternative pathway of complement was sufficient to promote IgG- and F(ab')(2)-mediated opsonization . PMN complement receptor type 3, but not complement receptor type 1, was involved in bacterial binding to PMNs induced by the combination of F(ab')(2) fragments and normal human serum . These results suggest that opsonization by antibodies potentially directed against bacterial carbohydrate, in conjunction with complement activation, has an important role in the host defense against phagocytosis-resistant E . faecium.

Biosci Biotechnol Biochem, 2000 May, 64(5), 1088 - 92
Sodium ATPase and sodium/proton antiporter are not obligatory for sodium homeostasis of Enterococcus hirae at acid pH; Ikegami M et al.; Enterococcus hirae grows in a broad pH range from 5 to 11 . An E . hirae mutant 7683 lacking the activities of two sodium pumps, Na+-ATPase and Na+/H+ antiporter, does not grow in high Na+ medium at pH above 7.5 . We found that 7683 grew normally in high Na+ medium at pH 5.5 . Although an energy-dependent sodium extrusion at pH 5.5 was missing, the intracellular levels of Na+ and K+ were normal in this mutant . The Na+ influx rates of 7683 and two other strains at pH 5.5 were much slower than those at pH 7.5 . These results suggest that Na+ elimination of this bacterium at acid pH is achieved by a decrease in Na+ entry and a normal K+ uptake.

J Clin Microbiol, 2000 Jul, 38(7), 2774 - 7
Characterization of glycopeptide-resistant enterococcus faecium (GRE) from broilers and pigs in Denmark: genetic evidence that persistence of GRE in pig herds is associated with coselection by resistance to macrolides; Aarestrup FM; Glycopeptide-resistant enterococci (GRE) from broilers and pigs were characterized to investigate the background for the persistence of GRE in pig herds . All porcine isolates belonged to closely related pulsed-field gel electrophoretic (PFGE) types, with the ermB and vanA genes located on the same transferable genetic element . Broiler isolates belonged to different PFGE types . The persistence of GRE in Danish pig herds after the ban of glycopeptides may be explained by the genetic link between ermB and vanA and coselection by use of macrolides for treatment and growth promotion.

J Hosp Infect, 2000 Apr, 44(4), 288 - 93
VRE in the Republic of Ireland: clinical significance, characteristics and molecular similarity of isolates; Nourse C et al.; There have been increasing reports worldwide of vancomycin resistant enterococci (VRE) since they were first noted over ten years ago . This study sought to investigate the clinical significance of VRE in Ireland and to compare the phenotypic, genotypic and molecular characteristics of isolates recovered from patients in different institutions . The relative contribution of inter-hospital transmission of strains to the dissemination of VRE in Ireland was assessed . Hospital surveillance for VRE is not well established in Ireland . The organism has been detected in seven hospitals . Detection has been predominantly in oncology inpatients in large tertiary referral hospitals in the Dublin metropolitan area in whom strains generally represent asymptomatic gastrointestinal tract colonization . The predominant species is E . faecium with the Van A resistance phenotype . Twenty-seven (87) of 31 isolates from one unit were shown to be of the same or closely related strain as were 10 (63%) of 16 from another unit, indicating significant nosocomial transmission within institutions . There was no evidence for inter-hospital transmission of VRE . VRE is established in Ireland and nosocomial transmission readily occurs . Regular surveillance for VRE is indicated in high-risk populations in large institutions, specific risk factors for the acquisition of VRE need to be defined and optimal control and preventative strategies need to he instituted to detect and preempt the spread of this organism.

Biochem Biophys Res Commun, 2000 Jun 24, 273(1), 164 - 9
Cytokine-inducing macromolecular glycolipids from Enterococcus hirae: improved method for separation and analysis of its effects on cellular activation; Hashimoto M et al.; Previously, we showed that several minor macromolecular glycolipids accounting for less than 5% of the lipoteichoic acid (LTA) fraction from Enterococcus hirae ATCC 9790 possess cytokine-inducing activity, whereas the purified LTA does not . In other words, the immunobiological activity of the LTA fraction reported in the 1980s was not attributable to LTA itself, but to other glycolipids coexisting in the fraction . In the present study, we improved the procedure of separation of the active glycolipids and evaluated their effects on cellular activation . The immunobiologically active glycolipids were separated from the crude glycolipid fraction obtained by hot phenol-water extraction of the cells . The total yield of active glycolipids was about fivefold higher than that separated by the previous method . Interleukin-6-inducing activities of the active glycolipids from 1,25-dihydroxy vitamin D(3)-differentiated human monocytic leukemia cells, THP-1, were inhibited by anti-CD14 mAbs in a dose-dependent manner . Macrophages from Toll-like receptor (TLR)-2-deficient or -4-deficient mice completely lacked the ability to produce tumor necrosis factor-alpha on stimulation with active glycolipids . These observations indicated that the cellular activation by the active glycolipids from E . hirae is mediated by CD14 and by both TLR2 and TLR4 .

J Bacteriol, 2000 Jul, 182(14), 4035 - 43
Integration and excision of a Bacteroides conjugative transposon, CTnDOT; Cheng Q et al.; Bacteroides conjugative transposons (CTns) are thought to transfer by first excising themselves from the chromosome to form a nonreplicating circle, which is then transferred by conjugation to a recipient . Earlier studies showed that transfer of most Bacteroides CTns is stimulated by tetracycline, but it was not known which step in transfer is regulated . We have cloned and sequenced both ends of the Bacteroides CTn, CTnDOT, and have used this information to examine excision and integration events . A segment of DNA that contains the joined ends of CTnDOT and an adjacent open reading frame (ORF), intDOT, was necessary and sufficient for integration into the Bacteroides chromosome . Integration of this miniature form of the CTn was not regulated by tetracycline . Excision of CTnDOT and formation of the circular intermediate were detected by PCR, using primers designed from the end sequences . Sequence analysis of the PCR products revealed that excision and integration involve a 5-bp coupling sequence-type mechanism possibly similar to that used by CTn Tn916, a CTn found originally in enterococci . PCR analysis also demonstrated that excision is a tetracycline-regulated step in transfer . The integrated minielement containing intDOT and the ends of CTnDOT did not excise, nor did a larger minielement that also contained an ORF located immediately downstream of intDOT designated orf2 . Thus, excision involves other genes besides intDOT and orf2 . Both intDOT and orf2 were disrupted by single-crossover insertions . Analysis of the disruption mutants showed that intDOT was essential for excision but orf2 was not . Despite its proximity to the integrase gene, orf2 appears not to be essential for excision.

Microb Drug Resist, 2000 Spring, 6(1), 63 - 70
Associations between the use of antimicrobial agents for growth promotion and the occurrence of resistance among Enterococcus faecium from broilers and pigs in Denmark, Finland, and Norway; Aarestrup FM et al.; This study compares the susceptibility of Enterococcus faecium isolated from pigs and poultry in Denmark, Finland, and Norway to antimicrobial agents used for growth promotion . E . faecium was isolated from 211 broilers and 55 pigs in Denmark in 1997, from Norwegian 55 poultry farms (turkey and broiler farms) and 4 swine farms between 1995 and 1997, and Finnish poultry (52) and swine (43) in 1996 and examined for susceptibility to avilamycin, avoparcin, bacitracin, flavomycin, monensin, salinomycin, spiramycin, tylosin, and virginiamycin . Only a limited number of isolates were categorized as resistant to monensin or salinomycin . In general, an association between the usage of antimicrobial agents in the respective countries and the occurrence of associated resistance was observed . Resistance to avilamycin was frequently observed among isolates from broilers in Denmark, where avilamycin has been used, whereas all isolates from Finland and Norway, where these drugs have not been used, were susceptible . The same phenomenon could be observed for avoparcin, bacitracin, tylosin, and virginiamycin; resistance was frequently observed among isolates from where these antimicrobials have been widely used, but rarely among isolates from where the use has been limited . Also for avoparcin and bacitracin, an association between usage and occurrence of resistance was observed . All isolates categorized as avoparcin resistant contained the vanX gene; isolates from broilers had the T variant in position 8,234 and isolates from pigs the G variant . Three (1%) of the 222 isolates resistant to tylosin contained the ermA gene and 196 (88%) ermB . Sixteen (11%) of the 146 virginiamycin-resistant isolates from broilers and two (7%) of the 27 virginiamycin-resistant isolates from pigs in Denmark contained the satA gene, whereas satA was not observed among any of the virginiamycin-resistant isolates from Finland . A total of 72% of the virginiamycin-resistant E . faecium from broilers in Denmark and all nine virginiamycin-resistant E . faecium from Finland contained satG . This gene was also observed among two (7%) of the virginiamycin-resistant isolates from pigs in Denmark . This study indicates that the use of antimicrobial agents for growth promotion in Denmark, Finland, and Norway have selected for resistance to most of these drugs among E . faecium in food animals.

Microb Drug Resist, 2000 Spring, 6(1), 49 - 57
Typeability of Tn1546-like elements in vancomycin-resistant enterococci using long-range PCRs and specific analysis of polymorphic regions; Simonsen GS et al.; Molecular subtyping of the VanA-type resistance element Tn1546 in an international collection of 81 genomically diverse vancomycin-resistant enterococci (VRE) from human, animal, and environmental reservoirs was evaluated by restriction analysis of long-range PCR amplicons (PCR-RFLP), single gene PCRs, Southern blot analysis of genomic digests, and partial DNA sequencing . A dominant Tn1546-RFLP in accordance with Enterococcus faecium BM4147 was detected in 43 of the 49 long-range PCR positive strains from ecologically diverse sources in several European countries and the US . Tn1546-like elements from the 32 (40%) long-range PCR negative strains were typed into 17 different groups by single-gene PCRs and Southern blot analysis of the ORF1, ORF2, vanS-vanH, vanX-vanY, and vanZ regions . All these isolates showed deletions in the ORF1 and/or vanZ primer binding regions explaining the failure of long-range PCR amplification . Enlarged vanS-vanH or vanX-vanY fragments were detected in 7 (22%) and 16 (50%) of the long-range PCR negative strains, respectively . The enlarged vanS-vanH regions of five clinical isolates from the US (n = 2), Ireland (n = 2), and Norway (n = 1) contained identical IS1251-like insertions indicating intercontinental spread of the vanA gene cluster . Intergenic vanS-vanH IS1251 insertions have so far not been reported in European studies . Structural rearrangements of Tn1546-like elements may represent single recombination events that can serve as fingerprints in the molecular examination of vanA gene cluster evolution and transmission . The optimal strategy for such analysis has yet to be determined . Two alternative long-range PCRs with subsequent RFLP analysis were successfully used to type the majority of vanA gene clusters in an ecologically and geographically heterogeneous VRE strain collection, but failed to detect and type a group of variant Tn1546-like elements truncated in the left-end ORF1/ORF2 region . Further subtyping of such variants should specifically target the polymorphic vanS-vanH and vanX-vanY regions.

Turk J Pediatr, 1997 Jan-Mar, 39(1), 13 - 7
Antibiotic susceptibilities of enterococci isolated from Turkish children; Akan O et al.; To evaluate the antibiotic resistance rates of enterococci isolated at Hacettepe Children's Hospital, in vitro antibiotic susceptibility tests were performed in 77 enterococci (32 hospital, 45 nonhospital strains) isolated from various clinical specimens in 1994 . Microbroth dilution tests against ampicillin, vancomycin, gentamicin and streptomycin were performed according to the NCCLS standards . High-level resistance to aminoglycosides was investigated . Ampicillin resistance rates were 21.9 percent and 2.2 percent for hospital and nonhospital strains, respectively (p < 0.01) . The same rates were 46.9 and 13.3 percent for gentamicin (p < 0.01), and 15.6 and 13.3 percent for streptomycin (p = 0.25) . No resistance was detected against vancomycin . Six strains (7.8%) showed high-level resistance to both aminoglycosides studied . Special attention should be paid to enterococci isolated from hospitalized patients . Appropriate antibiotic use in serious infections can only be achieved by choosing an appropriate regimen according to antibiotic susceptibility tests . Periodic evaluation of the antibiotic susceptibility patterns of enterococci is necessary for the empirical treatment of infections due to these microorganisms.

Microbiology, 2000 Jun, 146 ( Pt 6), 1481 - 9
Characterization of transposon Tn1549, conferring VanB-type resistance in Enterococcus spp; Garnier F et al.; Transfer of VanB-type resistance to glycopeptides among enterococci has been reported to be associated with the movement of large chromosomal genetic elements or of plasmids . The authors report the characterization of the 34 kb transposon Tn1549 borne by a plasmid related to pAD1 and conferring vancomycin resistance in clinical isolates of Enterococcus spp . Tn1549 contained 30 ORFs and appeared to be organized like the Tn916 family of conjugative transposons into three functional regions: (i) the right end, implicated in the excision-integration process; (ii) the central part, in which the vanB2 operon replaces the tet(M) gene; and (iii) the left extremity, in which eight of the 18 ORFs could be implicated in the conjugative transfer.

Microbiology, 2000 Jun, 146 ( Pt 6), 1469 - 79
Genetic linkage of the vanB2 gene cluster to Tn5382 in vancomycin-resistant enterococci and characterization of two novel insertion sequences; Dahl KH et al.; VanB-type vancomycin resistance is encoded by the vanB gene cluster, which disseminates by horizontal gene transfer and clonal spread of vancomycin-resistant enterococci (VRE) . Genetic linkage of the vanB gene cluster to transposon Tn5382 and the insertion sequences IS16 and IS256-like has previously been shown . In this study linkage of defined vanB gene cluster subtypes to these elements was examined . All the vanB2 subtype strains studied (n=14) revealed co-hybridization of vanB and Tn5382, whereas the strains of vanB1 (n=8) and vanB3 (n=1) subtypes were Tn5382 negative . Conjugative cotransfer of the vanB2 gene cluster and Tn5382 was demonstrated for two strains . DNA sequencing of the vanX(B)-ORFC region in vanB2 strains confirmed that the vanB2 gene cluster is an integral part of Tn5382 . No general pattern of linkage was observed with regard to IS16 and IS256-like . Two novel insertion sequences were identified in specific vanB2 subtype strains . (i) A 1611 bp element (ISEnfa110) was detected in the left flank of Tn5382 . Its insertion site, lack of terminal inverted and direct repeats, and two conserved motifs in its putative transposase all conform to the conventions of the IS110 family . (ii) A 787 bp element (ISEnfa200) was detected in the vanS(B)-vanY(B) intergenic region . Its ORF encoded a putative protein with 60-70% identity to transposases of the IS200 family . No further copies of ISEnfa110 were found by colony hybridization of 181 enterococcal isolates, whereas ISEnfa200 was found in four additional vanB2 strains from the USA . The five strains had identical ISEnfa200 element insertion sites, and Tn5382 was located downstream from a pbp5 gene conferring high-level ampicillin resistance . These isolates showed related PFGE patterns, suggesting possible clonal spread of a VRE strain harbouring a Tn5382-vanB2-ISEnfa200 element linked to a pbp5 gene conferring ampicillin resistance.

J Infect, 2000 Mar, 40(2), 145 - 9
Nosocomial enterococcal infections in children; Singh-Naz N et al.; OBJECTIVES: To identify factors that are associated with an increased risk of nosocomial enterococcal infection in children . METHODS: A matched case-control study was conducted between January 1989 and July 1993 at the Children's National Medical Center, Washington DC . One control patient for each case was identified . Control patients did not have nosocomial enterococcal infections and were matched with cases on the basis of age and time of admission closest to the case within a three-month period . Data were collected from systematic review of patient medical records . One hundred and one study patients (cases) were matched with 101 control patients . A case was defined as a patient with enterococcal infection who met the Centers for Disease Control and Prevention criteria for nosocomial infection . Microbiology methods included isolation, identification, and antimicrobial susceptibility testing of enterococci from clinical specimens . RESULTS: Risk factors associated with nosocomial enterococcal infections were determined by multiple conditional logistic regression analyses of the cases and controls . Factors identified were placement of a central line, gastrointestinal tract pathology, and administration of multiple antimicrobial agents . The median duration of antimicrobial therapy prior to diagnosis of nosocomial enterococcal infection was approximately 1 week . CONCLUSION: The incidence of nosocomial enterococcal infections in children may be controlled by limiting the number of antimicrobial agents administered to hospitalized high risk patients . The importance of our findings is relevant in an era of increasing rates of antimicrobial resistance in nosocomial enterococcal infections.

J Clin Microbiol, 2000 Jun, 38(6), 2409 - 11
Limitations of vitek GPS-418 cards in exact detection of vancomycin-resistant enterococci with the vanB genotype; Okabe T et al.; The susceptibilities of 20 strains of vancomycin-resistant enterococci (VRE) with the vanB genotype obtained by using Vitek GPS-418 cards were compared with those obtained by the broth dilution method of the National Committee for Clinical Laboratory Standards (NCCLS) (approved standard M7-A4) and with those obtained by the agar screen method using bile esculin azide agar containing 6 microgram of vancomycin per ml . Although both the broth dilution and agar screen methods disclosed no discordance, Vitek GPS-418 cards yielded a very major error compared with the results obtained by the reference broth dilution method of the NCCLS . Vitek GPS-418 cards were therefore found to have considerable room for improvement for the accurate detection of vanB VRE strains.

J Clin Microbiol, 2000 Jun, 38(6), 2392 - 4
Molecular characterization of the vanD gene cluster and a novel insertion element in a vancomycin-resistant enterococcus isolated in Canada; Boyd DA et al.; A single vanD-containing Enterococcus faecium strain (N97-330) was isolated in Canada . The vanD-containing region was cloned and sequenced . Although the proteins have more than 96% identity to a previously described vanD region in BM4339, the vanS(D) gene contains a frameshift mutation that leads to a predicted truncated protein . Furthermore, sequence analysis of the ddl gene revealed the presence of an IS982-like element (ISEfm1) which interrupted the D-Ala-D-Ala ligase . This suggested the constitutive expression of the vanD operon, which was confirmed . Pulsed-field gel electrophoresis fingerprinting demonstrated that BM4339 was not related to N97-330 (>15 band differences) . Both strains contained multiple copies of the IS982-like element.

Eur J Clin Microbiol Infect Dis, 2000 Apr, 19(4), 282 - 7
Prospective surveillance of vancomycin-resistant enterococci in a neonatal intensive care unit; Toledano H et al.; A point-prevalence study of vancomycin-resistant enterococci colonization of the gastrointestinal tract in an Israeli hospital revealed that 14.7% of the 320 inpatients were colonized . Vancomycin-resistant enterococci colonization was detected in most departments except the neonatal intensive care unit . Hence, a prospective longitudinal study of the prevalence of vancomycin-resistant enterococci colonization in the neonatal intensive care unit was conducted . A rectal swab was obtained from every newborn on admission to the neonatal intensive care unit and once weekly thereafter until the patient was discharged . Enterococci were isolated and tested for susceptibility to vancomycin . A total of 84 neonates were enrolled and monitored on average for 3 weeks (SD +/- 3.9, range 1-20 weeks) . Mean gestational age was 35.7 weeks (SD +/- 3.9, range 25-42 weeks), and mean birth weight was 2.4 kg (SD +/- 0.9, range 0.45-4.1 kg) . Most patients had one or more of the known risk factors associated with colonization with vancomycin-resistant enterococci . Eighty percent of the patients received antibiotics during the study, and 14.3% received vancomycin . The median duration of vancomycin treatment was 12.5 days (SD +/- 16.8, range 5-55 days) . Fifty-one of 84 (61%) patients acquired enterococci sensitive to vancomycin during the study period, but no newborn had vancomycin-resistant enterococci . Possible explanations for this finding may be physical isolation of the neonatal intensive care unit from the rest of the hospital, intrinsic differences in the bowel milieu of this age group and the lack of exposure to food and other environmental sources of vancomycin-resistant enterococci from the community.

J Hosp Infect, 2000 May, 45(1), 11 - 8
Experience of vancomycin-resistant enterococci in a children's hospital; Gray JW et al.; Vancomycin resistant enterococci (VRE) are increasingly important nosocomial pathogens . This paper describes our experience of the epidemiology and clinical impact of VRE in the two years since the occurrence of our first case of VRE infection . Following introduction of surveillance, gastrointestinal colonization with VRE was detected in 38.3% of Haematology/Oncology and 11.1% of Hepatology/Gastroenterology patients, but in only 2.3% of children in the Paediatric Intensive Care and 1.5% of children in the Renal Unit . Only five patients with gastrointestinal colonization subsequently developed clinical infection with VRE, giving an annual incidence of 7.5% . A further six children were colonized at extra-intestinal sites . Twelve children had clinical infections with VRE, of whom three (25%) died . Contamination of bedspaces was found in association with 2/3 (66.7%) children with extraintestinal colonization and 5/7 (71.4%) children with clinical infections, compared with 6/28 (21.4%) cases of gastrointestinal colonization . In the latter group, bedspace contamination was usually associated with widespread contamination of the ward with VRE and may have been the cause rather than the result of patients acquiring VRE . Originally we employed control measures based closely on the North American HICPAC guidelines, but our control strategy has since evolved in response to epidemiological and clinical observations .

Curr Med Chem, 2000 Aug, 7(8), 801 - 20
Inhibition of transglycosylation involved in bacterial peptidoglycan synthesis; Goldman RC et al.; The continuing spectre of resistance to antimicrobial agents has driven a sustained search for new agents that possess activity on drug resistant bacteria . Although several paths are available to reach this goal, the most generalized would be the discovery and clinical development of an agent that acts on a new target which has not yet experienced selective pressure in the clinical setting . Such a target should be essential to the growth and survival of bacteria, and sufficiently different from, or better still non-existent in, the human host . The transglycosylation reaction that polymerizes biochemical intermediates into peptidoglycan qualifies as such a target . This biochemical system accepts the basic unit N-acetylglucosamine-beta-1, 4-N-acetyl-muramyl-pentapeptide-pyrophosphoryl-undecaprenol (lipid II), and leads to polymerization of the N-acetylglucosamine -beta-1, 4-N-acetyl-muramyl-pentapeptide segment into peptidoglycan . Approaches to targeting this reaction include modification of known glycolipid and glycopeptide natural product antibiotics . The synthesis and antibacterial activity of synthetic analogs of moenomycin having novel antibacterial activities not present in the parent structure will be presented, together with the combinatorial chemistry and assay systems leading to their discovery . Likewise, we will discuss chemical modifications to specific glycopeptide antibiotics that have extended their spectrum to include vancomycin resistant enterococci that substitute D-alanyl-D-lactate for D-alanyl-D-alanine in their peptidoglycan . Two differing theories, one positing the generation of high affinity, specific binding to D-alanyl-D-lactate via glycopeptide dimerization and/or membrane anchoring, and the other supporting direct targeting of the modified glycopeptide to the transglycosylation complex, seek to explain the mechanism of action on vancomycin resistant enterococci . Biochemical evidence in support of these two theories will be discussed.

J Infect Dis, 2000 May, 181(5), 1830 - 3 Epub 2000 May 15.
Effect of parenteral antibiotic administration on the establishment of colonization with vancomycin-resistant Enterococcus faecium in the mouse gastrointestinal tract; Donskey CJ et al.; A mouse model of intestinal colonization with vancomycin-resistant enterococci (VRE) was used to study the effect of different beta-lactam antibiotics on establishment of VRE colonization . A clinical VanB VRE isolate, Enterococcus faecium C68 (102 or 104 cfu), was inoculated by gastric gavage in conjunction with subcutaneous administration of antibiotics . The MIC of ceftriaxone and ticarcillin against VRE strain C68 is >10,000 microg/mL, and the MIC of piperacillin is 1250 microg/mL . Ceftriaxone and ticarcillin-clavulanate treatment groups developed persistently high levels of stool VRE compared with both the saline and the piperacillin-tazobactam (Pip-Taz) groups (P<.008) . The level of stool VRE in the Pip-Taz group did not differ from that for the saline group . Thus, in this mouse model, beta-lactam antibiotics with minimal anti-enterococcal activity promoted establishment of high-level VRE colonization, but Pip-Taz (a beta-lactam antibiotic with more potent activity against VRE) did not.

J Antibiot (Tokyo), 2000 Mar, 53(3), 286 - 93
Structure-activity relationships in the series of eremomycin carboxamides; Miroshnikova OV et al.; A series of new carboxamides of the glycopeptide antibiotic eremomycin was synthesized and investigated in vitro . The goal of the study was the comparison of the influence of the substituents introduced onto the eremomycin skeleton on the activity of these compounds against vancomycin susceptible and resistant bacterial strains . Eremomycin amides derived from amines with small substituents (C0 approximately C4) demonstrated antibacterial activity against vancomycin susceptible strains similar to that of the parent antibiotic and were inactive against vancomycin resistant strains . The derivatives of alkylamines with linear lipophilic substituents (like C10H21) were active against VanA and VanB enterococci strains with the scope of activity similar to that of N'-decyl or 7d-CH2NH-decyl eremomycins described earlier . Eremomycin amides of 5-methoxy- and 5-benzyloxytryptamine were active both against vancomycin susceptible and resistant strains . The introduction of a spacer (lysine or piperazine) between the decyl and antibiotic moieties did not seriously influence antibacterial properties of the compounds in comparison with the corresponding derivatives without a spacer . The most active carboxamides are of interest for secondary modifications of the antibiotic.

Antimicrob Agents Chemother, 2000 Jun, 44(6), 1660 - 6
vanC cluster of vancomycin-resistant Enterococcus gallinarum BM4174; Arias CA et al.; Glycopeptide-resistant enterococci of the VanC type synthesize UDP-muramyl-pentapeptide{D-Ser} for cell wall assembly and prevent synthesis of peptidoglycan precursors ending in D-Ala . The vanC cluster of Enterococcus gallinarum BM4174 consists of five genes: vanC-1, vanXY(C), vanT, vanR(C), and vanS(C) . Three genes are sufficient for resistance: vanC-1 encodes a ligase that synthesizes the dipeptide D-Ala-D-Ser for addition to UDP-MurNAc-tripeptide, vanXY(C) encodes a D,D-dipeptidase-carboxypeptidase that hydrolyzes D-Ala-D-Ala and removes D-Ala from UDP-MurNAc-pentapeptide{D-Ala}, and vanT encodes a membrane-bound serine racemase that provides D-Ser for the synthetic pathway . The three genes are clustered: the start codons of vanXY(C) and vanT overlap the termination codons of vanC-1 and vanXY(C), respectively . Two genes which encode proteins with homology to the VanS-VanR two-component regulatory system were present downstream from the resistance genes . The predicted amino acid sequence of VanR(C) exhibited 50% identity to VanR and 33% identity to VanR(B) . VanS(C) had 40% identity to VanS over a region of 308 amino acids and 24% identity to VanS(B) over a region of 285 amino acids . All residues with important functions in response regulators and histidine kinases were conserved in VanR(C) and VanS(C), respectively . Induction experiments based on the determination of D,D-carboxypeptidase activity in cytoplasmic extracts confirmed that the genes were expressed constitutively . Using a promoter-probing vector, regions upstream from the resistance and regulatory genes were identified that have promoter activity.

Rinsho Byori, 2000 Jan, Suppl 111, 94 - 9
{Gene examination methods (detection and genotyping of resistant genes)--VRE}; Hitomi S; There are six types of resistant genes in vancomycin-resistant enterococci: vanA, vanB, vanC-1, vanC-2, vanC-3, and vanD . The typing of the resistant genes is essential in clinical settings because the kind of a resistant gene implies susceptibility of an organism to glycopeptides and because strict infection control practices are required when vanA or vanB gene, which is encoded on plasmids and transmissible to other organisms, is detected . We describe methods of detecting and typing vancomycin-resistant genes, which are routinely performed in our laboratory.

Rinsho Byori, 2000 Jan, Suppl 111, 56 - 63
{Detection methods for drug-resistant bacteria in routine examination--VRE}; Kawakami S et al.; When testing vancomycin susceptibility against enterococci, plates should be held a full 24 hours then examined using transmitted light . The presence of a haze or any growth within the zone of inhibition indicates resistance . Perform vancomycin MIC and tests for motility and pigment production to distinguish species with acquired resistance(vanA and vanB) from those with intrinsic, intermediate-level resistance to vancomycin(vanC) such as E . gallinarum, E . casseliflavus or E . flavescens.

Med Dosw Mikrobiol, 1999, 51(3-4), 249 - 57
{Hydroxamate siderophores in enterococci}; Lisiecki P et al.; In 70 enterococcal strains of diverse origin belonging to 16 species a hydrooxamate class siderophore was detected with chemical and biological tests . A correlation between hydrooxamate siderophore production, species affilIation and pathogenicity of enterococci was not found.

Chem Biol, 2000 May, 7(5), R109 - 19
Vancomycin resistance in enterococci: reprogramming of the D-ala-D-Ala ligases in bacterial peptidoglycan biosynthesis; Healy VL et al.; Vancomycin binds to bacterial cell-wall intermediates to achieve its antibiotic effect . Infections of vancomycin-resistant enterococci are, however, becoming an increasing problem; the bacteria are resistant because they synthesize different cell-wall intermediates . The enzymes involved in cell-wall biosynthesis, therefore, are potential targets for combating this resistance . Recent biochemical and crystallographic results are providing mechanistic and structural details about some of these targets.

J Antimicrob Chemother, 2000 May, 45(5), 677 - 80
Characterization of vancomycin-resistant and vancomycin-susceptible Enterococcus faecium isolates from humans, chickens and pigs by RiboPrinting and pulsed-field gel electrophoresis; Hammerum AM et al.; Forty-eight vancomycin-resistant and 35 vancomycin-sensitive Danish Enterococcus faecium isolates obtained from pigs, chickens and humans, as well as the human vanA reference isolate BM4147, were characterized by EcoRI RiboPrinting and SmaI pulsed-field gel electrophoresis . RiboPrinting of the 84 isolates yielded 40 types whereas PFGE-typing yielded 57 types discriminated by differences in more than three bands . By molecular typing, both clonal spread of E . faecium as well as horizontal transmission of Tn1546 between animals and humans was supported . Furthermore, it was found that the population of E . faecium spreads freely between the animal and human reservoir.

J Pak Med Assoc, 2000 Mar, 50(3), 91 - 4
Neonatal sepsis: an etiological study; Anwer SK et al.; OBJECTIVE: A periodic review of neonatal sepsis to asses any change in the infecting organism . METHOD: A prospective study was conducted at HMC and ASH, Karachi . The babies suspected to have or developed sepsis any time during hospitalization were investigated to establish the diagnosis and isolate the causative organism . Blood culture was taken at the time of admission or when sepsis was suspected . RESULTS: Out of 109 episodes of blood culture proven sepsis 68 presented as early onset (within 48 hours of birth) and 41 as late onset sepsis (after 48 hours of birth) . In early onset group Gram -ve and Gram +ve organisms were almost equal, i.e . 33 and 35 respectively . Among the gram -ve organism most of the cases were due to Klebsiella sp, and Enterococcus was the commonest Gram +ve organism . In late onset group majority of infections were due to gram +ve organisms, i.e . 30 out of 41 . Staph . aureus and Staph . epidermidis were commonest . The organisms were least sensitive to Ampicillin (< 20%) and highly sensitive to Amikacin (90% to 100%), Cefotaxime was also seen as a good choice of antibiotic with sensitivity of (84%-89%) . CONCLUSION: Gram +ve organisms were the main cause of neonatal sepsis . Klebsiella sp . is still the commonest organism causing early onset sepsis . The data must be periodically reviewed and antibiotic policy revised accordingly.

Int J Antimicrob Agents, 2000 May, 14(4), 337 - 42
Epidemiology and ecology of enterococci, with special reference to antibiotic resistant strains, in animals, humans and the environment . Example of an ongoing project within the European research programme; Kuhn I et al.; The objectives of the present study are to generate knowledge of the ecology and epidemiology of enterococci in the food chain by studying the following: (1) the population structure (in measures of abundance, number of vancomycin resistant strains, antibiotic resistance patterns, diversity, and stability) among enterococcal populations in different geographical regions and in different links of the food chain (2) possible transmission of strains through the food chain and between hospital environments and the food chain (3) the association between vancomycin resistance and individual strains of enterococci and (4) the diversity of the drug resistance genes in enterococci . So far, 1578 samples have been collected from different countries within the EU (Sweden, Denmark, UK and Spain), and from different habitats (pig farms, carcasses in slaughter houses, soil, manure, water, sewage, and humans) . Total and vancomycin resistant enterococcal populations in each sample have been enumerated and more than 12000 isolates have been characterised by phenotyping . Representative isolates are further species identified and characterised by genotyping and MIC determination and from antibiotic resistant isolates the resistance genes are characterised.

Diagn Microbiol Infect Dis, 2000 May, 37(1), 45 - 50
CPT-EIA assays for the detection of vancomycin resistant vanA and vanB genes in enterococci; Modrusan Z et al.; Cycling Probe Technology (CPT) was combined with a colorimetric enzyme-immuno assay (EIA) to develop two assays for the detection of vanA and vanB genes in vancomycin resistant enterococci (VRE) . The CPT-EIA assay employs a gene-specific fluorescein labeled DNA-RNA-DNA probe that gets cleaved within the probe : target duplex . The cleaved DNA probe fragments dissociate from the target, making it available for further cycling . Following the separation of cleaved probe fragments, anti-fluorescein-horseradish peroxidase antibodies are used for the detection of uncleaved probes . The two CPT-EIA assays were used to screen a collection of 440 clinical isolates (Modrusan et al., 1999) . All of the 154 VanA and 131 VanB isolates were correctly identified in the vanA and vanB CPT-EIA, respectively . The VanA and VanB isolates were differentiated from vancomycin sensitive enterococci (VSE) and also from the VanC isolates . In addition, an accurate VRE detection in the CPT-EIA assay was shown with cultures grown on eight different media.

J Biol Chem, 2000 May 5, 275(18), 13415 - 9
Na+ binding of V-type Na+-ATPase in Enterococcus hirae; Murata T et al.; Rotation catalysis theory has been successfully applied to the molecular mechanism of the ATP synthase (F(0)F(1)-ATPase) and probably of the vacuolar ATPase . We investigated the ion binding step to Enterococcus hirae Na(+)-translocating V-ATPase . The kinetics of Na(+) binding to purified V-ATPase suggested 6 +/- 1 Na(+) bound/enzyme molecule, with a single high affinity (K(d(Na(+()))) = 15 +/- 5 micrometer) . The number of cation binding sites is consistent with the model that V-ATPase proteolipids form a rotor ring consisting of hexamers, each having one cation binding site . Release of the bound (22)Na(+) from purified molecules in a chasing experiment showed two phases: a fast component (about two-thirds of the total amount of bound Na(+); k(exchange) > 1.7 min(-1)) and a slow component (about one-third of the total; k(exchange) = 0.16 min(-1)), which changes to the fast component by adding ATP or ATPgammaS . This suggested that about two-thirds of the Na(+) binding sites of the Na(+)-ATPase are readily accessible from the aqueous phase and that the slow component is important for the transport reaction.

Pediatr Surg Int, 2000, 16(3), 169 - 73
The effects of intravenous epidermal growth factor on bacterial translocation and central venous catheter infection in the rat total parenteral nutrition model; McAndrew HF et al.; Sepsis is a major complication of total parenteral nutrition (TPN) in children . Gut mucosal atrophy (GMA) and bacterial translocation (BT) occur in patients receiving TPN, and the translocated enteric organisms may cause central venous catheter (CVC) infection . Epidermal growth factor (EGF) has a trophic effect on the gut mucosa and may reduce BT, thereby reducing catheter infection . Using a rat TPN model, the relationship between GMA, BT, and catheter sepsis was examined and the effect on these of intravenous EGF was studied . There were four experimental groups . Group 1 had no CVC, Groups 2, 3, and 4 had a continuous central venous infusion as follows: group 2, saline; group 3, TPN; group 4, TPN with EGF . Groups 1 and 2 had free access to chow, groups 3 and 4 had no enteral feeds . After killing at 1 week, blood, tissue, and catheter specimens were cultured and mucosal morphology analysed . BT was defined as the presence of the same organism in cultures from the gut lumen and mesenteric lymph nodes (MLN) . TPN only (group 3) resulted in GMA and BT, and 5 of 12 animals with BT had the same gut bacteria in blood and/or catheter cultures . The addition of EGF to the TPN significantly reduced GMA, BT to the MLN, and blood and/or catheter infections (P = <0.05) . In animals carrying enterococci, there was a significant reduction in translocation of enterococci (group 3: 8/14; group 4: 0/11; P<0.05) and catheter infection by enterococci was prevented (group 3: 3/14; group 4: 0/11) . EGF thus reduced GMA, BT, and blood and/or catheter infection when given IV to rats receiving TPN . Enterococcal translocation and subsequent blood and/or catheter infection was completely prevented, suggesting a selective effect of EGF.

J Trauma, 2000 Apr, 48(4), 783 - 5
Vancomycin-dependent enterococcal strains: case report and review; Yowler CJ et al.; We report, to our knowledge, the first isolation of VDE from a burn unit . Our experience was similar to earlier reports, in that continuous administration of vancomycin and previous VRE isolation preceded the recovery of VDE . Given the increasing prevalence of VRE as a nosocomial pathogen, intensive care units must now be attuned to the emergence of VDE as serious pathogen.

Int J Food Microbiol, 2000 Mar 25, 54(3), 181 - 7
In vitro susceptibility of Enterococcus faecium isolated from food to growth-promoting and therapeutic antibiotics; Butaye P et al.; A total of 76 E . faecium strains, isolated at retail level from raw poultry meat, cheese, raw pork, and preparations of cheese and raw pork, were tested for their susceptibility and resistance to growth-promoting antibacterials used in animals and antibiotics used therapeutically in humans . All strains were uniformly susceptible to the growth promoters bambermycin and avilamycin . Resistance against bacitracin, virginiamycin and narasin was high among strains from poultry meat . With tylosin, a macrolide antibiotic used therapeutically and for growth promotion, resistance was mainly detected in strains originating from poultry meat, though also in some strains from pork and from pork and cheese preparations . The therapeutic antibiotic dalfopristin/quinupristin did not show full cross-resistance with the growth-promoting antibiotic virginiamycin . With dalfopristin/quinupristin two different levels of resistance were found . Only one E . faecium strain isolated from poultry was resistant to the glycopeptides avoparcin and vancomycin . Only one poultry meat strain was highly resistant to ampicillin . However, nearly all poultry meat strains showed decreased sensitivity . Only 3 out of 24 poultry strains were susceptible to minocycline, while all strains from other origins were susceptible to this tetracycline antibiotic . High-level streptomycin resistance was seen in strains of all origins, though infrequently . High-level gentamicin resistance was not found.

J Hosp Infect, 2000 Apr, 44(4), 294 - 300
Control of an outbreak of vancomycin-resistant Enterococcus faecium in an oncology ward in South Africa: effective use of limited resources; McCarthy KM et al.; An outbreak of vancomycin-resistant enterococci (VRE) occurred in an adult oncology ward of a large teaching hospital in Johannesburg, South Africa . The outbreak strain was identified as an Enterococcus faecium carrying the vanA resistance genotype . Macro-restriction analysis showed that the majority of strains were clonally related . Modified infection control interventions were implemented and control of the outbreak was achieved . Although the epidemiology of VRE is well documented in Europe, North America and Australia, this problem has only recently emerged in South Africa . The epidemiology of the outbreak appears similar to that described for outbreaks elsewhere .

Acta Crystallogr D Biol Crystallogr, 2000 May, 56 ( Pt 5), 640 - 2
Expression, purification and crystallization of enterococcus faecium streptogramin A acetyltransferase; Sugantino M et al.; The streptogramin A acetyltransferase from Enterococcus faecium (SWISS-PROT P50870) has been overexpressed in Escherichia coli, purified and crystallized . Crystallization conditions were screened using the hanging-drop vapor-diffusion method and resulted in two distinct crystal forms . Form I crystals diffract to 2.5 A and belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 68.6, b = 102.6, c = 107.5 A . Form II crystals diffract to 2.7 A and belong to space group F222, with unit-cell parameters a = 185.8, b = 185.8, c = 186.5 A . Rotation-function and packing analyses for both crystal forms indicate that the asymmetric unit may contain one and two copies of the trimeric enzyme for crystal forms I and II, respectively.

Antimicrob Agents Chemother, 2000 May, 44(5), 1362 - 4
Effects of the movement of insertion sequences on the structure of VanA glycopeptide resistance elements in Enterococcus faecium; Darini AL et al.; A Tn1546-related element with IS1216V at position 8839 underwent a structural change after storage of the host strain of Enterococcus faecium at 4 degrees C . The element acquired IS1542 at position 3932, nucleotides 8732 to 8831 were deleted, and the first 3417 nucleotides were lost and replaced by an inverted copy of the IS1216V-vanY-vanZ-inverted-repeat block from the 3' end . Insertion sequence movement is likely to play a key role in the evolution of VanA resistance elements.

Antimicrob Agents Chemother, 2000 May, 44(5), 1349 - 51
Geographic distribution of a large mobile element that transfers ampicillin and vancomycin resistance between Enterococcus faecium strains; Hanrahan J et al.; In several clonally unrelated VanB-type vancomycin-resistant Enterococcus faecium strains, we demonstrated a common physical relationship between pbp5 and Tn5382 as well as common mutations within pbp5 . The majority of these strains transferred vancomycin and ampicillin resistance to E . faecium in vitro, suggesting the dissemination of similar transferable pbp5-vanB-containing mobile elements throughout the United States.

Antimicrob Agents Chemother, 2000 May, 44(5), 1346 - 8
Glycopeptide-resistant Enterococcus faecium BM4416 is a VanD-type strain with an impaired D-Alanine:D-Alanine ligase; Perichon B et al.; VanD-type Enterococcus faecium BM4416 was constitutively resistant to vancomycin and to teicoplanin by synthesis of peptidoglycan precursors ending in D-alanyl-D-lactate . Like E . faecium BM4339, the only VanD-type strain described so far, BM4416 produced an impaired D-alanine:D-alanine ligase . Unlike for BM4339, which had a 5-bp insertion in ddl, inactivation of the gene in BM4416 was due to insertion of IS19.

J Bacteriol, 2000 May, 182(9), 2507 - 12
Evidence for Na(+) influx via the NtpJ protein of the KtrII K(+) uptake system in Enterococcus hirae; Kawano M et al.; The ntpJ gene, a cistron located at the tail end of the vacuolar-type Na(+)-ATPase (ntp) operon of Enterococcus hirae, encodes a transporter of the KtrII K(+) uptake system . We found that K(+) accumulation in the ntpJ-disrupted mutant JEM2 was markedly enhanced by addition of valinomycin at pH 10 . Studies of the membrane potential (DeltaPsi; inside negative) by 3, 3'-dihexyloxacarbocyanine iodide fluorescence revealed that the DeltaPsi was hyperpolarized at pH 10 in JEM2; the DeltaPsi values of the parent strain ATCC 9790 and JEM2, estimated by determining the equilibrium distribution of K(+) or Rb(+) in the presence of valinomycin, were -118 and -160 mV, respectively . DeltaPsi generation at pH 10 was accomplished by an electrogenic Na(+) efflux via the Na(+)-ATPase, whose levels in the two strains were quite similar . Na(+) uptake driven by an artificially imposed DeltaPsi (inside negative) was missing in JEM2, suggesting that NtpJ mediates Na(+) movement in addition to K(+) movement . Finally, the growth of JEM2 arrested in K(+)-limited high-Na(+) medium at pH 10 was restored by addition of valinomycin . These results suggest that NtpJ mediates electrogenic transport of K(+) as well as Na(+), that it likely mediates K(+) and Na(+) cotransport, and that Na(+) movement via NtpJ is the major Na(+) reentry pathway at high pH values.

FEMS Microbiol Lett, 2000 Apr 15, 185(2), 247 - 54
Amino acid substitutions in the VanS sensor of the VanA-type vancomycin-resistant Enterococcus strains result in high-level vancomycin resistance and low-level teicoplanin resistance; Hashimoto Y et al.; The vancomycin-resistant enterococci GV1, GV2 and GV3, which were isolated from droppings from broiler farms in Japan have been characterized as VanA-type VRE, which express high-level vancomycin resistance (256 or 512 microg ml(-1), MIC) and low-level teicoplanin resistance (1 or 2 microg ml(-1), MIC) . The vancomycin resistances were encoded on plasmids . The vancomycin resistance conjugative plasmid pMG2 was isolated from the GV2 strain . The VanA determinant of pMG2 showed the same genetic organization as that of the VanA genes encoded on the representative transposon Tn1546, which comprises vanRSHAXYZ . The nucleotide sequences of all the genes, except the gene related to the vanS gene on Tn1546, were completely identical to the genes encoded on Tn1546 . Three amino acid substitutions in the N-terminal region of the deduced VanS were detected in the nucleotide sequence of vanS encoded on pMG2 . There were also three amino acid substitutions in the vanS gene of the GV1 and GV3 strains in the same positions as in the vanS gene of pMG2 . Vancomycin induced the increased teicoplanin resistance in these strains.

Pediatr Infect Dis J, 2000 Mar, 19(3), 234 - 8
Experience with quinupristin/dalfopristin in treating infections with vancomycin-resistant Enterococcus faecium in children; Gray JW et al.; BACKGROUND: The emergence and spread of vancomycin-resistant Enterococcus faecium (VREF) has presented serious therapeutic difficulties because of the lack of reliably active antibiotics . Quinupristin/dalfopristin is a new injectable streptogramin antibiotic that is active against most strains of VREF . Experience with this agent in adults with VREF infections is well-documented; however, there are few reports of its use in children . We report on eight children with VREF infections who received quinupristin/dalfopristin under a compassionate use protocol . METHODS: Quinupristin/dalfopristin was administered according to the manufacturer's recommendations . Clinical and laboratory data were recorded for each patient . RESULTS: The infections treated comprised six cases of bacteremia and two of peritonitis . All patients had serious underlying conditions . Seven patients recovered fully . One patient died, having experienced a relapse of his infection after quinupristin/dalfopristin was discontinued . None of the patients experienced side effects or other adverse events . CONCLUSION: Quinupristin/dalfopristin was well-tolerated and generally effective in children with infections caused by VREF . There is increasing evidence that it may be more effective than other currently available antibiotics in some such patients.

J Biol Chem, 2000 Jun 2, 275(22), 16490 - 6
Novel mechanism of beta-lactam resistance due to bypass of DD-transpeptidation in Enterococcus faecium; Mainardi JL et al.; The peptidoglycan structure of in vitro selected ampicillin-resistant mutant Enterococcus faecium D344M512 and of the susceptible parental strain D344S was determined by reverse phase high performance liquid chromatography and mass spectrometry . The muropeptide monomers were almost identical in the two strains . The substantial majority (99.3%) of the oligomers from the susceptible strain D344S contained the usual d-alanyl --> d-asparaginyl (or d-aspartyl)-l-lysyl cross-link (d-Ala --> d-Asx-l-Lys) generated by beta-lactam-sensitive DD-transpeptidation . The remaining oligomers (0.7%) were produced by beta-lactam-insensitive LD-transpeptidation, because they contained l-Lys --> d-Asx-l-Lys cross-links . The muropeptide oligomers of the ampicillin-resistant mutant D344M512 contained only these l-Lys --> d-Asx-l-Lys cross-links indicating that resistance was due to the bypass of the beta-lactam-sensitive DD-transpeptidation reaction . The discovery of this novel resistance mechanism indicates that DD-transpeptidases cannot be considered anymore as the sole essential transpeptidase enzymes.

Diagn Microbiol Infect Dis, 2000 Mar, 36(3), 145 - 58
A nationwide, multicenter, case-control study comparing risk factors, treatment, and outcome for vancomycin-resistant and -susceptible enterococcal bacteremia; Bhavnani SM et al.; National Nosocomial Resistance Surveillance Group participants from 22 hospitals across the United States reviewed medical records for hospitalized patients with vancomycin-resistant enterococcal (VRE) or vancomycin-susceptible enterococcal (VSE) bacteremia to identify risk factors associated with the acquisition of VRE bacteremia, describe genetic traits of VRE strains, and identify factors predictive of clinical outcome . VRE cases were matched to VSE controls within each institution . Multiple logistic regression (LR) and classification and regression tree (CART) analysis were used to probe for factors associated with VRE bacteremia and clinical outcome . A total of 150 matched-pairs of VRE cases and VSE controls were collected from 1995 to 1997 . Using LR, the following were found to be highly associated with VRE bacteremia: history of AIDS, positive HIV status, or drug abuse (OR 9.58); prior exposure with parenteral vancomycin (OR 8.37); and liver transplant history (OR 6 . 75) . CART analysis revealed that isolation of Enterococcus faecium, prior vancomycin exposure, and serum creatinine values > or = 1.1 mg/dl were predictors of VRE bacteremia . Greater proportions of clinical failure (60% versus 40%, P < 0.001) and all-cause mortality (52% versus 27%, P < 0.001) were seen in patients with VRE versus VSE bacteremia . Results from both LR and CART indicated that patients with persisting enterococcal bacteremia, intubation at baseline, higher APACHE II scores, and VRE bacteremia were at greater risk for poor outcome.

Clin Infect Dis, 2000 Mar, 30(3), 466 - 72
Association between resistance to vancomycin and death in cases of Enterococcus faecium bacteremia; Garbutt JM et al.; We conducted a retrospective cohort study to determine the association between resistance to vancomycin and mortality among hospitalized patients with Enterococcus faecium bacteremia . We compared outcomes for patients infected with vancomycin-resistant versus vancomycin-susceptible E . faecium among 69 patients with bacteremia defined according to the National Nosocomial Infections Surveillance system . The univariate odds ratio (OR) for death associated with vancomycin resistance was 2.1 (P=.172) . After controlling for severity of illness, we found that vancomycin resistance was not associated with mortality (OR, 1.74; 95% confidence interval, 0.5-6.12; P=.39) . Vancomycin resistance does not independently increase mortality among patients with E . faecium bacteremia.

Epidemiol Infect, 2000 Feb, 124(1), 53 - 9
Eradication of vancomycin resistant Enterococcus faecium from a paediatric oncology unit and prevalence of colonization in hospitalized and community-based children; Nourse C et al.; We previously reported an outbreak of vancomycin resistant enterococci (VRE) in a paediatric oncology unit in December 1995 which was associated with widespread environmental contamination of the unit with VRE . We undertook this study to evaluate the effectiveness of the infection control policy instituted subsequent to the outbreak and to investigate the underlying prevalence of VRE colonization in hospitalized, outpatient and community-based children . We sought to establish the molecular similarity of VRE isolates from the study . Stool specimens were obtained from outpatients at risk of VRE, hospital inpatients and from healthy community-based children . VRE colonization was eradicated from the inpatient unit within 11 months, but in outpatients, 16 months after the outbreak, 4 of 137 (2.9 %) attending oncology outpatients, 5 of 65 (7.7%) with cystic fibrosis and 1 of 12 (8.3 %) with liver disease were found to be colonized with VRE . The isolates were all Enterococcus faecium, Van A phenotype except one E . casseliflavus of the Van C phenotype . All were unique in SmaI DNA macrorestriction patterns with the exception of two isolates, which were similar to the original outbreak strain and three further isolates of a single strain but which differed from the outbreak strain . Of 315 hospital inpatients, 2.5 % were colonized with VRE of the Van C resistance phenotype but VRE was not detected in 116 healthy, community-based children . We conclude that effective strategies can successfully control spread of VRE but despite a low prevalence of VRE colonization in hospital patients and in community-based children, outbreaks can occur when infection control practices are not optimal . Continued vigilance to detect VRE and limit spread within hospitals is therefore necessary.

J Clin Oncol, 2000 Mar, 18(6), 1269 - 78
Prevention of central venous catheter-related infections and thrombotic events in immunocompromised children by the use of vancomycin/ciprofloxacin/heparin flush solution: A randomized, multicenter, double-blind trial; Henrickson KJ et al.; PURPOSE: To determine whether an antibiotic flush solution containing vancomycin, heparin, and ciprofloxacin (VHC) can prevent the majority of line infections . PATIENTS AND METHODS: A prospective double-blind study was performed comparing VHC to vancomycin and heparin (VH) to heparin alone in 126 pediatric oncology patients . RESULTS: The 153 assessable lines resulted in 36,944 line days studied . There were 58 blood stream infections (43 gram-positive, 14 gram-negative, and one fungal) . Forty were defined as line infections (31 heparin, three VH, six VHC) . The time to develop a line infection was significantly increased using either antibiotic flush (VH, P =.011; VHC, P =.036) . The rate of total line infections (VH, P =.004; VHC, P =.005), gram-positive line infections (VH, P = . 028; VHC, P =.022), and gram-negative line infections (VH, P =.006; VHC, P =.003) was significantly reduced by either VH or VHC . Sixty-two (41%) of the lines developed 119 occlusion episodes (heparin, 3.99 per 1,000 line days; VHC, 1.75 per 1,000 line days; P =.0005) . Neither antibiotic could be detected after flushing, and no adverse events were detected, including increased incidence of vancomycin-resistant Enterococcus colonization or disease . CONCLUSION: The use of either VH or VHC flush solution significantly decreased the complications associated with the use of tunneled central venous lines in immunocompromised children and would save significant health care resources.

APMIS, 2000 Jan, 108(1), 67 - 73
Detection of vancomycin resistance genes combined with typing of Enterococci by means of multiplex PCR amplification and multiple primer DNA sequencing; Monstein HJ et al.; A multiplex PCR assay for the detection of vancomycin resistance (van) genes in enterococci was established . Primers targeting the 16S rRNA gene were included in the reaction mixture . Multiple-primer DNA sequencing of the PCR products provided species identification through partial nucleotide sequences of 16S rRNA genes, as well as confirmation of the correct identification of vanA, vanB, vanC-1, and vanC-2/3 genotypes . Thirty-nine enterococcal clinical isolates and type strains were examined for the presence of vancomycin resistance determinants . Twelve other isolates from a clinical reference collection (some of them having vanA, vanB, vanC-1, or vanC-2/3 genotypes) were used as controls . Hybridization and partial DNA sequence analysis of multiplex PCR products revealed that none of the clinical isolates had a vanA genotype and only one had a vanB genotype . vanC-1 was found in three clinical isolates, and vanC-2/3 in one . Results obtained with the reference and type strains were in agreement with earlier results.

J Endod, 1975 Nov, 1(11), 373 - 6
Antibiotic sensitivities of enterococci isolated from treated root canals; Heintz CE et al.; Enterococci that persisted in debrided, medicated root canals were tested by the Kirby-Bauer procedure for sensitivity to various antibiotics . The 50 strains tested were uniformly sensitive to ampicillin and vancomycin . More than 90% were also sensitive to erythromycin . Varying degrees of sensitivity and resistance were noted to bacitracin, cephaloridine, cephalothin, chloramphenicol, gentamicin, and tetracycline . All organisms were either partly or wholly resistant to clindamycin; penicillin; streptomycin; and sulfadiazine, sulfamerazine, and sulfamethazine (triple sulfas).

Zhonghua Yi Xue Za Zhi (Taipei), 2000 Feb, 63(2), 119 - 23
In vitro activity of quinupristin/dalfopristin and other antibiotics against ampicillin-resistant enterococcus faecium; Wang FD et al.; BACKGROUND: Enterococcus faecium constitutes approximately 10% of clinical isolates of enterococci and is noted for its antimicrobial resistance . In particular, E faecium is commonly resistant to ampicillin . The optimal treatment for severe infections caused by these multi-resistant organisms has yet to be determined . METHODS: Enterococci tested were isolated from blood, pleural fluid and cerebrospinal fluid . Ampicillin-resistant Enterococcus faecium (AREF) was identified using the API Rapid Strep Kit system . A total of 58 isolates of AREF were enrolled in this study . Ten different antibiotics were tested, including Synercid (quinupristin/dalfopristin), teicoplanin, vancomycin, ampicillin, trimethoprim/sulfamethoxazole (TMP/SMX), ciprofloxacin, gentamicin, chloramphenicol, rifampicin and tetracycline . The agar dilution method described by the National Committee for Clinical Laboratory Standards was used to determine the minimum inhibitory concentrations (MICs) of the antibiotics tested . RESULTS: Teicoplanin showed the best in vitro activity . Its MIC ranged from 0.25 to 2 micrograms/ml with an MIC90 of 1 microgram/ml . The MIC of vancomycin was 0.5-128 micrograms/ml with an MIC90 of 2 micrograms/ml . Three strains were vancomycin resistant, and they were the VanB phenotype . The MIC of quinupristin/dalfopristin was 0.5 to 8 micrograms/ml with an MIC90 of 2 micrograms/ml . Chloramphenicol and tetracycline showed moderate susceptibility . AREF showed high resistance to other antibiotics tested, including ciprofloxacin, gentamicin, TMP/SMX and rifampicin . High-level gentamicin resistance (MIC > 1,000 micrograms/ml) was found in 78% of AREF tested . CONCLUSIONS: Teicoplanin showed the best in vitro activity against AREF . Clinical studies are necessary to confirm the efficacy of quinupristin/dalfopristin in vivo.

FEMS Microbiol Lett, 2000 Feb 15, 183(2), 209 - 14
Chlorobiphenyl-desleucyl-vancomycin inhibits the transglycosylation process required for peptidoglycan synthesis in bacteria in the absence of dipeptide binding; Goldman RC et al.; Novel glycopeptide analogs are known that have activity on vancomycin resistant enterococci despite the fact that the primary site for drug interaction, D-ala-D-ala, is replaced with D-ala-D-lactate . The mechanism of action of these compounds may involve dimerization and/or membrane binding, thus enhancing interaction with D-ala-D-lactate, or a direct interaction with the transglycosylase enzymes involved in peptidoglycan polymerization . We evaluated the ability of vancomycin (V), desleucyl-vancomycin (desleucyl-V), chlorobiphenyl-vancomycin (CBP-V), and chlorobiphenyl-desleucyl-vancomycin (CBP-desleucyl-V) to inhibit (a) peptidoglycan synthesis in vitro using UDP-muramyl-pentapeptide and UDP-muramyl-tetrapeptide substrates and (b) growth and peptidoglycan synthesis in vancomycin resistant enterococci . Compared to V or CBP-V, CBP-desleucyl-V retained equivalent potency in these assays, whereas desleucyl-V was inactive . In addition, CBP-desleucyl-V caused accumulation of N-acetylglucosamine-beta-1, 4-MurNAc-pentapeptide-pyrophosphoryl-undecaprenol (lipid II) . These data show that CBP-desleucyl-V inhibits peptidoglycan synthesis at the transglycosylation stage in the absence of binding to dipeptide.

Clin Invest Med, 1999 Dec, 22(6), 256 - 64
Vancomycin use in 2 Ontario tertiary care hospitals: a survey; Kwan T et al.; OBJECTIVE: Use of vancomycin is a risk factor for acquiring vancomycin-resistant enterococci (VRE) . To optimize the use of vancomycin in hospitals, the Hospital Infection Control Practices Advisory Committee (HICPAC) published recommendations in 1995 . The objectives of this study were to determine the frequency, indications, and risk factors for inappropriate inpatient vancomycin prescriptions before and after publication of the HICPAC recommendations . DESIGN: Cross-sectional study . SETTING: Two tertiary care hospitals in Ontario . INTERVENTIONS: Vancomycin prescriptions were randomly sampled and hospital chart view performed for two 12-month periods, one before and one after publication of the HICPAC recommendations on vancomycin use . RESULTS: Based on the review of 189 charts from hospital A and 190 from hospital B, there was no significant change in the proportion of inappropriate vancomycin prescriptions at either hospital from before publication of the HICPAC recommendations to afterward (63% v . 71% at hospital A, p = 0.21; 48% v . 37% at hospital B, p = 0.11) . In 51% of all vancomycin prescriptions, the drug was prescribed instead of another antibiotic because of a recorded penicillin allergy . Surgical prophylaxis with more than 1 or 2 doses of vancomycin accounted for 66% (hospital A) and 58% (hospital B) of inappropriate prescriptions . In a multivariate analysis, surgical prophylaxis remained a significant risk factor for inappropriate use of vancomycin at both hospitals (odds ratio {OR} 5.6, 95% confidence interval {CI} 2.8 to 11.3, p = 0.01 for hospital A; OR 13.9, 95% CI 4.9 to 39.5, p = 0.01 for hospital B) . Prescription by the orthopedic service also remained a significant risk factor in the final logistic regression model for hospital B (OR 3.9, 95% CI 1.1 to 13.9, p = 0.01) . CONCLUSIONS: A high proportion of vancomycin prescriptions, surveyed before and after publication of the HICPAC recommendations on vancomycin use, were inappropriate . Excessive vancomycin use in surgical prophylaxis was an important factor . Our findings suggest that the use of standardized peri-operative order forms and of penicillin-allergy testing may help optimize vancomycin use in tertiary care hospitals.

Intensive Care Med, 1999 Dec, 25(12), 1427 - 31
Pharmacokinetics of cefpirome in critically ill patients with renal failure treated by continuous veno-venous hemofiltration; Van der Werf TS et al.; OBJECTIVE: To study the cefpirome pharmacokinetics of patients with sepsis and multiple organ failure treated with CVVH . DESIGN: Measurements of serum and ultrafiltrate (UF) concentrations and in vitro sensitivity testing of isolated micro-organisms . SETTING: University hospital-based, single ICU . PATIENTS: Six critically ill CVVH-dependent patients with sepsis and multiple organ dysfunction syndrome in need of antimicrobial therapy . Age range: 60-75 years; APACHE II score for severity of illness on admission: 19-30 . One patient survived . INTERVENTIONS: Cefpirome i.v . was started at 2 g in 30 min, then continued 1 g i.v.b.i.d . MEASUREMENTS: The UF rate was 27 +/- 7 ml/min on day 1 and 34 +/- 2 ml/min on day 2 . Serum and ultrafiltrate samples were measured by a validated high performance liquid chromatography assay . Volume of distribution: 23 x 5(SD +/- 4 x 6) l . Total cefpirome clearance was 32 +/- 6 x 3 ml/min; cefpirome CVVH clearance (ClCVVH): 17 +/- 4.2 ml/min; mean serum half-life (t1/2): 8.8 +/- 2.3 h; mass transfer on day 1: 660 +/- 123 mg/12 h (33 +/- 6% of administered dose) and day 2: 642 +/- 66 mg/12 h (64 +/- 7%) . Estimated sieving coefficient (ClCVVH/UF rate): 64 +/- 11% . In vitro sensitivity of isolated microbes was excellent except for two non-sensitive enterococci and Candida spp . CONCLUSIONS: The sieving coefficient (64%) indicates that a substantial fraction of the drug is not filtered; clearance by pathways other than CVVH mounted to 50% of the total clearance and increased on day 2, indicating that the dosing schedule used is appropriate for this setting . Cefpirome appeared to be safe in these patients and effective for most of the nosocomial microbial isolates . During more than 90% of the time, serum levels were maintained above killing concentrations for susceptible micro-organisms.

J Clin Microbiol, 2000 Feb, 38(2), 905 - 9
Epidemiology of glycopeptide-resistant enterococci colonizing high-risk patients in hospitals in Johannesburg, Republic of South Africa; von Gottberg A et al.; Recent cases of infections caused by glycopeptide-resistant enterococci (GRE) have highlighted the emergence of these organisms in the Republic of South Africa . During May 1998 we conducted a prevalence study in four hospitals in Johannesburg and obtained 184 rectal swabs from patients identified as being at high risk for GRE colonization . Twenty enterococcal isolates showing various glycopeptide resistance genotypes were recovered: 3 Enterococcus faecium vanA isolates, 10 E . faecium vanB isolates, 6 E . gallinarum vanC1 isolates, and 1 E . avium vanA isolate . Macrorestriction analysis was used to demonstrate the clonal spread of GRE strains within hospitals . Evidence also demonstrated the likely persistence of the original E . faecium vanA isolate associated with the first confirmed death contributed to by GRE infection in South Africa in March 1997.

Infect Control Hosp Epidemiol, 2000 Jan, 21(1 Suppl), S4 - 8
A pilot study of antibiotic cycling in a hematology-oncology unit; Dominguez EA et al.; OBJECTIVE: To determine the safety and treatment efficacy of cycling antibiotic regimens for prophylaxis or treatment of patients with profound neutropenia . DESIGN: A prospective, nonrandomized, observational trial . SETTING: A 20-bed adult hematology-oncology inpatient unit at a university referral hospital . PATIENTS: Hospitalized adult patients with chemotherapy- or radiation-induced neutropenia (absolute neutrophil count less than 500 cells/mm3) . INTERVENTION: Between July 1994 and January 1996, 295 hospitalized patients were evaluated on an intent-to-treat basis for the cycling protocol . Of these, 271 were eligible and assigned to one of four antibiotic regimens being used at the time of enrollment: (1) ceftazidime+vancomycin; (2) imipenem; (3) aztreonam+cefazolin; (4) ciprofloxacin+clindamycin . Data on infection rates and types, and antibiotic resistance patterns, toxicity, and effectiveness were collected . RESULTS: Twenty-four patients were excluded . Of the 271 evaluable patients, 123 (42%) were able to complete treatment on the assigned regimen . Of the 148 patients (50%) unable to do so, the reasons for failure included persistent fever (79%), breakthrough bacteremia (14%), and drug toxicity (7%) . The antibiotic susceptibility profiles over the study period showed no increase in resistance . However, there was a marked increase in enterococcal infections . CONCLUSIONS: Our data show no significant increase in side effects or decrease in efficacy while cycling antibiotics among neutropenic patients and thus support further study of its role.

J Food Prot, 2000 Jan, 63(1), 78 - 82
The microbiological quality of ice used to cool drinks and ready-to-eat food from retail and catering premises in the United Kingdom; Nichols G et al.; A survey of 4,346 samples of ice from retail and catering premises examined 3,528 samples (81%) used to cool drinks and 144 samples (3%) from food displays . For 674 samples (15%), the origin was not recorded . Most samples of ice used to cool drinks or ready-to-eat food on displays did not contain coliforms, Escherichia coli, or enterococci . Of the ice used to cool drinks, 9% contained coliforms, 1% E . coli, and 1% enterococci in excess of 10(2) CFU/100 ml, and 11% had an aerobic plate count at 37 degrees C in excess of 10(3) CFU/ml . The microbiological quality of ice used to cool drinks was poorer when melt water was present in the ice buckets . Ice used in food displays was more contaminated than ice used to cool drinks, with 23% containing coliforms, 5% E . coli, and 8% enterococci at 10(2) CFU/100 ml or more . Twenty-nine percent of samples had an aerobic plate count greater than 10(3) CFU/ml . Ice that had been used to cool shellfish was of a lower microbiological quality than samples used to cool ready-to-eat fish, salads, or dairy produce . Samples of ice produced in commercial production facilities were of higher microbiological quality than samples of ice that were not . The microbiological quality of ice was dependent on the type of use, the type of premises, and the type and place of production . Although most ice samples were of acceptable microbiological quality, evidence from this study suggests that the microbiological quality of ice prepared and used at certain premises in the UK is a cause for concern.

J Food Prot, 2000 Jan, 63(1), 51 - 5
Alternative indicator bacteria analyses for evaluating the sanitary condition of beef carcasses; Ingham SC et al.; Sponge samples were obtained from 47 (study 1) and 32 (study 2) beef carcasses in a small plant over 6 months . In study 2, slaughter equipment surfaces were also sampled . In study 1, the Petrifilm method was used to count presumptive Escherichia coli and spread plating on kanamycin esculin azide (KEA) agar with and without 40% added bile was used to count presumptive Enterococcus spp . Qualitative testing for presumptive E . coli and Enterococcus spp . in study 1 was done using lauryl sulfate tryptone broth (LST) + 4-methylumbelliferyl-beta-D-glucuronide (MUG) and KEA + 40% bile broth, respectively . In study 2, LST + MUG was used as a most probable number (MPN) method along with the Petrifilm method . In the two studies, 8 (17.0%) and 11 (34.4%) carcasses were contaminated with presumptive E . coli; all but one contaminated carcass contained <1 CFU/cm2 . Presumptive Enterococcus spp . were recovered from 15 carcasses (31.9%) in study 1, but the KEA + 40% bile agar method lacked specificity (only 31.3% of isolates confirmed as Enterococcus spp.) The LST + MUG and Petrifilm methods were significantly (P < 0.05) related in terms of detecting presumptive E . coli, but the presence of presumptive Enterococcus spp . was not significantly related to the presence of presumptive E . coli . However, on slaughter plant equipment in Study 2 there was a statistically significant (P < 0.05) relationship between the presence of presumptive E . coli and presumptive Enterococcus spp . In study 2, there was no significant (P < 0.05) difference in numbers of presumptive E . coli (obtained using Petrifilm) on carcasses chilled 1 day (n = 16) and 7 days (n = 16), although more of the 7-day carcasses were contaminated (five and seven carcasses, respectively) . For samples testing positive for presumptive E . coli, the 95% confidence intervals obtained using the LST + MUG MPN method included the Petrifilm value for all but one sample.

Antimicrob Agents Chemother, 2000 Feb, 44(2), 433 - 6
Mechanisms of resistance to quinupristin-dalfopristin among isolates of Enterococcus faecium from animals, raw meat, and hospital patients in Western Europe; Soltani M et al.; Twenty-eight quinupristin-dalfopristin-resistant isolates of Enterococcus faecium from hospital patients and nonhuman sources in European countries were studied . High-level resistance (MICs, >/=32 microg/ml) was associated with the presence of vat(E) (satG) (14 isolates inverted question mark50%) or vat(D) (satA) (6 isolates inverted question mark21%) . These genes were not detected in eight (29%) isolates with lower levels of quinupristin-dalfopristin resistance (MICs, 4 to 16 microg/ml) . This suggests the presence of further mechanisms of resistance to quinupristin-dalfopristin in E . faecium.

Chem Biol, 1999 Dec, 6(12), 891 - 9
Binding of glycopeptide antibiotics to a model of a vancomycin-resistant bacterium; Cooper MA et al.; BACKGROUND: The vancomycin group of glycopeptide antibiotics is active against a wide range of gram-positive bacteria . The increasing resistance to vancomycin is the result of a change of an amide linkage (D-Ala-D-Ala) to an ester linkage (D-Ala-D-Lactate) in the bacterial cell-wall precursors . RESULTS: We have used a peptide terminating in the sequence -Lys-D-Ala-D-Lactate linked by its amino terminus to a docosanoyl (C22) acyl chain and anchored in a supported lipid monolayer to mimic the surface of vancomycin-resistant enterococci . Surface plasmon resonance analysis was then used to investigate the binding of glycopeptide group antibiotics to this surface . Vancomycin, which dimerises weakly, bound with low affinity, whereas strongly dimerising antibiotics, such as chloroeremomycin, bound with higher affinities . Antibiotics that have attached hydrophobic groups, such as teicoplanin and biphenylchloroeremomycin (LY307599), bound to the lipid monolayer . This resulted in an enhanced affinity for the lipid-anchored peptide at the surface relative to affinities for an analogous non-anchored peptide in solution . CONCLUSIONS: We have shown that the affinities of glycopeptide antibiotics for a model of the surface of a vancomycin-resistant bacterium are enhanced relative to affinities determined in free solution . We have also shown that antibiotics that have membrane anchors bind tightly to the model surface and that this feature is an important determinant of the ability of an antibiotic to kill vancomycin-resistant enterococci.

Diagn Microbiol Infect Dis, 1999 Nov, 35(3), 219 - 25
Synergistic effect of gentamicin plus ampicillin on enterococci with differing sensitivity to gentamicin: a phenotypic assessment of NCCLS guidelines; Dressel DC et al.; Between December 1, 1993, and December 1, 1996, we tested 4,411 isolates of Enterococcus sp . at gentamicin concentrations of 500 micrograms/mL and 2000 micrograms/mL using agar dilution to phenotypically categorize them into 3 groups: those with a MIC < or = 500 micrograms/mL (n = 3,132; 71%); a MIC > 500, but < or = 2000 micrograms/mL (n = 441; 10%); and those with a MIC > 2000 micrograms/mL (n = 838; 19%) . Ten unique strains of each phenotype were tested to determine which gentamicin concentration was the best in vitro predictor of synergy with ampicillin . Testing was done by a time-kill method using clinically achievable levels of ampicillin and gentamicin . We found that for the gentamicin MIC < or = 500 micrograms/mL group, 7 of 10 isolates demonstrated synergy with ampicillin as manifested by a > or = 2 log10 increase in killing versus the effect of ampicillin alone (at 1/2 the MIC for ampicillin) . In the group sensitive to a gentamicin MIC range between > 500 and < or = 2,000 micrograms/mL, none of the 10 isolates demonstrated synergy . Absence of synergy was also found in the group resistant to 2,000 micrograms/mL of gentamicin . Assessment of eight additional enterococcal isolates with reduced sensitivity to ampicillin (MIC from 32-256 micrograms/mL) found no correlation between gentamicin sensitivity at 500 micrograms/mL and any in vitro test for synergy, nor with clinical therapeutic outcome . Gentamicin at 2 micrograms/mL combined with ampicillin was as effective in enhancing killing as a higher level of 4 micrograms/mL . These findings validate the current NCCLS guideline for predicting synergistic activity against enterococci in strains with usual susceptibility to ampicillin, and suggest that a therapeutic level less than maximal recommended dosing is sufficient when using gentamicin in this setting.

Chirurgie, 1999 Nov, 124(5), 551 - 4
{Gangrene of the round liver ligament: an unrecognized pathology}; Pans A et al.; The necrosis of the ligamentum teres hepatis is a very rare and unrecognized pathology . Two cases only were reported in the literature . The presence of generalized or epigastric peritoneal signs, simulates acute cholecystitis or perforated pyloric ulcer . The diagnosis could be suggested by ultrasonography and CT scan of the abdomen revealing a hyperechogenic and hypodense focal lesion at the junction of the segments III and IV of the liver, associated with inflammatory signs and/or collection along the ligamentum teres . The etiology of this necrosis remains unclear, although in this case report, a ligament infection with E . Coli, Enterococcus and Klebsiella pneumoniae was observed . However, the primum movens of the infection is unknown . The proposed treatment is resection of the ligament from umbilicus up to the liver, associated with systemic antibiotherapy, because of the possible risk of propagation of the infection to the portal vein.

J Agric Food Chem, 1999 Dec, 47(12), 4907 - 16
Influence of a probiotic adjunct culture of Enterococcus faecium on the quality of cheddar cheese; Gardiner GE et al.; Cheddar cheese has previously been shown to be an effective vehicle for delivery of viable cells of a probiotic Enterococcus faecium strain to the gastrointestinal tract . The particular strain, E . faecium PR88, has proven efficacy in the treatment of irritable bowel syndrome, and in this study it was evaluated for suitability as a starter adjunct for Cheddar cheese manufacture . When added to cheesemilk at an inoculum of 2 x 10(7) cfu/mL, the enterococcal adjunct maintained viability in Cheddar cheese at levels of up to 3 x 10(8) cfu/g during 9 months of ripening . Increased proteolysis and higher levels of some odor-active volatile compounds were observed in Cheddar cheeses containing the PR88 adjunct compared with the control throughout the ripening period . In addition, the enterococcal adjunct strain did not affect cheese composition . Although sensory evaluation showed no significant difference in flavor/aroma and body/texture scores between control and experimental cheeses, repeated comments by the commercial grader consistently described the cheeses containing PR88 as 'more advanced than the control' and as having 'better flavor' . These findings indicate that the presence of the PR88 adjunct strain in Cheddar cheese at levels of >/=10(8) cfu/g may positively influence Cheddar flavor.

Science, 1999 Dec 17, 286(5448), 2361 - 4
Use of the cell wall precursor lipid II by a pore-forming peptide antibiotic; Breukink E et al.; Resistance to antibiotics is increasing in some groups of clinically important pathogens . For instance, high vancomycin resistance has emerged in enterococci . Promising alternative antibiotics are the peptide antibiotics, abundant in host defense systems, which kill their targets by permeabilizing the plasma membrane . These peptides generally do not act via specific receptors and are active in the micromolar range . Here it is shown that vancomycin and the antibacterial peptide nisin Z use the same target: the membrane-anchored cell wall precursor Lipid II . Nisin combines high affinity for Lipid II with its pore-forming ability, thus causing the peptide to be highly active (in the nanomolar range).

Glycoconj J, 1999 Mar, 16(3), 213 - 21
A novel cytokine-inducing glycolipid isolated from the lipoteichoic acid fraction of Enterococcus hirae ATCC 9790: a fundamental structure of the hydrophilic part; Hashimoto M et al.; Previously, we showed that quantitatively minor several glycolipids totaling only less than 5% of the lipoteichoic acid (LTA) fraction from Enterococcus hirae ATCC 9790 possessed cytokine-inducing activity, whereas the major component (over 90%) did not {Suda et al . (1995) FEMS Immun Med Microbiol 12:97-112} . The major inactive component was shown to have the chemical structure as was proposed for the LTA by Fischer {Hashimoto et al . (1997) J Biochem 121:779-86}, suggesting that so-called LTA is not a cytokine-inducing component in the Gram-positive bacteria . In the present paper, the structure of the hydrophilic part of one of the cytokine-inducing glycolipid tentatively named GL4 is elucidated . GL4 was first subjected to hydrolysis with aqueous HF to give a polysaccharide and a mixture of low molecular weight products . The polysaccharide was composed mainly of highly branching mannan as concluded from NMR and MS analyses of its acetolysis products . The low molecular weight products consisted of phosphate and glycerol, suggesting the presence of a poly(glycerophosphate) structure in the original GL4 . From these observations, the hydrophilic part of GL4 was shown to consist of mannose-rich polysaccharide and poly(glycerophosphate), the latter being bound to the former by a phosphodiester linkage.

J Antimicrob Chemother, 1999 Nov, 44(5), 593 - 9
Interactions of alpha- and beta-avoparcin with bacterial cell-wall receptor-mimicking peptides studied by electrospray ionization mass spectrometry; van de Kerk-van Hoof A et al.; Solution phase affinity constants of the glycopeptide antibiotic alpha- and beta-avoparcin, with a range of bacterial cell-wall receptor-mimicking model peptides, were determined by a relatively new method: affinity electrospray ionization mass spectrometry (ESI-MS) . This method is relatively efficient and allows the parallel determination of several affinity constants in mixtures of antibiotics and receptors . The determined binding constants for alpha- and beta-avoparcin were compared with those of the related glycopeptide antibiotic vancomycin . The solution phase binding affinities of alpha- and beta-avoparcin on one hand, and vancomycin on the other, were found to be in the same order, at least for the range of receptor-mimicking peptides studied . However, beta-avoparcin displayed slightly higher binding affinities than alpha-avoparcin, particularly for strong binding receptor-mimicking peptides . The evidence that alpha- and beta-avoparcin and vancomycin are structurally similar, combined with the present data revealing their similar affinity for bacterial cell-wall receptor-mimicking peptides, supports the hypothesis that the appearance of vancomycin-resistant enterococci (VRE) might be linked to the widespread use of avoparcin.

J Antimicrob Chemother, 1999 Dec, 44(6), 831 - 4
Modified time-kill assay against multidrug-resistant Enterococcus faecium with novel antimicrobial combinations; Messick CR et al.; This study used a modified time-kill assay to compare the in-vitro activity of chloramphenicol and quinopristin/dalfopristin combined with vancomycin, ampicillin or gentamicin against multidrug-resistant Enterococcus faecium . The assay uses standardized time-kill methods with the following modifications: centrifugation of the test tubes at 1-2 h intervals, removal of supernatant and resuspension of bacteria in media containing antibiotic concentrations corresponding to simulated steady-state serum concentrations . None of the agents, alone or in combination, produced bactericidal or synergic activity . The modified time-kill assay more closely simulates in-vivo conditions and may provide a better qualitative assay to determine the interaction between antimicrobial agents and bacteria.

J Antimicrob Chemother, 1999 Dec, 44(6), 795 - 8
The prevalence and clonal expansion of high-level gentamicin-resistant enterococci isolated from blood cultures in a Dutch university hospital; van Den Braak N et al.; We studied the prevalence and clonality of high-level gentamicin-resistant enterococci (HLGRE) in a Dutch university hospital . Of 238 enterococcal strains isolated from blood cultures between 1991 and 1997, 57 were HLGRE . Genomic analysis of these strains revealed 19 different genotypes, two of which were encountered more frequently {type A (12/57), type B (23/57)} . The spread of these types largely explained the rise in HLGRE incidence from 14% in 1991 to 31% in 1997 . However, the contribution of unique strains to the total HLGRE burden also increased from 4% to 16% . We conclude that both clonal expansion and the emergence of unique HLGRE have contributed significantly to the increasing incidence of HLGRE.

Clin Infect Dis, 1999 Oct, 29(4), 912 - 6
Prevalence of vancomycin-resistant enterococci among children with end-stage renal failure . Mid-European Pediatric Peritoneal Dialysis Study Group; von Baum H et al.; To evaluate the prevalence of colonization with vancomycin-resistant enterococcus (VRE) in end-stage renal failure (ESRF), we screened the intestinal flora from 338 pediatric ESRF patients treated in 13 pediatric nephrology units in mid-Europe . Eighty-one patients were undergoing hemodialysis, 66 were undergoing chronic peritoneal dialysis, and 191 were transplant recipients . A total of 363 enterococcal strains were recovered from 232 patients . Twenty-seven enterococcal strains from 24 patients (7.1%) had reduced susceptibility to vancomycin (minimal inhibitory concentration {MIC}, >4 microg/mL) . Although two patients (0.6%) carried enterococci with high-level resistance to vancomycin (MIC, >32 microg/mL; i.e., VRE), strains of enterococcus with reduced susceptibility to vancomycin (ERSV) were recovered from the other 22 subjects . Past use of vancomycin (P = .05) and tacrolimus therapy (P = .011) were independent risk factors for ERSV or VRE carriage . Enterococcal infections occurred with a similar frequency among enterococcal carriers and noncarriers; no infections with VRE or ERSV were reported . In conclusion, the prevalence of ERSV carriage and the rate of VRE colonization among mid-European children and adolescents with ESRF currently are moderate and low, respectively.

J Hosp Infect, 1999 Nov, 43(3), 231 - 8
Rectal colonization with vancomycin-resistant enterococci among high-risk patients in an Israeli hospital; Dan M et al.; The prevalence of rectal carriage of vancomycin-resistant enterococci (VRE) in two high-risk populations--61 patients admitted to ICU and 92 patients on renal dialysis--was studied longitudinally over a period of six months in a 650-bed general hospital . ICU patients were swabbed weekly and dialysis patients monthly . Enterococcal isolates were fully identified using the ATB identification system, and MICs were determined according to the NCCLS recommendations . Enterococci were isolated in 52 (83.6%) ICU patients and 86 (93.4%) dialysis patients . VRE were recovered at least once in 14 (27%) ICU patients and four (4.8%) dialysis patients . All VRE isolates (MIC of vancomycin > or = 256 micrograms/mL) were resistant to teicoplanin (MIC > or = 32 micrograms/mL; vanA phenotype), 87.5% were ampicillin-resistant, and 92% showed high-level resistance to gentamicin; 88% were E . faecium . The main risk factors for acquisition of VRE included duration of hospitalization in the six months preceding entry into the study and during the survey (P = 0.009 and 0.007 respectively, for ICU patients), and duration of antibiotic administration (P = 0.005, for ICU patients) . The impact of vancomycin was most prominent (P = 0.005 for receipt and 0.06 for duration of administration, in ICU patients) . Six of the 18 VRE carriers developed bacteraemia, six isolates being vancomycin-susceptible and one vancomycin-resistant (one patient had both) . In this study, the first in Israel, a low rectal carriage rate occurred in renal dialysis patients and antibiotic use was the most important risk factor for VRE colonization.

Acta Microbiol Pol, 1999, 48(2), 203 - 7
Resistant enterococci: prevalence and factors associated with colonization in a Turkish university hospital; Ozkuyumcu C; The prevalence of high level aminoglycoside-resistant (HLAR) and vancomycin-resistant enterococci were investigated in this study . Enterococci were isolated from 264 of all specimens (70.9%) . Thirty strains were identified as high level aminoglycoside-resistant enterococci (11.4%) . Vancomycin resistant enterococcus has not been isolated in this study.

Infect Control Hosp Epidemiol, 1999 Nov, 20(11), 760 - 3
A case-control study to detect modifiable risk factors for colonization with vancomycin-resistant enterococci; Loeb M et al.; A case-control study was conducted to determine the modifiable risk factors associated with vancomycin-resistant Enterococcus (VRE) colonization during a hospital outbreak . Cephalosporin use was identified as the only independent risk factor (odds ratio, 13.8; 95% confidence interval, 2.5-76.3; P = .01) . Nursing work-load intensity was not associated with VRE colonization in this study.

Kansenshogaku Zasshi, 1999 Oct, 73(10), 1078 - 81
{Enterococcus gallinarum septicemia in a patient with acute myeloid leukemia}; Yoshimoto E et al.; A 62-year-old male was admitted with complaints of fever and body weight loss . The patient was diagnosed as acute myeloid leukemia (M1) and chemotherapy was started . About 80 days after admission, the patient developed diarrhea with high fever . And E . gallinarum was isolated from the blood culture . We carried out PCR using primers for vanA, vanB and vanC in our E . gallinarum, and showed the existence of the vanC1 . This organism should be considered as one of the possible pathogenes in the infectious complications of the immuno-compromized patient.

Mol Microbiol, 1999 Oct, 34(2), 385 - 94
Transposition genes of the Bacteroides mobilizable transposon Tn4555: role of a novel targeting gene; Tribble GD et al.; Conjugative transposons have been identified in several bacterial species, most notably the Gram-positive Enterococci and the Gram-negative Bacteroides . In Bacteroides species, these elements encode a complete conjugative machinery, which mediates their own intercellular transfer, and they can mobilize in trans co-resident elements . One such mobilizable element is the antibiotic resistance transposon, Tn4555, which was previously found to integrate into a specific genome target site via a site-specific recombination mechanism . In this work, we demonstrate that three Tn4555 genes were involved in integration of the element . These were int encoding a lambda-type integrase, which was absolutely required for integration of the transposon, and two accessory genes, which increased the frequency of integration . Interestingly, one of these accessory gene products, TnpA, directed the insertion of Tn4555 into the genome target site; in the absence of tnpA, the insertion pattern was essentially random . This is the first example of a site-specific recombinase that uses a specific targeting protein.

Antimicrob Agents Chemother, 1999 Nov, 43(11), 2776 - 9
Synergy testing of vancomycin-resistant Enterococcus faecium against quinupristin-dalfopristin in combination with other antimicrobial agents; Matsumura SO et al.; Using checkerboard and time-kill assays, we evaluated the in vitro activity of quinupristin-dalfopristin (RP 59500) alone and in combination with five other antimicrobial agents against 12 clinical strains of vancomycin-resistant Enterococcus faecium (VREF) . In time-kill studies, six VREF strains exhibited synergism with the combination of quinupristin-dalfopristin and doxycycline and three exhibited synergism with quinupristin-dalfopristin plus ampicillin-sulbactam . Combinations of quinupristin-dalfopristin with these and other agents warrant further clinical evaluation for the treatment of serious VREF infections.

EDTNA ERCA J, 1999 Apr-Jun, 25(2), 42 - 4
Nursing implications of a vancomycin resistant enterococcus outbreak in a renal unit; Taylor J et al.; Vancomycin Resistant Enterococcus is a difficult organism to treat and is becoming more prevalent world-wide . When it was identified in a busy renal unit, radical and expensive measures were taken to try and control the outbreak . Although these had costs to both patients and staff, the organism was eradicated from the unit.

Infect Control Hosp Epidemiol, 1999 Oct, 20(10), 686 - 9
Recovery of high-level streptomycin-resistant enterococci from hemodialysis water and dialysate in 85 Greek renal units; Arvanitidou M et al.; In the 85 renal units of Greece, enterococci were recovered from 10 samples of tap water, 6 of treated hemodialysis water, and 21 of dialysate . Eleven isolates were Enterococcus faecium, and 8 were Enterococcus raffinosus; 6 other additional enterococcal species were found . Twenty-two strains exhibited high-level resistance to streptomycin, 16 were resistant to rifampicin, and one to erythromycin . In our hemodialysis units, treated water and dialysate raise concern regarding transfer to patients of uncommon enterococcal species exhibiting high-level streptomycin resistance.

Infect Control Hosp Epidemiol, 1999 Oct, 20(10), 685 - 6
Undetected vancomycin-resistant Enterococcus in surgical intensive care unit patients; Zuckerman RA et al.; The rates of vancomycin-resistant Enterococcus (VRE) in a high-risk population were investigated prospectively using an active surveillance method . The costs of conducting active surveillance were calculated . Among the 10 patients found to have VRE, routine cultures identified 3 (30%); thus, 70% of the VRE-colonized patients would have gone undetected in the absence of active surveillance . The total cost for 5 weeks of active surveillance was $2,234 . Although active surveillance identified a high rate of VRE-colonized patients who otherwise may not have been identified, it remains to be determined if the additional costs are justified and result in reduced transmission.

Infect Control Hosp Epidemiol, 1999 Oct, 20(10), 671 - 5
Reporting of vancomycin-resistant enterococci in Connecticut: implementation and validation of a state-based surveillance system; Dembek ZF et al.; OBJECTIVE: To assess state-based surveillance for isolation from a sterile site of vancomycin-resistant enterococci (VRE) in Connecticut . DESIGN: Clinical laboratory reporting (passive surveillance) of VRE isolates to the Connecticut Department of Public Health (CDPH) was followed by state-initiated validation, laboratory proficiency testing, and review of hospital demographic characteristics . SETTINGS: All 45 clinical laboratories and all 37 (36 for 1995 and 1996) acute-care hospitals in Connecticut were included in the study . MAIN OUTCOME MEASURES: The outcome measures included determination of the statewide incidence of VRE and the accuracy of passive reporting, determination of clinical laboratory proficiency in detecting VRE, and analysis of hospital characteristics that might be associated with an increased incidence of VRE . RESULTS: During 1994 through 1996, 29 (78%) of 37 hospital-affiliated clinical laboratories and 1 (11%) of 9 commercial or other laboratories in Connecticut reported to the CDPH the isolation of VRE from sterile sites; 158 isolates were reported for these 3 years . Based on verification, we discovered that these laboratories actually detected 58 VRE isolates in 1994, 104 in 1995, and 104 in 1996 (total, 266) . The age-standardized incidence rate of VRE was 14.1 cases per million population in 1994 and 26.8 cases per million population for both 1995 and 1996 . Laboratory proficiency testing revealed that high-level vancomycin resistance was identified accurately and that low- and moderate-level resistance was not detected . The incidence of VRE isolates was three times greater in hospitals with over 300 beds compared with categories of hospitals with fewer beds . Increases in the number of VRE isolates were at least twice as likely in hospitals located in areas with a higher population density, or with a residency program or trauma center in the hospital . CONCLUSIONS: Passive reporting of VRE isolates from sterile sites markedly underestimated the actual number of iso lates, as determined in a statewide reporting system . Statewide passive surveillance systems for routine or emerging pathogens must be validated and laboratory proficiency ensured if results are to be accurate and substantial underreporting is to be corrected.

Infect Control Hosp Epidemiol, 1999 Oct, 20(10), 660 - 3
Association between mucositis severity and vancomycin-resistant enterococcal bloodstream infection in hospitalized cancer patients; Kuehnert MJ et al.; OBJECTIVE: To determine the role of mucositis severity in the development of vancomycin-resistant enterococcal (VRE) bloodstream infection (BSI) . SETTING: A tertiary-care university medical center . PARTICIPANTS: Hematology-oncology-unit inpatients . DESIGN: Patients with VRE BSI (case-patients) were compared with VRE-colonized (control) patients from September 1994 through August 1997 . Oral mucositis severity was recorded on the day of VRE BSI for case-patients and on hospital day 22 (median day of hospitalization of case-patient VRE BSI) for controls . There were 19 case-patients and 31 controls . RESULTS: In univariate analysis, case-patients were significantly more likely than controls to have a higher mucositis severity score, diarrhea, or a higher severity of illness score . In multivariate analysis, only mucositis remained as an independent risk factor, and increasing mucositis score was significantly associated with VRE BSI . CONCLUSIONS: Mucositis severity was independently associated with an increasing risk for VRE BSI . Interventions to alter mucositis severity may help to prevent VRE BSI in hospitalized cancer patients.

Infect Control Hosp Epidemiol, 1999 Oct, 20(10), 653 - 9
Molecular epidemiology of vancomycin-resistant enterococci: a 2-year perspective; Stosor V et al.; OBJECTIVE: To determine the molecular epidemiology of vancomycin-resistant enterococci (VRE) at our medical center in order to identify the extent of strain clonality and possible transmission patterns of this pathogen . DESIGN: An important facet of our infection control program includes molecular typing of all clinical and surveillance isolates of VRE to determine transmission patterns in the hospital . Molecular strain typing is performed by restriction endonuclease analysis (REA) of genomic DNA . REA patterns are visually compared to categorize VRE strains into type and subtype designations . SETTING: A 588-bed, university-affiliated, tertiary-care hospital and a neighboring 155-bed rehabilitation facility . RESULTS: From January 1995 through December 1996, 379 VRE isolates were collected from 197 patients . Thirty-three genotypes were determined by REA typing; 15 genotypes were implicated in 29 instances of potential nosocomial transmission . Three major clusters of VRE involving patients on multiple nursing units and two adjacent hospitals were identified . The remaining instances of nosocomial transmission occurred in small patient clusters . CONCLUSIONS: In conclusion, the VRE epidemic at this medical center is polyclonal . VRE transmission patterns are complex, and, while large clusters do occur, the usual pattern of nosocomial acquisition of this pathogen occurs in the setting of "mini-clusters".

Clin Infect Dis, 1999 Sep, 29(3), 573 - 9
A polyclonal outbreak of predominantly VanB vancomycin-resistant enterococci in northeast Ohio . Northeast Ohio Vancomycin-Resistant Enterococcus Surveillance Program; Donskey CJ et al.; We studied the molecular epidemiology of vancomycin-resistant enterococci (VRE) isolated in northeast Ohio during 1996 and examined the association between isolation of VRE from samples other than stool and antimicrobial purchases for five Cleveland hospitals . Susceptibility testing and pulsed-field gel electrophoresis were used to analyze 363 isolates from individual patients from 13 hospitals . Susceptibility testing indicated that 287 strains (79%) expressed the VanB phenotype and 76 (21%) expressed the VanA phenotype . The outbreak was polyclonal, with 30 total genotypes . Both VanA and VanB VRE demonstrated multiple genotypes . One genotype was present in all hospitals, suggesting spread between hospitals . For five teaching hospitals, rates of isolation from non-stool sources and from blood correlated positively with purchases of ticarcillin/clavulanic acid (P = .005) . In summary, this outbreak demonstrates transmission of VRE between several hospitals in a geographic region and suggests that use of certain beta-lactam antibiotics may be associated with an increased prevalence of VRE.

Biochemistry, 1999 Oct 19, 38(42), 14006 - 22
Determinants for differential effects on D-Ala-D-lactate vs D-Ala-D-Ala formation by the VanA ligase from vancomycin-resistant enterococci; Lessard IA et al.; Bacteria with either intrinsic or inducible resistance to vancomycin make peptidoglycan (PG) precursors of lowered affinity for the antibiotic by switching the PG-D-Ala-D-Ala termini that are the antibiotic-binding target to either PG-D-Ala-D-lactate or PG-D-Ala-D-Ser as a consequence of altered specificity of the D-Ala-D-X ligases in the cell wall biosynthetic pathway . The VanA ligase of vancomycin-resistant enterococci, a D-Ala-D-lactate depsipeptide ligase, has the ability to recognize and activate the weak nucleophile D-lactate selectively over D-Ala(2) to capture the D-Ala(1)-OPO(3)(2)(-) intermediate in the ligase active site . To ensure this selectivity in catalysis, VanA largely rejects the protonated (NH(3)(+)) form of D-Ala at subsite 2 (K(M2) of 210 mM at pH 7.5) but not at subsite 1 . In contrast, the deprotonated (NH(2)) form of D-Ala (K(M2) of 0.66 mM, k(cat) of 550 min(-)(1)) is a 17-fold better substrate compared to D-lactate (K(M) of 0.69 mM, k(cat) of 32 min(-)(1)) . The low concentration of the free amine form of D-Ala at physiological conditions (i.e., 0.1% at pH 7.0) explains the inefficiency of VanA in dipeptide synthesis . Mutational analysis revealed a residue in the putative omega-loop region, Arg242, which is partially responsible for electrostatically repelling the protonated form of D-Ala(2) . The VanA enzyme represents a subfamily of D-Ala-D-X ligases in which two key active-site residues (Lys215 and Tyr216) in the active-site omega-loop of the Escherichia coli D-Ala-D-Ala ligase are absent . To look for functional complements in VanA, we have mutated 20 residues and evaluated effects on catalytic efficiency for both D-Ala-D-Ala dipeptide and D-Ala-D-lactate depsipeptide ligation . Mutation of Asp232 caused substantial defects in both dipeptide and depsipeptide ligase activity, suggesting a role in maintaining the loop position . In contrast, the H244A mutation caused an increase in K(M2) for D-lactate but not D-Ala, indicating a differential role for His244 in the recognition of the weaker nucleophile D-lactate . Replacement of the VanA omega-loop by that of VanC2, a D-Ala-D-Ser ligase, eliminated D-Ala-D-lactate activity while improving by 3-fold the catalytic efficacy of D-Ala-D-Ala and D-Ala-D-Ser activity.

Clin Infect Dis, 1999 Nov, 29(5), 1268 - 73
An outbreak of vancomycin-dependent Enterococcus faecium in a bone marrow transplant unit; Kirkpatrick BD et al.; Outbreaks of vancomycin-resistant enterococci (VRE) are well described . The presence of mutants of VRE, such as vancomycin-dependent enterococci (VDE), in individual patients has been documented, but their potential to spread nosocomially has not been known . We present the first cluster of patients who acquired VDE nosocomially . Five bone marrow transplantation patients were infected or colonized by a genotypically indistinguishable multiantibiotic-resistant strain of Enterococcus faecium . Vancomycin dependence in 3 of the 5 isolates was demonstrated . All cluster patients had received protracted prophylactic treatment with vancomycin (mean, 22.6 days), and specimens from >/=2 body sites were repeatedly culture-positive for the outbreak strain . The outbreak was controlled with aggressive infection control strategies, and prophylactic antibiotic policies were revised . Awareness of the potential for nosocomial spread of multiantibiotic-resistant VDE is vital for the care of immunocompromised patients, especially those receiving prophylactic antibiotics.

J Clin Microbiol, 1999 Nov, 37(11), 3756 - 8
Evaluation of the revised MicroScan dried overnight gram-positive identification panel to identify Enterococcus species; Iwen PC et al.; The revised MicroScan Dried Overnight Gram-Positive Identification panel was evaluated for its efficacy at identifying Enterococcus species in comparison with conventional biochemical tests . Supplemental testing of ampicillin-susceptible Enterococcus faecium for motility and the ability to acidify methyl-alpha-D-glucopyranoside helped recognize E . gallinarum and increased the accuracy of the panel for identifying Enterococcus species to 98.5%.

Am J Infect Control, 1999 Oct, 27(5), 411 - 7
Molecular epidemiology of vancomycin-resistant enterococci from 6 hospitals in New York State; Bopp LH et al.; BACKGROUND: Vancomycin resistance among enterococci is an emerging nosocomial problem . Consequently, it is important to understand the distribution of vancomycin-resistant enterococci (VRE) within and between hospitals to implement appropriate infection control measures . METHODS: In this study, 116 VRE isolates obtained from patients in 6 New York State hospitals were analyzed by antibiotic susceptibility testing, pulsed-field gel electrophoresis (PFGE) fingerprinting, plasmid profile analysis, vanA and vanB polymerase chain reaction, and DNA:DNA hybridization with vanA and vanB probes . RESULTS: PFGE and plasmid typing generally agreed, but plasmid profiles were more variable . These analyses revealed that genetic heterogeneity among isolates from within each of the 6 hospitals varied considerably . Among 23 Enterococcus faecium isolates from one hospital, there were only 3 PFGE types, and 20 isolates had the same type . However, in another hospital, each isolate was genetically distinct . Closely related strains were not found in separate hospitals . VRE strains with vanA genes and strains with vanB genes were found in 3 hospitals . Both plasmid and chromosomal carriage of these genes was detected . CONCLUSIONS: PFGE typing showed that nosocomial VRE transmission had occurred in some hospitals . However, there was no evidence for it in others . Neither was there evidence for intrahospital transmission or for emergence of an endemic strain . These observations demonstrate that it is important to evaluate genetic heterogeneity among VRE before implementation of infection control measures . PFGE is the method of choice for epidemiologic typing, but polymerase chain reaction, plasmid, and hybridization studies can provide important information concerning the presence and potential for transfer of vancomycin resistance genes.

J Antimicrob Chemother, 1999 Sep, 44 Suppl A, 25 - 30
Quinupristin/dalfopristin: therapeutic potential for vancomycin-resistant enterococcal infections; Moellering RC; Vancomycin-resistant Enterococcus faecium (VREF) is an opportunistic pathogen, which causes infections among severely ill, hospitalized patients, in whom it is likely to increase the risk of progressive local or systemic disease and to worsen the prognosis . Because these organisms are often highly resistant to penicillin, ampicillin and many other antimicrobials including the glycopeptides, there are few proven therapeutic alternatives for the treatment of infection caused by VREF . Quinupristin/dalfopristin is highly active against VREF in vitro . A prolonged post-antibiotic effect, good polymorphonuclear leucocyte/macrophage penetration and slow release, and active metabolites allow this agent to be used with an 8 or 12 h dosing interval . The combined results from a Phase III non-comparative study and an emergency-use study of quinupristin/dalfopristin for the treatment of VREF infection produced a clinical response rate (cure or improvement) in 142 (73.6%) of 193 clinically evaluable patients . The baseline pathogen was eradicated or presumed eradicated from 110 of 156 (70.5%) bacteriologically evaluable patients . Fifty-two per cent of the severely ill patients in these two studies died, but no death was attributed to quinupristin/dalfopristin therapy . The most common adverse event was arthralgia (9.1%) . Quinupristin/dalfopristin has demonstrated efficacy for the treatment of serious VREF infections, including those that have failed conventional therapy.

Appl Environ Microbiol, 1999 Oct, 65(10), 4425 - 30
Identification of Enterococcus spp . with a biochemical key; Manero A et al.; A six-step biochemical key is presented for the identification of all recognized Enterococcus spp . The key consists of 12 tests, but no more than 6 are needed for the most complicated identification . The reliability of the key has been evaluated with collection type strains and clinical and environmental isolates . This key has fewer tests than those reported in previous studies . There is no commercial kit that includes the whole set of tests . However, some of the tests are included in enzyme activity-based kits that could be used with the proposed key . The key is designed for use in routine applications, especially in environmental and clinical studies with a high number of isolates.

Antimicrob Agents Chemother, 1999 Oct, 43(10), 2513 - 6
Association of alterations in ParC and GyrA proteins with resistance of clinical isolates of Enterococcus faecium to nine different fluoroquinolones; Brisse S et al.; The parC and gyrA genes of 73 ciprofloxacin-resistant and 6 ciprofloxacin-susceptible Enterococcus faecium clinical isolates were partly sequenced . Alterations in ParC and GyrA, possibly in combination with other resistance mechanisms, severely restricted the in vitro activities of the nine quinolones tested . For all isolates, clinafloxacin and sitafloxacin showed the best activities.

Proc Natl Acad Sci U S A, 1999 Sep 28, 96(20), 11028 - 32
VanX, a bacterial D-alanyl-D-alanine dipeptidase: resistance, immunity, or survival function?
Lessard IA, Walsh CT.
The zinc-containing D-alanyl-D-alanine (D-Ala-D-Ala) dipeptidase VanX has been detected in both Gram-positive and Gram-negative bacteria, where it appears to have adapted to at least three distinct physiological roles . In pathogenic vancomycin-resistant enterococci, vanX is part of a five-gene cluster that is switched on to reprogram cell-wall biosynthesis to produce peptidoglycan chain precursors terminating in D-alanyl-D-lactate (D-Ala-D-lactate) rather than D-Ala-D-Ala . The modified peptidoglycan exhibits a 1, 000-fold decrease in affinity for vancomycin, accounting for the observed phenotypic resistance . In the glycopeptide antibiotic producers Streptomyces toyocaensis and Amylocatopsis orientalis, a vanHAX operon may have coevolved with antibiotic biosynthesis genes to provide immunity by reprogramming cell-wall termini to D-Ala-D-lactate as antibiotic biosynthesis is initiated . In the Gram-negative bacterium Escherichia coli, which is never challenged by the glycopeptide antibiotics because they cannot penetrate the outer membrane permeability barrier, the vanX homologue (ddpX) is cotranscribed with a putative dipeptide transport system (ddpABCDF) in stationary phase by the transcription factor RpoS (sigma(s)) . The combined action of DdpX and the permease would permit hydrolysis of D-Ala-D-Ala transported back into the cytoplasm from the periplasm as cell-wall crosslinks are refashioned . The D-Ala product could then be oxidized as an energy source for cell survival under starvation conditions.

Lett Appl Microbiol, 1999 Aug, 29(2), 118 - 22
Isolation and molecular characterization of vancomycin-resistant Enterococcus faecium in Malaysia; Son R et al.; Nineteen strains of vancomycin-resistant Enterococcus faecium isolated from 10 of 75 (13.3%) tenderloin beef samples were examined for resistance to selected antibiotics, presence of plasmids, and genetic diversity by random amplification of polymorphic DNA analysis . All strains showed multiple resistant to the antibiotics tested . Multiple antibiotic indexing of the vancomycin-resistant E . faecium strains showed that all (100%) originated from high risk contamination environments where antibiotics were often used . Plasmids ranging in size from 1.5 to 36 megadalton were detected in 15 of 19 (79%) strains . Thus, three plasmid profiles and eight antibiotypes were observed among the E . faecium strains . A high degree of polymorphism was obtained by combining the results of the two primers used; with the 19 E . faecium strains being differentiated into 19 RAPD-types . These preliminary results suggest that RAPD-PCR has application for epidemiologic studies and that resistance patterns and plasmid profiling could be used as an adjunct to RAPD for the typing of E . faecium in the study area.

Int J Antimicrob Agents, 1999 Aug, 12(4), 333 - 9
In vitro selection of glycopeptide-resistant variants of Enterococci; Puntorieri M et al.; In order to study the possible phenotypic and genotypic changes related to glycopeptide pressure on enterococci, a study was undertaken using stepwise in vitro exposure to achieve the following objectives: (i) to evaluate the development of resistance and cross-resistance between vancomycin and teicoplanin; (ii) to determine the stability of the acquired level of resistance; (iii) to determine the phenotypic and genotypic changes related to glycopeptide pressure; and (iv) to assess the spectrum of antibiotic-susceptibility of all strains . Our results showed that no variants resistant to glycopeptides could be selected after in vitro glycopeptide exposure experiments . However some strains showed increased MIC values: 8 mg/l to vancomycin in eight strains selected by vancomycin itself, while teicoplanin produced intermediate values to vancomycin in only three strains . The phenotypes were stable in vitro after numerous passages in antibiotic-free medium and three out of nine strains with a changed MIC level, showed 40, 42 and 43 kDa proteins in cell membrane preparations . The profile of antibiotic resistance was comparable in all isogenic strains tested with the exception of three selected strains that became susceptible to penicillin G . The pressure produced by glycopeptides, particularly vancomycin has contributed to an increased level of MIC that can influence the acquisition and/or full expression of this resistance.

Int J Antimicrob Agents, 1999 Aug, 12(4), 293 - 9
Antiviral activity of enterocin CRL35 against herpesviruses; Wachsman MB et al.; Enterocin CRL35 is an antibacterial polypeptide of 3.5 x 10(3) Da produced by Enterococcus faecium CRL35 . A series of experiments are described that show the enterocin also had antiviral activity against thymidine-kinase positive (tk+) and deficient (tk-) strains of herpes simplex (HSV) type 1 and 2 in Vero and BHK-21 cells . This activity was observed at 100 microg/ml, 15-fold lower than the cytotoxic concentration . In both cell lines there was a 2 log inhibition of infectivity . The compound inhibited viral multiplication in a dose-dependent manner and had no virucidal effect . Enterocin CRL35 also inhibited the virion-associated host shutoff in infected Vero cells showing that intracellular viral multiplication was affected.

Curr Microbiol, 1999 Nov, 39(5), 282 - 90
Biochemical and genetic evidence of enterocin P production by two Enterococcus faecium-like strains isolated from fermented sausages; Herranz C et al.; Two bacteriocin-producing Enterococcus faecium-like strains were independently isolated from fermented sausages . Bacteriocins were purified to homogeneity by ammonium sulfate precipitation, gel filtration, cationic exchange, hydrophobic interaction, and reverse-phase liquid chromatography . Two peptide inhibitory fractions were purified from each strain, denominated A and B for E . faecium AA13, and C and D for E . faecium G16 . Fraction B was blocked for amino acid sequencing by Edman degradation, while the amino acid sequences obtained from peptides A, C, and D contained the YGNGV consensus motif in positions 5 to 9, and the ATRS sequence in positions 1 to 4 . By use of PCR techniques and nucleotide sequencing, the structural gene of enterocin P was found both in E . faecium AA13 and E . faecium G16 . Metabolic and genetic features of the two strains suggest that they are slightly different, they may produce more than one bacteriocin, and both produce enterocin P.

J Infect Dis, 1999 Oct, 180(4), 1177 - 85
A cluster of VanD vancomycin-resistant Enterococcus faecium: molecular characterization and clinical epidemiology; Ostrowsky BE et al.; VanD-mediated glycopeptide resistance has been reported for an isolate of Enterococcus faecium, BM4339 . Three clinical isolates of vancomycin-resistant E . faecium collected from 3 patients during a 6-week period in 1993 had agar dilution MICs of vancomycin and teicoplanin of 128 and 4 microg/mL, respectively . Polymerase chain reaction (PCR) using degenerate primers complementary to genes encoding d-Ala-d-X ligases yielded a 630-bp product that was similar to the published partial sequence of vanD . By use of inverse PCR, vanD, vanHD, and two partial flanking open-reading frames were sequenced . The deduced amino acid sequence of VanD showed 67% identity with VanA and VanB . vanD appeared to be located on the chromosome and was not transferable to other enterococci . The 3 isolates were indistinguishable by pulsed-field gel electrophoresis and differed from BM4339 . No other isolates carrying vanD were found in a subset of 875 recent US isolates of vancomycin-resistant enterococci.

Clin Infect Dis, 1999 Aug, 29(2), 361 - 6
Lack of efficacy of oral bacitracin plus doxycycline for the eradication of stool colonization with vancomycin-resistant Enterococcus faecium; Weinstein MR et al.; In a prospective observational cohort study designed to assess the role of oral bacitracin solution plus doxycycline in the eradication of intestinal carriage of vancomycin-resistant Enterococcus faecium (VREF) in patients on a renal ward, rectal swab specimens were obtained from 15 treated and 24 control patients . Cultures of the rectal swabs were negative for 15 (100%) of the antibiotic-treated vs . eight (33.3%) of the untreated patients (P < .001) on day 14 . However, follow-up for a mean of 127 and 130 days revealed 9 of 15 (60%) and 15 of 24 (62.5%) in the treated and untreated cohorts (P = .86), respectively, carried VREF intermittently or persistently . Quantitative VREF stool cultures in the treated cohort revealed an initial 3.1-log10/g decrease, but there was an increase to pretreatment levels at 2-4 and 5-7 weeks post-treatment (7.8 and 7.4 log10/g) . Oral bacitracin and doxycycline were not efficacious in reducing the carriage of VREF beyond the 2-week interval during which they were given.

Med J Aust, 1999 Aug 2, 171(3), 144 - 6
Vancomycin-resistant enterococci and use of avoparcin in animal feed: is there a link?
Collignon PJ.
Australia is unique among Western countries in allowing animal use of this vancomycin-like antibiotic.

Lancet, 1999 Aug 28, 354(9180), 741 - 2
Decrease of vancomycin-resistant enterococci in poultry meat after avoparcin ban; Pantosti A et al.; In Italy, 18 months after the ban of avoparcin, the percentage of poultry meat samples containing vanA gene-positive vancomycin-resistant enterococci fell from 14.6% to 8%.

Microbiology, 1999 Aug, 145 ( Pt 8), 1849 - 58
Regulated interactions between partner and non-partner sensors and response regulators that control glycopeptide resistance gene expression in enterococci; Arthur M et al.; Transcription of the vanA and vanB glycopeptide resistance gene clusters is regulated by the VanRS and VanRBSB two-component regulatory systems, respectively . Histidine to glutamine substitutions were introduced at positions 164 of VanS and 233 of VanSB to prevent autophosphorylation of the sensor kinases and transfer of the phosphate groups to the VanR and VanRB response regulators . VanSH164Q and VanSBH233Q abolished activation of VanR and VanRB by host kinases . The phosphatase activity of VanSBH233Q was negatively modulated by vancomycin whereas VanSH164Q prevented transcription of the resistance genes under all growth conditions . Cross-talk was detected between VanRB and VanS in a vanSB null mutant . VanR is required for activation of promoters PR and PH allowing transcription of the regulatory (vanRS) and resistance (vanHAXYZ) genes, respectively . Under non-inducing conditions, activation of VanR by cross-talk was blocked by the presence of a multicopy plasmid carrying PH . Presence of the high-affinity VanR-binding sites of the regulatory region of PH on the multicopy vector probably sequestered VanR, thereby preventing autoactivation of the PR promoter . Under such circumstances, stimulation of the host kinase by glycopeptides or moenomycin was required for expression of the resistance genes.

Diagn Microbiol Infect Dis, 1999 Aug, 34(4), 269 - 73
Phenotypic characteristics of Enterococcus faecium variants confirmed by intergenic ribosomal polymerase chain reaction and E . faecium polymerase chain reaction; Park YJ et al.; Enterococcus faecium has recently emerged as a serious nosocomial pathogen . The emergence of multiple antimicrobial agent-resistant E . faecium has been remarkable; with its strains it is one of the most phenotypically heterogeneous of all enterococcal species . About 15% of enterococcal strains isolated from human clinical specimens were found to have atypical biochemical characteristics . In order to determine if these strains were E . faecium variants, intergenic ribosomal polymerase chain reaction (ITS-PCR) and E . faecium PCR (EfPCR) were performed in 45 atypical strains, and the two PCR results were used to analyze phenotypic characteristics of the strains . As many as 60% (27/45) of the atypical strains were identified as E . faecium . Thus, it is concluded that if an enterococcal strain shows positive reaction to arabinose, arginine, and ribose and negative reaction to methyl-alpha-D-glucopyranoside and pigment, it should be identified as E . faecium.

Ann Intern Med, 1999 Aug 17, 131(4), 269 - 72
Infection-control measures reduce transmission of vancomycin-resistant enterococci in an endemic setting; Montecalvo MA et al.; BACKGROUND: Vancomycin-resistant enterococci (VRE) are nosocomial pathogens in many U . S . hospitals . OBJECTIVE: To determine whether enhanced infection-control strategies reduce transmission of VRE in an endemic setting . DESIGN: Prospective cohort study . SETTING: Adult oncology inpatient unit . PATIENTS: 259 patients evaluated during use of enhanced infection-control strategies and 184 patients evaluated during use of standard infection-control practices . INTERVENTIONS: Patient surveillance cultures were taken, patients were assigned to geographic cohorts, nurses were assigned to patient cohorts, gowns and gloves were worn on room entry, compliance with infection-control procedures was monitored, patients were educated about VRE transmission, patients taking antimicrobial agents were evaluated by an infectious disease specialist, and environmental surveillance was performed . MEASUREMENTS: VRE infection rates, VRE colonization rates, and changes in antimicrobial use . RESULTS: During use of enhanced infection-control strategies, incidence of VRE bloodstream infections decreased significantly (0.45 patients per 1000 patient-days compared with 2.1 patients per 1000 patient-days; relative rate ratio, 0.22 {95% CI, 0.05 to 0.92}; P = 0.04), as did VRE colonization (10.3 patients per 1000 patient-days compared with 20.7 patients per 1000 patient-days; relative rate ratio, 0.5 {CI, 0.33 to 0.75}; P < 0.001) . Use of all antimicrobial agents except clindamycin and amikacin was significantly reduced . CONCLUSION: Enhanced infection-control strategies reduced VRE transmission in an oncology unit in which VRE were endemic.

Public Health Nutr, 1999 Jun, 2(2), 223 - 9
Public health issues arising from microbiological and labelling quality of foods and supplements containing probiotic microorganisms; Hamilton-Miller JM et al.; OBJECTIVE: To assess the accuracy and helpfulness of labelling on products containing probiotic bacteria . DESIGN AND SETTING: 52 such products - 44 from the UK (21 supplements, 15 fermented functional foods, eight 'health-care' products) and eight from continental Europe - have been tested for microbiological content, and results compared to the information available on their labels . Products were stored in the dark at 4 degrees C and analysed before their expiry or sell-by date . Careful note was taken of wording on labels, package inserts, packaging, promotional literature and catalogue descriptions, as applicable . Products were cultured on appropriate bacteriological media, and organisms grown were counted and identified . RESULTS: Bioyoghurts gave no indication of numbers, and only five accurately described their bacterial content; results of culture were usually satisfactory . 'Healthcare' products (mostly intended for the bowel) usually indicated the presence of bacteria, but the numerical content was hard to ascertain, and cultural results fell short of label claims . Supplements were sometimes incorrectly labelled in bacteriological terms, and often contained markedly reduced numbers and/or had extraneous strains and/or strains specified on the label were missing . Products from continental Europe (that were sold for specific medical indications) seemed of a higher microbiological standard . The potential pathogen Enterococcus faecium was found in nine products . The most successful of the new functional foods in Britain now contain probiotics, and probiotic preparations are prominent among the expanding range of nutritional supplements presently available to consumers . CONCLUSIONS: Our findings have public health implications, and suggest that improvements are needed in labelling and quality assurance procedures for products containing probiotic organisms . The presence of the potential pathogen Enterococcus faecium (intentionally or as a contaminant) in some products calls for a review of the value of this species as a probiotic.

Eur J Clin Microbiol Infect Dis, 1999 Jun, 18(6), 422 - 7
Validity of screening procedures for glycopeptide-resistant enterococci; Wendt C et al.; Screening agars containing different vancomycin concentrations and different susceptibility testing procedures were compared to determine their validity for the detection of glycopeptide-resistant enterococci (GRE) . Direct streaking of rectal swabs over the surface of a commercially available agar (Enterococcosel; Becton Dickinson, Germany) containing 4 microg/ml and 16 microg/ml vancomycin was followed by incubation for 24 to 48 h . Susceptibility tests were done by microbroth dilution, disk diffusion, and the E test (AB Biodisk, Sweden) . The microbroth dilution method according to National Committee for Clinical Laboratory Standards (NCCLS) was used as the gold standard for detection of GRE . Resistant and intermediately susceptible enterococcal isolates were differentiated to the species level . To detect resistance genes, the polymerase chain reaction was performed on all intermediately resistant isolates, on all isolates of VanB phenotype, and on 30% of isolates of VanA phenotype . Screening agar containing 4 microg/ml vancomycin displayed high sensitivity (97.6%) but only low specificity (35%) for the detection of GRE . Screening agar containing 16 microg/ml vancomycin had a high specificity of 89.3% and only a slightly lower sensitivity (92.7%) than the screening agar containing 4 microg/ml vancomycin . For the disk diffusion test, a breakpoint of < 16 mm yielded the optimal combination of sensitivity (98.8%) and specificity (99.6%) . Both sensitivity and specificity of the E test for GRE detection were 100% . However, the E test is too expensive for testing of all enterococci . In conclusion, the combination of an inexpensive screening agar with either the E test or the disk diffusion test constitutes a valid and cost-effective method for the detection of GRE from screening specimens.

Mol Cell Probes, 1999 Aug, 13(4), 275 - 81
Direct detection of vanA and vanB genes in clinical specimens for rapid identification of vancomycin resistant enterococci (VRE) using multiplex PCR; Petrich AK et al.; Surveillance for vancomycin resistant enterococci (VRE) by culture can be labour intensive and time consuming . We have developed a multiplex polymerase chain reaction (MPCR) which can be performed directly on the clinical specimen . The assay allows sensitive detection of enterococci with vanA - and vanB -mediated resistance to vancomycin . DNA was purified from stool and rectal specimens using the XTRAX(TM)DNA Extraction Kit (Gull Labs) . Multiplex PCR amplified vanA and vanB targets were detected using a microtiter plate EIA . Two-hundred specimens were tested by routine culture and MPCR . Culture identified 44 VRE isolates and MPCR detected 38 of the 44 culture positives . Multiplex PCR detected three additional positive VRE specimens missed by culture for a sensitivity and specificity of 86.4 and 98.1%, respectively . When the presence of PCR inhibitors was addressed in the six culture positive/MPCR negative specimens, four additional VRE positive specimens were detected . Performing MPCR on the original specimens and on a 1:10 dilution of all specimens to minimize the effect of inhibitors gave a sensitivity and specificity of 95.5 and 98.1%, respectively . Multiplex PCR with confirmation by microtiter plate hybridization could be completed in 8 h compared with 24-48 h required for culture .

J Hosp Infect, 1999 Jul, 42(3), 193 - 200
Prevalence of colonization with vancomycin-resistant enterococci in various population groups in Berlin, Germany; Wendt C et al.; In order to prevent the spread of vancomycin-resistant enterococci (VRE), the epidemiology of this micro-organism must be defined . The prevalence of colonization with VRE in various population groups in Berlin was investigated and the risk factors associated with VRE colonization assessed . In a cross-sectional study, rectal swabs were taken from seven population groups (healthy students, outpatients, home nursing patients, normal care and critical care patients of a community hospital and university hospital) . Every one completed a questionnaire (age, gender, previous hospital stays, antibiotic therapy) . Rectal swabs were examined for the presence of normal gut flora and VRE . All VRE isolates were typed by pulsed-field gel electrophoresis (PFGE) . VRE colonization prevalence ranged from 0.9% (students) to 4.2% (nursing-home patients) in non-hospitalized subjects; in hospitalized patients prevalence ranged from 1.8% (regular care ward of a community hospital) to 16.3% (ICU patients of a university hospital) . Location (university hospital, OR = 3.5) and age (> or = 60 years, OR = 2.2) were independent risk factors for VRE colonization . Within one population group, isolates with identical PFGE patterns were found in up to three people; one strain was found in four subjects belonging to different groups . Our findings suggest that VRE are imported from the community into hospitals with subsequent spread within the institution.

Microb Drug Resist, 1999 Summer, 5(2), 159 - 62
First confirmed case of a vancomycin-resistant Enterococcus faecium with vanA phenotype from Brazil: isolation from a meningitis case in São Paulo; Zanella RC et al.; The importance of enterococci as a nosocomial etiologic agent is well documented; however, enterococci are also capable of causing a variety of community-acquired infections . Vancomycin resistance in a clinical Enterococcus isolate was first reported in 1986, and since then vancomycin-resistant enterococci (VRE) have been reported world-wide . This report describes a case of E . faecium with the VanA phenotype, isolated from meningitis in Sao Paulo, Brazil . Two E . faecium strains were isolated . One strain showed VanA phenotype, and the molecular characterization of the VanA gene was confirmed by polymerase chain reaction . The other strain was susceptible to vancomycin and teicoplanin . The authors would like to call the attention of the scientific community to this first identification of a VRE case in Sao Paulo, Brazil.

Antimicrob Agents Chemother, 1999 Aug, 43(8), 2032 - 7
Comparison of glycopeptide-resistant Enterococcus faecium isolates and glycopeptide resistance genes of human and animal origins; Descheemaeker PR et al.; One hundred thirty-two glycopeptide-resistant Enterococcus faecium (GREF) isolates from different hospitals and pig and poultry farms in Belgium were compared on the basis of (i) their antibiotic susceptibilities, (ii) their SmaI pulsed-field gel electrophoresis (PFGE) patterns, and (iii) the organization of their Tn1546 or related elements in order to detect possible phenotypic and genotypic relationships among both groups of isolates . Human and animal vanA-positive GREF isolates were found to have similar susceptibility patterns; they remained susceptible to gentamicin and were, in general, susceptible to ampicillin . PFGE demonstrated a very high degree of genomic heterogeneity in both groups of isolates . However, indistinguishable isolates were found within different farms or hospitals, and in two instances, epidemiologically unrelated pig and human isolates showed indistinguishable PFGE patterns . In total, eight different transposon types were identified, and all were related to the prototype transposon Tn1546 . The two predominant types, Tn1546 and type 2 transposons, which differed at three band positions, were present in both human and animal isolates . Type 2 transposons were significantly associated with pig isolates . The other types were seldom detected . These data suggest a possible exchange of glycopeptide resistance markers between animals and humans.

J Biol Chem, 1999 Aug 6, 274(32), 22597 - 603
NMR structure and metal interactions of the CopZ copper chaperone; Wimmer R et al.; A recently discovered family of proteins that function as copper chaperones route copper to proteins that either require it for their function or are involved in its transport . In Enterococcus hirae the copper chaperone function is performed by the 8-kDa protein CopZ . This paper describes the NMR structure of apo-CopZ, obtained using uniformly (15)N-labeled CopZ overexpressed in Escherichia coli and NMR studies of the impact of Cu(I) binding on the CopZ structure . The protein has a betaalphabetabetaalphabeta fold, where the four beta-strands form an antiparallel twisted beta-sheet, and the two helices are located on the same side of the beta-sheet . A sequence motif GMXCXXC in the loop between the first beta-strand and the first alpha-helix contains the primary ligands, which bind copper(I) . Binding of copper(I) caused major structural changes in this molecular region, as manifested by the fact that most NMR signals of the loop and the N-terminal part of the first helix were broadened beyond detection . This effect was strictly localized, because the remainder of the apo-CopZ structure was maintained after addition of Cu(I) . NMR relaxation data showed a decreased correlation time of overall molecular tumbling for Cu(I)-CopZ when compared with apo-CopZ, indicating aggregation of Cu(I)-CopZ . The structure of CopZ is the first three-dimensional structure of a cupro-protein for which the metal ion is an exchangeable substrate rather than an integral part of the structure . Implications of the present structural work for the in vivo function of CopZ are discussed, whereby it is of special interest that the distribution of charged residues on the CopZ surface is highly uneven and suggests preferred recognition sites for other proteins that might be involved in copper transfer.

Biosci Biotechnol Biochem, 1999 Jun, 63(6), 1125 - 9
Indispensable glutamic acid residue-139 of NtpK proteolipid in the reaction of vacuolar Na(+)-translocating ATPase in Enterococcus hirae; Takase K et al.; Enterococcus hirae vacuolar ATPase catalyzes translocation of Na+ or Li+ coupled with ATP hydrolysis . It is suggested that the glutamic acid residue (Glu139) of NtpK proteolipid subunit of this multisubunit enzyme is the binding site of these ions for translocation . Here we established a complementation system for the ntpK gene with its deletion mutant, and found that the ATPase activity disappeared upon replacement of Glu139 by aspartic acid . The side-chain length of this acidic residue of NtpK is thus important for this ATPase reaction.

Acta Crystallogr D Biol Crystallogr, 1999 Aug, 55 ( Pt 8), 1481 - 3
Crystallization and preliminary X-ray characterization of VanA from Enterococcus faecium BM4147: towards the molecular basis of bacterial resistance to the glycopeptide antibiotic vancomycin; Huyton T et al.; A recombinant form of Enterococcus facieum BM4147 D-alanine-D-lactate ligase (VanA) has been prepared and crystallized . VanA was found to crystallize only in the presence of a phosphinate inhibitor analogue of D-alanine-D-alanine . The crystals grow in 40-45% ammonium sulfate, 0.1 M 3-(N-morpholino)-propanesulfonic acid pH 6.0 and reach dimensions of 0.4 x 0.2 x 0.1 mm . The crystals diffract to at least 2.5 A and are in the centred orthorhombic space group C222(1), with unit-cell dimensions a = 123.2, b = 225.4, c = 72.4 A.

J Bacteriol, 1999 Aug, 181(15), 4696 - 9
Molecular cloning, sequence analysis, and characterization of a penicillin-resistant DD-carboxypeptidase of Myxococcus xanthus; Kimura Y et al.; We have cloned a gene, pdcA, from the genomic library of Myxococcus xanthus with an oligonucleotide probe representing conserved regions of penicillin-resistant DD-carboxypeptidases . The amino- and carboxy-terminal halves of the predicted pdcA gene product showed significant sequence similarity to N-acetylmuramoyl-L-alanine amidase and penicillin-resistant DD-carboxypeptidase, respectively . The pdcA gene was expressed in Escherichia coli, and the characteristics of the gene product were similar to those of DD-carboxypeptidase (VanY) of vancomycin-resistant enterococci . No apparent changes in cell growth, sporulation, or germination were observed in pdcA deletion mutants.

Acta Paediatr, 1999 Jun, 88(6), 651 - 4
Clinical and molecular biological analysis of a nosocomial outbreak of vancomycin-resistant enterococci in a neonatal intensive care unit; Lee HK et al.; Vancomycin-resistant enterococci (VRE) have emerged as important nosocomial pathogens since 1988 . We report here an outbreak of VRE between April 1997 and May 1997 in our neonatal intensive care unit (NICU) . All isolates from four patients were identified as Enterococcus faecium positive and were resistant to vancomycin and teicoplanin . All of the patients with VRE were isolated for at least 5 d after admission to the unit and the positive cultures lasted between 13 and 31 d . There were no cases of sepsis or mortality in the patients with VRE . Two cases had previously received vancomycin therapy . All isolates were shown to have the vanA gene and had the same band pattern on repetitive PCR . After the four episodes, all equipment used to care for the patients were decontaminated and the staff engaged in therapy used disposable gloves and gowns . There were no more episodes . However, the NICU is no longer a safety area with regards to vancomycin-resistant enterococcal infection.

Zentralbl Hyg Umweltmed, 1999 Jun, 202(1), 41 - 50
Resistance of enterococci to heat and chemical agents; Renner P et al.; Within the framework of the standardisation efforts on disinfectant testing on the European level the test germ Enterococcus hirae ATCC 10541 has been included for some time in the test requirements whereas the test strain Enterococcus faecium, which has frequently been used up to now, has been largely ignored . We compared the thermal and the chemical resistance of both test germ species . In the quantitative suspension test with active ingredients from the group of aldehydes, phenols, quaternaries and oxidizing agents with the exception of peracetic acid, no significant differences were determined between the two strains . In the case of the studies on thermal resistance at 65 degrees C and 68 degrees C, Enterococcus faecium ATCC 6057, by contrast, proved to be far more resistant than Enterococcus hirae ATCC 10541 . According to these results, priority should be given to Enterococcus faecium over Enterococcus hirae as the test germ for chemical and also chemothermal disinfection.

Proc Assoc Am Physicians, 1999 Jul-Aug, 111(4), 328 - 34
Enterococci: new aspects of an old organism; Murray BE et al.; Enterococci are a long-known cause of bacterial endocarditis and a more recently recognized cause of nosocomial infection and superinfection . While much is known about the many antibiotic resistances of enterococci, less is known about the organism itself and how it causes disease . This article presents a brief overview of enterococci and its possible virulence factors and summarizes the authors' efforts to understand the features of this organism that may contribute to its disease potential.

FEBS Lett, 1999 Jul 2, 454(1-2), 67 - 70
Enterococcus hirae vacuolar ATPase is expressed in response to pH as well as sodium; Ikegami M et al.; The Enterococcus hirae ntp operon encodes both a vacuolar ATPase, which transports Na+ as well as Li+, and the KtrII K+ transporter . A plasmid, in which the chloramphenicol acetyltransferase gene (CAT) was placed downstream of the ntp promoter, was introduced into a mutant totally defective in Na+ extrusion . The CAT activity of this transformant was increased preferentially by addition of NaCl, but not by LiCl, in the media or by elevating the medium pH, correlating well with the increase in amounts of the ATPase subunits observed by Western blotting . The physiological significance of these responses of the ntp promoter is discussed.

J Med Microbiol, 1999 Jul, 48(7), 695 - 6
Identification of clinically isolated vancomycin-resistant enterococci: comparison of API and BBL Crystal systems; Hamilton-Miller JM et al.; Twenty-eight phenotypically separate strains of clinically isolated vancomycin-resistant enterococci have been investigated with two API identification kit systems (20 Strep and Rapid ID 32 Strep) and two BBL Crystal kits (Gram Positive and Rapid Gram Positive) . All strains were identified as Enterococcus faecium by a reference laboratory . The Rapid ID 32 kit positively identified 15 of 28 strains (54%), but only two (7%) were identified correctly: 11 were identified as 'doubtful' or 'to genus level' and two gave 'unacceptable' profiles . The API 20 Strep kit identified 27 strains (96%), but only 16 (57%) were identified correctly as E . faecium . The Rapid ID 32 kit erred by either positively misidentifying vancomycin-resistant E . faecium as E . casseliflavus or E . gallinarum, or indicated that this was the most likely identification, while the API 20 Strep kit more commonly produced a misidentification as E . casseliflavus . The Crystal Gram Positive and Rapid Gram Positive kits correctly identified 26 (93%) and 27 (96%) of the strains, respectively.

Arch Intern Med, 1999 Jul 12, 159(13), 1467 - 72
Vancomycin-resistant enterococci in intensive care units: high frequency of stool carriage during a non-outbreak period; Ostrowsky BE et al.; BACKGROUND: We aimed to define the epidemiological associations of vancomycin-resistant enterococci (VRE) in intensive care units (ICUs) during a non-outbreak period by examining prevalence, risk factors for colonization, frequency of acquisition, and molecular strain types . DESIGN: A prospective cohort design was followed . Consecutive patient admissions to 2 surgical ICUs at a tertiary care hospital were enrolled . The main outcome measures were results of serial surveillance cultures screened for VRE . RESULTS: Of 290 patients enrolled, 35 (12%) had colonization with VRE on admission . The VRE colonization or infection had been previously detected by clinical cultures in only 4 of these patients . Using logistic regression, VRE colonization at the time of ICU admission was associated with second- and third-generation cephalosporins (odds ratio {OR} = 6.0, P<.0001), length of stay prior to surgical ICU admission (OR = 1.06, P = .001) greater than 1 prior ICU stay (OR = 9.6, P = .002), and a history of solid-organ transplantation (OR = 3.8, P = .021) . Eleven (12.8%) of 78 patients with follow-up cultures acquired VRE . By pulsed-field gel electrophoresis, 2 strains predominated, one of which was associated with an overt outbreak on a non-ICU ward near the end of the study period . CONCLUSIONS: Colonization was common and usually not recognized by clinical culture . Most patients who had colonization with VRE and were on the surgical ICU acquired VRE prior to surgical ICU entry . Exposure to second- and third-generation cephalosporins, but not vancomycin, was an independent risk factor for colonization . Prospective surveillance of hospitalized patients may yield useful insights about the dissemination of nosocomial VRE beyond what is appreciated by clinical cultures alone.

J Infect Dis, 1999 Aug, 180(2), 391 - 6
Regional dissemination of vancomycin-resistant enterococci resulting from interfacility transfer of colonized patients; Trick WE et al.; During early 1997, the Siouxland District Health Department (SDHD; Sioux City, IA) reported an increased incidence of vancomycin-resistant enterococcal (VRE) isolates at area health care facilities . To determine the prevalence and risk factors for colonization with VRE strains at 32 health care facilities in the SDHD region, a prevalence survey and case-control study were performed . Of 2266 patients and residents, 1934 (85%) participated, and 40 (2.1%) were positive for (gastrointestinal) VRE colonization . The prevalence of VRE isolates was significantly higher in acute care facilities (ACFs) than in long-term care facilities (LTCFs) (10/152 {6.6%} vs . 30/1782 {1.7%}; odds ratio {OR}, 4.1; 95% confidence interval {CI}, 1.8-9.0) . LTCF case patients were significantly more likely than controls to have been inpatients at any ACF (19/30 vs . 12/66; OR, 8.0; 95% CI, 2.7-23.8) . Of 40 VRE isolates, 34 (85%) were a related strain . The predominant strain was present in all 12 LTCFs that had at least 1 case patient in each facility . Soon after the introduction of VRE isolates into this region, dissemination to multiple LTCFs resulted from resident transfer from ACFs to LTCFs.

J Infect Dis, 1999 Aug, 180(2), 384 - 90
Effect of parenteral antibiotic administration on persistence of vancomycin-resistant Enterococcus faecium in the mouse gastrointestinal tract; Donskey CJ et al.; A mouse model of vancomycin-resistant Enterococcus faecium (VRE) intestinal colonization was used to study the effect of different subcutaneous antibiotics on persistence and density of VRE colonization . Gastric inoculation of a clinical VanB VRE isolate, in conjunction with oral vancomycin in drinking water (250 microgram/mL), resulted in high-level VRE colonization (mean, 9.5 log10 cfu/g) in all 169 experimental mice . After discontinuation of oral vancomycin, the level of VRE in the stool specimens of mice receiving subcutaneous saline steadily decreased (mean, 3.59 log10 cfu/g at day 19) . Subcutaneous vancomycin, clindamycin, piperacillin-tazobactam, ticarcillin-clavulanic acid, metronidazole, cefotetan, ampicillin, and ampicillin-sulbactam all promoted persistent high levels of stool VRE . Subcutaneous ceftriaxone, cefepime, ciprofloxacin, and aztreonam promoted increased VRE density to a lesser degree or not at all . Thus, in a mouse model, vancomycin and antibiotics with potent antianaerobic activity promoted persistent high-density intestinal VRE colonization, whereas antibiotics lacking potent antianaerobic activity did not.

Arch Pathol Lab Med, 1999 Jul, 123(7), 622 - 5
Comparison of the Vitek GPS-TB card with disk diffusion testing for predicting the susceptibility of enterococci to vancomycin; Williams-Bouyer N et al.; OBJECTIVE: To compare the ability of the Vitek GPS-TB card with disk diffusion testing for determining the susceptibility of enterococci to vancomycin . DESIGN: Vitek susceptibility testing was performed using the GPS-TB card and software version R05.03 . Disk diffusion susceptibility testing was performed according to National Committee for Clinical Laboratory Standards guidelines . When discrepancies occurred between the interpretation of Vitek and disk diffusion, both tests were repeated and the epsilometer test (E test) and agar screen containing 6 microgram/mL vancomycin were performed . RESULTS: Of 415 isolates tested, 313 were susceptible to vancomycin and 97 were resistant to vancomycin by both test methods . Two isolates were intermediate by Vitek and resistant by disk diffusion, 2 were intermediate by Vitek and susceptible by disk diffusion, and 1 was susceptible by Vitek and intermediate by disk diffusion . All but 1 of these latter 5 isolates (intermediate by Vitek and susceptible by disk diffusion) were available for retesting . On repeat testing, the 2 isolates that were intermediate by Vitek and resistant by disk diffusion were resistant by both methods, the 1 isolate that was intermediate by Vitek and susceptible by disk diffusion was susceptible by both methods, and the isolate that was susceptible by Vitek and intermediate by disk diffusion was also susceptible by both methods . These results were confirmed by E test and agar screen . CONCLUSION: We found the results of the GPS-TB card compared well with disk diffusion . However, isolates with intermediate results by Vitek should be retested using another method, such as the E test.

Biochemistry, 1999 Jun 29, 38(26), 8485 - 91
Molecular mechanism of VanHst, an alpha-ketoacid dehydrogenase required for glycopeptide antibiotic resistance from a glycopeptide producing organism; Marshall CG et al.; The vancomycin resistance enzyme VanH is an alpha-ketoacid dehydrogenase that stereospecifically reduces pyruvate to D-lactate, which is required for the synthesis of the depsipeptide D-alanine-D-lactate . This compound then forms an integral part of the bacterial cell wall replacing the vancomycin target dipeptide D-alanine-D-alanine, thus the presence of VanH is essential for glycopeptide resistance . In this work, the VanH homologue from the glycopeptide antibiotic producing organism Streptomyces toyocaensis NRRL 15009, VanHst, has been overexpressed in Escherichia coli and purified, and its substrate specificity and mechanism were probed by steady-state kinetic methods and site-directed mutagenesis . The enzyme is highly efficient at pyruvate reduction with kcat/Km = 1.3 x 10(5) M-1 s-1 and has a more restricted alpha-ketoacid substrate specificity than VanH from vancomycin resistant enterococci (VRE) . Conversely, VanHst shows no preference between NADH and NADPH while VanH from VRE prefers NADPH . The kinetic mechanism for VanHst was determined using product and dead-end inhibitors to be ordered BiBi with NADH binding first followed by pyruvate and products leaving in the order D-lactate, NAD+ . Site-directed mutagenesis indicated that Arg237 plays a role in pyruvate binding and catalysis and that His298 is a candidate for an active-site proton donor . Glu266, which has been suggested to modulate the pKa of the catalytic His in other D-lactate dehydrogenases, was found to fulfill a similar role in VanHst, lowering a pKa value of kcat/Km nearly 2 units . These results now provide the framework for additional structure and inhibitor design work on the VanH family of antibiotic resistance enzymes.

Kansenshogaku Zasshi, 1999 May, 73(5), 473 - 6
{A case of lymphocyst infection caused by vanB type VRE}; Imafuku Y et al.; A case of post-operative abdominal lymphocyst infection caused by vanB type vancomycin resistant enterococcus (VRE) in reported . A 27-year-old female was diagnosed as pregnancy with uterine cervical carcinoma and underwent Cesarean section and radical hysterectomy . After discharge, she developed a high fever which was diagnosed as a lymphocyst infection . Microbiological examination demonstrated the presence of vanB type VRE in the cyst fluid . Cyst cleaning and minocyclin injection were effective . This is the first case of VRE infection in Japan.

J Bacteriol, 1999 Jul, 181(13), 4103 - 5
Isolation and properties of Enterococcus hirae mutants defective in the potassium/proton antiport system; Kakinuma Y et al.; A K+/H+ antiporter regulates cytoplasmic pH in Enterococcus hirae growing at alkaline pH . Mutants defective in this antiport activity were alkaline pH sensitive . One mutant, Pop1, lacked both K+/methylamine exchange at pH 9.5 and concomitant acidification of cytoplasmic pH . Pop1 grew well at pHs below 8 but did not at pHs above 9, conditions under which cytoplasmic pH was not fully acidified.

Clin Transplant, 1999 Jun, 13(3), 245 - 52
A randomized trial of surgical antimicrobial prophylaxis with and without vancomycin in organ transplant patients; Pfundstein J et al.; BACKGROUND: Gram-positive organisms, including vancomycin-resistant enterococci (VRE), have emerged as major pathogens on the organ transplant service at our institution . We hypothesized that our use of vancomycin as part of routine surgical prophylaxis increased the risk of VRE colonization and infection; conversely, there was concern that failure to use vancomycin prophylaxis would increase peri-operative morbidity due to gram-positive organisms . METHODS: Renal transplant recipients (n = 88) were randomized to receive either a) vancomycin/ceftriaxone or b) cefazolin; and pancreas transplants (n = 24) to receive either a) vancomycin/gentamicin or b) cefazolin/gentamicin . Stool samples or rectal swabs were obtained for culture for enterococci within 24 h of transplantation and weekly while hospitalized . RESULTS: Enterococci were isolated on stool culture from 38 (34%) of 102 patients at the time of transplantation; 4 (11%) of the isolates were VRE . The percentage of patients who subsequently acquired VRE was low (1-7% per wk) but remained constant during hospitalization . There was no association between new VRE detection and vancomycin use for either prophylactic or therapeutic purposes . Forty-four patients (39%) had a post-operative infection with 46% of these infections due to gram-positive organisms; rates were unaffected by prophylactic vancomycin use . Pancreas transplant patients who did not receive vancomycin prophylaxis had a significantly longer initial hospitalization (p = 0.03); however, differences were not statistically significant when total length of stay (LOS) within the first 90 d of transplantation was compared . CONCLUSIONS: Vancomycin surgical prophylaxis does not appear to have an effect on VRE colonization or infection, or on rates of infection with gram-positive bacteria . Elimination of vancomycin prophylaxis in renal transplant patients may be a reasonable part of an overall program to limit vancomycin usage, although as a single measure, its impact may be minimal . Vancomycin surgical prophylaxis may be of greater importance in pancreas transplants.

Biosci Biotechnol Biochem, 1999 May, 63(5), 875 - 8
Potassium/proton antiport system is dispensable for growth of Enterococcus hirae at low pH; Kakinuma Y et al.; An energy-dependent K+/H+ antiport system is found in Enterococcus hirae ATCC 9790 cultured in a standard complex medium (Y . Kakinuma, and K . Igarashi, J . Biol . Chem . 263:14166-14170, 1988) . We have now found that the activity of this antiport system was totally missing in cells cultured in a defined medium . In this defined medium, E . hirae did not grow well at pH near 9, but grew normally at pH below 7.5 . This antiport system is important at high pH but dispensable at lower pH for ion homeostasis of this bacterium.

APMIS, 1999 Jun, 107(6), 545 - 9
Carrier rate of resistant enterococci in a tertiary care hospital in Norway; Torfoss D et al.; The prevalence of resistant enterococci varies geographically . In the present study we looked at the carrier rate of resistant enterococci in the hematology and gastrointestinal surgery units of a tertiary care hospital in Norway . Anal swabs were taken from all 82 hospitalized patients on 4 different dates, at least 4 weeks apart, in 1995 . 51% had positive cultures for enterococci . 6% of all patients carried enterococci resistant to ampicillin . 7% carried enterococci with high-level gentamicin resistance . Two strains resistant to vancomycin were found, including the first vanA Enterococcus faecium isolated in a Norwegian hospital . There was a correlation between use of antibiotics and being a carrier of enterococci per se, but the correlation with resistant enterococci did not reach statistical significance owing to the small number of isolates . The carrier rates both for presence of enterococci and for resistant enterococci were generally lower than those found in other studies.

Chem Biol, 1999 Jun, 6(6), 353 - 9
Binding of a dimeric derivative of vancomycin to L-Lys-D-Ala-D-lactate in solution and at a surface; Rao J et al.; BACKGROUND: The emergence of bacteria that are resistant to vancomycin (V), a glycopeptide antibiotic, results from the replacement of the carboxy-terminal D-Ala-D-Ala of bacterial cell wall precursors by D-Ala-D-lactate . Recently, it has been demonstrated that covalent dimeric variants of V are active against vancomycin-resistant enterococci (VRE) . To study the contribution of divalency to the activities of these variants, we modeled the interactions of V and a dimeric V with L-Lys-D-Ala-D-lactate, an analog of the cell-wall precursors of the vancomycin-resistant bacteria . RESULTS: A dimeric derivative of V (V-Rd-V) was found to be much more effective than V in inhibiting the growth of VRE . The interactions of V and V-Rd-V with a monomeric lactate ligand - diacetyl-L-Lys-D-Ala-D-lactate (Ac2KDADLac) - and a dimeric derivative of L-Lys-D-Ala-D-lactate (Lac-R'd-Lac) in solution have been examined using isothermal titration calorimetry and UV spectroscopy titrations; the results reveal that V-Rd-V binds Lac-R'd-Lac approximately 40 times more tightly than V binds Ac2KDADLac . Binding of V and of V-Rd-V to Nalpha-Ac-L-Lys-D-Ala-D-lactate presented on the surface of mixed self-assembled monolayers (SAMs) of alkanethiolates on gold indicates that the apparent off-rate for dissociation of V-Rd-V from the surface is much slower than that of V from the same surface . CONCLUSIONS: The results are compatible with the hypothesis that divalency is responsible for tight binding, which correlates with small values of minimum inhibitory concentrations of V and V-Rd-V.

Mol Cell Probes, 1999 Jun, 13(3), 223 - 31
Detection of vancomycin resistant genes vanA and vanB by cycling probe technology; Modrusan Z et al.; Cycling Probe Technology (CPT) has been used to develop gene-based assays for detection of vancomycin resistance genes vanA and vanB in enterococci (VRE) . Cycling Probe Technology utilizes a chimeric DNA-RNA-DNA probe that is cleaved by the enzyme RNase H when hybridized to its complementary DNA target . Conversion of full-length probe into the cleaved probe fragments is the basis for detection and quantification of the CPT reaction . Two gene-specific probes, each one unique to either the vanA or vanB gene, were utilized for development of vanA and vanB CPT assays, respectively . Both vanA and vanB CPT assays were used to determine the presence or absence of the corresponding gene in 440 clinical enterococcal isolates . The presence of vanA and vanB gene sequences was detected in 154 and 131 isolates, respectively . Phenotypic characterization of all isolates was determined through interpretation of conventional susceptibility data obtained with the disk diffusion method . Comparison between disk diffusion characterization and CPT assays revealed 11 discrepant isolates . The identity of these isolates was resolved by polymerase chain reaction (PCR) which confirmed the vanA and vanB CPT assay data . Therefore, compared to conventional phenotyping, both the vanA and vanB CPT assays appeared superior for accurate identification of VanA and VanB isolates .

J Bacteriol, 1999 Jun, 181(12), 3644 - 8
Characterization of the vanD glycopeptide resistance gene cluster from Enterococcus faecium BM4339; Casadewall B et al.; VanD-type resistance to glycopeptides in Enterococcus faecium BM4339 is due to constitutive synthesis of D-alanyl-D-lactate-terminating peptidoglycan precursors (B . Perichon, P . Reynolds, and P . Courvalin, Antimicrob . Agents Chemother . 41:2016-2018, 1997) . The sequence of a 5,780-bp fragment was determined and revealed six open reading frames . The 3' distal part encoded the VanHD dehydrogenase, the VanD ligase, and the VanXD DD-dipeptidase, which were highly similar to the corresponding proteins in VanA and VanB types of resistance . The deduced VanYD protein was homologous to penicillin-binding proteins that display DD-carboxypeptidase activity . The 5' end coded for the putative VanRD-VanSD two-component regulatory system . Due to a frameshift mutation in the chromosomal ddl gene, BM4339 produced an impaired D-alanine:D-alanine ligase . However, since expression of the resistance genes is constitutive, growth of E . faecium BM4339 was not dependent on the presence of glycopeptides in the culture medium.

Langenbecks Arch Surg, 1999 Feb, 384(1), 24 - 32
Risk factors associated with intraabdominal infections: a prospective multicenter study . Peritonitis Study Group; Wacha H et al.; INTRODUCTION AND METHODS: A prospective observational multicenter study with 18 hospitals was performed to assess preoperative risk, therapeutic management and outcome of patients with peritonitis . Data collection was carried out according to standardized and recommended definitions . Included in the study were 355 patients with macroscopically confirmed peritonitis . RESULTS: In the univariate analysis, the following factors influenced both the mortality and the incidence of postoperative complications: age, presence of certain concomitant disease, site of origin of peritonitis, type of admission and the ability of the surgeon to eliminate the source of infection . In addition, postoperative infective complications were related to the etiology of peritonitis and the exudate . In the multivariate analysis, APACHE II (P<0.001), successful operation (P<0.001), age (P<0.001), liver disease (P<0.03), malignant disease (P<0.04) and renal disease (P<0.05) turned out to be significant with respect to death . Escherichia coli was the predominant organism (51%), following by enterococci (30%) and bacteroides (25%) . There was a significantly higher postoperative infection rate in patients with no adequate treatment of enterococci than patients with adequate treatment or no enterococci (P<0.05) . CONCLUSION: The study demonstrated the important role of the physiological reserve of the patient and of the surgeon, which is not adequately reflected in existing scoring systems . Further investigations are needed to study the impact of enterococci on the outcome.

J Clin Microbiol, 1999 Jul, 37(7), 2148 - 52
Proficiency of clinical laboratories in Spain in detecting vancomycin-resistant Enterococcus spp . The Spanish VRE Study Group; Alonso-Echanove J et al.; Studies in a variety of U.S . clinical laboratories have demonstrated difficulty in detecting intermediate and low-level vancomycin-resistant enterococci (VRE) . The misclassification of "at least intermediate resistant isolates" as vancomycin susceptible may have both clinical implications and a negative impact on measures to control the spread of VRE . No published study has assessed the ability of clinical laboratories in Europe to detect VRE . So, the apparent low prevalence of VRE in European hospitals may be, in part, secondary to the inability of these laboratories to detect all VRE . In an effort to assess European laboratories' proficiency in detecting VRE, we identified 22 laboratories in Spain and asked them to test four VRE strains and one susceptible enterococcal strain from the Centers for Disease Control and Prevention collection . Each organism was tested by the routine antimicrobial susceptibility testing method used by each laboratory . Overall, VRE were correctly identified in 61 of 88 (69.1%) instances . The accuracy of VRE detection varied with the level of resistance and the antimicrobial susceptibility method . The high-level-resistant strain (Enterococcus faecium; MIC, 512 microg/ml) was accurately detected in 20 of 22 (91 . 3%) instances, whereas the intermediate-resistant isolate (Enterococcus gallinarum; MIC, 8 microg/ml) was accurately detected in only 11 of 22 (50%) instances . Classification errors occurred in 27 of 88 (30.9%) instances . Misclassification as vancomycin susceptible was the most common error (16 of 27 {59.3%} instances) . Our study shows that the participating Spanish laboratories had an overall acceptable proficiency in detecting VRE but that a substantial proportion of VRE isolates with low or intermediate levels of resistance were not detected . We recommend that studies be conducted to validate laboratory proficiency testing as an important step in the prevention and control of the spread of antimicrobial resistance.

Am J Surg, 1999 May, 177(5), 418 - 22
Vancomycin-resistant Enterococcus in liver transplant patients; Orloff SL et al.; BACKGROUND: Vancomycin-resistant Enterococcus (VRE) infection is emerging in the transplant population, and there is no effective antibiotic therapy available . The aims of this retrospective review were to (1) investigate the outcome of and (2) identify common characteristics associated with VRE infection and colonization in orthotopic liver transplant (OLTx) candidates . METHODS: From October 1994 through September 1998, 126 isolates of VRE were identified in 42 of 234 OLTx recipients and 5 OLTx candidates who did not proceed to transplantation . Data were collected by patient chart review or from a computerized hospital database . RESULTS: The 1-year mortality rate with VRE infection was 82%, and with VRE colonization, 7% . This mortality rate contrasts with a 14% 1-year mortality for non-VRE transplant patients (P <0.01, infected patients and colonized patients) . Characteristics of VRE colonized and infected patients included recent prior vancomycin (87%), coinfection by other microbial pathogens (74%), recent prior susceptible enterococcal infection (72%), concurrent fungal infection (62%), additional post-OLTx laparotomies (47%), and renal failure (Cr >2.5 mg/dL or need for dialysis; 43%) . Biliary complications were seen in 52% of post-OLTx VRE-infected or VRE-colonized patients (versus 22% in non-VRE transplant patients, P <0.05) . CONCLUSION: VRE infection is associated with a very high mortality rate after liver transplantation . The incidence of biliary complications prior to VRE isolation is very high in VRE-infected and VRE-colonized patients . The most common characteristics of VRE patients were recent prior vancomycin use, recent prior susceptible enterococcal infection, coinfection with other microbial pathogens, and concurrent fungal infection . With no proven effective antimicrobial therapy for VRE, stringent infection control measures, including strict and limited use of vancomycin, must be practiced.

Biochem Biophys Res Commun, 1999 Jun 7, 259(2), 443 - 9
Effects of promoter mutations on the in vivo regulation of the cop operon of Enterococcus hirae by copper(I) and copper(II); Wunderli-Ye H et al.; The cop operon of Enterococcus hirae encodes a repressor, CopY, a copper chaperone, CopZ, and two copper ATPases, CopA and CopB . Regulation of the cop operon is bi-phasic, with copper addition as well as copper chelation leading to induction . Using a plasmid-borne system with a reporter gene, induction of wild-type and mutant cop promoters by high and low copper conditions was investigated . Only mutations that impaired the interaction of CopY with both DNA binding sites had a marked effect on regulation, leading to hyperinduction by copper(I) or copper(II) . Chelation of copper(II), but not copper(I), also induced the operon, but induction by copper chelation was not significantly affected by the mutations . E . hirae mutants with reduced extracellular copper reductase activity exhibited the same induction kinetics as wild-type cells . These results show that copper addition and copper chelation induce the cop operon by different routes .

Proc Natl Acad Sci U S A, 1999 Jun 8, 96(12), 6908 - 13
Vancomycin-resistant enterococci in intensive-care hospital settings: transmission dynamics, persistence, and the impact of infection control programs; Austin DJ et al.; Vancomycin-resistant enterococci (VRE) recently have emerged as a nosocomial pathogen especially in intensive-care units (ICUs) worldwide . Transmission via the hands of health-care workers is an important determinant of spread and persistence in a VRE-endemic ICU . We describe the transmission of nosocomial pathogens by using a micro-epidemiological framework based on the transmission dynamics of vector-borne diseases . By using the concept of a basic reproductive number, R0, defined as the average number of secondary cases generated by one primary case, we show quantitatively how infection control measures such as hand washing, cohorting, and antibiotic restriction affect nosocomial cross-transmission . By using detailed molecular epidemiological surveillance and compliance monitoring, we found that the estimated basic reproductive number for VRE during a study at the Cook County Hospital, Chicago, was approximately 3-4 without infection control and 0.7 when infection control measures were included . The impact of infection control was to reduce the prevalence from a predicted 79% to an observed 36% . Hand washing and staff cohorting are the most powerful control measures although their efficacy depends on the magnitude of R0 . Under the circumstances tested, endemicity of VRE was stabilized despite infection control measures, by the constant introduction of colonized patients . Multiple stochastic simulations of the model revealed excellent agreement with observed pattern . In conjunction with detailed microbiological surveillance, a mathematical framework provides a precise template to describe the colonization dynamics of VRE in ICUs and impact of infection control measures . Our analyses suggest that compliance for hand washing significantly in excess of reported levels, or the cohorting of nursing staff, are needed to prevent nosocomial transmission of VRE in endemic settings.

Infect Control Hosp Epidemiol, 1999 May, 20(5), 341 - 3
Lack of transmission of vancomycin-resistant enterococci in three long-term-care facilities; Greenaway CA et al.; Three patients colonized with vancomycin-resistant Enterococcus were admitted to one or more of three long-term-care facilities . Six point-prevalence surveys revealed no transmission of vancomycin-resistant Enterococcus after a total of 234 days of exposure during which moderately strict infection control measures were implemented . Four of 116 environmental cultures were positive.

Infect Control Hosp Epidemiol, 1999 May, 20(5), 318 - 23
Enterococcal bacteremia: risk factors for vancomycin resistance and predictors of mortality; Lautenbach E et al.; OBJECTIVE: To identify risk factors for vancomycin resistance and mortality in enterococcal bacteremia . DESIGN: Historical cohort study . SETTING: A large academic medical center with a high prevalence of vancomycin-resistant enterococci (VRE) . PATIENTS: Two hundred sixty patients with enterococcal bacteremia, of whom 72 (28%) had VRE . RESULTS: Independent risk factors for infection with VRE were the mean number of antibiotic days (P<.001), renal insufficiency (P<.001), mean days of vancomycin use (P = .005), and neutropenia (P = .013) . A trend toward a significant association between metronidazole use and VRE also was noted (P = .068) . Mortality was attributable to the bacteremia in 96 patients (37%) . Severity of illness (P<.001) and age (P = .020) were independent risk factors for mortality . Vancomycin resistance was not, however, an independent predictor of mortality . CONCLUSION: These results suggest that restrictions on antibiotic use, particularly in patients with renal insufficiency and neutropenia, may help to combat the rising incidence of VRE . Although patients with VRE bacteremia demonstrated higher mortality rates than patients with infection due to susceptible isolates, vancomycin resistance was not an independent predictor of mortality in these patients and likely serves more as a marker of underlying severity of illness.

J Biol Chem, 1999 Jun 4, 274(23), 16295 - 303
The carbamoyl-phosphate synthetase of Pyrococcus furiosus is enzymologically and structurally a carbamate kinase; Uriarte M et al.; The hyperthermophiles Pyrococcus furiosus and Pyrococcus abyssi make pyrimidines and arginine from carbamoyl phosphate (CP) synthesized by an enzyme that differs from other carbamoyl-phosphate synthetases and that resembles carbamate kinase (CK) in polypeptide mass, amino acid sequence, and oligomeric organization . This enzyme was reported to use ammonia, bicarbonate, and two ATP molecules as carbamoyl-phosphate synthetases to make CP and to exhibit bicarbonatedependent ATPase activity . We have reexamined these findings using the enzyme of P . furiosus expressed in Escherichia coli from the corresponding gene cloned in a plasmid . We show that the enzyme uses chemically made carbamate rather than ammonia and bicarbonate and catalyzes a reaction with the stoichiometry and equilibrium that are typical for CK . Furthermore, the enzyme catalyzes actively full reversion of the CK reaction and exhibits little bicarbonate-dependent ATPase . In addition, it cross-reacts with antibodies raised against CK from Enterococcus faecium, and its three-dimensional structure, judged by x-ray crystallography of enzyme crystals, is very similar to that of CK . Thus, the enzyme is, in all respects other than its function in vivo, a CK . Because in other organisms the function of CK is to make ATP from ADP and CP derived from arginine catabolism, this is the first example of using CK for making rather than using CP . The reasons for this use and the adaptation of the enzyme to this new function are discussed.

Emerg Infect Dis, 1999 May-Jun, 5(3), 329 - 35
Use of antimicrobial growth promoters in food animals and Enterococcus faecium resistance to therapeutic antimicrobial drugs in Europe; Wegener HC et al.; Supplementing animal feed with antimicrobial agents to enhance growth has been common practice for more than 30 years and is estimated to constitute more than half the total antimicrobial use worldwide . The potential public health consequences of this use have been debated; however, until recently, clear evidence of a health risk was not available . Accumulating evidence now indicates that the use of the glycopeptide avoparcin as a growth promoter has created in food animals a major reservoir of Enterococcus faecium, which contains the high level glycopeptide resistance determinant vanA, located on the Tn1546 transposon . Furthermore, glycopeptide-resistant strains, as well as resistance determinants, can be transmitted from animals to humans . Two antimicrobial classes expected to provide the future therapeutic options for treatment of infections with vancomycin-resistant enterococci have analogues among the growth promoters, and a huge animal reservoir of resistant E . faecium has already been created, posing a new public health problem.

J Bioenerg Biomembr, 1999 Feb, 31(1), 7 - 14
Structure and function of vacuolar Na+-translocating ATPase in Enterococcus hirae; Kakinuma Y et al.; A Na+-translocating ATPase was discovered in a gram-positive bacterium Enterococcus hirae . Our biochemical and molecular biological studies revealed that this Na+-ATPase belongs to the vacuolar-type enzyme . Purified Na+-ATPase consisted of nine subunits: NtpA, B, C, D, E, F, G, I, and K; reconstituted proteoliposomes showed ATP-driven electrogenic Na+ translocation . All these subunits were encoded by the ntp operon: ntpFIKECGABDHJ . The deduced amino acid sequences of the major subunits, A, B, and K (16 kDa proteolipid), were highly similar to those of A, B, and proteolipid subunits of vacuolar ATPases, although the similarities of other subunits were moderate . The ntpJ gene encoded a K+ transporter independent of the Na+-ATPase . Expression of this operon, encoding two transport systems for Na+ and K+ ions, was regulated at transcriptional level by intracellular Na+ as the signal . Two related cation pumps, vacuolar Na+-ATPase and F0F1, H+-ATPase, coexist in this bacterium.

Microb Drug Resist, 1999 Spring, 5(1), 53 - 6
Glycopeptide resistance in Enterococcus faecium from broilers and pigs following discontinued use of avoparcin; Bager F et al.; The use of the glycopeptide growth promoter avoparcin was discontinued in Denmark in 1995 following concerns that vancomycin-resistant Enterococcus faecium occurring as a result of its use could be transferred to humans via food . The present study is an analysis of results obtained by the continuous surveillance of an antimicrobial resistance in Denmark (DANMAP) with the aim of determining the effect of the ban on the occurrence of glycopeptide resistance among E . faecium isolated from broilers and pigs . Among isolates from broilers, the proportion that were resistant to glycopeptides has shown a statistically high significant decline between the end of 1995 and the first half of 1998, whereas in pigs the ban appears to have no such effect . One possible explanation is that the broiler industry generally uses all in-all out production compared with continuous production in pig herds . Alternatively, the results indicate that the different outcomes may result from different co-selection patterns in pigs and broilers . In pigs, the antimicrobials most commonly used favored co-selection of glycopeptide resistant strains of E . faecium while in broilers the antimicrobials most widely used selected for glycopeptide-susceptible strains . The results show that intervention to reduce antimicrobial resistance may not always be effective and preventing resistance problems therefore becomes essential.

J Clin Microbiol, 1999 Jun, 37(6), 2090 - 2
Detection of clinically relevant genotypes of vancomycin-resistant enterococci in nosocomial surveillance specimens by PCR; Jayaratne P et al.; This study evaluated a PCR method for the rapid detection of clinically significant genotypes of vancomycin-resistant enterococci (VRE) in nosocomial surveillance specimens . Detection of the vanA and vanB genes by multiplex PCR using 657 specimens that showed presumptive growth of VRE on bile esculin azide agar containing 6 mg of vancomycin/liter was compared to the conventional method . The diagnostic values for the PCR compared to the phenotypic method were as follows: 99.8% specificity, 95.4% sensitivity, 98.8% positive predictive value, and 99.3% negative predictive value . The average cost per test for PCR is $8.26, compared to $9.45 for the phenotypic method . The average turnaround time for detecting a VRE is 48 h for PCR, compared to 96 h for the conventional method.

Am J Knee Surg, 1999 Spring, 12(2), 88 - 90
Simultaneous primary and contralateral revision total knee arthroplasty; Ries MD; Seven patients underwent primary and contralateral revision total knee arthroplasty (TKA) under one anesthetic in a sequential fashion . The average patient age was 67.6+/-6.9 years . Average blood loss was 764+/-568 cc, average operative time was 269+/-107 minutes, and average length of hospital stay was 9.6+/-3.4 days . One patient with a history of hypertension, diabetes, and coronary heart disease died from pulmonary embolism 7 days after surgery . Deep infection with enterococcus developed in the revised knee of another patient 3 months after surgery . For the six surviving patients, knee pain and function were improved by surgery . However, in this small series of patients, two major complications occurred . These results indicate that if this procedure is considered at all, it should be reserved for only healthy patients with relatively uncomplicated knee reconstructions.

Invest Ophthalmol Vis Sci, 1999 May, 40(6), 1305 - 9
Retinopathy associated with enterococcus enteropathy in the neonatal rat; Zhang S et al.; PURPOSE: Preretinal neovascularization has been previously observed in neonatal rats with spontaneously occurring diarrhea . This neovascularization appears analogous to retinopathy of prematurity (ROP), which occurs in human neonates . A new enterococcus species, designated Enterococcus rattus, has been isolated from the duodenum of these rats . In the present controlled study, the effect of the enteropathy induced by this organism on the retinal vasculature in the neonatal rat was further investigated . METHODS: One hundred fifty newborn Sprague-Dawley rats were randomly assigned to 6 expanded litters (n = 25) . On the second day of life, animals were gavaged with either 100 microl of E . rattus suspension (1.0 X 10(7) colony forming units, inoculated group, n = 100 rats) or 100 microl saline (control group, n = 50 rats) . All rats were raised in room air and were killed on day 13 of life . Duodenal and blood samples were cultured . The retinal vasculature was assessed using fluorescent microscopy and ADPase staining in a masked manner . Two additional inoculated litters and one control litter were studied for evaluation of arterial blood gases and validation of the grading method for preretinal neovascularization . RESULTS: One hundred percent of rats in the inoculated group developed severe diarrhea and had duodenal cultures positive for E . rattus compared with 0% in the control group . Preretinal neovascularization similar to ROP occurred in 55% of rats in the inoculated group compared with 2% in the control group (P = 0.001) . Retinal vascular areas were reduced in the inoculated group (mean +/- SD, 89% +/- 5% versus 96% +/- 2%; P < 0.001) . Rats in the inoculated group demonstrated severe growth retardation (final weight, 9.7 +/- 2.2 versus 16.7 +/- 2.7 g, P < 0.001) . Inoculated animals also experienced acidosis (pH 7.31 +/- 0.06 versus 7.39 +/- 0.06 control, P = 0.04) . CONCLUSIONS: A previously undescribed enterococcal enteropathy was associated with preretinal neovascularization similar to ROP in the neonatal rat . This supports an independent role for factors other than inspired oxygen in the development of ROP.

APMIS, 1999 Apr, 107(4), 404 - 12
Detection of clinical vancomycin-resistant enterococci in Denmark by multiplex PCR and sandwich hybridization; Poulsen RL et al.; Since the first cases of human infection with vancomycin-resistant enterococci (VRE) were reported in the late eighties, there has been a dramatic increase in VRE all over the world . So far, there have not been any reports of clinical VRE in Denmark . In this study we have investigated 131 clinically important enterococci sent to Statens Serum Institut from all over Denmark during the period July 1995 to May 1997 . The susceptibility to vancomycin, teicoplanin, ampicillin and gentamicin was tested by the agar dilution method . In addition, two methods were developed to detect the different genotypes of glycopeptide resistance described in enterococci: a multiplex PCR assay for detection of vanA, vanB, vanC-1, vanC-2/3 ligase genes including 16S rRNA gene control primers and a sandwich hybridization assay to confirm vanA and vanB PCR-positive strains . The highest frequency of resistance to the tested antibiotics was found in the Enterococcus faecium group . Four strains were found with acquired resistance to glycopeptides: one E . faecium and one E . gallinarum were vanA positive, and two E . faecium isolates were vanB positive . These strains were isolated from different hospitals in different periods of time, and all patients recovered from their infections with VRE . Today, the PCR and sandwich hybridization methods are used for screening of vancomycin-resistant enterococci in humans as part of the Danish surveillance programme.

FEMS Microbiol Lett, 1999 Apr 15, 173(2), 341 - 6
Nucleotide sequence of IS1542, an insertion sequence identified within VanA glycopeptide resistance elements of enterococci; Darini AL et al.; IS1542 is an insertion sequence-like element which was originally identified in the orf2-vanR intergenic region of VanA resistance elements of glycopeptide-resistant Enterococcus faecium from hospital patients and from non-human sources in the UK . The nucleotide sequence of IS1542 was determined . It showed 81% homology with IS256 and contained an open reading frame sufficient to encode a 390 amino acid peptide predicted to have 87.2% identity with the transposase of IS256 . By PCR, IS1542 was detected in the genomes of 26 of 28 (93%) VanA enterococci isolated from poultry in the UK and Ireland, but in only two of 65 (3%) glycopeptide-sensitive or VanC enterococci from hospital patients in the UK and Brazil . IS1542 may be a useful marker for evolutionary and epidemiological studies of VanA glycopeptide resistance in enterococci.

Pediatr Infect Dis J, 1999 Apr, 18(4), 352 - 6
Epidemiology and control of vancomycin-resistant enterococci in a regional neonatal intensive care unit; Malik RK et al.; BACKGROUND: After the occurrence of two cases of bloodstream infection with vancomycin-resistant enterococci (VRE) in our regional neonatal intensive care unit, we studied the epidemiology of VRE and applied extensive infection control measures to the unit to control VRE transmission . METHODS: Infection control measures applied to the unit included weekly surveillance for VRE colonization; education; cohorting of VRE-positive, VRE-negative and VRE-exposed babies with separate personnel and equipment for each group; use of gowns and gloves on room entry; and hand washing before and after each patient contact . Risk factors for VRE colonization were determined with a stepwise logistic regression model . RESULTS: Thirty-three (40.2%) babies became colonized with VRE . The VRE colonization rate was reduced from 67% to 7% after implementation of infection control measures . Prolonged antimicrobial treatment and low birth weight were significantly associated with an increased risk of VRE colonization . CONCLUSION: VRE can spread rapidly among newborns in a regional neonatal intensive care unit . Strict infection control measures can reduce the rate of VRE colonization among neonates.

Lakartidningen, 1999 Apr 7, 96(14), 1694 - 5
{Aminoglycoside-resistant enterococci a new bacterial hazard}; Melhus A; Enterococci are common causative agents in a broad range of human infections . Although formerly considered to be of low virulence, in recent years they have emerged as important pathogens, particularly in the hospital environment . Enterococci are not only intrinsically resistant to several antibiotics, but are also characterised by a potent and unique ability to exchange genetic material . With the increasing prevalence of strains resistant to ampicillin, aminoglycosides and glycopeptides, serious therapeutic difficulties have become more common . Epidemiological aspects, the mechanisms of action, the detection of antibiotic resistance, and the situation of enterococci in Sweden are discussed in the article.

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