Epidemiologic analysis and genotypic characterization of a nosocomial outbreak of vancomycin-resistant enterococci

Real-Time PCR Assay for Rapid and Simultaneous Detection of vanA and vanB Genes in Clinical Strains

Here, we develop a robust and sensitive real-time PCR assay which allows the simultaneous detection of vanA and vanB genes using common primers. The system was designed using the Primer3 online software. The specificity of primers and probes was first checked by in silico PCR and by BlastN analysis. The genomic DNA of 255 bacterial isolates, including Enterococcus spp., Gram-negative, and Gram-positive strains, as well as a collection of 50 stool and 50 rectal swab samples, were tested to evaluate the specificity of the new real-time PCR (RT-PCR) system. The results of the designed RT-PCR were 100% specific and 100% positive on tested vancomycin resistant isolates harboring either the vanA or vanB gene. RT-PCR assays were negative for all other bacterial species tested including vancomycin-sensitive Enterococci and Enterococcus strains harboring vanC genes. The limit of detection of vanA and vanB genes by RT-PCR assay was 47 CFU/mL and 32 CFU/mL, respectively. The rapid and accurate detection of vancomycin-resistant Enterococci is the cornerstone for minimizing the risk of nosocomial transmissions and outbreaks. We believe that this assay will strengthen routine diagnostics and surveillance programs.

Ciprofloxacin and Cefazolin as a Combination for Empirical Initial Therapy of Peritoneal Dialysis-Related Peritonitis: Five-year Follow-up

The treatment of peritoneal dialysis (PD)-related peritonitis has been a matter of extensive investigation, frequently generating therapeutic trials. Several combinations of antibiotics have served as newer protocols and tended to be efficacious, comfortable, and cost-effective. According to the more recent recommendations from the International Society for Peritoneal Dialysis, the rationale for empirical initial therapy of clinically detected peritonitis in PD patients has been to follow the bacterial profile derived from cultured specimens of PD effluents.

The current study describes 5 year's experience with the use of a new antibiotic regimen for the treatment of peritonitis. We herein analyze the outcome of 95 episodes of peritonitis in 54 patients on either automated PD or continuous ambulatory PD at the dialysis unit of the Federal University of Rio de Janeiro. Peritoneal dialysis-related peritonitis was treated with the combination of oral ciprofloxacin and intraperitoneal cefazolin. The observed cure rate was 85.2% and the sensitivity test was observed to be positive for this combination of antibiotics in 88.9% of positive cultures. Of the 14 unsuccessful episodes, 7 were due to catheter colonization and the rest did not respond to the proposed therapy within 48 hours. These 7 cases were also related to peritoneal fluid cultures that were resistant to both ciprofloxacin and cefazolin.

From this study, we propose this combination of oral ciprofloxacin and intraperitoneal cefazolin as a first choice for empirical initial therapy of PD-related peritonitis, given its efficacy and low cost. However, in order to apply the most adequate cost-effective therapy, careful examination of the bacterial profile and sensitivities to antibiotics used in each unit is strongly recommended.

Oral Vancomycin May Be Associated With Earlier Symptom Resolution Than Metronidazole for Hospitalized Children With Nonsevere Clostridiodes difficile Infections

OBJECTIVE

National guidelines recommend oral vancomycin over oral metronidazole as first-line treatment for nonsevere Clostridioides difficile infection (CDI) in adults. Guidelines recommend metronidazole for children with nonsevere CDI, emphasizing that comparative effectiveness studies comparing the relative efficacy of vancomycin and metronidazole are lacking in children.

METHOD

We conducted an observational study of hospitalized children with nonsevere CDI treated with metronidazole versus vancomycin using an inverse probability of treatment-weighted propensity-score analysis. All of the following criteria had to be present for children with positive CDI testing for study eligibility: (1) ≥3 new-onset unformed stools within a 24-hour period; (2) 2-17 years of age; (3) hospitalization for ≥48 hours for CDI; (4) no laxative use ≤48 hours; (5) no alternate etiology for diarrhea; (6) no previous episode of CDI ≤3 months; (7) no concurrent non-CDI-targeted antibiotic therapy, and (8) no severe or fulminant CDI.

RESULTS

One hundred ninety-two patients met eligibility criteria; 141 (73.4%) received oral metronidazole and 51 (26.6%) children received oral vancomycin. Baseline characteristics were similar between the 2 groups in the weighted cohort. Of 141 patients, 101 (71.7%) children receiving metronidazole had clinical improvement by day 5, whereas 44 of 51 (86.3%) cases resolved with vancomycin (odds ratio, 0.40; 95% confidence interval, 0.17-0.97; P = .04). The odds of CDI recurrence within 12 weeks were similar between the groups.

CONCLUSIONS

Our study suggests that children with nonsevere CDI have earlier resolution of clinical symptoms when prescribed vancomycin compared with metronidazole. Large interventional studies are necessary to evaluate the reproducibility of our findings.

Local Application of Vancomycin in Spine Surgery Does Not Result in Increased Vancomycin-Resistant Bacteria-10-Year Data

STUDY DESIGN

Case-control study.

OBJECTIVES

To analyze the microbial flora in surgical spine infections and their antibiotic resistance patterns across time and determine the correlation between vancomycin application in the wound and vancomycin-resistant microbes.

SUMMARY OF BACKGROUND DATA

Prior studies show a reduction in surgical site infections with intrawound vancomycin placement. No data are available on the potential negative effects of this intervention, in particular, whether there would be a resultant increase in vancomycin-resistant organisms or bacterial resistance profiles.

METHODS

All culture-positive surgical site infections at a single institution were analyzed from 2007 to 2017. Each bacterium was assessed independently for resistance patterns. The two-tailed Fisher exact test was used to determine the correlation between vancomycin application and the presence of vancomycin-resistant bacteria, polymicrobial infections, or gram-negative bacterial infections.

RESULTS

One hundred and eight bacteria were isolated from 113 surgical site infections from 2007 to 2017. The most common organisms were staphylococcus with varying resistance patterns and Escherichia coli. Vancomycin-resistant Enterococcus faecium was isolated in three infections. Out of the 4,878 surgical cases from 2011 to 2017, vancomycin was placed in 48.3%, and no vancomycin in 51.7%. There were 33 infections (1.4%) in the vancomycin group and 20 infections (0.8%) in the no-vancomycin group (χ² = 0.0521). There was no correlation between vancomycin application in the wound and vancomycin-resistant microbes (χ² = 0.2334) and polymicrobial infections (χ² = 0.1328). There was an increased rate of gram-negative organisms in infections after vancomycin application in the wound versus no vancomycin (χ² = 0.0254).

CONCLUSIONS

Topical vancomycin within the surgical site is not correlated with vancomycin-resistant bacteria. However, there was an increased incidence of gram-negative organisms in infections after vancomycin application in the wound versus no vancomycin. Continued surveillance with prospectively collected randomized data is necessary to better understand bacterial evolution against current antimicrobial techniques.

LEVEL OF EVIDENCE

Level III.

Prevalence of vancomycin resistance among isolates of enterococci in Iran: a systematic review and meta-analysis

Introduction

Enterococcus is responsible for 10% of hospital-acquired infections. The purpose of this review was to evaluate the prevalence of vancomycin-resistant Enterococcus (VRE) isolates in Iran using a meta-analysis method.

Materials and methods

Iranian databases, including Magiran and IranDoc, and international databases, including PubMed and MedLib, were examined carefully, and a total of 20 articles published between 2000 and 2011 were extracted. The data were subjected to meta-analysis and random-effects models. In addition, heterogeneous studies were assessed using the I ² index. Finally, the data were analyzed using R and STATA software.

Results

The results showed that the strain of Enterococcus faecalis had been more common than Enterococcus faecium in clinical infection (69% vs 28%). However, resistance to vancomycin was higher among strains of E. faecium compared with strains of E. faecalis (33% vs 3%). The complete resistance, intermediate resistance, and sensitivity to vancomycin among Enterococcus isolates were 14% (95% CI: 11, 18), 14% (95% CI: 5, 23), and 74% (95% CI: 65, 83), respectively. The resistance patterns, depending on the sample type, did not show a significant difference. In addition, the resistance of isolated strains to vancomycin in outpatients was significantly higher than that in inpatients (16% vs 1%). Moreover, 80%-86% of resistant strains were genotype van A and 14%-20% of resistant strains were genotype van B.

Conclusion

The findings of the present review show that there is a high frequency of resistant Enterococcus in Iran. Therefore, consideration of the prevalence and frequency of subjected resistant strains can be helpful for decision makers to implement proper health policies in this direction.

Effectiveness of a Lytic Phage SRG1 against Vancomycin-Resistant Enterococcus faecalis in Compost and Soil

Nosocomial infections caused by vancomycin-resistant Enterococcus have become a major problem. Bacteriophage therapy is proposed as a potential alternative therapy. Bacteriophages are viruses that infect bacteria and are ubiquitous in nature. Lytic bacteriophage was isolated from sewage water that infects VREF, the causative agent of endocarditis, bacteraemia, and urinary tract infections (UTIs). The phage produced clear plaques with unique clear morphology and well-defined boundaries. TEM results of phage revealed it to be 108 ± 0.2 nm long and 90 ± 0.5 nm wide. The characterization of bacteriophage revealed that infection process of phage was calcium and magnesium dependent and phage titers were highest under optimum conditions for VREF, with an optimal temperature range of 37–50°C. The maximum growth was observed at 37°C, hence having 100% viability. The latent period for phage was small with a burst size of 512 viral particles per bacterial cell. The phage was tested against various clinical strains and results proved it to be host specific. It can be used as a potential therapeutic agent for VREF infections. The phage efficiently eradicated VREF inoculated in cattle compost, poultry compost, and a soil sample which makes it a potential agent for clearing compost and soil sample.

Molecular Characterization and Resistant Spectrum of Enterococci Isolated from a Haematology Unit in China

OBJECTIVES

The present study screened clinical isolates of E. faecalis and E. faecium to determine resistant spectrum and the potential virulence genes characterization among them of haematology patients.

METHODS

Clinical Enterococci isolates were obtained from a haematology unit in a tertiary care hospital in China.

RESULTS

Among 125 isolates available for the investigation, 46 were identified as E. faecium, and 79 were E. faecalis. Urine was the most common source (82, 65.6%). E. faecium isolates were more resistant than E. faecalis. Among E. faecium, maximum resistance was seen against PEN 93.5% and AMP 93.5% followed by CIP 87%. Eight vancomycin-resistant E. faecium (VREfm) isolates were obtained, positive for vanA genotype. Of 125 Enterococci isolates, 67(53.6%) were acm, and 42.4%, 25.6%, 25.6%, 24.8%, 23.2%, 20.8%, 10.4% and 7.2% of isolates were positive for esp, cylL-A, asa 1, cylL-S, cpd, cylL-L, gel-E and ace, respectively. E. faecalis isolates have more virulence genes (VGs) than E. faecium. MLST analysis of VREfm identified three different STs (ST17, ST78 and ST203).

CONCLUSION

The study provides the molecular characterization and resistant spectrum of Enterococci isolated from a haematology unit in China. Molecular analysis showed that all VREfm isolates belonged to pandemic clonal complex-17(CC17), associated with hospital-related isolates. Therefore, determining resistant spectrum and virulence characterization is crucial for the prevention and control of the spread of nosocomial infections caused by Enterococci in the haematology unit.

Guideline for Prevention of Intravascular-Device–Related Infections

The “Guideline for Prevention of Intravascular Device-Related Infections” is designed to reduce the incidence of intravascular device-related infections by providing an over view of the evidence for recommendations considered prudent by consensus of Hospital Infection Control Practices Advisor y Committee (HICPAC) members. This two-part document updates and replaces the previously published Centers for Disease Control's (CDC) Guideline for Intravascular Infections (Am J Infect Control1983;11:183-199). Part I, “Intravascular Device-Related Infections: An Over view” discusses many of the issues and controversies in intravascular-device use and maintenance. These issues include definitions and diagnosis of catheter-related infection, appropriate barrier precautions during catheter insertion, inter vals for replacement of catheters, intravenous (IV) fluids and administration sets, catheter-site care, the role of specialized IV personnel, and the use of prophylactic antimi-crobials, flush solutions, and anticoagulants. Part II, “Recommendations for Prevention of Intravascular Device-Related Infections” provides consensus recommendations of the HICPAC for the prevention and control of intravascular device-related infections. A working draft of this document also was reviewed by experts in hospital infection control, internal medicine, pediatrics, and intravenous therapy. However, all recommendations contained in the guideline may not reflect the opinion of all reviewers.

Outcomes Associated With Vancomycin-Resistant Enterococci: A Meta-Analysis

Background:

Because patients with vancomycin-resistantEnterococcusbacteremia (VREB) usually have a higher severity of illness, it has been unclear whether VREB is worse than vancomycin-susceptibleEnterococcusbacteremia (VSEB).

Methods:

Data on morbidity and case fatality rates and costs were pooled from studies comparing VREB and VSEB, identified by Medline (January 1986 to April 2002) and meeting abstracts. Heterogeneity across studies was assessed with contingency table chi-square. Multivariate analyses (MVAs) controlling for other predictors were evaluated.

Results:

Thirteen studies compared case-fatality rates of VREB and VSEB. VREB case fatality was significantly higher (48.9% vs 19%; RR, 2.57; CI95, 2.27 to 2.91; attributable mortality = 30%). Five studies compared VREB with VSEB when bacteremia was the direct cause of death; VREB case fatality was significantly higher (39.1% vs 21.8%; RR, 1.79; CI95, 1.28 to 2.5; attributable mortality = 17%). Four MVAs found significant increases in case-fatality rates (OR 2.10 to 4.0), 3 showed trends toward increase (OR, 1.74 to 3.34 with wide confidence intervals), and 3 with low statistical power found no difference. VREB recurred in 16.9% versus 3.7% with VSEB (P< .0001). Three studies reported significant increases in LOS, costs, or both with VREB.

Conclusion:

Most studies have had inadequate sample size, inadequate adjustment for other predictors of adverse outcomes, or both, but available data suggest that VREB is associated with higher recurrence, mortality, and excess costs than VSEB including multiple studies adjusting for severity of illness.

Effects of Pharmacist Intervention on the Utilization of Vancomycin in a Teaching Hospital

In order to investigate the effect of pharmacist intervention on vancomycin use, this study was performed on all patients receiving vancomycin in the intensive care unit (ICU) and hematology-oncology ward of Taleghani Educational Hospital in Tehran, Iran. Vancomycin use was assessed during a pre- and post-intervention period in accordance with the Center of Disease Control and prevention (CDC) and Infectious Diseases Society of America (IDSA) guidelines. Following the intervention, there was a significant change in appropriate initiation of vancomycin (P = 0.009) and no significant improvement was observed in adequate dosage and the duration of therapy (P = 0.15 and P = 0.54 respectively); however, informing the physician resulted in discontinuation of the drug in 50% of inappropriate cases and vancomycin dosage was adjustedin 31% of cases. Temperature charts, culture results and pre-treatment CBC tests changed significantly (P = 0.02, P = 0.009 and P = 0.04 respectively). The rate of infusion related adverse drug reactions did not decrease significantly (P = 0.06); yet in 100% of patients, these reactions were resolved after notifying the nursing team. After pharmacist intervention,vancomycin use improved in some aspects. A significant improvement in appropriate initiation of therapy was observed; however, treatments continued despite negative cultures. It is necessary to optimize the use of vancomycin by performing more educational interventions.

Clinical features, risk factors and outcomes of bacteremia due to enterococci with high-level gentamicin resistance: comparison with bacteremia due to enterococci without high-level gentamicin resistance

High-level gentamicin resistance (HLGR) in enterococci has increased since the 1980s, but the clinical significance of the resistance and its impact on outcome have not been established. One hundred and thirty-six patients with bacteremia caused by enterococci with HLGR (HLGR group) were compared with 79 patients with bacteremia caused by enterococci without HLGR (non-HLGR group). Hematologic malignancy, neutropenia, Enterococcus faecium infection, nosocomial infection and monomicrobial bacteremia were more common in the HLGR group than the non-HLGR group, and APACHE II scores were also higher (P<0.05, in each case). Neutropenia, monomicrobial infection, stay in intensive care at culture, and use of 3rd generation cephalosporin, were independent risk factors for acquisition of HLGR enterococcal bacteremia. Fourteen-day and 30-day mortalities were higher in the HLGR group than the non-HLGR group in univariate analysis (37% vs. 15%, P=0.001; 50% vs. 22%, P<0.001). However, HLGR was not an independent risk factor for mortality due to enterococcal bacteremia in multivariate analysis. Therefore, HLGR enterococcal bacteremia is associated with more severe comorbid conditions and higher mortality than non-HLGR enterococcal bacteremia but the HLGR itself does not contribute significantly to mortality.

Technical improvement to prevent DNA degradation of Leptospira spp. in pulsed field gel electrophoresis

Leptospirosis is a public health problem. Infection with pathogenic Leptospira occurs by exposure to many environments and is traditionally associated with occupational risk activities. Pulsed-field gel electrophoresis was used to investigate the epidemiological relatedness among Leptospira isolates. However, analysis by PFGE yielded inconclusive data as a result of extensive DNA degradation. This degradation can be significantly reduced by the inclusion of thiourea in the electrophoresis buffer, improving the analysis of DNA banding patterns.

Distribution and genetic relatedness of vancomycin-resistant enterococci (VRE) isolated from healthy slaughtered chickens in Hungary from 2001 to 2004

The presence of the vanA gene was determined in enterococci from healthy poultry, originating from the Hungarian resistance monitoring system between 2001 and 2004. Enterococci (n = 562) were collected from intestinal samples of slaughtered broiler chickens. The presence of van genes was detected by polymerase chain reaction (PCR). The vancomycin-resistant enterococcus (VRE) strains carried only the vanA gene. Genus- and species-level identification of the vanA gene carrier strains was carried out by PCR using specific primers. In 2001, 25 out of the 289 isolated strains (8.6%) were vanA carriers (1 Enterococcus mundtii, 13 E. durans and 11 E.faecium). In 2002 (n = 87), 20 (23%) strains were vanA positive (11 E. durans and 9 E. faecium). In 2003 and 2004, none of the strains (n = 95 and 91, respectively) were positive for the most common van genes. In 2003, there was only one strain for which higher minimum inhibitory concentrations (MIC) of vancomycin (4 mg/L) and teicoplanin (8 mg/L) were found. In 2004 there were three strains for which the MIC of vancomycin was 8 mg/L, and 2 strains and 1 strain with teicoplanin MICs of 4 mg/L and 8 mg/L, respectively. The potential similarity of these strains was studied by pulsed-field gel electrophoresis (PFGE). The VRE strains were not closely related to one another. The annual data of vancomycin resistance indicate an association between the recovery of vancomycin-resistant enterococci and the use of avoparcin in animal feeds. This study indicates that with the reduced use of antibiotics in food animals, it is possible to decrease the rate of resistant bacteria. Although the use of avoparcin had been banned in 1998, the VRE strains disappeared only five years later.

A population-based investigation of invasive vancomycin-resistant Enterococcus infection in metropolitan Atlanta, Georgia, and predictors of mortality

BACKGROUND

Vancomycin-resistant Enterococcus organisms (VRE) have emerged as common nosocomial pathogens, but few population-based data are available on the impact of invasive VRE infections.

METHODS

We assessed the incidence of invasive VRE infections and predictors of mortality among patients identified during prospective, population-based surveillance performed in the metropolitan statistical area (MSA) of Atlanta, Georgia.

RESULTS

From July 1997 through June 2000, a total of 192 patients who resided in the Atlanta MSA developed an invasive VRE infection, for a rate of 1.57 cases per 100,000 person-years. The incidence of invasive VRE disease significantly increased from 0.91 cases per 100,000 person-years during the first year of the study to 1.73 cases per 100,000 person-years during the third year of the study (P<.001). Rates of invasive VRE infection were significantly higher among African American patients than white patients (2.59 vs 0.70 cases per 100,000 person-years; P<.001). Blood was the most common sterile site from which VRE was recovered (161 [83%] of 193 isolates), followed by deep surgical sites (17 [9%]), peritoneal fluid (10 [5%]), pleural fluid (3 [2%]), and cerebrospinal fluid (1 [0.5%]). In multivariate analysis, a Charlson comorbidity index of 5 or greater, previous receipt of antibiotic therapy, having 2 or more sets of blood cultures positive for VRE, and receipt of central parenteral nutrition were independent predictors of mortality, whereas receipt of an antibiotic with in vitro activity against the VRE isolate was associated with a decreased risk of mortality. Molecular typing revealed 38 different pulsed-field gel electrophoresis patterns, but the 2 most common pulsed-field gel electrophoresis types were found at 3 Emory University-affiliated hospitals.

CONCLUSIONS

The incidence of invasive VRE infection significantly increased in the Atlanta MSA during the 3-year study period, with significant racial disparities detected. Receipt of an antimicrobial agent with in vitro activity against VRE was associated with a lower mortality rate. Molecular typing results demonstrated polyclonal emergence of VRE in Atlanta.

A comparison of vancomycin and metronidazole for the treatment of Clostridium difficile-associated diarrhea, stratified by disease severity

BACKGROUND

The incidence and severity of Clostridium difficile-associated diarrhea (CDAD) has been increasing, and there have been recent reports of metronidazole treatment failure. Metronidazole is still commonly used as first-line treatment for CDAD but has never been compared with vancomycin in a prospective, randomized, double-blind, placebo-controlled trial. We conducted such a trial, stratifying patients according to disease severity, to investigate whether one agent was superior for treating either mild or severe disease.

METHODS

From October 1994 through June 2002, patients with CDAD were stratified according to whether they had mild or severe disease based on clinical criteria and were randomly assigned to receive oral metronidazole (250 mg 4 times per day) or oral vancomycin (125 mg 4 times per day) for 10 days. Both groups received an oral placebo in addition to the study drug. Patients were followed up for 21 days to assess cure, treatment failure, relapse, or intolerance.

RESULTS

One hundred seventy-two patients were enrolled, and 150 of these patients successfully completed the trial. Among the patients with mild CDAD, treatment with metronidazole or vancomycin resulted in clinical cure in 90% and 98% of the patients, respectively (P=.36). Among the patients with severe CDAD, treatment with metronidazole or vancomycin resulted in clinical cure in 76% and 97% of the patients, respectively (P=.02). Clinical symptoms recurred in 15% of the patients treated with metronidazole and 14% of those treated with vancomycin.

CONCLUSIONS

Our findings suggest that metronidazole and vancomycin are equally effective for the treatment of mild CDAD, but vancomycin is superior for treating patients with severe CDAD.

A 24-hour screening protocol for identification of vancomycin-resistant Enterococcus faecium

We describe a 24-h protocol for the identification of patients who are positive for vancomycin-resistant Enterococcus faecium (VRE), using stool and rectal swab samples and VRE screening broth, automated DNA extraction, and real-time PCR for vanA and vanB genes. Compared to conventional screening methods, this protocol had a high sensitivity and specificity and a negative predictive value.

The influence of antibiotic use on the occurrence of vancomycin-resistant enterococci

BACKGROUND

Several studies have documented the influence of antibiotic selective pressure, mainly from the use of glycopeptides, third-generation cephalosporins, quinolones and lincosamides, on the frequency of vancomycin-resistant enterococci (VRE) occurrence in hospitals. The aim of this study was to evaluate the relationship between VRE occurrence and antibiotic use in the Department of Hemato-Oncology of the Teaching Hospital in Olomouc (DHO), Czech Republic, over a 6-year period under standard and unchanged hygienic and epidemiological conditions.

METHODS

During the period of 1998-2003, Enterococcus sp. strains and VRE were isolated by standard methods from clinical samples taken from DHO in-patients. The frequency of VRE occurrence was expressed as the number of isolated strains per 100 bed-days/year. DHO antibiotic consumption data were processed according to the anatomical therapeutic chemical (ATC)/defined daily dose (DDD) system valid in 2003 and expressed in defined daily dose per 100 bed-days (DDD/100 bed-days) for each year of the period.

RESULTS

Since 1998, the occurrence of VRE decreased significantly (from 0.28 to 0.17 VRE/100 bed-days in 2001). Between 2001 and 2003, a significant (P < 0.05) increase from 0.17 to 0.38 was observed. The antibiotic use decreased from 205.2 in 1998 to 161.0 DDD/100 bed-days in 1999 and after an increase in 2001 (to 181.8 DDD/100 bed-days) it remained relatively stable. A significant decrease was observed in third-generation cephalosporins and quinolones (from 29.5 to 9.7 and from 42.2 to 30.2 DDD/100 bed-days respectively) between 1998 and 1999. In 2002-2003, the use of third-generation cephalosporins and glycopeptides increased substantially (from 10.1 to 13.9 and from 11.3 to 15.2 DDD/100 bed-days respectively). The Pearson correlation value was significantly positive (P < 0.05) for VRE occurrence and the use of glycopeptides and third-generation cephalosporins.

CONCLUSIONS

While our study confirms the effect of use of glycopeptides and third-generation cephalosporins on occurrence of VRE, no influence of quinolones and lincosamides over the 6-year period was shown.

Antimicrobial stewardship programs in health care systems

Antimicrobial stewardship programs in hospitals seek to optimize antimicrobial prescribing in order to improve individual patient care as well as reduce hospital costs and slow the spread of antimicrobial resistance. With antimicrobial resistance on the rise worldwide and few new agents in development, antimicrobial stewardship programs are more important than ever in ensuring the continued efficacy of available antimicrobials. The design of antimicrobial management programs should be based on the best current understanding of the relationship between antimicrobial use and resistance. Such programs should be administered by multidisciplinary teams composed of infectious diseases physicians, clinical pharmacists, clinical microbiologists, and infection control practitioners and should be actively supported by hospital administrators. Strategies for changing antimicrobial prescribing behavior include education of prescribers regarding proper antimicrobial usage, creation of an antimicrobial formulary with restricted prescribing of targeted agents, and review of antimicrobial prescribing with feedback to prescribers. Clinical computer systems can aid in the implementation of each of these strategies, especially as expert systems able to provide patient-specific data and suggestions at the point of care. Antibiotic rotation strategies control the prescribing process by scheduled changes of antimicrobial classes used for empirical therapy. When instituting an antimicrobial stewardship program, a hospital should tailor its choice of strategies to its needs and available resources.

Vancomycin-resistant enterococcal bacteremia in a hematology unit: molecular epidemiology and analysis of clinical course

An increase in vancomycin-resistant enterococcal (VRE) bacteremia in hemato-oncological patients (n=19) in our institution from 2000 through 2001 led us to analyze the molecular epidemiologic patterns and clinical features unique to our cases. The pulsed field gel electrophoresis of the isolates revealed that the bacteremia was not originated from a single clone but rather showed endemic pattern of diverse clones with small clusters. A different DNA pattern of blood and stool isolates from one patient suggested exogenous rather than endogenous route of infection. Enterococcus faecium carrying vanA gene was the causative pathogen in all cases. Patients with VRE bacteremia showed similar clinical courses compared with those with vancomycin-susceptible enterococcal (VSE) bacteremia. Vancomycin resistance did not seem to be a poor prognostic factor because of similar mortality (5/8, 62.5%) noted in VSE bacteremia. Initial disease severity and neutropenic status may be major determinants of prognosis in patients with VRE bacteraemia.

Clonal dissemination of VanA-type glycopeptide-resistant Enterococcus faecalis between hospitals of two cities located 100 km apart

Nosocomial dissemination of glycopeptide-resistant enterococci represents a major problem in hospitals worldwide. In Brazil, the dissemination among hospitals in the city of São Paulo of polyclonal DNA profiles was previously described for vancomycin-resistant Enterococcus faecium. We describe here the dissemination of VanA phenotype E. faecalis between two hospitals located in different cities in the State of São Paulo. The index outbreak occurred in a tertiary care university hospital (HCUSP) in the city of São Paulo and three years later a cluster caused by the same strain was recognized in two patients hospitalized in a private tertiary care hospital (CMC) located 100 km away in the interior of the state. From May to July 1999, 10 strains of vancomycin-resistant E. faecalis were isolated from 10 patients hospitalized in the HCUSP. The DNA genotyping using pulsed-field gel electrophoresis (PFGE) showed that all isolates were originated from the same clone, suggesting nosocomial dissemination. From May to July 2002, three strains of vancomycin-resistant E. faecalis were isolated from two patients hospitalized in CMC and both patients were colonized by the vancomycin-resistant Enterococcus in skin lesions. All isolates from CMC and HCUSP were highly resistant to vancomycin and teicoplanin. The three strains from CMC had minimum inhibitory concentration >256 micro g/ml for vancomycin, and 64 (CMC 1 and CMC 2) and 96 micro g/ml (CMC 3) for teicoplanin, characterizing a profile of VanA resistance to glycopeptides. All strains had the presence of the transposon Tn1546 detected by PCR and were closely related when typed by PFGE. The dissemination of the E. faecalis VanA phenotype among hospitals located in different cities is of great concern because E. faecalis commonly colonizes the gastrointestinal tract of patients and healthy persons for periods varying from weeks to years, which, together with the persistence of vancomycin-resistant Enterococcus in hospital rooms after standard cleaning procedures, increases the risk of the dissemination and reservoir of the bacteria.

Failure to develop vancomycin-resistant Enterococcus with oral vancomycin treatment of Clostridium difficile

OBJECTIVE

Oral vancomycin therapy has been a risk factor for turning culture positive for vancomycin-resistant Enterococcus (VRE). VRE colonization status was reviewed for all patients who received oral vancomycin and underwent prospective cultures.

METHODS

Data were extracted from the medical records of all patients receiving oral vancomycin between August 1995 and February 2001 regarding history, hospital course, and perirectal VRE cultures. Hospital policy required contact isolation for patients receiving oral vancomycin until colonization with VRE was excluded.

RESULTS

Twenty-six courses of oral vancomycin were given to 22 patients. VRE colonization status after completion of therapy was evaluated for 23 courses in 20 (91%) of these patients. None of these patients became VRE culture positive during a median follow-up of 18 days (range, 9 to 39 days), with a median duration of treatment of 10 days (range, 3 to 58 days), and with a median total dose of 6,500 mg (range, 1,250 to 29,000 mg). All patients received other antibiotics within 30 days prior to therapy with oral vancomycin, during therapy with oral vancomycin, or both; 95% had received anti-anaerobic therapy and 35% had received parenteral vancomycin.

CONCLUSIONS

Even when other risk factors were present, no patient receiving oral vancomycin at our facility subsequently became culture positive for VRE. This suggests that oral vancomycin therapy or other antibiotic use, including anti-anaerobic therapy, may not be a significant independent risk factor for turning culture positive for VRE among patients not previously exposed to the microbe.

Molecular epidemiology of gram-negative bacilli from infected neonates and health care workers' hands in neonatal intensive care units

We sought to characterize the molecular epidemiology of gram-negative bacilli (GNB) causing infections in infants and associated with carriage on nurses' hands after hand hygiene was performed. From March 2001 to January 2003, GNB caused 192 (34%) of 562 hospital-acquired infections in the 2 participating neonatal intensive care units (NICUs) and were isolated from the hands of 45 (38%) of 119 nurses. Five species--Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens and Enterobacter cloacae, all of which were typed by pulsed-field gel electrophoresis--caused 169 (88%) of 192 of GNB infections. Overall, 58% of infections were caused by unique strains not cultured from other infants or nurses, and 31% of infections were part of unrecognized molecular clusters. In contrast, only 9% of strains that caused infections were cultured from nurses' hands. These data suggest that practices in addition to hand hygiene are needed to prevent horizontal transmission of GNB in the NICU.

Association between antecedent intravenous antimicrobial exposure and isolation of vancomycin-resistant enterococci

Vancomycin-resistant enterococci (VRE) have become important causes of nosocomial infections. This study evaluated the association between a variety of intravenous antimicrobial exposures and the isolation of VRE using two control groups: (1) a vancomycin-susceptible enterococci (VSE) group, to assess factors associated with development of VRE, and (2) a nonenterococci control group, to assess factors associated with positive cultures for enterococci without regard to vancomycin resistance. After adjusting for the effect of other antimicrobials, time at risk, and patient morbidity, compared to vancomycin-susceptible enterococci controls, exposures to imipenem (OR = 4.9, 95% CI = 1.6-14.1) and ceftazidime (OR = 2.6, 95% CI = 1.1-6.1) were significant predictors of VRE. When compared to nonenterococci controls, exposures to ampicillin (OR = 20.1, 95% CI = 1.5-263.1) and imipenem (OR = 5.1, 95% CI = 1.5-17.1) were significantly associated with VRE. Neither piperacillin nor vancomycin was associated with VRE compared to either control group. This study offers further evidence that the replacement of broad-spectrum cephalosporins by extended-spectrum penicillins, specifically piperacillin, may be effective in reducing VRE.

Methods used for the isolation, enumeration, characterisation and identification of Enterococcus spp

This paper reviews the methodology applied for the identification and characterisation of enterococci and covers phenotypic, genotypic and phylogenetic techniques. Although conventional phenotypic typing schemes are useful for rapid and simple identification of enterococcal species for routine applications, other methods like standardised sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), multilocus enzyme electrophoresis (MLEE), antimicrobial susceptibility testing, serotyping, pyrolysis mass spectrometry (pyMS) and vibrational spectroscopic methods allow a more in-depth characterisation of enterococci. Many of the recently described enterococcal species exhibit deviations from hitherto so-called classical enterococci with regard to their phenotypical properties. Therefore, genotypic methods have to be used to clarify their possible assignment to the genus Enterococcus. In this review, special emphasis is given on recently developed polymerase chain reaction (PCR)-based typing methods such as random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), specific and random amplification (SARA) and modifications of PCR-ribotyping as well as pulsed-field gel electrophoresis (PFGE) and partial sequence analysis. The use of PCR and probes for genus and species identification of enterococci is also considered like the application of sequence data of conserved DNA regions (e.g., ribosomal ribonucleic acid (rRNA) genes) in the case of species identification.

Phenotypic and genotypic characterization of VanA Enterococcus isolated during the first nosocomial outbreak in Brazil

We report the phenotypic and genotypic characterization of 50 VanA Enterococcus clinical isolates from infected patients and 97 isolates from colonized patients obtained during a nosocomial outbreak in a single hospital in São Paulo, Brazil during 1998. The identification of strains to the species level by conventional biochemical and phenotypic tests and by multiplex PCR assay had 100% agreement. Both E. faecalis and E. faecium were isolated from patients during this outbreak. The vanA genotype was confirmed by PCR. Antibiotic susceptibility testing showed that E. faecium isolates are generally less susceptible to antibiotics than E. faecalis. By PCR, 24 of 26 VRE strains tested carried the Tn1546 element. Pulsed-field gel electrophoresis identified five distinct patterns for E. faecalis (A, B, C, D, E) and three for E. faecium (M, N, and O). A single PFGE pattern was identified in the majority of strains of each species and does not discriminate between case and carrier isolates.

Vancomycin use in hospitalized pediatric patients

OBJECTIVES

To assess vancomycin utilization at children's hospitals, to determine risk factors for vancomycin use and length of therapy, and to facilitate adapting recommendations to optimize vancomycin prescribing practices in pediatric patients.

METHODS

Two surveys were conducted at Pediatric Prevention Network hospitals. The first (Survey I) evaluated vancomycin control programs. The second (Survey II) prospectively reviewed individual patient records. Each hospital was asked to complete questionnaires on 25 consecutive patients or all patients for whom vancomycin was prescribed during a 1-month period.

RESULTS

In Survey I, 55 of 65 (85%) hospitals reported their vancomycin control policies. Three quarters had specific policies in place to restrict vancomycin use. One half had at least 3 vancomycin restriction measures. In Survey II, personnel at 22 hospitals reviewed 416 vancomycin courses, with 2 to 25 (median = 12) patients tracked per hospital. Eighty-two percent of the vancomycin prescribed was for treatment of neonatal sepsis, fever/neutropenia, fever of unknown origin, positive blood culture, pneumonia, or meningitis. In an additional 6% (26/416), vancomycin was prescribed for patients with beta-lactam allergies and in 13% (56/416) for prophylaxis. Median duration of prophylaxis was 2 days (range: 1-15 days). Almost half (196, 47%) of the patients who received vancomycin were in intensive care units; 27% of the vancomycin courses were initiated by neonatologists and 19% by hematologists/oncologists. The predominant risk factor at the time of vancomycin initiation was the presence of vascular catheters (322, 77%); other host factors included cancer chemotherapy (55, 13%), transplant (30, 7%), shock (24, 6%), other immunosuppressant therapy (17, 4%), or hyposplenic state (2, <1%). Other clinical considerations were severity of illness (96, 23%), uncertainty about diagnosis (51, 12%), patient not responding to current antibiotic therapy (40, 10%), or implant infection (13, 3%). When vancomycin was initiated, blood cultures were positive in 85 patients (20%); cultures from other sites were positive in 45 (11%), and Gram stains of body fluids were positive in 37 (9%). In 29 (7%) patients, organisms sensitive only to vancomycin were isolated before vancomycin initiation. Reasons for discontinuing vancomycin included: therapeutic course completed (125, 30%), negative cultures (106, 25%), alternative antibiotics initiated (75, 18%), illness resolved (14, 3%), or patient expired (13, 3%). Final results of blood culture isolates resistant to beta-lactam antibiotics included 48 coagulase-negative staphylococcus, 5 Staphylococcus aureus, and 10 other species.

CONCLUSIONS

At children's hospitals, vancomycin is initiated for therapy in patients who have vascular catheters and compromised host factors. Only 7% had laboratory-confirmed beta-lactam-resistant organisms isolated at the time vancomycin was prescribed. Efforts to modify empiric vancomycin use in children's hospitals should be targeted at intensivists, neonatologists, and hematologists. Initiatives to decrease length of therapy by decreasing the number of surgical prophylaxis doses and days of therapy before laboratory results may decrease vancomycin exposure.

Vancomycin-resistant enterococci: a road map on how to prevent the emergence and transmission of antimicrobial resistance

Nosocomial acquisition of microorganisms resistant to multiple antibiotics represents a threat to patient safety. Here we review the mechanisms that have allowed highly resistant strains belonging to the Enterococcus genus to proliferate within our health-care institutions. These mechanisms indicate that decreasing the prevalence of resistant organisms requires active surveillance, adherence to vigorous isolation, hand hygiene and environmental decontamination measures, and effective antibiotic stewardship. We suggest how to tailor such a complex, multidisciplinary program to the needs of a particular health-care setting so as to maximize cost-effectiveness.

Vancomycin-resistant enterococci: 15 years and counting

We review the history of vancomycin-resistant enterococci (VRE) and propose a causal model illustrating the roles of exposure to VRE reservoirs, patient characteristics, antimicrobial exposure, and prevalence of VRE in the progression from potential VRE reservoirs to active disease in hospitalized patients. Differences in VRE colonization and VRE infection are discussed with respect to hospital surveillance methodology and implications for interventions. We further document clonal transmission of VRE in a large, urban, teaching hospital and demonstrate VRE susceptibility to a wide array of antimicrobial agents. This model can guide the identification of mutable factors that are focal points for intervention.

Changes in the prevalence of vancomycin-resistant enterococci in response to antimicrobial formulary interventions: impact of progressive restrictions on use of vancomycin and third-generation cephalosporins

This study sought to assess the impact of restricting use of vancomycin and third-generation cephalosporins on vancomycin-resistant enterococci (VRE) prevalence. All clinical enterococcal isolates identified at a large academic medical center during a 10-year period were analyzed. Changes in VRE prevalence after sequential restrictions on use of vancomycin and third-generation cephalosporins were evaluated. The correlation between antibiotic use and VRE prevalence was also investigated. Vancomycin use initially decreased by 23.9% but returned to preintervention levels by the end of the study. Third-generation cephalosporin use decreased by 85.8%. However, VRE prevalence increased steadily from 17.4% to 29.6% during the 10-year period (P<.001). Clindamycin use was significantly correlated with VRE prevalence. Restricting the use of vancomycin and third-generations cephalosporins had little impact on VRE prevalence. The association between clindamycin use and the prevalence of VRE suggests that restriction of this and perhaps other antianaerobic agents might be an important component of future antimicrobial interventions.

Effect of gastrointestinal bleeding and oral medications on acquisition of vancomycin-resistant Enterococcus faecium in hospitalized patients

There has been minimal investigation of medications that affect gastrointestinal function as potential risk factors for the acquisition of vancomycin-resistant enterococci (VRE). We performed a retrospective case-control study, with control subjects matched to case patients by time and location of hospitalization. Strict exclusion criteria were applied to ensure that only case patients with a known time of acquisition of VRE were included. Control patients were patients with > or =1 culture negative for VRE. The risk factors identified were use of vancomycin (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.7-6.0; P=.0003), presence of central venous lines (OR, 2.2; 95% CI, 1.04-4.6; P=.04), and use of antacids (OR, 2.9; 95% CI, 1.5-5.6; P=.002). Two protective factors included gastrointestinal bleeding (OR, 0.26; 95% CI, 0.08-0.79; P=.02) and use of Vicodin (Knoll Labs; hydrocodone and acetaminophen; OR, 0.93; 95% CI, 0.90-0.97; P=.0003). Changes in gastrointestinal function, whether due to bleeding or to the effects of oral medications, may affect whether patients become colonized with VRE.

Human infections caused by glycopeptide-resistant Enterococcus spp: are they a zoonosis?

Following the detection of glycopeptide-resistant enterococci (GRE) in 1986 and their subsequent global dissemination during the 1990s, many studies have attempted to identify the reservoirs and lines of resistance transmission as a basis for intervention. The eradication of reservoirs and the prevention of GRE spread is of major importance for two reasons: (i) the emergence of high-level glycopeptide resistance in invasive enterococcal clinical isolates that are already multiresistant, has left clinicians with therapeutic options that are only at the experimental stage; and (ii) the resistance genes may spread to more virulent bacterial species such as Staphylococcus aureus, Streptococcus pneumoniae and Clostridium difficile. VanA-type strains, resistant to high levels of both vancomycin and teicoplanin, are the most commonly encountered enterococci with acquired glycopeptide resistance in humans. A widespread VanA-type GRE reservoir was detected early in farm animals that were exposed to the glycopeptide growth-promoter avoparcin. Numerous studies have provided indirect evidence for the transfer of VanA-type GRE and their resistance determinants from animal reservoirs to humans. The data collected have expanded our understanding of the promiscuous nature of antibiotic resistance, and have provided the groundwork for logical decision-making with the objective of deterring the dissemination of resistant bacteria and of their resistance genes.

Outbreak of vancomycin-resistant Enterococcus faecium in a haematology unit: risk factor assessment and successful control of the epidemic

We describe an outbreak of vancomycin-resistant Enterococcus faecium (VRE) on the haematology ward of a Dutch university hospital. After the occurrence of three consecutive cases of bacteraemia with VRE, strains were genotyped and found to be identical. During the next 4 months an intensive surveillance programme identified 21 additional patients to be colonized with VRE, while two more patients developed bacteraemia. A case-control study was carried out to identify risk factors for VRE acquisition. In comparison with VRE-negative control patients (n=49), cases (n=24) had a longer stay on the ward during the year preceding the outbreak (25.8 versus 10.1 d, P=0.02), more cases with acute myeloid leukaemia [11 versus 4, odds ratio (OR) 9.5, 95% confidence interval (CI95) 2.4-32.2] and higher grades of mucositis (P=0.03). Logistic regression analysis identified antibiotic use within 1 month before admission (OR 13.0, CI95 2.1-80.5, P=0.006) and low albumin levels at baseline (OR 1.2, CI95 1.1-1.3, P=0.02) to be independent risk factors. Four patients with VRE-bacteraemia were successfully treated with quinupristin/dalfopristin (Synercid). Control of the outbreak was achieved by step-wise implementation of intensive infection control measures, which included the cohorting of patients, allocation of nurses and reinforcement of hand hygiene.

Clinical prevalence, antimicrobial susceptibility, and geographic resistance patterns of enterococci: results from the SENTRY Antimicrobial Surveillance Program, 1997-1999

As part of the SENTRY Antimicrobial Resistance Surveillance Program, a total of 4998 strains of enterococci isolated from 1997 to 1999 were processed. The occurrence of enterococcal infections by species and site of infection was analyzed, as were the occurrence of vancomycin-resistant enterococci (VRE) and their resistance phenotypes and genotypes. Trends in antimicrobial susceptibility to a variety of agents (including experimental compounds) were also reported. Enterococci accounted for >9% of isolates from all bloodstream infections (BSIs) in North America. Ampicillin was active against strains from Latin America and Europe but not against those from the United States and Canada. US isolates were considerably more resistant to vancomycin (17% resistant strains in 1999) than were those from patients in the rest of the world. The highest proportion of VRE was observed among BSI isolates (81.7%). Quinupristin-dalfopristin, chloramphenicol, and doxycycline were the most active agents tested against VRE. The results of this study confirm the worldwide trend in increasing occurrence of enterococci and the emerging pattern of antimicrobial resistance among such isolates.

Antimicrobial management measures to limit resistance: A process-based conceptual framework

To curb the trend toward increasingly resistant microorganisms, we must at least ensure that antibiotics are used in accordance with the best available scientific evidence. Here we review the control and streamlining measures aimed at optimizing the use of antibiotics, placing an emphasis on their demonstrated effectiveness in the intensive care unit environment. Because of their wide variety, the measures have been organized along the process of choosing, dosing, delivering, and then adjusting the initial antibiotics according to the culture results. By clarifying the range of options available, this process-based conceptual framework assists in best adapting a creative mixture of control measures to a particular healthcare system. The framework also facilitates the overview of a proposed multidisciplinary antibiotic management program, thereby helping to secure the administrative and local provider support necessary for its implementation and continued improvement.

A hospital epidemic of vancomycin-resistant Enterococcus: risk factors and control

OBJECTIVE

To determine risk factors for vancomycin-resistant Enterococcus (VRE) colonization during a hospital outbreak and to evaluate Centers for Disease Control and Prevention (CDC)-recommended control measures.

DESIGN

Epidemiological study involving prospective identification of colonization and a case-control study.

SETTING

A university hospital.

PARTICIPANTS

Patients on eight wards involved in outbreak from late 1994 through early 1995.

METHODS

Cases were matched by ward and culture date with up to two controls. Risk factors were evaluated with four multivariate models using conditional logistic regression. The first evaluated proximity to other VRE patients and isolation status. The second evaluated proximity to unisolated VRE cases and three variables independently predictive after adjustment for proximity. The third evaluated seven significant univariate predictors in addition to proximity to unisolated VRE in backward, stepwise logistic regression. The fourth assessed proximity to VRE with all other variables collected, clustered in a principal components analysis. Pulsed-field gel electrophoresis was performed to assess clonality of two outbreak strains.

RESULTS

The incidence of transmission declined significantly after CDC guidelines were implemented. Proximity to unisolated VRE cases during the prior week was a significant predictor of acquisition in each of four multivariate models. Other significant risk factors in multivariate models included a history of major trauma and treatment with metronidazole. Pulsed-field gel electrophoresis confirmed the clonality of two outbreak strains.

CONCLUSIONS

VRE was transmitted between patients during a hospital epidemic, with proximity to previously unisolated VRE patients being an important risk factor. Weekly surveillance cultures and contact isolation of colonized patients significantly reduced spread

Vancomycin-resistant enterococci

After they were first identified in the mid-1980s, vancomycin-resistant enterococci (VRE) spread rapidly and became a major problem in many institutions both in Europe and the United States. Since VRE have intrinsic resistance to most of the commonly used antibiotics and the ability to acquire resistance to most of the current available antibiotics, either by mutation or by receipt of foreign genetic material, they have a selective advantage over other microorganisms in the intestinal flora and pose a major therapeutic challenge. The possibility of transfer of vancomycin resistance genes to other gram-positive organisms raises significant concerns about the emergence of vancomycin-resistant Staphylococcus aureus. We review VRE, including their history, mechanisms of resistance, epidemiology, control measures, and treatment.

Typing of Enterococcus faecium by polymerase chain reaction and pulsed field gel electrophoresis

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 São 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 São 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.

Antienterococcal antibiotics

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.

Enterococcal infections in a Greek intensive care unit: a 5-y study

In this study we determined the incidence, resistance pattern, and mortality rate associated with infection caused by Enterococcus faecalis and Enterococcus faecium among patients in a multidisciplinary intensive care unit (ICU). A total of 111 patients with E. faecalis and 60 with E. faecium infections were identified during a 5-y period (1992-96). We observed an increase in the incidence of enterococcal infections (from 5.46 to 8.46 per 1000 patients-days, p = 0.0112), due mainly to the increased incidence of E. faecium (from 0.45 to 4.06 per 1000 patients-days, p = 0.002). Blood was the most common site of enterococcus isolation. E. faecium was more resistant to antibiotics than E. faecalis, but no vancomycin resistant enterococcus was isolated. Patients with E. faecium infection had a significantly higher mortality than patients with E. faecalis infection (66% vs. 41.5%, p = 0.0035 for infection from any site and 85.7 vs. 47.7%, p = 0.012 for bacteremic patients). r 4n- D I .- .- - .. . .

Vancomycin-resistant enterococci

After they were first identified in the mid-1980s, vancomycin-resistant enterococci (VRE) spread rapidly and became a major problem in many institutions both in Europe and the United States. Since VRE have intrinsic resistance to most of the commonly used antibiotics and the ability to acquire resistance to most of the current available antibiotics, either by mutation or by receipt of foreign genetic material, they have a selective advantage over other microorganisms in the intestinal flora and pose a major therapeutic challenge. The possibility of transfer of vancomycin resistance genes to other gram-positive organisms raises significant concerns about the emergence of vancomycin-resistant Staphylococcus aureus. We review VRE, including their history, mechanisms of resistance, epidemiology, control measures, and treatment.