Three-year survey of bacteremia and fungemia in a pediatric intensive care unit

BACKGROUND

Knowledge of the pattern of blood stream infection (BSI) in patients in intensive care units (ICUs) can help determine antibiotic prescribing policy and infection control procedures. However, there have been few pediatric-based studies.

METHODS

Surveillance of BSI in a pediatric ICU for 3 years, amounting to 131 episodes of significant bacteremia and fungemia.

RESULTS

The incidence of BSI was 39.0 per 1,000 admissions (10.6 per 1,000 bed days). Eighty-four (64.1%) episodes were ICU-acquired, and 27 (20.6%) were community-acquired. Gram-positive, Gram-negative and anaerobic bacteria accounted for 62.2, 30.8 and 1.4%, respectively, of the 143 microorganisms isolated, 5.6% were yeasts. Neisseria meningitidis was the most common species in community-acquired infections, and staphylococci predominated in hospital-acquired episodes. Eighty-seven percent of patients had significant underlying disease, including 60.3% with congenitally acquired conditions. Intravascular devices were the most common source of infection, accounting for 41.2% of all episodes. The crude mortality in children with BSI was 26.5%, compared with 8.1% in those without BSI.

CONCLUSIONS

The pattern of BSI in ICUs is partly determined by the type of patient treated. However, some observations are generally applicable, notably the increasing importance of antibiotic-resistant bacteria that are often of low virulence and device-associated. Our experience suggests that universal use of broad spectrum empiric antibiotics to cover these pathogens (which risks further promoting antibiotic resistance) may not improve patient outcome. Our study provides a basis for other pediatric ICUs to evaluate their rates and outcomes of BSI.

Management of an outbreak of vancomycin-resistant enterococci in the medical intensive care unit of a cancer center

Between November 1996 and February 1997, 17 episodes of vancomycin-resistant enterococci (VRE) infection or colonization (9 infections, 8 colonizations), all with the same or a similar genomic DNA pattern, were identified in the medical intensive care unit (MICU) of a tertiary-care cancer hospital. The cases were genotypically traced to a patient who was admitted to the hospital in September 1996 and who, by December 1996, had four different admissions to the MICU. Multifaceted infection control measures, including decontamination of the environment and of nondisposable equipment, halted the nosocomial transmission of VRE in the MICU.

Infection control measures to limit antimicrobial resistance

Increasing antimicrobial resistance has resulted in a rapidly decreasing array of therapeutic options for infections in the critical care setting. Reports of reduced susceptibility to vancomycin in Staphylococcus aureus raise the possibility of patients being infected with a virulent pathogen for which most antibiotics are ineffective. Infection control methods to contain resistance, exclusive of antimicrobial restrictions, focus on surveillance to identify carriers of resistant organisms, prevention of nosocomial infections, adequate hand hygiene, isolation of patients who harbor resistant organisms, and the use of barrier techniques such as gowns and gloves. Surveillance using clinical isolates alone is inadequate for the identification of the majority of patients who carry resistant organisms. However, it is unclear what intensity of surveillance is needed to control the spread of these organisms in the intensive care unit in nonoutbreak situations. Attempts at eradicating carriage are often unsuccessful when there is extranasal colonization with methicillin-resistant S. aureus. Transmission of resistant organisms is primarily the result of transient contamination of healthcare workers' hands. Adequate handwashing, isolation of carriers, and barrier techniques are all necessary for containing resistance within the intensive care unit, however, compliance with these measures can be compromised by high staff turnover and heavy workload.

The effect of topical povidone-iodine, intraocular vancomycin, or both on aqueous humor cultures at the time of cataract surgery

PURPOSE

To investigate whether the use of topical povidone-iodine before surgery, the addition of vancomycin to the irrigating solutions during phacoemulsification, or both reduces the frequency of positive intraocular cultures at the end of surgery.

METHODS

A two-part, clinical study was performed. In the preliminary study, intracameral antibiotic concentrations were measured immediately after surgery (in 11 eyes) and 2 hours after surgery (in 11 eyes) in patients treated with vancomycin. In the primary study, 400(1) patients were divided into four groups composed of 100 eyes each. The first and the second groups received vancomycin (20 microg/ml) in the irrigating fluid. The third and the fourth groups received irrigating fluid only without antibiotics. The first and third groups received a topical 5% povidone-iodine solution 10 and 5 minutes before surgery; a topical placebo solution was used in the second and the fourth groups. All patients in the primary study underwent anterior chamber aspiration after surgery, and culturing was performed 2 hours later. Identification and quantification of positive cultures in thioglycolate broth and chocolate agar were performed.

RESULTS

In the preliminary study, the half-life of intraocular vancomycin was less than 2 hours. In the primary study, intraocular aspirates yielded positive cultures in two (2%), five (5%), 11 (11%), and 13 (13%) specimens from the first, second, third, and fourth groups, respectively.

CONCLUSIONS

We found a lower rate of positive cultures in the group that received vancomycin in the irrigating fluid; 2 hours of contact between the antibiotic solution and bacteria produced results that reached statistical significance (P = 0.032).

Treatment of Clostridium difficile-associated diarrhea and colitis

Treatment of C. difficile diarrhea with metronidazole or vancomycin is highly effective at relieving symptoms. The high rate of diarrhea recurrence is concerning, but fortunately most patients respond to a second course of treatment. The problem of vancomycin resistance in hospital organisms has markedly reduced usage of this agent as a first-line treatment for C. difficile diarrhea, leaving metronidazole as the mainstay of treatment in the United States where teicoplanin and fusidic acid are not marketed. It is likely that any new antimicrobial agent used to treat C. difficile will be similarly plagued by a high rate of recurrence, presumably incurred as a result of disruption of normal bowel flora. There is a need for improved treatment and prevention of this increasingly frequent and debilitating nosocomial infection. Treatments that utilize passive antibodies, immunization, nontoxigenic C. difficile, or other forms of biotherapy may hold the key to improved treatment and prevention of C. difficile disease in the future. In the meantime, it behooves all practitioners to use antimicrobials judiciously in order to prevent as many cases of C. difficile diarrhea as possible.

Outpatient vancomycin use and vancomycin-resistant enterococcal colonization in maintenance dialysis patients

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.

An outbreak of imipenem-resistant Acinetobacter baumannii in critically ill surgical patients

OBJECTIVE

To describe an outbreak of imipenem-resistant Acinetobacter baumannii (IR-Ab) and the measures for its control, and to investigate risk factors for IR-Ab acquisition.

DESIGN

An observational and a case-control study.

SETTING

A surgical intensive care unit (ICU) in a university tertiary care hospital.

METHODS

After admission to the ICU of an IR-Ab-positive patient, patients were prospectively screened for IR-Ab carriage upon admission and then once a week. Environmental cleaning and barrier safety measures were used for IR-Ab carriers. A case-control study was performed to identify factors associated with IR-Ab acquisition. Cases were patients who acquired IR-Ab. Controls were patients who were hospitalized in the ICU at the same time as cases and were exposed to IR-Ab for a similar duration as cases. The following variables were investigated as potential risk factors: baseline characteristics, scores for severity of illness and therapeutic intervention, presence and duration of invasive procedures, and antimicrobial administration.

RESULTS

Beginning in May 1996, the outbreak involved 17 patients over 9 months, of whom 12 acquired IR-Ab (cases), 4 had IR-Ab isolates on admission to the ICU, and 1 could not be classified. Genotypic analysis identified two different IR-Ab isolates, responsible for three clusters. Ten of the 12 nosocomial cases developed infection. Control measures included reinforcement of barrier safety measures, limitation of the number of admissions, and thorough environmental cleaning. No new case was identified after January 1997. Eleven of the 12 cases could be compared to 19 controls. After adjustment for severity of illness, a high individual therapeutic intervention score appeared to be a risk factor for IR-Ab acquisition.

CONCLUSION

The outbreak ended after strict application of control measures. Our results suggest that high work load contributes to IR-Ab acquisition.

Fulminant late-onset sepsis in a neonatal intensive care unit, 1988-1997, and the impact of avoiding empiric vancomycin therapy

OBJECTIVE

To determine the pathogens associated with fulminant (lethal within 48 hours) late-onset sepsis (occurring after 3 days of age) in a neonatal intensive care unit (NICU) and the frequency of fulminant late-onset sepsis for the most common pathogens.

METHODS

A retrospective study was conducted of sepsis in infants in a NICU over a 10-year period (1988-1997).

RESULTS

There were 825 episodes of late-onset sepsis occurring in 536 infants. Thirty-four of 49 (69%; 95% confidence interval [CI]: 55%-82%) cases of fulminant late-onset sepsis were caused by Gram-negative organisms, including Pseudomonas sp., 20 (42%); Escherichia coli, 5 (10%); Enterobacter sp., 4 (8%); and Klebsiella sp., 4 (8%). The frequency of fulminant sepsis was highest for Pseudomonas sp., 20 of 36 (56%; 95% CI: 38%-72%) and lowest for coagulase-negative staphylococci, 4 of 277 (1%; 95%CI: 0%-4%). The very low frequency of fulminant sepsis caused by coagulase-negative staphylococci did not increase during the period when oxacillin was used instead of vancomycin as the empiric antibiotic for Gram-positive organisms.

CONCLUSIONS

These data suggest that empiric antibiotics selected for treatment of suspected sepsis in infants >3 days old need to effectively treat Gram-negative pathogens, particularly Pseudomonas sp., because these organisms, although less frequent, are strongly associated with fulminant late-onset sepsis in the NICU. Avoiding empiric vancomycin therapy seemed to be a reasonable approach to late-onset sepsis, because of the very low frequency of fulminant sepsis caused by coagulase-negative staphylococci.

Comparison of three methods to recover vancomycin-resistant enterococci (VRE) from perianal and environmental samples collected during a hospital outbreak of VRE

OBJECTIVE

To establish an efficient and sensitive technique for recovering vancomycin-resistant enterococci (VRE) from perianal and environmental samples collected during implementation of control measures for an outbreak of VRE.

DESIGN

Perianal and environmental samples were collected in triplicate on sterile swabs. One swab was used to inoculate a selective broth medium containing 6 pg of vancomycin and 8 pg of ciprofloxacin per mL, one to inoculate Campylobacter agar containing 10 microg/mL of vancomycin, and one to inoculate Enterococcosel agar containing 8 microg/mL of vancomycin.

SETTING

Samples were collected in the intensive care units of a 600-bed university hospital over a period of 2 months. SAMPLE SELECTION: Patients and their immediate environment were sampled if they resided in a ward with a patient known to be colonized or infected with VRE.

RESULTS

Of the 88 perianal samples obtained from 63 patients, 37 were positive for VRE by broth culture, with 36 also recovered on both types of solid media (sensitivity, 97.3%; negative predictive value, 98.1%). Of the initial samples collected from each of the 63 patients, 20 were positive for VRE by all methods. Of the 500 environmental samples cultured, 139 were positive for VRE in broth, with only 33 recovered on Campylobacter agar (sensitivity, 23.7%; negative predictive value, 77.2%) and 22 on Enterococcosel agar (sensitivity, 15.8%; negative predictive value, 75.2%).

CONCLUSIONS

Our data indicate that, when performing surveillance cultures during an outbreak of VRE, use of an enrichment broth medium is required to recover VRE contaminating environmental surfaces; however, direct inoculation to selective solid medium is adequate to recover VRE in patient perianal specimens.

National guidelines for the judicious use of glycopeptides in Belgium

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.

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.

Relationships between enterococcal virulence and antimicrobial resistance

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.

Persistent contamination of fabric-covered furniture by vancomycin-resistant enterococci: implications for upholstery selection in hospitals

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.

Short-term benefit from oral vancomycin treatment of regressive-onset autism

In most cases symptoms of autism begin in early infancy. However, a subset of children appears to develop normally until a clear deterioration is observed. Many parents of children with "regressive"-onset autism have noted antecedent antibiotic exposure followed by chronic diarrhea. We speculated that, in a subgroup of children, disruption of indigenous gut flora might promote colonization by one or more neurotoxin-producing bacteria, contributing, at least in part, to their autistic symptomatology. To help test this hypothesis, 11 children with regressive-onset autism were recruited for an intervention trial using a minimally absorbed oral antibiotic. Entry criteria included antecedent broad-spectrum antimicrobial exposure followed by chronic persistent diarrhea, deterioration of previously acquired skills, and then autistic features. Short-term improvement was noted using multiple pre- and post-therapy evaluations. These included coded, paired videotapes scored by a clinical psychologist blinded to treatment status; these noted improvement in 8 of 10 children studied. Unfortunately, these gains had largely waned at follow-up. Although the protocol used is not suggested as useful therapy, these results indicate that a possible gut flora-brain connection warrants further investigation, as it might lead to greater pathophysiologic insight and meaningful prevention or treatment in a subset of children with autism.

Isolation and characterization of glycopeptide-resistant enterococci from hospitalized patients over a 30-month period

In February 1996, a Hospital Infection Control Practices Advisory Committee-style screening program was commenced to isolate and subsequently characterize glycopeptide-resistant enterococci (GRE) from patients at a hospital trust in Glasgow, Scotland. Over the next 30 months, GRE were isolated from 154 patients. GRE were isolated from patients in traditionally high-risk areas such as the renal unit and intensive care unit and also in areas considered to be lower risk, including medical wards and associated long-stay geriatric hospitals. The majority (90%) of isolates were Enterococcus faecium vanB. The remaining isolates consisted of seven E. faecalis (vanA), three E. gallinarum (vanC), and a further six E. faecium (five vanA, one both vanA and vanB) isolates. Analysis of SmaI-digested DNA by pulsed-field gel electrophoresis revealed that 34 of 40 (85%) VanB E. faecium isolates were identical or closely related, while 11 of 13 (85%) VanA GRE were distinct. High-level aminoglycoside resistance was seen in less than 8% of isolates. VanB E. faecium isolates were almost uniformly resistant to ampicillin and tetracycline. In this study, GRE have been isolated over a prolonged period from a broad range of patients. Glycopeptide resistance within the study hospital trust appeared to be mainly due to the clonal dissemination of a single strain of E. faecium VanB.

Rapid detection of mecA-positive and mecA-negative coagulase-negative staphylococci by an anti-penicillin binding protein 2a slide latex agglutination test

A rapid slide latex agglutination (LA) test, MRSA-Screen (Denka Seiken Co., Niigata, Japan), which detects PBP 2a, was tested for its ability to differentiate between mecA-positive and -negative coagulase-negative staphylococci. A total of 463 isolates from 13 species were included in the study. The mecA gene was detected by PCR, and the oxacillin MIC was determined by the agar dilution method according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). The LA test was performed with oxacillin-induced isolates. The true-positive and true-negative results were defined on the basis of the presence or the absence of the mecA gene. By PCR, 251 isolates were mecA positive and 212 were mecA negative. The sensitivities, specificities, and positive and negative predictive values for the LA test compared to the NCCLS breakpoint for oxacillin resistance (>/=0.5 mg/liter) were as follows: for the LA test, 100, 99.5, 99.6, and 100%, respectively; for the NCCLS breakpoint, 100, 60.8, 75.1, and 100%, respectively. One hundred twenty-five mecA-positive isolates were also tested by the LA test without induction of PBP 2a; only 72 (57.6%) gave a positive result and required 3 to 15 min for reaction. With induction, all 251 isolates were positive within 3 min. The LA test was reliable in classifying mecA-negative isolates, but it classified isolates for which the oxacillin MIC was >/=0.5 mg/liter as oxacillin susceptible. For the reliable detection of oxacillin resistance by the MRSA-Screen in coagulase-negative staphylococci, induction of the mecA gene appears to be necessary.

Experience of vancomycin-resistant enterococci in a children's hospital

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.

[Methicillin-resistant Staphylococcus aureus: factors responsible for its incidence]

INTRODUCTION

How can we explain that the proportion of methicillin-resistant Staphylococcus aureus (MRSA) varies between the European countries, ranging from < 1% in Scandinavia to > 30% in Spain, France and Italy? This paper is aimed at attempting to determine factors at the origin of the spreading of endemic MRSA strains as of the early 1980s. Those strains are characterized by their ability to develop resistance to current antibiotics and make treatment of severe and deep infections more complex.

CURRENT KNOWLEDGE AND KEY POINTS

Differences in the virulence of MRSA strains and that of susceptible strains appear unlikely. MRSA prevalence seems to be a growing problem, especially in Southern Europe where rates of resistance to other anti-staphylococcal antibiotics are high. General policies for antibiotic therapy as well as the implementation of strategies for prevention and control of MRSA might be responsible for such rates. Indeed, once MRSA is introduced into a facility without control program, this multiresistant bacteria rapidly spreads within the hospital and becomes endemic, expanding its reservoir. FUTURE PROSPECTS ET PROJECTS: Due to the introduction of new methods in microbiology and communication, infection control measures including procedures for isolation and identification of MRSA reservoirs are still feasible; however, their implementation requires human and material resources. Areas requiring improvement in the detection of MRSA outbreaks are identified in this paper, with particular emphasis on the need for national surveillance of MRSA prevalence and reappraisal of MRSA control strategies in French hospitals.

Control of an outbreak of vancomycin-resistant Enterococcus faecium in an oncology ward in South Africa: effective use of limited resources

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.

[Effects of restrictions on use of vancomycin in a German university hospital]

BACKGROUND

Recently, increasing antibiotic resistance has been observed among gram-positive bacteria. However, only few isolates were found to be resistant against glycopeptides. Therefore, internationally accepted guidelines recommend a restricted use of vancomycin and other glycopeptide antibiotics in order to prevent the development of resistance against these clinically important antibiotics. In many countries, the hospital pharmacies play a key role in control and reinforcement of antibiotic formulary restrictions. In Germany, however, the hospital pharmacies usually do not take over such control functions, and most wards keep a stock of regularly used drugs including antibiotics, which makes reinforcement of restrictions difficult.

METHODS

In an attempt to achieve a restriction of vancomycin use, the pharmacy of our university hospital was advised to deliver vancomycin to the wards only on request with a special order form signed by an attending, individually for every patient who should receive vancomycin. The efficacy of this restriction measure was evaluated in 3-month periods before and after the restriction became effective.

RESULTS

Hospitalwide, this led to a 20.1% reduction of i.v. vancomycin and an 85.7% reduction of oral vancomycin use per 1000 patient days. If the hematology/oncology units were not considered, the reduction of i.v. vancomycin use was 41.8%, and the total use after the restriction 24.2 g per 1000 patient days. Microbiology results which justified the use of vancomycin decreased by 8.3% (10.9% hematology/oncology units not considered) between the 2 observation periods. Assuming a 7-day mean course of i.v. vancomycin therapy, the empirical use of i.v. vancomycin decreased from 39.9% to 8% after the restriction had been instituted.

CONCLUSION

Allowing only experienced physicians (attendings) to decide on the use of vancomycin therapy, proved in our experience to be an effective measure to reduce unnecessary vancomycin use.

Correlation of oxacillin MIC with mecA gene carriage in coagulase-negative staphylococci

The National Committee for Clinical Laboratory Standards has recently changed the oxacillin breakpoint from >/=4 mg/liter to >/=0. 5 mg/liter to detect methicillin-resistant coagulase-negative staphylococci (CoNS) because the previous breakpoint lacked sensitivity. To determine the correlation between the new oxacillin breakpoint and the presence of the mecA gene, 493 CoNS of 11 species were tested. The presence of the mecA gene was determined by PCR, and oxacillin susceptibility was determined by the agar dilution method with Mueller-Hinton agar containing 2% NaCl and oxacillin (0. 125 to 4.0 mg/liter). The new breakpoint correctly classified all CoNS strains with mecA as methicillin resistant and strains of Staphylococcus epidermidis, S. haemolyticus, and S. hominis without mecA as methicillin susceptible. The breakpoint of >/=0.5 mg/liter was not specific for S. cohnii, S. lugdunensis, S. saprophyticus, S. warneri, and S. xylosus, in that it categorized 70 of 74 strains of these species without mecA (94.6%) as methicillin resistant. The results of this study indicate that the new oxacillin breakpoint accurately identifies strains of CoNS with mecA but is not specific for strains of certain species of CoNS without mecA.

Practical guidelines for vancomycin usage, with prospective drug-utilization evaluation

To strengthen guidelines for vancomycin use, practical guidelines were developed. A prospective survey was conducted of all patients receiving vancomycin during two 1-month periods, 1 year apart, during which significant improvements were noted. Practical guidelines may contribute to appropriateness of vancomycin use, serve as educational tools, and facilitate improved surveillance.

Vancomycin use in pediatric hematology-oncology patients

Across-sectional study was performed of pediatric hematology-oncology patients who received vancomycin; use was compared to the Centers for Disease Control and Prevention (CDC) recommendations for vancomycin use. Thirty-seven patients received 308 doses of vancomycin. AR patients initially received vancomycin as empirical therapy; 100% of this use was not consistent with the CDC recommendations.

Vancomycin prescribing practices in hospitalized chronic hemodialysis patients

To determine the prevalence of and indications for vancomycin administration among hospitalized chronic hemodialysis patients, we performed a 3-month prospective cohort study at a tertiary care center. Modified guidelines for vancomycin use from the Hospital Infections Control Practices Advisory Committee of the Centers for Disease Control and Prevention were used. Vancomycin was administered during 56 of 144 admissions (39%) requiring chronic hemodialysis compared with 336 of 7,212 admissions (5%) not requiring hemodialysis (relative risk, 11; 95% confidence interval, 8 to 15; P < 0.001). Among chronic hemodialysis patients, vancomycin use was judged appropriate for 131 of the 164 vancomycin doses (80%). The most common appropriate indication was empiric therapy in a febrile patient before culture or susceptibility results. Of 32 infections identified in patients who received empiric vancomycin, 15 infections (47%) were caused by beta-lactam-resistant pathogens. Among the 33 doses (20%) judged inappropriate, continued therapy for a presumed infection despite failure to identify a beta-lactam-resistant pathogen was the most common indication. Although vancomycin administration was frequent among hospitalized chronic hemodialysis patients, its use was justified in the majority of cases. Efforts should focus on limiting vancomycin administration for treating infections caused by beta-lactam-sensitive pathogens.

Chlorhexidine compared with povidone-iodine as skin preparation before blood culture. A randomized, controlled trial

BACKGROUND

Chlorhexidine is better than povidone-iodine for care of catheter sites, but it is not known whether chlorhexidine is superior in reducing blood culture contamination.

OBJECTIVE

To determine whether alcoholic chlorhexidine is a more effective skin antiseptic for collection of blood cultures than aqueous povidone-iodine.

DESIGN

Randomized, controlled trial.

SETTING

Three adult intensive care units in a French university hospital.

PATIENTS

403 adults who had at least one blood culture drawn through a peripheral vein.

INTERVENTIONS

Patients were randomly assigned to receive skin preparation with an aqueous solution of 10% povidone-iodine or an alcoholic solution of 0.5% chlorhexidine before phlebotomy.

MEASUREMENTS

Contamination rates of blood cultures.

RESULTS

Of 2041 blood cultures collected in 403 patients, 124 yielded pathogens. Chlorhexidine reduced the incidence of blood culture contamination more than povidone-iodine (14 of 1019 cultures [1.4%] compared with 34 of 1022 cultures [3.3%]; odds ratio, 0.40 [95% CI, 0.21 to 0.75]; P = 0.004).

CONCLUSION

Skin preparation with alcoholic chlorhexidine is more efficacious than skin preparation with aqueous povidone-iodine in reducing contamination of blood cultures.

Molecular epidemiology of vancomycin-resistant Enterococcus faecium in a large urban hospital over a 5-year period

To investigate the dissemination of vancomycin-resistant Enterococcus faecium (VREF) in a 728-bed tertiary-care hospital, all clinical VREF isolates recovered from June 1992 to June 1997 were typed by pulsed-field gel electrophoresis, and the transfer histories of the patients were documented. A total of 413 VREF isolates from urine (52%), wounds (16%), blood (11%), catheter tips (6%), and other sites (15%) were studied. VREF specimens mostly came from patients on wards (66%) but 34% came from patients in an intensive care unit. The number of VREF isolates progressively increased over time, with higher rates of isolation during the winter months and lower rates in the late summer months. Four distinct banding patterns were detected by pulsed-field gel electrophoresis among 316 samples (76%). Strain A (122 samples; 30%) appeared in June 1992 as the first VREF strain and was found until December 1994 throughout the entire hospital. Type B (92 samples; 22%) was initially detected in January 1994 and disappeared in November 1996. Strain C (10 samples; 2%) was limited to late 1996 and early 1997. Strain D (92 samples; 22%) showed two major peaks during March 1996 to August 1996 and January 1997 to February 1997. Unrelated strains (97 samples; 24%) appeared 1 year after the appearance of the first VREF isolate, and the numbers increased slightly over the years. Nosocomial acquisition (i.e., no known detection prior to admission and first isolation from cultures performed with samples retrieved >/=2 days after hospitalization) was found for 316 (91%) of 347 patients. Despite the implementation of Centers for Disease Control and Prevention guidelines, the proportion of related strains and high number of nosocomial cases of infection indicate a high transmission rate inside the hospital. The results imply an urgent need for stringent enforcement of more effective infection control measures.

Development of a PCR assay for rapid detection of enterococci

Enterococci are becoming major nosocomial pathogens, and increasing resistance to vancomycin has been well documented. Conventional identification methods, which are based on culturing, require 2 to 3 days to provide results. PCR has provided a means for the culture-independent detection of enterococci in a variety of clinical specimens and is capable of yielding results in just a few hours. However, all PCR-based assays developed so far are species specific only for clinically important enterococci. We have developed a PCR-based assay which allows the detection of enterococci at the genus level by targeting the tuf gene, which encodes elongation factor EF-Tu. Initially, we compared the nucleotide sequences of the tuf gene from several bacterial species (available in public databases) and designed degenerate PCR primers derived from conserved regions. These primers were used to amplify a target region of 803 bp from four enterococcal species (Enterococcus avium, E. faecalis, E. faecium, and E. gallinarum). Subsequently, the complete nucleotide sequences of these amplicons were determined. The analysis of a multiple alignment of these sequences revealed regions conserved among enterococci but distinct from those of other bacteria. PCR primers complementary to these regions allowed amplification of genomic DNAs from 14 of 15 species of enterococci tested (E. solitarius DNA could not be amplified). There was no amplification with a majority of 79 nonenterococcal bacterial species, except for 2 Abiotrophia species and several Listeria species. Furthermore, this assay efficiently amplified all 159 clinical isolates of enterococci tested (61 E. faecium, 77 E. faecalis, 9 E. gallinarum, and 12 E. casseliflavus isolates). Interestingly, the preliminary sequence comparison of the amplicons for four enterococcal species demonstrated that there were some sequence variations which may be used to generate species-specific internal probes. In conclusion, this rapid PCR-based assay is capable of detecting all clinically important enterococci and has potential for use in clinical microbiology laboratories.

Adverse effects of contact isolation

Health-care workers are half as likely to enter the rooms of patients in contact isolation, but are more likely to wash their hands after caring for them than after caring for patients not in isolation.

Reporting of vancomycin-resistant enterococci in Connecticut: implementation and validation of a state-based surveillance system

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.

Mopping up hospital infection

Hospital cleaning is a neglected component of infection control. In the UK, financial constraints have forced managers to re-evaluate domestic services and general cleaning has been reduced to the bare minimum. Services have been contracted out in some hospitals, which has further lowered standards of hygiene. Control of infection personnel believe that cleaning is important in preventing hospital-acquired infections but they do not manage domestic budgets and have failed to stop their erosion. It is difficult to defend high levels of hygiene when there is little scientific evidence to support cleaning practices. This review examines the common micro-organisms associated with hospital-acquired infection and their ability to survive in the hospital environment. It also describes studies which suggest that comprehensive cleaning disrupts the chain of infection between these organisms and patients. It is likely that restoring hygienic standards in hospitals would be a cost-effective method of controlling hospital-acquired infection. Furthermore, good cleaning is achievable whereas the enforcement of hand washing and good antibiotic prescribing are not.

Life-threatening reaction to vancomycin given for noninfectious fever

OBJECTIVE

To report a case of vancomycin-induced anaphylaxis (or anaphylactoid reaction) in a patient with a fever of unrecognized noninfectious origin.

CASE SUMMARY

An 83-year-old white man, who was a patient of the Veterans Affairs Medical Center, developed a serious anaphylactic (or anaphylactoid) reaction while receiving intravenous vancomycin as empiric therapy for a nosocomial fever of unknown origin. The fever was subsequently proved to have been due to acute polyarticular gout rather than an infection.

DISCUSSION

This patient developed respiratory distress and an increased serum troponin concentration, suggestive of a myocardial enzymatic leak as a result of vancomycin therapy. Vancomycin was given before the noninfectious cause of his fever was recognized.

CONCLUSIONS

Even with cautious slow infusion, intravenous vancomycin can precipitate life-threatening infusion-related reactions in some patients. Because of this, and to reduce selective pressure for vancomycin resistance, sources of fever that do not require treatment with vancomycin should be diligently investigated prior to the institution of empiric vancomycin therapy in febrile patients, particularly when the past medical history is suggestive of an alternative diagnosis.

Molecular epidemiology of vancomycin-resistant enterococci: a 2-year perspective

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".

Undetected vancomycin-resistant Enterococcus in surgical intensive care unit patients

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.

Intrinsically vancomycin-resistant gram-positive organisms: clinical relevance and implications for infection control

Intrinsic resistance to vancomycin in gram-positive bacteria presumably predates acquired vancomycin resistance in enterococci but it has only recently generated interest. Intrinsically resistant enterococci possessing the vanC gene and the non-enterococcal genera Leuconostoc, Lactobacillus, Pediococcus and Erysipelothrix are known to cause human infection. This review examines the available data on their identification, resistance mechanisms, epidemiology, clinical infections and antimicrobial susceptibility. Intrinsically vancomycin-resistant gram-positives are usually opportunistic pathogens. Although serious infections may occur, treatment options remain available. No additional infection control measures for the intrinsically resistant genera appear justified with currently available evidence, although vigilance should be maintained to detect future changes in susceptibility patterns.

Comparison of the Vitek GPS-TB card with disk diffusion testing for predicting the susceptibility of enterococci to vancomycin

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.

Prevalence of colonization with vancomycin-resistant enterococci in various population groups in Berlin, Germany

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.

Efficacy of hand disinfectants against vancomycin-resistant enterococci in vitro

Vancomycin-resistant enterococci (VRE) may be spread within a hospital via the contaminated hands of the healthcare worker. Effective hand disinfectants are necessary to break chains of transmission. We determined the bactericidal activity of 1-propanol, chlorhexidine digluconate (0.5 and 4%). Sterillium (45% 2-propanol, 30% 1-propanol and 0.2% mecetronium etilsulphate), Skinsept F (70% 2-propanol, 0.5% chlorhexidine digluconate and 0.45% hydrogen peroxide) and Hibisol (70% 2-propanol and 0.5% chlorhexidine gluconate) against 11 clonally distinct enterococcal isolates in a quantitative suspension test. Four isolates were vancomycin susceptible, four were vanA and the remainder vanB positive. Eight isolates were identified as Enterococcus faecium, two as Enterococcus faecalis and one as Enterococcus gallinarum. The investigator was blinded to the species and the genotype. Four parallel experiments were carried out for each isolate, each preparation, each dilution and each reaction time. 1-Propanol (60%), Sterillium, Skinsept F and Hibisol were all highly bactericidal after 15 and 30 s against VRE and vancomycin-susceptible enterococci (VSE) with reduction factors (RF) > 6.4, even in dilution of 50% (v/v). No significant difference was observed between vanA isolates, vanB isolates and VSE. Chlorhexidine digluconate (0.5% and 4%) was found to be less bactericidal after 30, 60 and 300 sec (RF < or = 2.5). The vanB genotype isolates were found to be significantly more susceptible to chlorhexidine (0.5%) than the vanA isolates (60 sec; one-way ANOVA model; P = 0.05). After 300 sec the vanB genotype isolates were found to be significantly more susceptible to chlorhexidine (0.5%) than the other two genotype isolates (P = 0.016). The vanA isolates were found to be significantly more susceptible to chlorhexidine (4%) than the vanB isolates (300 s; P = 0.024). E. faecium was found to be less susceptible to chlorhexidine than E. faecalis at all concentrations and reaction times, but significant differences between RF were only observed at 60 sec for both chlorhexidine concentrations (P < 0.05; t-test for independent samples). Propanol is much more effective against enterococci than chlorhexidine and combination of the two may be useful in providing an immediate and long lasting effect.

The threat of vancomycin resistance

Vancomycin, produced in 1958, an essential antibiotic in the modern age, often is reserved for use in patients who are gravely ill or for infections caused by organisms resistant to penicillin, cephalosporin, or other antibiotics. Bacterial resistance to vancomycin has caused great concern among many healthcare professionals. First reported in 1986 in Europe and in 1988 in the United States, vancomycin-resistant enterococci (VRE) have become a major cause of nosocomial infections. During this time, scattered reports of clinical infections caused by vancomycin-resistant coagulase-negative staphylococci also were reported. Recently, enterococci that require vancomycin in media for growth, vancomycin-dependent enterococci (VDE), have been reported to cause clinically significant infections. Vancomycin or other glycopeptide intermediately resistant Staphylococcus aureus (VISA/GISA) also has emerged. The mechanisms of resistance to vancomycin for VRE, and probably for VISA/GISA, relate to the acquired ability of these organisms to circumvent the vancomycin-mediated disruption of bacterial cell wall synthesis. Risk factors that lead to VRE colonization or infection include prior antibiotic therapy, prolonged hospitalization, hospitalization in an intensive care unit, concomitant serious medical and surgical illnesses, exposure to equipment contaminated with VRE, and exposure to patients with VRE. Patients colonized or infected with VRE, healthcare workers with contaminated hands, and environmental surfaces in healthcare facilities are major reservoirs of VRE. Risk factors for VDE and VISA/GISA are less well understood, although both organisms emerge in patients receiving vancomycin or other glycopeptide antibiotics. Infection and antibiotic control procedures for both organisms, including restriction of vancomycin use, optimization of the antibiotic formulary, education of hospital personnel, early detection and reporting of vancomycin resistance, isolation of colonized patients, and appropriate cleansing of the environment are used to prevent the spread of these organisms in healthcare settings.

Enterococcal bacteremia: risk factors for vancomycin resistance and predictors of mortality

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.

Lack of transmission of vancomycin-resistant enterococci in three long-term-care facilities

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.

Guideline for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee

The “Guideline for Prevention of Surgical Site Infection, 1999” presents the Centers for Disease Control and Prevention (CDC)'s recommendations for the prevention of surgical site infections (SSIs), formerly called surgical wound infections. This two-part guideline updates and replaces previous guidelines.

Part I, “Surgical Site Infection: An Overview,” describes the epidemiology, definitions, microbiology, pathogenesis, and surveillance of SSIs. Included is a detailed discussion of the pre-, intra-, and postoperative issues relevant to SSI genesis.

Vancomycin-resistant Enterococcus faecium colonization in children

Nosocomial vancomycin-resistant Enterococcus (VRE) infections have been described in only small numbers of pediatric patients. In none of these studies were multivariate analyses performed to assess which factors were independent risk factors in these patients. In the present cohort study of patients admitted to our hematology/oncology unit, surveillance cultures revealed a colonization rate of 24% and all isolates were identified as Enterococcus faecium. Risk factors associated with colonization with VRE identified by multiple logistic regression analysis included young age and chemotherapy with antineoplastic agents, cefotaxime, vancomycin, and ceftazidime. A molecular epidemiological tool, pulsed-field gel electrophoresis, was used to determine the relatedness of the VRE isolates detected. DNA analysis by this method identified two major clusters of VRE isolates. Young children with gastrointestinal colonization with VRE, without evidence of clinical infection, can serve as a reservoir for the spread of VRE.