Vancomycin-resistant enterococci (VRE) remain a significant nosocomial pathogen. Current guidelines of the Hospital Infection Control Practices Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention (CDC) recommend the use of gowns and gloves for some interactions with VRE-infected or -colonized patients to prevent nosocomial transmission of VRE.

To assess the effect of disposable cover gowns on preventing nosocomial transmission of VRE.

Prospective study in a 16-bed medical intensive care unit of a university teaching hospital.

All patients who were at risk to acquire VRE, were admitted to the intensive care unit from August 1998 to January 1999, and had at least two perirectal cultures were included in the analysis of VRE acquisition.

VRE isolation precautions were changed from gowns and gloves to gloves alone.

VRE acquisition rates and risk factors for VRE acquisition.

The VRE acquisition rate was 1.80 cases per 100 days at risk in the gown and gloves period compared with 3.78 in the gloves only period (P= .04). In a proportional hazards model adjusted for length of stay, gloves only precautions with a hazard ratio of 2.5 (P = .02; 95% confidence interval, 1.2 to 5.3) were the only independent risk factor for VRE acquisition.

Our data lend support to current HICPAC recommendations for the use of cover gowns to decrease nosocomial transmission of VRE.

Several hospitals opting not to use active surveillance cultures to identify carriers of vancomycin-resistant Enterococcus (VRE) have reported that adoption of other parts of the Centers for Disease Control and Prevention guideline for controlling VRE has had little to no impact. Because use of surveillance cultures and contact isolation controlled a large outbreak at this hospital, their costs were estimated for comparison with the excess costs of VRE bacteremias occurring at a higher rate at a hospital not employing these measures.

Two university hospitals.

Inpatients deemed high risk for VRE acquisition at this hospital underwent weekly perirectal surveillance cultures. Estimated costs of cultures and resulting isolation during a 2-year period were compared with the estimated excess costs of more frequent VRE bacteremias at another hospital of similar size and complexity not using surveillance cultures to control spread throughout the hospital.

Of 54,052 patients admitted, 10,400 had perirectal swabs taken. Cultures and isolation cost an estimated $253,099. VRE culture positivity was limited to 193 (0.38%) and VRE bacteremia to 1 (0.002%) as compared with 29 bacteremias at the comparison hospital. The estimated attributable cost of VRE bacteremia at the comparison hospital of $761,320 exceeded the cost of the control program at this hospital by threefold.

The excess costs of VRE bacteremia may justify the costs of preventive measures. The costs of VRE infections at other body sites, of deaths from untreatable infections, and of dissemination of genes for vancomycin resistance also help to justify the costs of implementing an effective control program.

To test the hypothesis that antibiotic therapy may promote recurrence of vancomycin-resistant Enterococcus (VRE) stool colonization in patients who have previously had three consecutive negative stool cultures obtained at least 1 week apart.

One-year prospective cohort study examining the effect of antibiotic therapy on recurrence and density of VRE stool colonization in patients who have cleared colonization. Pulsed-field gel electrophoresis (PFGE) was performed to determine whether recurrent VRE strains were the same clone as the previous colonizing strain.

A Department of Veterans Affairs medical center including an acute care hospital and nursing home.

All patients with at least one stool culture positive for VRE who subsequently had three consecutive negative stool cultures obtained at least 1 week apart.

Of the 16 patients who cleared VRE colonization, 13 received antibiotic therapy during the study period. Eight (62%) of the 13 patients who received antibiotics developed recurrent high-density VRE stool colonization (range, 4.9 to 9.1 log10 colony-forming units per gram) during a course of therapy. Five patients had VRE strains available for PFGE analysis; recurrent strains were unrelated to the prior strain in 3 patients, closely related in 1 patient, and indistinguishable in 1 patient.

Antibiotic therapy may be associated with recurrent high-density VRE stool colonization in many patients who have previously had three consecutive negative stool cultures. These patients should be screened for recurrent stool colonization when antibiotic therapy is administered.

To investigate an outbreak of multidrug-resistant Pseudomonas aeruginosa in an intensive care unit (ICU).

Epidemiologic investigation, environmental assessment, and ambidirectional cohort study.

A secondary-care university hospital with a 10-bed ICU.

All patients admitted to the ICU receiving ventilator treatment from December 1,1999, to September 1, 2000.

An outbreak in an ICU with multidrug-resistant isolates of P. aeruginosa belonging to one amplified fragment-length polymorphism (AFLP)–defined genetic cluster was identified, characterized, and cleared. Molecular typing of bacterial isolates with AFLP made it possible to identify the outbreak and make rational decisions during the outbreak period. The outbreak included 19 patients during the study period. Infection with bacterial isolates belonging to the AFLP cluster was associated with reduced survival (odds ratio, 5.26; 95% confidence interval, 1.14 to 24.26). Enhanced barrier and hygiene precautions, cohorting of patients, and altered antibiotic policy were not sufficient to eliminate the outbreak. At the end of the study period (in July), there was a change in the outbreak pattern from long (December to June) to short Quly) incubation times before colonization and from primarily tracheal colonization (December to June) to primarily gastric or enteral Quly) colonization. In this period, the bacterium was also isolated from water taps.

Complete elimination of the outbreak was achieved after weekly pasteurization of the water taps of the ICU and use of sterile water as a solvent in the gastric tubes.

To evaluate clonal dissemination of methicillin-resistant coagulase-negative staphylococci (CNS).

Neonatal intensive care unit of a 180-bed, university-affiliated general hospital.

Neonates admitted to the neonatal intensive care unit between March 1999 and October 2000, from whom CNS were isolated as a unique pathogen. Patients from other wards from whom epidemiologically unrelated staphylococci strains were obtained served as control-patients.

Conventional methods were used for phenotypic characterization of CNS. Methicillin resistance was determined by mecA polymerase chain reaction (PCR) amplification. Genotypic characterization was done by random amplification of DNA with degenerated primers (RAPD) and repetitive element sequence-based PCR (rep-PCR).

Forty methicillin-resistant CNS isolates obtained from neonates were characterized as Staphylococcus epidermidis (33), S. hominis (5), S. warneri (1), and S. auricularis (1). Both RAPD and rep-PCR indicated the presence of 4 different clones among the 33 S. epidermidis isolates. In turn, the 4 randomly selected, epidemiologically unrelated methicillin-resistant CNS strains obtained from control-patients showed 3 new profiles by RAPD and 2 by rep-PCR, which differed from the corresponding patterns mentioned earlier. Persistence of S. hominis in a neonate could be assessed by both genotypic techniques.

The molecular characterization of the methicillin-resistant CNS studied indicated dissemination of one particular methicillin-resistant CNS clone among the neonates in the ward studied. Although RAPD showed a superior power to discriminate among methicillin-resistant CNS isolates, both RAPD and rep-PCR detected intraspecific and interspecific genomic diversity.

To determine the frequency of colonization by Enterobacter aerogenes in patients in the intensive care unit (ICU) for more than 48 hours and to evaluate the risk factors for infection in patients colonized by this bacteria.

An 8-month prospective study.

A 12-bed medical–surgical ICU in a 450-bed, university-affiliated, tertiary-care hospital in Belgium.

Pulsed-field gel electrophoresis was used to determine the genotypes of E. aerogenes isolates.

We observed two major clones of E. aerogenes in the ICU. Interestingly, 87.5% of infected patients had the same genomic profile for colonization and infection. Risk factors for infection in this particular population included younger age, prolonged hospital stay, mechanical ventilation, and bronchoscopy.

Colonization is a major prerequisite for infection. The identification of risk factors for infection in colonized patients can optimize the quality of treatment in the ICU.

To investigate and describe an outbreak of Serratia marcescens in a neonatal intensive care unit (NICU) and to report the interventions leading to cessation of the outbreak.

A 2,168-bed, tertiary-care, university teaching hospital in Vienna, Austria, with an 8-bed NICU.

We conducted a case–control study to identify risk factors for colonization and infection with S. marcescens. A case-patient was defined as any neonate in the NICU with a positive culture for S. marcescens between October 1, 2000, and February 28, 2001. Polymerase chain reaction was applied to type isolates.

During unannounced observations, the NICU was examined and existing policies were reviewed. Staff were reinstructed in hand antisepsis and gloving policies. Admissions were halted on December 27. During previously planned technical maintenance of the ward, the NICU was closed for 10 days and thorough aldehyde-based disinfection of the NICU was performed.

Ten neonates met the case definition: 6 with infections (among them 3 with cerebral abscesses) and 4 with asymptomatic colonization. Previous antibiotic treatment of the mothers with cefuroxime was the single significant risk factor for colonization or infection (P = .028; odds ratio, 17; 95% confidence interval, 1.3 to 489.5).

S. marcescens can cause rapidly spreading outbreaks associated with fatal infections in NICUs. With aggressive infection control measures, such outbreaks can be stopped at an early stage. Affected neonates themselves may well be the source of cross-infection to other patients on the ward. Antibiotic treatment of mothers should be reevaluated to avoid unnecessary exposure to antibiotics with the potential of overgrowth of resistant organisms.

To study the role of amoeba-associated alpha Proteobacteria as infecting agents in intensive care units (ICUs).

Amoeba-associated alpha Proteobacteria were isolated from water samples taken from ICU taps and general hospital reservoir tanks using an amoebal co-culture procedure. Isolates were identified by 16S rDNA gene sequence comparison, and one isolate of each species was used as an antigen in a microimmunofluorescence assay to test the sera of the patients in the ICUs and compare them with those of control subjects.

The four university hospitals in Marseilles, France.

The sera of 85 patients in the ICUs with nosocomial pneumonia were tested.

We isolated 64 bacterial strains that were identified as Afipia species or close relatives within the Rhizobiaceae subgroup of alpha Proteobacteria. These bacteria were assigned to 8 different species. Eleven patients were found to have an elevated antibody titer to either Afipia genospecies 1, or 3 still unnamed bacteria. No specific antibodies were detected in 100 control subjects (P<.01).

These preliminary results support the hypothesis that ICU patients are exposed to amoeba-associated alpha Proteobacteria.