Vancomycin-resistant Enterococcus faecium on a pediatric oncology ward: duration of stool shedding and incidence of clinical infection

Abstract

Objective: To determine the duration of stool shedding and incidence of clinical infection among pediatric oncology patients colonized with vancomycin-resistant Enterococcus faecium (VRE) in our institution.

Methods: Stool cultures were obtained from all patients admitted from May 15 to August 2, 1994. Patients were followed for evidence of clinical VRE infection and surveillance stool results through August 15, 1995. Genetic relatedness of stool-clinical isolate pairs and serial stool samples was evaluated using pulsed field gel electrophoresis.

Results: Twenty-three (32%) of 73 screened patients were colonized with VRE. Eight (35%) of the colonized patients cleared VRE from stool; 10 (43%) were persistent carriers, excreting organisms for 19 to 331 days (median, 112 days); and 5 patients had an insufficient number of stools to determine length of carriage. Persistent carriers had a median of 6 hospital readmissions; 8 of 10 were positive at first or second readmission Clinical VRE infection developed in 6 of 73 patients (annual incidence, 8.2%). Clinical cases had more days of neutropenia between colonization and infection than colonized patients during a comparable follow-up (49 vs. 16 days, P = 0.04). Five of 6 stool-clinical isolate pairs were identical by pulsed field gel electrophoresis. Serial stools from 6 of 7 patients (collected 20 to 343 days apart) were identical by pulsed field gel electrophoresis.

Conclusion: Persistent gastrointestinal colonization with VRE is common among pediatric oncology patients. Carriage of the same VRE clone for up to 1 year was demonstrated. In the majority of cases invasive and colonizing isolates were identical by DNA fingerprinting techniques, suggesting that the colonizing VRE was the source of infection. Intermittent excretion of organisms in stool makes vigilant tracking and immediate isolation of such patients crucial to control efforts. Prolonged neutropenia may increase the risk of developing clinical infection among VRE-colonized patients.