Colonization by vancomycin-resistant enterococci of the intestinal tract of patients in intensive care units from French general hospitals

Abstract

OBJECTIVE: To evaluate the prevalence of fecal carriage of vancomycin-resistant enterococci (VRE) by patients hospitalized in intensive care units from 24 French general hospitals. METHODS: Rectal swabs were obtained from 647 patients hospitalized in intensive care units during the month of June 1994 and plated on agar medium selective for vancomycin-resistant enterococci. The glycopeptide resistance phenotypes and genotypes of the enterococci detected were characterized. RESULTS: Thirty-two of 647 patients (4.9%) carried VRE. Thirteen strains (2%) were identified as Enterococcus faecium and 19 (2.9%) as Enterococcus gallinarum or Enterococcus casseliflavus. None of these strains was highly resistant to gentamicin. The E. gallinarum and E. casseliflavus strains contained the vanC1 and vanC2 genes, respectively. The E. faecium strains were highly resistant to vancomycin and teicoplanin and carried the vanA gene. No infection due to VRE was observed during the study period. Pulsed-field gel analysis of total DNA following digestion with SmaI or KspI from 13 VanA-type E. faecium strains revealed intra- and inter-hospital strain heterogeneity. However, the finding of isolates with indistinguishable pulsed-field types within the same ward and in two medical centers suggests patient-to-patient transmission or a common source. Four E. faecium strains were isolated within 48 h after admission of patients. CONCLUSIONS: These results indicate that VRE form part of the normal flora of patients and that, despite the actual scarcity of infections due to VRE, there is a potential risk for dissemination of these strains in French hospitals.