Last update:
11-Nov-2004

OBJECTIVE The frequency of colonization and infection with vancomycin resistant enterococci (VRE) is increasing and is associated with factors frequently encountered in chronic hemodialysis (HD) patients. The purpose of this study was to determine the frequency of VRE colonization among a patient population treated at four dialysis units located in the same geographical area, to characterize isolated VRE by phenotypic and genotypic methods and to define risk factors for colonization.

METHOD During a 4-month period (from 1/9/ 01 to 30/12/01) 334 fecal or rectal swab specimens were collected from the same number of HD patients, receiving treatment at four units (I–IV) located in the western Attica region. The following patient data were recorded: gender, age, time on hemodialysis, type of dialysis catheter, and hospitalization and administration of antimicrobials during the previous six months. The swab specimens were inoculated into Enterococcosel agar with 6 μg/mL vancomycin. Species identification, susceptibility testing to seven antimicrobials (vancomycin, teicoplanin, ampicillin, erythromycin, ciprofloxacin, streptomycin and gentamicin) and detection of the resistance genotype to glycopeptides were performed by ATB and Vitek systems, E-test and a multiplex PCR. The genomic fingerprint of isolates was obtained by pulsed field gel electrophoresis (PFGE).

RESULTS Thirteen vanA positive Enterococcus faecium strains were isolated. The frequency of colonization was 3.89%. All strains were resistant to ampicillin, erythromycin, ciprofloxacin and streptomycin and 3 strains were also resistant to gentamicin. PFGE separated the 13 strains into 7 types: type A (2 strains), type B (6) and types C to G (1 each). Four type B strains and 2 type A strains originated from patients treated at unit IV. Type B strains were isolated from three units. The following parameters were identified as risk factors: previous hospitalization (P=0.001), administration of antimicrobials during the previous 6 months (P=0.026) and male gender (P=0.019).

CONCLUSIONS This is the first report of VRE colonization among HD patients in Greece. Despite the low number of VRE isolates, transmission of clones was detected between patients from different units as well as those in the same unit. In combination with the recognition of previous hospitalization as a significant risk factor these findings imply that the VRE strains were transmitted within a health care environment.

Key words: Chronic hemodialysis patients, Enterococcus, Vancomycin.