Résumé
BACKGROUND: Nosocomial infections caused by vancomycin-resistant enterococci (VRE) are increasing problem in Korea. Until now, no nationwide study has been performed. The aim of the present study was to monitor the antimicrobial resistance of vancomycin-resistant Enterococcus faecium (VREF). METHODS: Two hundred and two E. faecium isolated in 10 teaching hospital were studied. To detect VRE, the brain heart infusion agar containing 6 /mL vancomycin was used as the screening agar. The MIC was determined using agar dilution test. The vancomycin resistance genes (vanA, vanB & vanD) and genes (aac(6 ') Ie-aph(2 ") Ia & ant(6 ') Ia encoding the aminoglycoside-modifying enzymes were detected by multiplex PCR using specific primers. RESULTS: Thirty-nine VREF were detected from 202 isolates. All had vancomycin MICs > or =256 /mL and harboured vanA gene. No isolates revealed positive results for the vanB or vanD gene. However, the MIC range for teicoplanin was 2 to > or =256 /mL. All isolates with gentamicin MIC > or = 500 /mL gave positive results for the aac(6 ') Ie aph(2 ") Ia genes and with streptomycin > or =2000 /mL gave positive results for the ant(6 ') Ia gene. CONCLUSIONS: All VREF harboured vanA gene. According to MIC tests, 7 isolates(18%) showed intermediate or susceptible to teicoplanin. Therefore we need a study concerning the clinical meaning. The VREF in Korea contain at least one of genes encoding the aminoglycoside-modifying enzymes. This means there are only limited numbers of antibiotics to choose.