Vancomycin-resistant enterococci from animal sources in Korea

Enterococci for which the minimum inhibitory concentration (MIC) of vancomycin was ≥ 8 mg/l were isolated from meat, feces, and raw milk samples collected in Korea from March to November 2003. Among the 243 vancomycin-resistant enterococci (VRE) that were identified the vanA vancomycin resistance gene was carried by 51 Enterococcus faecium and one Enterococcus sp., vanC1 was carried by 151 Enterococcus gallinarum, vanC2 was carried by 39 Enterococcus casseliflavus, and one Enterococcus sp. carried no van genes. Of the isolated enterococci carrying vanA, 4% were found to be highly resistant to gentamicin and 11% were resistant to ampicillin. Further genotyping of the E. faecium isolates carrying vanA using pulsed-field gel electrophoresis (PFGE) revealed extensive heterogeneity. The vancomycin resistance transferability test revealed that only two of the 52 enterococci carrying the vanA gene were able to transfer vancomycin resistance to other enterococci. The VRE were recovered from various animal sources with a particularly high prevalence of E. faecium carrying the vanA gene being found in poultry meat.