Clinical glycopeptide-resistant enterococci isolated from patients after solid organ transplantation

The aim of this study was to confirm the identification and resistance to vancomycin and teicoplanin of nosocomial enterococcal strains using molecular biology methods. Glycopeptide-resistant enterococci (GRE) strains were isolated from clinical specimens of hospitalized patients. Bacterial identification was performed in an automatic ATB Expression system (bioMérieux SA). Susceptibility to glycopeptides was determined by the disc diffusion method and Etest (AB BIODISK, Sweden). We performed polymerase chain reactions (PCR) for Enterococcus faecium and E. faecalis identification and van genes detection. Fifteen GRE strains were cultured over 2 years (2003-2004). Fourteen isolates were highly resistant to vancomycin (MIC range, 128->256 mg/L) and teicoplanin (MIC range, 32->256 mg/L). Twelve strains harbored van A gene (Van A phenotype). Seven isolates were identified as E. faecium and seven as E. faecalis by the multiplex-PCR method. One strain-E. casseliflavus-showed low resistance to vancomycin (MIC 8 mg/L) with retained susceptibility to teicoplanin (MIC 4 mg/L). It harbored the van C2/C3 gene and was identified as the Van C2/C3 phenotype. GRE strains were more often isolated from hospitalized patients in Poland. Constant monitoring by reliable microbiological methods has become necessary to prevent the spread of these strains in the hospital environment.