IN-VITRO SUSCEPTIBILITY STUDIES AND DETECTION OF VANCOMYCIN RESISTANCE GENES IN CLINICAL ISOLATES OF ENTEROCOCCI IN NAGASAKI, JAPAN

Glycopeptide resistance in enterococci is now a cause of clinical conc ern in the United States and Europe. However, details of vancomycin re sistance in enterococci in Japan have been unknown. We measured minimu m inhibitory concentrations (MICs) of various antimicrobial agents for a total of 218 clinical strains of enterococci isolated in our hospit al in 1995-6 in addition to 15 strains with known genotypic markers of resistance. We also screened vancomycin resistance genes using a sing le step multiplex-PCR. In clinical isolates, only two strains of Enter ococcus gallinarum were of intermediate resistance to vancomycin (MIG, 8 mu g/ml), while the others were all susceptible. Glycopeptides (van comycin and teicoplanin) and streptogramins (RP 58500 and RPR 106972) showed potent antimicrobial effects for the isolates. In addition, amp icillin was also potent for Enterococcus faecalis, while ampicillin, m inocycline and gentamicin were potent for Enterococcus avium. No vanA or vanB genes were detected, while vanC(1), and vanC(23) genes were de tected from two and four strains, respectively. Our results suggest th at incidence of VRE in Japan may be estimated as still very low at thi s time.