Glycopeptide resistance in enterococci is now a cause of clinical
concern in the United States
and Europe. However, details of vancomycin resistance in enterococci in
Japan have been
unknown. We measured minimum inhibitory concentrations (MICs) of various
antimicrobial agents for a total of 218 clinical strains of enterococci
isolated in
our hospital in 1995–6 in
addition to 15 strains with known genotypic markers of resistance. We also
screened
vancomycin resistance genes using a single step multiplex-PCR.
In clinical isolates, only two strains of Enterococcus gallinarum
were of intermediate
resistance to vancomycin (MIC, 8 μg/ml), while the others
were all susceptible. Glycopeptides
(vancomycin and teicoplanin) and streptogramins (RP 58500 and RPR 106972)
showed potent
antimicrobial effects for the isolates. In addition, ampicillin was also
potent for Enterococcus
faecalis, while ampicillin, minocycline and gentamicin were potent
for
Enterococcus avium. No
vanA or vanB genes were detected, while
vanC1 and vanC23 genes were detected
from two and
four strains, respectively. Our results suggest that incidence of VRE in
Japan
may be estimated as still very low at this time.