Antimicrobial susceptibility of clinical isolates of enterococci

To describe antimicrobial resistance patterns of Enterococcus spp., we measured minimal inhibitory concentrations (MICs) of five antimicrobial agents for 174 clinical isolates of enterococci collected in Taichung Veterans General Hospital from November, 1996 to January, 1998. Major sources included blood (48), the genitourinary tract (39), soft tissue and wounds (28), and the gynecological tract (16). The sensitivity test of vancomycin was performed using the broth microdilution method. The susceptibility of ampicillin, penicillin, gentamicin, and teicoplanin was tested by the agar dilution method. The MIC90 of penicillin, ampicillin, gentamicin, teicoplanin and vancomycin were 2, 1, > 2,048, 0.125 and 2 microg/mL, respectively. Ampicillin-resistant isolates represented only 4.6% of all enterococci tested. These results reveal that vancomycin-resistant enterococci were found in 1.7% of all enterococci isolates in this study. However, all isolates were sensitive to teicoplanin.