Abstract
We analyzed the antibiotics in vitro susceptibility of 108 strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated in November 1998, when teicoplanin was first used in clinically in Japan. In comparison with 1990 to 1994 data, the piperacillin-or imipenem-resistant strains increased, whereas, the gentamicin-or flomoxef-susceptible strains increased. The minimum inhibitory concentration (MIC) distribution was found to differ among the three carbapenems ; imipenem, panipenem and meropenem ; panipenem was shown to be the best effective. All the strains showed susceptibility to minocycline, arbekacin, vancomycin and teicoplanin, and 92% showed susceptibility to sulbactam/ampicillin. MIC distribution of both vancomycin and teicoplanin showed a peak of 0.025μg/ml. All the strains showed a MIC value of
0.025μg/ ml for vancomycin. On the other hand, 5 isolates showed a MIC value of >1μg/ml for teicoplanin. Although it should not be concluded that these strains are pre-resistant, our results suggest that continuous surveillance and measure of antibiotic-resistant MRSA is necessary.
