Antimicrobial activities of arbekacin against methicillin-resistant Staphylococcus aureus

In order to evaluate antimicrobial activity of arbekacin (ABK), coagulase-type and minimum inhibitory concentrations (MICs) of ABK and other drugs were determined against 700 strains of methicillin-resistant Staphylococcus aureus (MRSA) that were obtained in our laboratory from 1990 to 1996, 7 years. The results are summarized as follows; 1. The MIC-distributions of ABK against 100 strains of MRSA obtained yearly did not show stochastically significant differences. 2. The coagulase-type distributions showed differences over the years. Coagulase-type II strains increased and type IV strains decreased, and MIC-distributions of ABK and other drugs were different according to coagulase-types. 3. The detection frequencies of ABK-resistant strains (MIC of ABK: > or = 12.5 micrograms/ml) were 2.0 approximately 8.0% through the years. The frequency reported in 1980 was equal to the frequency obtained in 1992 approximately 1993 in a nationwide survey. Coagulase-types II, IV and VII that were ABK-resistant strains were frequently obtained, and most of ABK-resistant strains were also highly resistant to gentamicin.