[Epidemiological survey of methicillin-resistant Staphylococcus aureus isolated from 34 hospitals in Japan]

Eight hundred and seventy-two isolates of clinically significant methicillin-resistant Staphylococcus aureus (MRSA) with their clinical information were obtained between 1992 and 1993 from thirty-four hospitals in Japan. The isolation frequency of MRSA was high in sputum (42.9%), pus (33.1%) and blood (14.0%). Pseudomonas aeruginosa was a major bacterial species in polymicrobial infections with MRSA. Enterobacteriaceae and Candida sp. were also frequently isolated with MRSA. Four different coagulase types were identified. Coagulase type II was found in 85.6% of all MRSA strains tested. The isolation frequencies of coagulase type III, type IV and type VII were 3.1%, 3.6% and 3.2%, respectively. The strains of MRSA contained coagulase type II were prevalent in all geographical areas of Japan, but other coagulase types were limited in western areas of the country. The strains of MRSA were tested for their susceptibility to twelve antimicrobial agents and for production of penicillinase. More than 80% of MRSA strains were highly resistant to methicillin, and were also resistant to macrolide antibiotics and tobramycin. Frequencies of resistance to gentamicin, minocycline or ofloxacin were approximately 60%, 50% or 70%, respectively. But only a small percentage of strains were resistant to arbekacin and all of the MRSA tested were susceptible to vancomycin.