Frequency of Clinical Isolates and Antimicrobial Susceptibility of Methicillin-resistant Staphylococcus aureus （MRSA） in Niigata University Hospital (Nosocomial Infections caused by Methicillin-Resistant Staphyllococcus aureus（MRSA）: The Present Problems and The Strategies for Prevention)

In Niigata University Hospital, Methicillin-resistant Staphylococcus aureus （MRSA） was isolated from 1981. After that, it increased year by year. The frequency of MRSA in all S.aureus isolated from inpatients was 73.3% （305/415） in 1988, but has never increased up to recently. The isolates of MRSA from outpatients were only 96 strains （24.2%） in the year. MRSA was frequently isolated from sputum and pus. Most strains of MRSA were coagulase type II （51.1%） and IV （46.4%） in the 1988 study. In 1992, type II strains have become 84.9% of all MRSA isolates. Almost of all MRSA strains were resistant to β-lactam antibiotics, erythromycin and clindamycin. 65.4% of MRSA strains were resistant to ofloxacin. On the other, 72.9% of MRSA strains were sensitive to minocyclin, and almost sensitive to arbekacin, vamcomycin and sulfamethoxazole-trimethoprim