JAC pp471-76 MW3161

Strains of methicillin-resistant Staphylococcus aureus (MRSA) were detected in 1961, shortly after methicillin came into clinical use. However, such strains occurred sporadically and were resistant only to -lactam antibiotics, causing no major problems. By contrast, the resistant strains that appeared in Australia in the late 1970s were entirely different; they were resistant to other types of antibiotics, such as aminoglycosides, macrolides, tetracyclines and, more recently, quinolones, and have spread worldwide, while retaining their virulence. In Japan, most strains of MRSA now exhibit high-level resistance to various antibiotics and therefore pose a serious problem clinically and epidemiologically, among compromised in-patients in particular, as the causative pathogen of nosocomial infection. Arbekacin is a broad-spectrum aminoglycoside antibiotic, and is active against MRSA that have a variety of aminoglycoside-inactivating enzymes. In this study, the bactericidal activity and post-antibiotic effects (PAEs) of arbekacin were compared with those of vancomycin against MRSA strain 1936, a clinical isolate. The morphological changes of the strain caused by exposure to these agents were also examined.