Nosocomial Infection Caused by Multidrug-Resistant Staphylococcus aureus with Reduced Susceptibility to Vancomycin and Teicoplanin.-Yamagata prefecture, Japan; May 2004-Jun 2005

Nosocomial infection caused by methicillin-resistant Staphylococcus aureus (MRSA) occurred at a major in Yamagata prefecture hospital between May 2004 and June 2005. We studied pulsed-field gel electrophoresis patterns, antimicrobial susceptibility patterns, and bacteriological features, such as coaglase type for eight isolates, including two of methicillin-resistant Staphylococcus epidermidis (MRSE). Our results suggest that this case was caused by a single strain of multidrug-resistant S. aureus. These 8 clinical isolates indicated reduced susceptibility to vancomycin and teicoplanin. PCR assay results for detection of the staphylococcal vanA, vanB, and vanC gene were all negative as all isolates. In transmission electron microscopy, cell walls appeared thicker than those of a susceptible strain from food poisoning. MRSA with reduced susceptibility to glycopeptide antibiotics may not be treated successfully with vancomycin or teicoplanin, making it important to closely observe MRSA with reduced susceptibility to glycopeptide antibiotics.