Typing and antimicrobial susceptibilities of methicillin resistant Staphylococcus aureus (MRSA) strains isolated in a hospital in Korea.

Methicillin-resistant Staphylococcus aureus (MRSA) strains may cause serious nosocomial infections, including pneumonia and septicemia. The rate of methicillin-resistance among S. aureus isolates in Korea is over 50%. In this study, 90 MRSA isolates from Kyung Hee University Hospital were characterized employing bacteriophage typing, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. Eighty percent of the strains could be phage-typed. The largest group or 40% of the strains belonged to lyso group III, followed by 32% of the isolates which produced a reaction with regional additional phages. Phage type 83A was most frequently encountered, followed by phage type D11. PFGE patterns confirmed the presence of two major clusters, which comprise the isolates belonging to lyso group III and the strains that were typable with regional additional phages. The latter group also contained a number of strains that were nontypable with bacteriophages. The resistance rates to ciprofloxacin, erythromycin, tetracycline, gentamicin and clindamycin were over 94%. Strains with intermediate resistance to vancomycin strains or resistance to mupirocin were not found. In conclusion, this study demonstrates that the results of phage typing are confirmed and supplemented by PFGE data.