Epidemiologic Study of methicillin-resistant Staphylococcus aureus by Coagulase Gene Polymorphism

Abstract

An epidemiologic study of methicillin-resistant Staphylococcus aureus (MRSA) was conducted by antibiotype, coagulase gene typing and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. A total of 129 MRSA strains were isolated from 17 hospitals in the regions of the central, northern, northeastern and eastern Thailand during November 2003 – March 2004. Antimicrobial susceptibility testing with a panel of 10 antimicrobial agents showed 9 different antibiotypes. The antibiotypes 1 and 2 were the most common phenotypes with 44.2% and 35.6% of the isolates, respectively. Coagulase gene typing of MRSA strains generated 4 different genotypes: I, II, III, IV, the PCR products of which were 492 20, 654 20, 735 20 and 816 20 bp with the percentages of 1.5 (2/129), 2.3 (3/129), 82.2 (106/129) and 14 (18/129), respectively. Coagulase gene PCR-RFLPs exhibited 4 patterns: A, B, C and D, with AluI digested PCR product fragments at 220 20 and 220 20 bp (pattern A); 400 20 and 220 20 bp (pattern B); 420 20 and 220 20 bp (pattern C); and 510 20 and 220 20 bp (pattern D). The percentage values for each pattern were compatible with those from the coagulase gene typing method. The results indicated that antibiotypes 1, 2, coagulase gene type III and PCR-RFLP pattern C were the epidemic strains while the rest were sporadic strains.