Analysis of methicillin-resistant and methicillin-susceptibleStaphylococcus aureusby a molecular typing method based on coagulase gene polymorphisms

Abstract

Summary: A molecular typing method forStaphylococcus aureusbased on coagulase gene polymorphisms (coagulase gene typing) was evaluated by examining a total of 240 isolates which comprised 210 methicillin-resistantS. aureus(MRSA) and 30 methicillin-susceptibleS. aureus(MSSA) collected from a single hospital. ByAlulrestriction enzyme digestion of the PCR-amplified 3′-end region of the coagulase gene including 81-bp repeated units, the MRSA and MSSA isolates examined were divided into 6 and 12 restriction fragment length polymorphism (RFLP) patterns, respectively, whereas five patterns were commonly detected in MRSA and MSSA. MRSA isolates that showed a particular RFLP pattern were considered to be predominant in the hospital. Coagulase typing with type-specific antisera was also performed for allS. aureusisolates for comparison. Coagulase types II and VII were most frequently detected and included isolates with four and five differentAluIRFLP patterns, respectively, whereas each of the other coagulase types corresponded to a single RFLP pattern. These results indicated that RFLP typing was more discriminatory than serological typing, for typingS. aureusand demonstrated its utility in epidemiologic investigation ofS. aureusinfection in hospitals.