MRSA is a major pathogen worldwide and its infections are associated with increased morbidity and mortality, in comparison with other S. aureus infections. The study was designed to characterize the mecA gene and staphylococcal cassette chromosome (SCCmec) in methicillin resistance S. aureus (MRSA). A total of 20 presumptive S. aureus strains were collected from one of the teaching hospitals in Selangor. Using standard biochemical tests, all the isolates were verified as S. aureus. When tested against cefoxitin, 80% of the isolates were confirmed as MRSA. All the MRSA isolates were further subjected to polymerase chain reaction (PCR) to detect the presence of mecA gene. Nine out of the 16 MRSA isolates (56%) were mecA positive, whereas the remaining four were mecA negative. The 16 MRSA with positive mecA gene were further subjected to SCCmec typing of type I, II, III, IV and V. The most frequent SCCmec types were type III (56%) followed by type II (33%), and type IV (11%). None of the isolates were of SCCmec type I or V. Our study indicates that SCCmec type III is predominant among the isolates which is in agreement with other studies conducted on clinical strains of MRSA.
A total number of 38 clinical strains of Staphylococcus haemolyticus originally obtained from Hospital Tuanku Ampuan Rahimah, Klang Selangor, were used in this study. The antimicrobial susceptibility of these nosocomial pathogens was tested against penicillin and cefoxitin. Except for one strain (B200) which was sensitive, the rest of the isolates were resistant to penicillin. Similarly, only one strain (F4) was sensitive against oxacillin while the rest were resistant. For cefoxitin, 34 or 89.5% of the isolates were resistant to this antibiotic and classified as Methicillin resistance Staphylococcus haemolyticus (MRSH). Amplification of the mecA gene showed among the MRSH strains 19 or 55.9% harbour the mecA gene but 15 or 44.1% were found negative for this gene. This could be due to the mec gene complex which does not only consist of the mecA gene but could also harbour other classes of mec genes such as mecB, mecC, mecD or mecE. However, one of the Methicillin-sensitive Staphylococcus haemolyticus (MSSH) strains susceptible against cefoxitin was also found to harbour the mecA gene. All the 20 isolates positive for mecA gene were further subjected to Staphylococcal Cassette Chromosome mec (SCCmec) type I, II, III, IV and V. The results showed that two or 10.0% of the strains (B14 and R27) expressed SCCmec type II while only one isolate (P29) expressed SCCmec type III. For the remaining 17 isolates, SCCmec typing was not detected suggesting that these isolates do not harbour SCCmec I, IV or V. Hence, there is a possibility that these isolates carry other types of SCCmec.