Abstract
Recent reports of increasing community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) infection in our neighbouring country Singapore (Hsu et al., 2006) indicate the possibility of such a serious infection in Malaysia as well. This prompted us to investigate the presence of CA-MRSA strains in the Malaysian population. For the purposes of this study, CA-MRSA was defined as an isolate from a subject who had no health-care exposure or antibiotic therapy in the previous 6 months which contained staphylococcal chromosomal cassette mec (SCCmec) type IV or V. The presence of PVL was an added value.
A nasal culture survey among 100 university students from the faculty of medicine and health sciences (Universiti Putra Malaysia, Serdang) was conducted with ethical approval to screen for the presence of CA-MRSA. All participating subjects were students who did not attend clinical wards. Moreover, the faculty where the screening took place was not directly affiliated to the hospital, thereby minimizing the risk of acquisition from the hospital.
Only subjects without obvious risk factors (exposure to the health-care system and usage of any antibiotic during the previous 6 months) for CA-MRSA carriage or infection were included in the study. S. aureus was isolated from the nasal swabs of participating subjects by standard procedures. Among the 100 subjects, 26 (26 %) were colonized with S. aureus, which is in agreement with previously reported data (Choi et al., 2006).
The susceptibilities of the S. aureus carriage isolates to oxacillin, erythromycin, gentamicin, rifampicin, fusidic acid, mupirocin and vancomycin were determined by Kirby–Bauer disc diffusion and interpreted according to the CLSI (2005) standards. Antibiotic susceptibility testing revealed one (3.8 %) isolate to be resistant to rifampicin and erythromycin while six (23 %) were intermediately resistant to erythromycin and fusidic acid (Table 1). All isolates were susceptible to gentamicin, mupirocin and vancomycin. Antibiotic susceptibility profiles indicated that 85 % of the carriage isolates were sensitive to all antibiotics tested. Not a single strain was resistant to more than three classes of antibiotics such as β-lactams, macrolides and fusidic acid.