Emergence of community-associated methicillin-resistant Staphylococcus aureus in Singapore: a further six cases.

INTRODUCTION: The clinical features and molecular epidemiology of further cases of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in Singapore are described.

METHODS: Six cases of CA-MRSA infection that occurred between April and October 2004 are described. The bacterial isolates were tested for the presence of Panton-Valentine leukocidin (PVL) genes and typed via pulsedfield gel electrophoresis, staphylococcal chromosomal cassette mec (SCCmec) and multi-locus sequence typing. The results were compared with that of previously-reported local and international CA-MRSA isolates.

RESULTS: There were four cases of cutaneous abscesses and one each of chronic osteomyelitis and endocarditis. CA-MRSA isolates from the last two cases tested negative for PVL genes. Three isolates were identical and related to the Oceanian clone, and one isolate to the predominant Taiwanese clone. The isolate causing osteomyelitis had a novel sequence type.

CONCLUSION: CA-MRSA, though uncommon, is being isolated with increasing frequency in Singapore. A predominant clone (ST30- MRSA-IV) seems to be emerging locally.