Community-associated meticillin-resistant Staphylococcus aureus in children in Taiwan, 2000s

Meticillin-resistant Staphylococcus aureus (MRSA) has been increasingly identified as the major cause of community-associated (CA) infections in previously healthy hosts since the late 1990s. CA-MRSA strains were recognised as a novel pathogen that is genetically different from healthcare-associated MRSA, and five major epidemic clones have been identified worldwide. In Taiwan, a significantly increasing rate of MRSA carriage and infection amongst healthy subjects was observed in the past decade. Up to 9.5% of healthy Taiwanese children carried MRSA in the nares and >50% of paediatric CA S. aureus infections were MRSA. The adult population was also affected, but this was relatively limited. The majority of CA-MRSA isolates in Taiwan belonged to the sequence type (ST) 59 lineage, defined by multilocus sequence typing, and were multiresistant to non-β-lactams. The clone of ST59 lineage can be further classified into at least two major clones by pulsed-field gel electrophoresis (PFGE) typing, staphylococcal chromosomal cassette mec (SCCmec) elements and Panton-Valentine leukocidin (PVL) genes. The clone characterised as ST59/PFGE type C/SCCmec IV/PVL-negative was prevalent amongst the colonising isolates, whereas ST59/PFGE type D/SCCmec VT/PVL-positive was prevalent amongst the clinical isolates. Evidence suggested that the ST59 CA-MRSA clone was not only circulating in Taiwan but also in other areas of the world. In this article, the current status of CA-MRSA in Taiwan was extensively reviewed. The information provided here is not only important for local public health but can also enhance a general understanding of the successful epidemic clones of CA-MRSA worldwide.