Community-associated Staphylococcus Aureus Infections in China: Epidemiology, Molecular Characteristics, Treatment, and Outcome

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), strains of MRSA that are able to infect otherwise healthy people outside of hospital settings, emerged in the late 1990s and have recently arisen in many countries around the globe. CA-MRSA strains are usually distinguished from their HA-MRSA counterparts by the following characteristics: Firstly, CA-MRSA strains are usually susceptible to non-lactam antibiotics. Secondly, CA-MRSA harbors type IV and V SCCmec elements, which are shorter than the traditional type I, II, and III SCCmec elements found in HA-MRSA strains. Thirdly, certain successful clones are associated with outbreaks of CA-MRSA infections reported in specific geographical locations. For example, ST1 and ST8 isolates are mostly reported in the USA and Canada, ST80 isolates are commonly found in Europe, and ST59 isolates are encountered in the Asia-Pacific region. Notably, all these characteristics have substantial limitations for discriminating CA-MRSA isolates due to their complex backgrounds. Although there were more and more studies of CA-MRSA in European countries and the US, few national epidemiological data were available about China. In this study, we investigated the epidemiological, clinical and molecular characteristics of CA-MRSA isolates recovered in Chinese hospitals, in order to understand the changing epidemiology of MRSA in China.