AUTHOR=Yang Xiaojuan , Zhang Jumei , Yu Shubo , Wu Qingping , Guo Weipeng , Huang Jiahui , Cai Shuzhen 

TITLE=Prevalence of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus in Retail Ready-to-Eat Foods in China

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.00816

DOI=10.3389/fmicb.2016.00816

ISSN=1664-302X

ABSTRACT=<p><italic>Staphylococcus aureus</italic>, particularly methicillin-resistant <italic>S</italic>.aureus (MRSA), is a life-threatening pathogen in humans, and its presence in food is a public health concern. MRSA has been identified in foods in China, but little information is available regarding MRSA in ready-to-eat (RTE) foods. We aimed to investigate the prevalence of <italic>S. aureus</italic> and MRSA in Chinese retail RTE foods. All isolated <italic>S. aureus</italic> were tested for antimicrobial susceptibility, and MRSA isolates were further characterized by multilocus sequence typing (MLST) and staphylococcal cassette chromosome <italic>mec</italic> (SCC<italic>mec</italic>) typing. Of the 550 RTE foods collected from 2011 to 2014, 69 (12.5%) were positive for <italic>S. aureus</italic>. Contamination levels were mostly in the range of 0.3–10 most probable number (MPN)/g, with five samples exceeding 10 MPN/g. Of the 69 <italic>S. aureus</italic> isolates, seven were identified as MRSA by cefoxitin disc diffusion test. Six isolates were <italic>mecA</italic>-positive, while no <italic>mecC</italic>-positive isolates were identified. In total, 75.8% (47/62) of the methicillin-susceptible <italic>S. aureus</italic> isolates and all of the MRSA isolates were resistant to three or more antibiotics. Amongst the MRSA isolates, four were identified as community-acquired strains (ST59-MRSA-IVa (<italic>n</italic> = 2), ST338-MRSA-V, ST1-MRSA-V), while one was a livestock-associated strain (ST9, harboring an unreported SCC<italic>mec</italic> type 2C2). One novel sequence type was identified (ST3239), the SCC<italic>mec</italic> gene of which could not be typed. Overall, our findings showed that Chinese retail RTE foods are likely vehicles for transmission of multidrug-resistant <italic>S. aureus</italic> and MRSA lineages. This is a serious public health risk and highlights the need to implement good hygiene practices.</p>