Antimicrobial Resistance, Virulence, and Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Recovered from Ready-to-Eat (RTE) Food in China: A New Challenge for Food Safety

The objective of the present study was to determine the prevalence, antimicrobial resistance, virulence profiles, and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) obtained from ready-to-eat (RTE) foods in China.

Two hundred fifty isolates (90.6%) were resistant to at least one antimicrobial agent; 73 (26.4%) isolates were multi-drug resistant (MDR). Thirty MRSA isolates were identified, among which nine toxin genes (sea, seb, sec, sed, seh, selk, sell, selq, and tsst-1) were detected. Sixty percent (18/30) of the MRSA isolates harbored multiple toxin genes. Four virulence gene patterns were identified, with seb-selk-selq (30/30) being the most common pattern. Thirteen sequence types, as well as 13 spa and 4 SCCmec types were found among 30 MRSA isolates. The most prevalent MRSA lineages were CC59-t437-SCCmecIV/V (23.3% [7/30]), CC398-t011-SCCmecV (23.3% [7/30]), and CC1-t114-SCCmecIV (16.7% [5/30]).

Our findings highlight the importance for the identification of prevalent clones, assessment of drug-resistance and virulence, and formulation of food safety measures for public health.