Detection and molecular characterisation of methicillin-resistant Staphylococcus aureus isolated from raw meat in the retail market

Objectives: This study aimed to detect and characterise methicillin-resistant Staphylococcus aureus (MRSA) from retail meat in the Czech Republic. Methods: Isolates were identified by PCR detection of the S. aureus-specific fragment Sa442 and mecA gene. spa typing, MLST, detection of genes encoding staphylococcal enterotoxins, Panton-Valentine leuko-cidin (pvl), exfoliative toxins A and B (eta and etb), toxic shock syndrome toxin (tst) and staphylokinase (sak ), detection of phi Sa3 prophage and antimicrobial susceptibility testing were performed. Results: Of 65 raw meat samples examined (poultry, beef, pork and rabbit), 23 (35.4%) were positive for MRSA. Twelve positive samples originated from poultry (12/33; 36.4%), while the remaining eleven came from pork (9/9; 100%) and pork/beef mixed minced meat (2/5; 40.0%). Eight spa types belonging to five different sequence types (STs) were identified. ST398 was the most frequent (28/36; 77.8%), presenting spa types t011, t034, t2576, t4132, t588 and t899. Other livestock-associated MRSA STs (ST9-t899, ST5-t002, ST692-t8646 or the newly described ST4034-t899) were also sporadically identified. In seven isolates (19.4%), one or more staphylococcal enterotoxin genes were detected, with sea, seg and sei prevailing. Three isolates from turkey [ST398-t899 (n = 2) and ST398-t011] harboured the sak gene, and the latter also harboured the sea gene. Seven isolates from poultry harboured the phi Sa3 prophage and were resistant to tetracycline. Conclusion: Specific kinds of meat appear to be a possible source of MRSA, although the risk to humans is hard to define. Therefore, surveillance of MRSA in meat as well as hygienic practices should be improved. (C) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.

Automated summary

MRSA was detected in 35.4% of raw meat samples in the Czech Republic, with poultry being the main source. The predominant ST was ST398, with common spa types including t011, t034, and t2576. Genes associated with infection, such as sea, seg, and sei, were detected in some isolates.