Prevalence and Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Isolated from Pigs in Japan

Prevalence and Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Isolated from Pigs in Japan

Blog Article

We investigated the prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pig slaughterhouses from 2018 to 2022 in Japan and the isolates were examined for antimicrobial susceptibility and genetic characteristics by whole-genome analysis.Although the positive LA-MRSA rates on farms (29.6%) and samples (9.9%) in 2022 in Japan remained lower than those observed in European countries exhibiting extremely high rates of confirmed human LA-MRSA infections, these rates showed a gradually increasing trend over five years.The ST398/t034 strain was predominant, followed by ST5/t002, and differences were identified between 5326058hx ST398 and ST5 in terms of antimicrobial susceptibility and the resistance genes carried.

Notably, LA-MRSA possessed resistance genes toward many antimicrobial classes, with 91.4% of the ST398 strains harboring zinc resistance genes.These findings indicate that the co-selection pressure associated with multidrug and zinc resistance may have contributed markedly to LA-MRSA persistence.SNP analysis revealed that ST398 and ST5 of swine origin were classified into a different cluster of MRSA from humans, showing the same ST in Japan and lacking the immune evasion genes (scn, sak, or chp).Although swine-origin LA-MRSA borstlist självhäftande is currently unlikely to spread to humans and become a problem in current clinical practice, preventing its dissemination requires using antimicrobials prudently, limiting zinc utilization to the minimum required nutrient, and practicing fundamental hygiene measures.