Genetic characteristics and antimicrobial resistance of Staphylococcus aureus isolates from pig farms in Korea: emergence of cfr-positive CC398 lineage

Livestock-associated Staphylococcus aureus (LA-SA) has become a global concern due to its ability to colonize farm animals and transmit to the environment and humans, leading to symptomatic infections and the spread of antimicrobial resistance (AMR). A study analyzing 163 S. aureus isolates from healthy pigs, farm environments, and farm workers found that 51 (31.3%) were methicillin-resistant and 112 (68.7%) were methicillin-susceptible. The majority (98.8%) were from the CC398 lineage. High levels of resistance to commonly used antibiotics have been observed on Korean pig farms. Notably, 21 cfr-positive CC398 isolates displaying increased resistance to linezolid were identified in healthy pigs.