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

• Published in: BMC veterinary research Vol. 20; no. 1; pp. 503 - 9
• Main Authors: Lee, Jun Bong, Lim, Ji Hyun, Park, Ji Heon, Lee, Gi Yong, Park, Kun Taek, Yang, Soo-Jin
• Format: Journal Article
• Language: English
• Published: BioMed Central Ltd 01.11.2024; BMC
• Subjects: Antibacterial agents; Antimicrobial resistance; Care and treatment; Clonal complex 398; Complications and side effects; Disease transmission; Diseases; Dosage and administration; Drug resistance in microorganisms; Genetic aspects; Growth; Linezolid resistance; Pig farms; Prevention; Staphylococcus aureus; Staphylococcus aureus infections; Swine; South Korea
• ISSN: 1746-6148; 1746-6148
• DOI: 10.1186/s12917-024-04360-w

Abstract Background Livestock-associated Staphylococcus aureus (LA-SA) has gained global attention because of its ability to colonize farm animals and transmit to the environment and humans, leading to symptomatic infections and the spread of antimicrobial resistance (AMR). In the last decade, numerous studies have reported a high prevalence of S. aureus clonal complex (CC) 398 in pig farms. Results In this study, 163 S. aureus isolates were collected from healthy pigs ( n = 110), farm environments ( n = 42), and farm workers ( n = 11), and their AMR profiles and epidemiological characteristics were analyzed. We identified 51 (31.3%) methicillin-resistant S. aureus (MRSA) and 112 (68.7%) methicillin-susceptible S. aureus (MSSA), with 161 (98.8%) isolates belonging to the CC398 lineage. The highest prevalence of spa type t571 was observed among the CC398 isolates. All 47 sequence type (ST) 398 MRSA isolates carried staphylococcal cassette chromosome mec (SCC mec ) V, while four ST541 isolates carried SCC mec IV. High levels of resistance to commonly used antibiotics, including phenicols, quinolones, lincosamides, macrolides, aminoglycosides, and tetracyclines, have been observed on Korean pig farms. Notably, 21 cfr -positive CC398 isolates (four ST541-SCC mec IV MRSA and 17 ST398 MSSA) displaying increased resistance to linezolid were identified in healthy pigs. Conclusions In summary, these findings suggest that the multidrug-resistant CC398 S. aureus lineage predominantly colonizes healthy pigs and farm environments in Korea. The emergence of cfr -positive S. aureus at human-animal interfaces presents a significant threat to food safety and public health.