Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains among pigs

Growing evidence of resistance of Staphylococcus aureus to methicillin (MRSA) is worrying. Domestic pigs are potential asymptomatic carriers of S. aureus, including strains resistant to methicillin, which poses a serious threat to meat consumers. This study was therefore aimed at assessing the prevalence of methicillin-resistant S. aureus (MRSA) in nasal swaps of selected pigs. This study investigated one hundred and fifty (150) nasal swabs of pigs from fifteen (15) selected pig farms (PGF) within Benin City, Edo State, Nigeria, to assess their levels of exposure to S. aureus and MRSA carriage. Isolation, characterization, and identification of S. aureus and MRSA were done using Mannitol Salt Agar (Oxoid, UK) and Mannitol Salt Agar supplemented with 4µg/ml oxacillin, respectively. Antibiotic susceptibility patterns were done using disc diffusion protocols, while presence of MRSA mecA genes was characterised using PCR. Thirty percent (30 %) of 150 analyzed swabs were positive for S. aureus, of which 13 (28.9 %) contained MRSA. MRSA were found in nasal swabs of animals from 9 different farms. All 13 (100%) MRSA isolates contained the mecA gene and were resistant to penicillin, 5 (38.5 %) were resistant to vancomycin and were characterized by multidrug resistance. The results of this study show that 38.5 % of examined pigs were infected with MRSA posing a serious threat to humans. These findings highlight the significant threat posed by MRSA in pigs, raising concerns for human health and emphasizing the importance of effective surveillance and control measures in livestock production to mitigate the transmission of antibiotic-resistant pathogens to consumers. Therefore, it was concluded that the MRSA was detected in pig from 9 different farms, indicating a widespread distribution.