Prevalence And Molecular Characterization Of Methicillin-Resistant Staphylococcus Aureus (Mrsa) In Poultry Production Systems In Southwestern Nigeria: A Review

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important antimicrobial resistance (AMR) challenge affecting both human and animal health, and poultry production systems provide favourable conditions for the emergence, maintenance, and dissemination of resistant bacteria owing to intensive production practices, frequent antimicrobial exposure, and close interaction between poultry birds, farm workers, and the environment. This review synthesizes current evidence on the prevalence, antimicrobial resistance profiles, molecular characteristics, transmission pathways, and public health implications of MRSA associated with poultry production systems in Southwestern Nigeria, drawing on literature retrieved from PubMed, Google Scholar, ScienceDirect, Scopus, and African Journals Online (AJOL) covering studies published between 2010 and 2026. Available evidence indicates that MRSA is present among poultry birds, poultry handlers, poultry products, and farm environments across Lagos, Ogun, and Oyo States, with mecA-positive isolates confirmed through culture, antimicrobial susceptibility testing, and, in select studies, whole-genome sequencing. Poultry-associated MRSA isolates frequently exhibit multidrug resistance involving β-lactams, tetracyclines, macrolides, aminoglycosides, fluoroquinolones, and sulfonamides, mediated by resistance genes such as mecA, blaZ, tet, aacA-aphD, and dfr variants, reflecting inappropriate antimicrobial use, inadequate biosecurity, poor hygiene, and environmental contamination across the poultry production chain. However, molecular surveillance remains comparatively limited, with few studies incorporating SCCmec typing, spa typing, multilocus sequence typing, or whole-genome sequencing alongside phenotypic detection, and most available evidence remains concentrated in a small number of states. Strengthening antimicrobial stewardship, establishing routine surveillance, improving farm biosecurity, and expanding molecular epidemiological studies within a coordinated One Health framework linking veterinary, medical, environmental, and public health sectors are necessary strategies for reducing MRSA dissemination in Southwestern Nigeria.