Molecular Characterization and Antimicrobial Resistance Profile of Biofilm-Producing Methicillin-Resistant Staphylococcus aureus (MRSA) in Caprine Mastitis

Abstract

The global rise of methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat to both human and animal health. This study aimed to detect MRSA in goat mastitis cases, identify resistance-associated genes, and assess biofilm-forming virulence. A total of 46 milk samples were collected from clinically mastitis-affected Black Bengal goats in Dinajpur Sadar and Chirirbandar. Conventional biochemical and cultural methods, along with PCR, were used for bacterial identification. The mecA gene, conferring methicillin resistance, and the nuc gene, a species-specific marker, were amplified via PCR. Statistical analysis was conducted using SPSS v25 and R v2024. The results showed an 82.6% prevalence of S. aureus, with MRSA identified in 13.16% (5/38) of isolates. Antibiotic susceptibility testing revealed 100% resistance to methicillin, oxacillin, vancomycin, and cefoxitin, followed by 85.71% resistance to ampicillin. The presence of biofilm-forming MRSA highlights its role in persistent infections and therapeutic failures. These findings underscore the need for effective, evidence-based control strategies to mitigate the spread of MRSA in livestock and safeguard public health.