Abstract
Hospital-generated biomedical waste is a critical, yet understudied, reservoir for multidrug-resistant pathogens, particularly methicillin-resistant Staphylococcus aureus (MRSA). This study investigated the prevalence, characteristics, and virulence potential of MRSA in biomedical waste from healthcare facilities across three districts in Karnataka, India. Sixty biomedical waste samples were collected and subjected to systematic microbiological analyses, including culture-based isolation, biochemical characterization, molecular identification through 16S rRNA sequencing, and comprehensive antimicrobial susceptibility testing. Advanced bioinformatics tools including, PICRUSt2 were employed to assess the virulence profiles and functional potential. The results revealed that 63.3% of the samples showed bacterial growth, with 36.8% testing positive for presumptive S. aureus on mannitol salt agar. Biochemical and molecular characterization confirmed the presence of multidrug-resistant MRSA with extensive resistance to multiple antibiotic classes including β-lactams, fluoroquinolones, aminoglycosides, and macrolides. The isolated strains demonstrated significant virulence characteristics, including robust hemolytic activity and diverse metabolic capabilities that enhance environmental persistence. Phylogenetic analysis revealed close relationships with clinically significant strains, suggesting potential bidirectional transmission between clinical and environmental reservoirs. Geographic variations in the prevalence across districts indicate disparities in waste management practices and infection control protocols. Computational analyses revealed genes associated with nitrate reduction, environmental persistence, adhesion proteins, and immune evasion. These findings establish biomedical waste as an active ecological niche for enhanced pathogenic traits, posing substantial risks for healthcare-associated infections and environmental contamination. This study highlights the urgent need for enhanced waste surveillance, improved treatment technologies, and targeted management interventions to prevent the dissemination of MDR pathogens and protect public health.