Quality of Winam gulf water: Bacterial pathogens and their antimicrobial resistance patterns in Winam gulf, Lake Victoria, Kenya

This study assessed microbiological water quality and antimicrobial resistance (AMR) in Lake Victoria’s Winam Gulf, Kenya. Water samples (n=86) from 14 sites (estuaries, fish landing areas, and an effluent stream) yielded 196 bacterial isolates, predominantly Staphylococcus aureus (19.4%) and Escherichia coli (11.2%), including pathogens like E. coli O157, Vibrio parahaemolyticus, and V. cholerae. AMR testing of 62 isolates against nine antibiotics revealed widespread resistance, with Pseudomonas spp. showing the highest multiple antibiotic resistance (MAR) index (0.667) and resistance to nine classes. Multidrug resistance (≥50% of antibiotics) was observed in S. aureus, Enterobacter spp., and Pseudomonas spp. Hierarchical clustering grouped isolates into four clusters, suggesting shared resistance mechanisms. The presence of resistant pathogens underscores urgent public health risks, necessitating enhanced antimicrobial stewardship, water quality management, and sanitation improvements to safeguard Lake Victoria’s ecological and public health integrity.