Spatiotemporal patterns of antimicrobial resistance in shared human-animal waterpoints in the Maasai Mara Ecosystem, Kenya

Antimicrobial resistance (AMR) presents an existential One Health threat. The spread of AMR in arid and semi-arid landscapes is modulated by ecological interactions and exacerbated by endemicity of livestock diseases and poor sanitation in shared human-animal systems leading to misuse of antibiotics. This study characterized the prevalence, resistance patterns, and spatiotemporal variations of AMR in surface water sources in the Maasai Mara Ecosystem (MME), a rapidly changing water-stressed socio-ecological landscape. Employing cross-sectional study design, water samples were collected from 28 water points between April 2024 and May 2025. Cultured Escherichia coli isolates were evaluated for resistance to eight antibiotics, following CLSI susceptibility testing protocols. AMR prevalence was calculated as proportions, with associations between sampling sites and seasons assessed using chi-square. Local clustering of resistant isolates was evaluated using spatial multinomial modelling, while cost-distance analysis against water points identified the proportion of the MME population with limited access to potable water. E. coli was detected in 92.9% water sources, with all isolates resistant to at least one antibiotic. High resistance rates were observed for Penicillin (100%), Amoxicillin (92.6%), Nitrofurantoin (78.6%), and Ceftazidime (52.9%). River samples exhibited higher resistance (51.4%) than open water pans (40.4%). AMR peaked during short-wet and short-dry seasons (51.3%; 51.5% respectively), with seasonal variations being significant ( p = 0.04 ). Multi-drug-resistant isolates (MDR: resistant to ≥3 antibiotic classes) were detected across all seasons, peaking in the short-wet season. MDR relationship between water sources was insignificant across all sampling sites and seasons ( p > 0.05 ). Spatial analysis ( p > 0.05 ) identified two exploratory clusters: Cluster 1 near dense human areas (RR = 0.78) while Cluster 2 in human-livestock-wildlife zones (RR = 1.26). Cost-distance analysis ( p < 0.05 ) revealed one-third of the MME population is at risk of AMR due to limited access to potable water. Our findings reveal widespread distribution of AMR isolates in shared waterpoints, necessitating targeted One Health Quadripartite interventions.