Environmental factors driving antimicrobial resistance in Indian flying foxes (Pteropus medius): one health implications

Wildlife living near human settlements may be disproportionately exposed to environmental AMR. Pteropus medius, a large colonial fruit-eating bat species in South Asia, commonly roosts and forages in human-dominated landscapes, exposing it to anthropogenically shaped resistomes across a wide geographic area. Moreover, seasonal variations in environmental conditions and food resources may influence bat movements and their exposure to AMR. We investigated the prevalence of AMR in P. medius and explored AMR risk at seven different roosting sites in Pakistan, while considering variations in seasons and Land Use and Land Cover (LULC) types as predictors for AMR exposure. We tested fecal samples for resistance to twelve antibiotics and sought blaTEM, blaSHV and blaCTX-M resistance genes using PCR. Moderate to high resistance prevalence was identified in five out of twelve tested antibiotics, with resistance to aztreonam, cefradine and gentamicin exhibiting a significant seasonal effect. Similarly, tested antibiotics and genes were positively influenced by land use at 14.5 km buffer around the roosting sites. Approx. 37% of E. coli isolates were ESBL producers in both seasons and carried blaTEM genes (> 90%). Strong correlations were found in AMR patterns between P. medius and livestock (cattle and poultry). However, when resistance prevalence data were organized by season and province, the strength of these correlations varied considerably, highlighting the need for further research. The high level of AMR in P. medius, together with the positive influence of land use, highlights the need for an integrated One Health approach to combat AMR.