Exploring the diversity and burden of antimicrobial resistance genes carried by white stork (Ciconia ciconia) throughout the breeding season in Madrid, Spain

Abstract

Anthropogenic environments are critical hotspots for the emergence and persistence of antimicrobial resistance (AMR). Extensive livestock pastures and landfills are of particular concern due to their high bacterial diversity and frequent wildlife visitation, facilitating the transfer of antimicrobial resistance genes (ARGs). The white stork (Ciconia ciconia) heavily exploits landfills and extensive pastures in Spain, providing an ideal model to study AMR emergence. We evaluated the diversity and burden of ARGs in breeding white storks across three stages of the breeding season, reflecting different foraging strategies. These findings suggest that foraging dynamics, rather than landfill exposure alone, strongly influence ARG acquisition in white storks. Agricultural pastures and other anthropogenic environments may play a larger role in shaping resistomes than previously assumed. Understanding how wildlife foraging behavior drives AMR carriage is crucial to better characterize AMR transmission risk at the wildlife-livestock interface.