Exploring water, sediment, and avifauna from an urban recreational lagoon: focus on WHO priority pathogens

Environmental dissemination of antimicrobial-resistant (AMR) pathogens is a growing global concern under the One Health framework, yet remains underexplored in biodiverse and human-impacted ecosystems such as Brazil's coastal lagoons. This study assessed the occurrence and distribution of AMR bacteria, including WHO-designated critical-priority pathogens, in water, sediment, and avifauna from Lagoa da Conceição, a coastal lagoon in southern Brazil.

From December 2022 to November 2023, 96 environmental and 251 avian samples were collected and analyzed using selective culture, antimicrobial susceptibility testing, and molecular screening for resistance genes. A total of 625 bacterial isolates were recovered from water and sediment, of which 35.5% were multidrug-resistant and 26.7% met WHO critical-priority criteria. Key resistance genes identified included blaTEM, blaCTX-M, blaNDM, blaOXA-143, and mcr-1, with high spatial heterogeneity across sampling sites. WHO critical-priority pathogens were also isolated from 9.6% of sampled birds, suggesting the role of avifauna as environmental sentinels and reservoirs. Generalized linear models revealed that population density and precipitation were positively associated with the abundance of critical-priority isolates.

These findings highlight anthropogenic and climatic drivers of AMR dissemination in coastal environments and underscore the urgent need for integrated monitoring and mitigation strategies to protect ecosystems and public health.