Birds as Sentinels of Methicillin-Resistant Staphylococcaceae in Brazilian Protected Areas

Antimicrobial resistance (AMR) poses a growing threat to One Health, with wild birds serving as sentinels and reservoirs for resistant pathogens. Despite Brazil's rich avian biodiversity, studies on AMR in wild bird populations are limited. This study investigated methicillin-resistant Staphylococcaceae in wild birds from Southern Brazil, analyzing molecular characteristics of isolates. Oropharyngeal swabs were collected from 248 birds in two protected areas and two wildlife rehabilitation centers over one year. The sample included resident, partially migratory, and migratory species from terrestrial and aquatic habitats. Using selective culture and molecular tests, methicillin-resistant isolates were identified in 2.8% of the birds. These isolates also exhibited multidrug resistance and were predominantly found in resident birds within protected areas and nearby, suggesting environmental circulation of resistance genes. This is the first report of methicillin-resistant S. haemolyticus with SCCmec type I in Brazilian wild birds. The detection of mecA-positive isolates human-impacted areas underscores the need for ongoing surveillance. By addressing a critical knowledge gap, this study highlights the importance of monitoring AMR dynamics in biodiversity-rich regions to mitigate the spread of resistant bacteria and safeguard both environmental and public health.