Antibiotic Resistance and Virulence Genes in Escherichia coli from Wild Birds in a Peruvian Wetland

Espinoza K.; Caffo X.; Hernández J.; Palomino-Kobayashi L.A.; Ruiz J.; Pons M.J. · EcoHealth (2026) · DOI: 10.1007/s10393-026-01797-3

Resumen

The role of wildlife in carrying and disseminating resistant and pathogenic bacteria has been established, yet data from wildlife in Peru are limited. This study evaluated the antibiotic resistance, presence of virulence genes, and clonality of E. coli isolated from wild birds from wetlands in Lima, Peru. Twenty-three isolates were obtained from 41 free-living birds (belonging to 15 bird species) through cloacal and feather swabs (n = 30) and fresh feces (n = 11) collected in 2021. Nineteen pulsotypes were identified by Pulsed Field Gel Electrophoresis. High resistance rates were observed for tobramycin 60.9% (14/23) and ampicillin 52.2% (12/23). The resistance to sulfamethoxazole–trimethoprim was 26.1% (6/23) Lower resistance rates were observed for quinolones and cephalosporins, each with 17.4% (4/23) resistance. Multidrug resistance (MDR) was detected in 34.8% (8/23) of isolates, and 8.7% (2/23) were extended-spectrum beta lactamase (ESBL)-producing E. coli. (from Coragyps atratus (1/2 sampled 50%) and Phalacrocorax brasilianus (1/3 sampled 33.3%)) carrying blaCTX-M-55. Phylogroup A predominated (34.8%). Virulence genes were found in 30.4% of the isolates, including stx-1 (13.1%), agn43 (17.4%), and virA (4.3%). Whole-genome sequencing of ESBL isolates (ST2172, O9:H4, phylogroup A) revealed an extensive resistome including blaCTX-M-55, blaTEM-1, chromosomal AmpC, multiple aminoglycosides, tetracycline, sulfonamide, fosfomycin, and efflux pump genes, along with quinolone-resistant mutations. The virulome included adhesins, CFA/I fimbriae, ECP, hemorrhagic pilus, type I fimbriae, and invasion-associated genes. These findings highlight the circulation of MDR and ESBL-producing E. coli in wild birds, underscoring the importance of wildlife surveillance within a One Health approach. © The Author(s), under exclusive licence to Nature.Health.Global., Inc 2026.

Instituciones: Universidad Nacional Mayor de San Marcos; Universidad Científica del Sur