Virulence and Antimicrobial Resistance Patterns of Salmonella spp. Recovered From Migratory and Captive Wild Birds

Background: Salmonella spp., especially those are resistant to extended-spectrum β-lactamase (ESBL), are considered as major concern to global health due to their emergence and dissemination.

Aim: The aim of this study was to investigate the virulence and antimicrobial resistance (AMR) profile of Salmonella spp. from migratory and captive wild birds.

Method: A total 262 faecal samples were collected, and the identification of Salmonella spp. was carried out using a standard culture and PCR as well as molecular detection of virulence and AMR genes.

Results: The overall prevalence of Salmonella was determined to be 30.92% (95% CI = 25.63-36.75). Migratory birds exhibited highest prevalence (38.10%), whereas wild birds in captivity showed a lower prevalence (23.40%). The agfA gene was detected at a higher rate at 24.69%. Salmonella spp. exhibited 100% resistance to tetracycline, followed by 58% ampicillin and 46% streptomycin. In addition, there was a resistance rate to ceftriaxone of 17% and to colistin sulphate of 25%. Interestingly, levofloxacin alone displayed 100% sensitivity across all isolates, while ciprofloxacin and azithromycin showed 73% and 64% sensitivity, respectively. The MAR index was 0.25 and 0.42, and 74.07% of all isolates showed multidrug resistance (MDR). It was shown that migratory and captive wild birds contained ESBL genes blaTEM (94.34% and 49.06%) and blaSHV (13.33% and 10%), respectively. Genes responsible for sulphonamide (sul1) resistance were detected in 13.33% and 79% of wild and migratory birds, respectively.

Conclusion: Salmonella has been found in captive wild and migratory birds and could act as reservoirs for the transmission of MDR and ESBL bacteria.