Abstract

Background:
Paratyphoid Salmonella (PT) in domestic pigeons represents a significant threat to public safety.

Aim:
This study investigated the occurrence, virulence genes, and antimicrobial resistance profiles of PT isolated from apparently healthy domestic pigeons (Columba livia) in the Kurdistan region of Iraq.

Methods:
A total of 165 cloacal samples were collected from apparently healthy pigeons on private farms in different cities. Salmonella isolation was performed uxsing standard bacteriological culture, including selective enrichment in Rappaport-Vassiliadis broth, and presumptive isolates were subsequently confirmed and serotyped by PCR targeting Salmonella spp., Salmonella typhimurium (fliC), and Salmonella enteritidis (sefA). Virulence genes (invA, spvC, and hilA) and antimicrobial resistance genes (blaTEM, blaIMP, tetA, and qnrA) were identified by PCR, and susceptibility to 10 commonly used antimicrobials was determined by Kirby–Bauer disk diffusion using Clinical and Laboratory Standards Institute breakpoints.

Results:
Salmonella spp. were found in 7/165 (4.24%) of the tested samples. All the isolates were identified as Salmonella enterica subsp. enterica serovar typhimurium and S. enteritidis were not found. The invA, spvC, and hilA genes were detected in all isolates. Phenotypically, the highest resistance was found for gentamicin and tetracycline (42.9% each), followed by colistin (28.6%), while complete resistance to ciprofloxacin, cefixime, amoxicillin–clavulanic acid, azithromycin, nalidixic acid, and neomycin was not observed despite a common intermediate susceptibility pattern of these drugs. Genotypically, blaTEM and tetA were found in in 71.4% of isolates, qnrA in 42.9%, and blaIMP in 14.3%. In addition, several multi-resistant gene patterns were found.

Conclusion:
These results show that even apparently healthy pigeons in Kurdistan may carry multidrug-resistant S. typhimurium with pathogenic potential, underlining the urgent need for stronger biosecurity measures, responsible antibiotic use, and integrated One Health surveillance strategies to lower the risk of zoonotic disease transmission.

Key words: Antimicrobial resistance; Iraq; Pigeons; Salmonella; Virulence genes.