Prevalence, Phylogeny, and Virulence Genes of Campylobacter jejuni and Campylobacter coli in Slaughtered Broilers in Iraq

Background: Campylobacter is a leading cause of bacterial foodborne illness worldwide, affecting developed and developing countries. Objectives: This study aimed to identify Campylobacter jejuni and Campylobacter coli species in broilers at slaughter in four governorates in Iraq and analyze phylogeny and occurrence of virulence genes in both species. Methods: A total of 200 broilers were randomly selected from 20 farms. Cecal samples were collected and subjected to bacteriological identification. Multiplex PCR was used to identify C. jejuni and C. coli using specific primers for the hipO and glyA genes. 16S rRNA sequencing and PCR-based detection of virulence genes (cadF and cdtB) were also performed. Results: The overall prevalence of Campylobacter spp. was 36.5%, with C. jejuni (75.3%) being more prevalent than C. coli (24.7%). Phylogenetic analysis of 16S rRNA sequences of C. jejuni isolates are grouped into a cluster with four clades. The local strains showed close genetic relationships with two C. jejuni strains from Thailand (MZ948926.1 and MZ948908.1) and India (ON920206.1), while the greatest divergence was observed between the local isolates, Polish (MN708183.1), and Philippine (MZ028017.1) strains. The local C. coli isolates (OP263114, OP263119, OP263120) exhibit a high degree of genetic relatedness to C. coli isolates from Spain (MT453963.1; MT453947.1; MT453968.1; MT453951.1), but greater genetic distance from a Campylobacter sp. isolate from Germany (PP989493.1). The virulence genes cadF and cdtB were detected in 76.7% and 82.2% of the isolates, respectively. The cadF gene was more prevalent in C. coli (77.7%) than in C. jejuni (76.36%) isolates, while cdtB was more prevalent in C. jejuni (83.6%) than in C. coli (77.7%) isolates. Conclusion: This study highlights the high prevalence, genetic diversity, and virulence potential of C. jejuni and C. coli in Iraqi broilers at slaughterhouses, emphasizing the need for enhanced surveillance, biosecurity measures, and genomic studies to mitigate public health risks.