Molecular Detection Of Virulence Genes Involved In Cytolethal Distending Toxin (CDT) Production In Campylobacter jejuni And Campylobacter coli Isolated From Poultry Faeces

Molecular Detection Of Virulence Genes Involved In Cytolethal Distending Toxin (CDT) Production In Campylobacter jejuni And Campylobacter coli Isolated From Poultry Faeces
Hamid Mahmoodipour ,^1,* Omid Mahmoodipour ,² Maziar Mohammadi Niaei ,³
1. Department of Nursing and Midwifery, Behbahan Branch, Islamic Azad University, Behbahan, Iran
2. Department of Nursing and Midwifery, Behbahan Branch, Islamic Azad University, Behbahan, Iran
3. Department of Nursing and Midwifery, Behbahan Branch, Islamic Azad University, Behbahan, Iran
Introduction: Food-borne disease is an important problem worldwide that can be caused by the ingestion of public health bacteria, virus, fungi, and parasites, or toxins that have contaminated food(Abebe et al., 2020). Campylobacter jejuni and Campylobacter coli are the major food-borne pathogens that cause human bacterial gastroenteritis in both developed and developing countries(Zbrun et al., 2020). Every year, approximately 1% of the population in Europe is contaminated with Campylobacter(Epps et al., 2013). Many domestic animals, such as poultry are considered reservoirs for Campylobacter spp. (Khoshbakht et al., 2013). Campylobacter jejuni and Campylobacter coli are often related with the development of immunoreactive confusions. For example, these may lead to polyarthralgia, GuillainBarre, and Miller Fisher disorders, and eventually death(Casabonne et al., 2016). Several genes have been linked to Campylobacter virulence, but the most important are cytolethal distending toxin (cdt), which disrupts mucosal ¬barriers by causing host cell death (Barakat et al., 2020). Cytolethal distending toxin (cdt) in Campylobacter spp. is among the significant virulence factors of these bacteria in the intestine(Gharajalar et al., 2020).
Methods: To perform the study 182 fecal samples were collected from poultry . All samples were subjected for isolation of Campylobacter spp. using prêt KB method and the presumptive isolates authenticated by DNA sequencing of 16srRNA genes. Finally, Campylobacter isolates assessed for detection of Cytolethal distending toxin (cdt) gene.
Results: Sampling from the poultry faeces was conducted between March 2019 and August 2019 in behbahan city, khuzestan province, iran. The results obtained indicated that 39 strains of Campylobacter spp. were isolated. Among the 39 Campylobacter strains, including 30 Campylobacter jejuni and 9 Campylobacter coli, the prevalence of cdtA, cdtB, cdtC, virulence genes were 69.23% (27/39), 84.62% (33/39), 84.62% (33/39), respectively.
Conclusion: The research works on the virulence characteristics of potentially pathogenic bacteria in domestic animals and in foods containing animal origin are essential for the safety of the user. Although for assessing campylobacteriosis risk, heterogenic identification and virulence of genes of Campylobacter species isolated from the faeces samples of poultry are needed, so far it has not been done in the Khuzestan province. Different measures for the clarity of variable clinical type associated with Campylobacter infection have been suggested and phenotypic characteristics associated with different Campylobacter species could be related to their genetic variation. So, the aim of this study is to evaluate the prevalence of virulence-associated genes(CDT genes) in Campylobacter jejuni and Campylobacter coli isolates from poultry faeces samples. One of the other common virulence genes is cdt, which relates to cytotoxin production. This toxin is composed of three components cdtA, cdtB, and cdtC. By interference with division and cell disparity in the intestinal crypts, it causes diarrhoea. The presence of each of the three subunits is required for total toxin activity. CdtA and cdtC are essential for connection to the host cell. CdtB is an active section that enters the cells, arrests the cell cycle in the G2/M stage, and leads to cell death. Our research results demonstrated that the prevalence rates of cdtA, cdtB, and cdtC genes were 69.23% , 84.62%, 84.62%, respectively. Our research showed that the prevalence of genes involved in toxin production is more compared to genes involved in adherence and invasion. The results of our study showed that over 80% of the Campylobacter isolates have genes interfering in toxin production (cdtB, cdtC), which signifies that most of the Campylobacter isolates have powerful pathogenic .
Keywords: Campylobacter, Virulence genes, Cytolethal distending toxin, Poultry, Molecular Detection