Health Reference Laboratory Research Center, Reference Health Laboratory, Ministry of Health and Medical Education, Tehran, Iran.
Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Dig Dis Sci. 2022 Dec;67(12):5522-5528. doi: 10.1007/s10620-022-07468-x. Epub 2022 Mar 31.
Cytolethal distending toxin (Cdt) is one of the bacterial toxins that present in a variety of gram-negative human pathogens, such as E. coli, Salmonella spp., and Campylobacter spp. CDT is composed of three subunits encoded by three adjacent genes, including cdtA, cdtB, and cdtC. cdtB has been shown to have toxic activity and cause DNA damage in host cells. Despite its presence in different bacterial species, the role of CdtB in acute and chronic infections, such as gastroenteritis and irritable bowel syndrome (IBS), is unclear. To analyze this correlation, we studied the prevalence of cdtB among different enteropathogenic bacteria in patients with gastroenteritis and IBS compared with healthy people.
In this cross-sectional descriptive study, 230 stool samples were collected from patients with gastroenteritis, IBS, and healthy people. The presence of CdtB encoding bacteria, including Escherichia coli, Campylobacter spp., Yersinia entercolitica, Providencia alkalifacience, and Salmonella enterica, was examined by polymerase chain reaction using genus-specific primers.
Out of 230 stool samples, CdtB encoding Campylobacter spp. were found in 34.6% (52/150), 6.25% (5/80), and 4% (2/50) of the patients with gastroenteritis, IBS, and the control group, respectively. Carriage of CdtB encoding Salmonella enterica was characterized among 5.3% (8/150) of the patients with gastroenteritis and 17.5% (14/80) of the IBS patients. Although none of the patients carried CdtB encoding E. coli and Providencia spp., cdtB of Y. enterocolitica was detected in one of the patients with gastroenteritis (0.6%). Statistical analysis showed significant correlation between infection with CdtB encoding Campylobacter spp. and IBS-D subtype. No significant correlation was found between infection with CdtB encoding bacteria and other clinical and demographic data.
Our results confirmed a relatively higher frequency of CdtB encoding bacteria in the intestine of patients with gastroenteritis and those with IBS compared with healthy individuals. Regarding the frequency of CdtB encoding Salmonella and Campylobacter bacteria, it was proposed that infection with these enteropathogens could be considered a risk factor for the development or progression of IBS among Iranian patients. Further studies are needed to establish this involvement.
细胞致死扩张毒素（Cdt）是一种存在于多种革兰氏阴性人类病原体中的细菌毒素，如大肠杆菌、沙门氏菌和弯曲杆菌。CDT 由三个相邻基因编码的三个亚基组成，包括 cdtA、cdtB 和 cdtC。cdtB 已被证明具有毒性活性，并在宿主细胞中引起 DNA 损伤。尽管它存在于不同的细菌物种中，但 CdtB 在急性和慢性感染（如肠胃炎和肠易激综合征（IBS））中的作用尚不清楚。为了分析这种相关性，我们研究了与健康人相比，肠胃炎和 IBS 患者中不同肠致病性细菌中 cdtB 的流行情况。
在这项横断面描述性研究中，我们收集了 230 份来自肠胃炎、IBS 和健康人的粪便样本。使用属特异性引物通过聚合酶链反应检测 CdtB 编码细菌，包括大肠杆菌、弯曲杆菌、耶尔森氏菌、产碱普罗威登斯菌和沙门氏菌的存在。
在 230 份粪便样本中，CdtB 编码的弯曲杆菌在肠胃炎患者中分别发现 34.6%（52/150）、6.25%（5/80）和 4%（2/50），在 IBS 患者和对照组中分别发现 4%（2/50）。CdtB 编码的沙门氏菌的携带率在肠胃炎患者中为 5.3%（8/150），在 IBS 患者中为 17.5%（14/80）。尽管没有患者携带 CdtB 编码的大肠杆菌和普罗威登斯菌，但在一名肠胃炎患者中检测到 CdtB 编码的耶尔森氏菌（0.6%）。统计分析显示，感染 CdtB 编码的弯曲杆菌与 IBS-D 亚型之间存在显著相关性。感染 CdtB 编码细菌与其他临床和人口统计学数据之间无显著相关性。
我们的结果证实，与健康个体相比，肠胃炎和 IBS 患者肠道中 CdtB 编码细菌的频率相对较高。关于 CdtB 编码沙门氏菌和弯曲杆菌的频率，建议将这些肠病原体的感染视为伊朗患者发生或进展为 IBS 的危险因素。需要进一步的研究来确定这种相关性。
