Association of Helicobacter bilis Infection with the Development of Colorectal Cancer

Helicobacter bilis Contributes to the Occurrence of Inflammatory Bowel Disease by Inducing Host Immune Disorders

Gut microbiota coevolve with humans to achieve a symbiotic relationship, which ultimately leads to physiological homeostasis. A variety of diseases can occur once this balance is disrupted. Helicobacter bilis (H. bilis) is an opportunistic pathogen in humans, triggering multiple diseases, including inflammatory bowel disease (IBD). IBD is a chronic immunologically mediated inflammation of the human gastrointestinal tract, and its occurrence is closely related to the gut microbiota. Several studies have demonstrated that H. bilis colonization is associated with IBD, and its mechanism is related to host immunity. However, few studies have investigated these mechanisms of action. Therefore, this article is aimed at reviewing these studies and summarizing the mechanisms of H. bilis-induced IBD from two perspectives: adaptive immunity and innate immunity. Furthermore, this study provides a preliminary discussion on treating H. bilis-related IBD. In addition, we also demonstrated that H. bilis played an important role in promoting the carcinogenesis of IBD and discussed its mechanism.

Prevalence, diversity and public health implications of Helicobacter species in pet and stray dogs

Background

It is probable that humans can acquire H. pylori and non—H. pylori Helicobacter infections via domestic animals. The prevalence and risk factors of infections of Helicobacter species in canines of Taipei city were therefore analysed in this study.

Materials and methods

A total of 95 canine faecal samples were collected from different animal shelters and hospitals in Taipei city. Total DNA was extracted for semi-nested PCR detection of Helicobacter species. The PCR products were sequenced for further comparative database and phylogenetic analyses.

Results

The overall prevalence of Helicobacter species in canines of Taipei city was 75.79% (72/95). Two gastric, seven enterohepatic and two unclassified Helicobacter species were identified, all of which have been implicated in the aetiology of human diseases. The predominant species detected included H. canis (27.78%), H. pylori (26.39%), H. canicola (18.06%), and H. bilis (13.89%) in decreasing order, while H. canadensis and H. typhlonius were identified for the first time in canines. The genotypes in H. pylori and H. canicola clusters grouped together, with their respective reference strains, showed a close evolutionary distance in the phylogenetic tree, indicating a common ancestry may have existed in these clusters respectively. The residential region of canines, dog living status (pet or stray) and breed (purebred or mixed-breed) are the risk factors associated with Helicobacter infections in the canines examined.

Conclusion

The high prevalence of Helicobacter infections in canines highlights a potential public health risk of zoonotic transmission among dogs, humans and other animals, and therefore, the need for proper methods in controlling the transmission routes. In addition, the 16S rRNA gene amplification method was found to be useful for bacterial identification and phylogenetic analysis.

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The prevalence of Helicobacter infection in dogs of Taipei city was found to be 75.79%.

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Species detected included H. canis, H. pylori, H. canicola, H. bilis and others, including 2 unclassified species.

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Almost all the species detected are identical with those reported to be found in humans in some other studies, suggesting possible cross-transmission between humans and canines.

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Residential region, living status (pet or stray) and breed type of canines are risk factors associated with Helicobacter infections in the canines.

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Phylogenetic analysis indicated an evolutionary pattern in H. pylori and H. canicola clusters, suggesting a common ancestry may have existed in these clusters respectively.