Detection of Helicobacter spp. DNA in the colonic biopsies of stray dogs: molecular and histopathological investigations

Helicobacter pylori: Routes of Infection, Antimicrobial Resistance, and Alternative Therapies as a Means to Develop Infection Control

Helicobacter pylori (H. pylori) is a Gram-negative, spiral-shaped bacterium that colonizes the gastric epithelium and is associated with a range of gastrointestinal disorders, exhibiting a global prevalence of approximately 50%. Despite the availability of treatment options, H. pylori frequently reemerges and demonstrates increasing antibiotic resistance, which diminishes the efficacy of conventional therapies. Consequently, it is imperative to explore non-antibiotic treatment alternatives to mitigate the inappropriate use of antibiotics. This review examines H. pylori infection, encompassing transmission pathways, treatment modalities, antibiotic resistance, and eradication strategies. Additionally, it discusses alternative therapeutic approaches such as probiotics, anti-biofilm agents, phytotherapy, phototherapy, phage therapy, lactoferrin therapy, and vaccine development. These strategies aim to reduce antimicrobial resistance and enhance treatment outcomes for H. pylori infections. While alternative therapies can maintain low bacterial levels, they do not achieve complete eradication of H. pylori. These therapies are designed to bolster the immune response, minimize side effects, and provide gastroprotective benefits, rendering them suitable for adjunctive use alongside conventional treatments. Probiotics may serve as adjunctive therapy for H. pylori; however, their effectiveness as a monotherapy is limited. Photodynamic and phage therapies exhibit potential in targeting H. pylori infections, including those caused by drug-resistant strains, without the use of antibiotics. The development of a reliable vaccine is also critical for the eradication of H. pylori. This review identifies candidate antigens such as VacA, CagA, and HspA, along with various vaccine formulations, including vector-based and subunit vaccines. Some vaccines have demonstrated efficacy in clinical trials, while others have shown robust immune protection in preclinical studies. Nevertheless, each of the aforementioned alternative therapies requires thorough preclinical and clinical evaluation to ascertain their efficacy, side effects, cost-effectiveness, and patient compliance.

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.

Helicobacter genus in the intestine and liver of stray cats: the molecular, histopathological, and immunohistochemical study

OBJECTIVES

The study was designed to determine the presence of Helicobacter genus and three species of H. pylori, H. bilis, and H. canis, in the duodenum, ileum, colon, and liver of stray cats. Moreover, the histopathological and immunohistochemical analyses have been performed.

METHODS

Samples were taken from the duodenum, ileum, colon, and liver of 30 cats for molecular and histopathological evaluations. Polymerase chain reaction was carried out for the detection of the Helicobacter genus in the mentioned samples. Then, species-specific primers were used in Helicobacter-positive samples.

RESULTS

Helicobacter genus prevalence rates in the duodenum, ileum, colon, and liver samples were 50%, 60%, 50%, and 43.3%, respectively. Helicobacter pylori, H. canis, and H. bilis were isolated from at least one tissue of 18 (60%), 13 (43.3%), and 8 (26.7%) of the cats, respectively. Immunohistochemical findings confirmed the presence of bacteria in the intestinal crypt or the mucosal layer of duodenum, ileum, colon, and hepatic sinusoids.

CONCLUSION

In the present study, the concurrent infection of duodenum and liver was noticeable. Furthermore, the high prevalence of H. pylori in cats, as a well-known human pathogen, should be considered. High incidence of Helicobacter in gut and liver of Ahvaz stray cats is noticeable. According to the zoonotic importance of Helicobacter, more studies in the field of treatment and prevention are highly recommended.

Identification of Helicobacter and Wolinella spp. in Oral Cavity of Toy Breed Dogs With Periodontal Disease

Periodontal diseases are the most common oral cavity infectious diseases in adult dogs. We aimed in this study to identify Helicobacter and Wolinella spp. in saliva and dental plaque of dogs with periodontitis. Sixty-two small-breed pet dogs, aged more than 6 years from both sexes, were categorized into healthy and periodontitis groups. Samples from saliva and dental plaques were collected, and Helicobacter and Wolinella were identified on genus and species levels using polymerase chain reaction. Our results showed significant increase in infection rate of Wolinella spp. in periodontitis compared with healthy dogs (P = .002). Furthermore, infection rate of Helicobacter genus was significantly higher in periodontitis compared with healthy dogs (P = .007). Infection with Wolinella spp. showed higher rate than Helicobacter spp. in dogs with periodontitis. According to species-specific polymerase chain reaction results, Helicobacter felis (9.76%) was the main Helicobacter spp. in dogs with periodontitis compared with healthy dogs (P < .001). Oral cavity of pet dogs with periodontitis could be considered as an important source of Wolinella and Helicobacter spp. infections.

Differentiation of five enterohepatic Helicobacter species by nested PCR with high-resolution melting curve analysis

BACKGROUND

Enterohepatic Helicobacter species (EHS) are widespread in rodent species around the world. Several studies have demonstrated that infection with EHS can interfere with the outcomes of animal experiments in cancer research and significantly influence the study results. Therefore, it is essential to establish a rapid detection and identification of EHS for biomedical research using laboratory rodents. Our study aimed to develop a rapid and sensitive method to detect and distinguish five enterohepatic Helicobacter species.

MATERIALS AND METHODS

Nested PCR followed by high-resolution melting curve analysis (HRM) was developed for identification of H. bilis, H. rodentium, H. muridarum, H. typhlonius, as well as H. hepaticus. To validate the accuracy of nested PCR-HRM analysis, quantitative real-time PCR methods for five different enterohepatic Helicobacter species were developed. A total of 50 cecal samples were tested using both nested PCR-HRM analysis and qPCR method.

RESULTS

The nested PCR-HRM method could distinguish five enterohepatic Helicobacter species by different melting temperatures. The melting curve were characterized by peaks of 78.7 ± 0.12°C for H. rodentium, 80.51 ± 0.09°C for H. bilis, 81.6 ± 0.1°C for H. typhlonius, 82.11 ± 0.18°C for H. muridarum, and 82.95 ± 0.09°C for H. hepaticus.

CONCLUSIONS

The nested PCR-HRM assay is a simple, rapid, and cost-effective assay. This assay could be a useful tool for molecular epidemiology study of enterohepatic Helicobacter infection and an attractive alternative for genotyping of enterohepatic Helicobacter species.

PREVALÊNCIA DE Helicobacter spp. EM CÃES DE CAMPO GRANDE-MS

Resumo A Helicobacter spp. é uma bactéria Gram negativa espiralada, de grande importância clínica, que se relaciona a patogenias como gastrite e úlceras pépticas e, mais recentemente, com o carcinoma gástrico em humanos. Evidências sugerem o potencial dos animais, principalmente os domésticos, como fonte de infecção zoonótica das helicobactérias, já que bactérias com morfologia similar às encontradas em animais foram observadas no estômago de humanos com gastrite. Nesse contexto, os cães podem ser um importante reservatório de agentes infecciosos como a Helicobacter spp. O presente trabalho teve como objetivo avaliar a prevalência de Helicobacter spp. em cães do Centro de Controle de Zoonoses de Campo Grande/MS. Para tanto, foram utilizados 96 cães dos quais foram colhidas amostras do corpo, fundo e antro gástrico, para avaliação da presença da Helicobacter spp. por meio do teste rápido de urease e análise histológica. O teste rápido de urease permitiu a detecção de Helicobacter spp. em 94,7% dos cães; já a análise histológica indicou a presença de Helicobacter spp. em 100% dos animais avaliados com predominio da bactéria na região do fundo do estômago.

Gastric and enterohepatic helicobacters other than Helicobacter pylori

During the past year, research on non-Helicobacter pylori species has intensified. H. valdiviensis was isolated from wild birds, and putative novel species have been isolated from Bengal tigers and Australian marsupials. Various genomes have been sequenced: H. bilis, H. canis, H. macacae, H. fennelliae, H. cetorum, and H. suis. Several studies highlighted the virulence of non-H. pylori species including H. cinaedi in humans and hyperlipidemic mice or H. macacae in geriatric rhesus monkeys with intestinal adenocarcinoma. Not surprisingly, increased attention has been paid to the position of Helicobacter species in the microbiota of children and animal species (mice, chickens, penguins, and migrating birds). A large number of experimental studies have been performed in animal models of Helicobacter induced typhlocolitis, showing that the gastrointestinal microbial community is involved in modulation of host pathways leading to chronic inflammation. Animal models of H. suis, H. heilmannii, and H. felis infection have been used to study the development of severe inflammation-related pathologies, including gastric MALT lymphoma and adenocarcinoma.