Immunogenicity and pathogenicity of Helicobacter infections of veterinary animals

Helicobacter pullorum and Helicobacter canadensis: Etiology, pathogenicity, epidemiology, identification, and antibiotic resistance implicating food and public health

Nowadays, it is well-established that the consumption of poultry meat, especially chicken meat products has been drastically increasing. Even though more attentions are being paid to the major foodborne pathogens, it seems that scientists in the area of food safety and public health would prefer tackling the minor food borne zoonotic emerging or reemerging pathogens, namely Helicobacter species. Recently, understanding the novel aspects of zoonotic Enterohepatic Helicobacter species, including pathogenesis, isolation, identification, and genomic features is regarded as a serious challenge. In this regard, considerable attention is given to emerging elusive zoonotic Enterohepatic Helicobacter species, comprising Helicobacter pullorum and Helicobacter canadensis. In conclusion, the current review paper would attempt to elaborately summarize and somewhat compare the etiology, pathogenesis, cultivation process, identification, genotyping, and antimicrobial resistance profile of both H. pullorum and H. Canadensis. Further, H. pullorum has been introduced as the most significant food borne pathogen in chicken meat products.

Oral and Cloacal Helicobacter Detection in Wild and Captive Orinoco Crocodiles (Crocodylus intermedius) in Venezuela

Helicobacter species can colonize digestive tract of animals and humans and have been associated with gastrointestinal diseases; however, this genus has not been studied in crocodiles. Our objective was to detect by PCR Helicobacter genus and Helicobacter pylori in oral and cloacal swabs from Orinoco crocodiles of two wild (Cojedes River System and Capanaparo River) and two captive breeding centers (CBCs; Masaguaral Ranch and UNELLEZ) populations. Bacterial DNA was found in 100% of oral samples (10 wild and 10 captives), and in the 95% of cloacal samples (10 wild and 9 captives). In wild populations, Helicobacter spp. was not detected, whereas in CBCs, Helicobacter was detected in 10% of the oral samples, and 66.7% of cloacal samples. H. pylori was detected in two Orinoco crocodiles. Two cloacal non-pylori Helicobacter amplicons were sequenced, showing low similarity (≤97%) to Helicobacter sequences reported. This is the first report of Helicobacter species, including H. pylori in Crocodylus intermedius from CBCs.

Temporal Stability and the Effect of Transgenerational Transfer on Fecal Microbiota Structure in a Long Distance Migratory Bird

Animal bodies are inhabited by a taxonomically and functionally diverse community of symbiotic and commensal microorganisms. From an ecological and evolutionary perspective, inter-individual variation in host-associated microbiota contributes to physiological and immune system variation. As such, host-associated microbiota may be considered an integral part of the host’s phenotype, serving as a substrate for natural selection. This assumes that host-associated microbiota exhibits high temporal stability, however, and that its composition is shaped by trans-generational transfer or heritable host-associated microbiota modulators encoded by the host genome. Although this concept is widely accepted, its crucial assumptions have rarely been tested in wild vertebrate populations. We performed 16S rRNA metabarcoding on an extensive set of fecal microbiota (FM) samples from an insectivorous, long-distance migratory bird, the barn swallow (Hirundo rustica). Our data revealed clear differences in FM among juveniles and adults as regards taxonomic and functional composition, diversity and co-occurrence network complexity. Multiple FM samples from the same juvenile or adult collected within single breeding seasons exhibited higher similarity than expected by chance, as did adult FM samples over two consecutive years. Despite low effect sizes for FM stability over time at the community level, we identified an adult FM subset with relative abundances exhibiting significant temporal consistency, possibly inducing long-term effects on the host phenotype. Our data also indicate a slight maternal (but not paternal) effect on FM composition in social offspring, though this is unlikely to persist into adulthood. We discuss our findings in the context of both evolution and ecology of microbiota vs. host interactions and barn swallow biology.

Comparison of in vivo confocal endomicroscopy with other diagnostic modalities to detect intracellular helicobacters

Intracellular colonisation may serve as a protected niche where Helicobacter spp. organisms evade effective treatment. In dogs, non-Helicobacter pylori-helicobacters are frequently intracellular. Confocal endomicroscopy allows in vivo gastrointestinal imaging and has aided real-time identification of Helicobacter pylori and other intracellular and mucosally associated bacteria. The objectives of this study were: (1) to determine the utility of confocal endomicroscopy to identify non-Helicobacter pylori-helicobacters compared with other diagnostic modalities, and (2) to assess its ability to identify intracellular organisms. Fourteen clinically healthy dogs underwent standard gastroduodenoscopy followed by confocal endomicroscopy using topical acriflavine. Confocal images were obtained from at least five gastric sites. Endoscopic biopsies were obtained for histopathology, PCR and fluorescence in situ hybridisation (FISH). Methodologies were compared for their ability to determine the presence and spatial distribution of gastric helicobacters in dogs. Confocal endomicroscopy provided high quality images allowing in vivo identification of non-Helicobacter pylori-helicobacters in 13 dogs. Histopathology identified helicobacters in 11 dogs. Organisms were identified within the superficial gastric mucus and within gastric pits, and distribution throughout the stomach was diffuse and multi-focal. Confocal endomicroscopy findings correlated with PCR and FISH post-procedure analysis. Only FISH identified intracellular organisms, which were present in 13/14 dogs. Confocal endomicroscopy provided in vivo histology images and was capable of identifying non-Helicobacter pylori-helicobacters during gastroscopy, but was unable to identify intracellular organisms using the current fluorophore protocol.

A mixed population of Helicobacter pylori, Helicobacter bizzozeronii and "Helicobacter heilmannii" in the gastric mucosa of a domestic cat

Background

The presence of Helicobacter within the gastric mucosa is responsible for producing pathology in many animal species, including man. Since humans have been shown to harbour many of the same bacterial species as domestic carnivores, concern over their zoonotic potential has been growing. Helicobacter pylori, a class 1 carcinogen responsible for cases of gastritis and gastric cancer in humans, produces similar pathology in pet carnivores and is considered an example of anthroponosis. The case here presented refers to a 13 year-old mixed breed spayed female cat seen at necropsy.

Findings

Stomach samples were analysed for the presence of Helicobacter spp. by cytology, histopathology and PCR. Mild mucosal atrophy was observed in the fundus and antrum, while lymphoplasmocytic infiltrates where noted in the lamina propria of the antrum. Helicobacter-like organisms were observed in the corpus and antrum, occupying gastric glands and surface mucosa. It was possible to detect Helicobacter spp., H. pylori, H. heilmannii and H. bizzozeronii in the fundus, corpus and antrum by PCR, while in the antrum PCR samples were positive for H. pylori.

Conclusions

The spayed female under study could represent either a yet un-described population of domestic cats infected with H. pylori or a case of anthroponosis.

Traditional risk factors for Helicobacter pylori infection not found among patients undergoing diagnostic upper endoscopy-Republic of Georgia, 2007-2008

OBJECTIVES

Helicobacter pylori causes gastritis, duodenal ulcers, and gastric cancer. Although household crowding, low socioeconomic status (SES), and poor sanitation are associated with infection elsewhere, risk factors of infection in the Republic of Georgia (ROG), a country with a high prevalence rate (>70%), remain unknown. In this study we explored potential risk factors of infection among symptomatic patients in ROG.

METHODS

During 2007-2008, we prospectively recruited 390 subjects with gastrointestinal symptoms referred to five tertiary care centers for diagnostic upper endoscopy. We administered a questionnaire on potential risk factors and tested patients using three diagnostic tests: gastric biopsies underwent histological evaluation and rapid urease test (CLO test), and an ELISA was used to detect IgG against H. pylori in serum. We defined a case as having two or more positive results from the three available tests. Univariate and multivariate logistic regression analyses were performed.

RESULTS

Overall, 217 (56%) patients met the study case definition. Subjects diagnosed with cancer had the highest rate of H. pylori infection (62%), followed by those with gastritis (55%), and ulcer (54%). Age >30 years (adjusted odds ratio (aOR 2.6, 95% confidence interval (CI) 1.6-4.3) and residing in the capital city (aOR 0.6, 95% CI 0.4-0.9) were significantly associated with infection.

CONCLUSIONS

In this large cohort with gastrointestinal symptoms, only age >30 years and living in the capital were significant factors associated with infection. Lower SES, less education, and crowding did not confer an increased risk, in contrast to the findings of previous studies. Population-based studies are needed to identify potential routes and risk factors of H. pylori infection in ROG.

Gastroesophageal reflux and laryngeal dysfunction in a dog

CASE DESCRIPTION

A 7-year-old neutered male Saint Bernard was evaluated because of a 6-month history of coughing, gagging, change in phonation, excessive panting, and chronic intermittent vomiting and diarrhea.

CLINICAL FINDINGS

Physical examination revealed no remarkable findings other than panting. Total thyroxine concentration and results of a CBC, serum biochemistry analysis, urinalysis, and thoracic radiography were within reference limits. A laryngeal examination revealed edema, erythema, and ulceration of the larynx and pharynx, with normal laryngeal movement. Results of bronchoscopy and cytologic examination of bronchoalveolar lavage fluid were diagnostic only for distal tracheitis. Esophagoscopy and an esophagography revealed esophagitis consistent with gastroesophageal reflux. Gastroduodenoscopy and histologic examination of biopsy specimens revealed Helicobacter colonization and lymphocytic or plasmacytic enteritis.

TREATMENT AND OUTCOME

Following treatment for gastroesophageal reflux and suspected Helicobacter infection with combination antacid and antimicrobial treatment, the dog's respiratory signs resolved but vomiting continued. Gastroduodenoscopy revealed complete resolution of the previous laryngitis, pharyngitis, and esophagitis. Treatment for the lymphocytic or plasmacytic enteritis was initiated with prednisone (1 mg/kg [0.45 mg/lb], p.o., q 12 h) and a novel protein diet. The previous treatment was also continued. Complete resolution of clinical signs was maintained 4 months after initiation of appropriate treatment.

CLINICAL RELEVANCE

Laryngeal dysfunction induced by gastroesophageal reflux as occurred in the patient described in this report is a previously undocumented association in the veterinary literature. This association could be a potential consideration in dogs with concurrent respiratory and gastrointestinal signs. The present report may provide a basis for further studies investigating this association.

A molecular enrichment strategy based on cpn60 for detection of epsilon-proteobacteria in the dog fecal microbiome

Members of the rare microbiome can be important components of complex microbial communities. For example, pet dog ownership is a known risk factor for human campylobacteriosis, and Campylobacter is commonly detected in dog feces by targeted assays. However, these organisms have not been detected by metagenomic methods. The goal of this study was to characterize fecal microbiota from healthy and diarrheic pet dogs using two different levels of molecular detection. PCR amplification and pyrosequencing of the universal cpn60 gene target was used to obtain microbial profiles from each dog. To investigate the relatively rare epsilon-proteobacteria component of the microbiome, a molecular enrichment was carried out using a PCR that first amplified the cpn10-cpn60 region from epsilon-proteobacteria, followed by universal cpn60 target amplification and pyrosequencing. From the non-enriched survey, the major finding was a significantly higher proportion of Bacteroidetes, notably Bacteroides vulgatus, in healthy dogs compared to diarrheic dogs. Epsilon-proteobacteria from the genera Helicobacter and Campylobacter were also detected at a low level in the non-enriched profiles of some dogs. Molecular enrichment increased the proportion of epsilon-proteobacteria sequences detected from each dog, as well as identified novel, presumably rare sequences not seen in the non-enriched profiles. Enriched profiles contained known species of Arcobacter, Campylobacter, Flexispira, and Helicobacter and identified two possibly novel species. These findings add to our understanding of the canine fecal microbiome in general, the epsilon-proteobacteria component specifically, and present a novel modification to traditional metagenomic approaches for study of the rare microbiome.

High prevalence of dna from non-H. pylori helicobacters in the gastric mucosa of venezuelan pet dogs and its histological alterations

Non-H. pylori helicobacters (NHPH) have been demonstrated as gastric spiral-shaped bacteria in specimens obtained from dogs; however, their roles in the pathogenesis of upper gastrointestinal disease have not yet been clearly established. The purpose of this study was to evaluate the prevalence of NHPH DNA in the gastric mucosa of dogs and its association with histopathology. Helicobacter was detected through histopathological techniques, PCR, and FISH analysis from fundic biopsies of twenty dogs with or without signs of gastrointestinal disease. PCR and FISH were based on partial 16S rRNA gene sequences. Nineteen dogs showed mild to marked gastritis in the fundus, and only one dog had a healthy gastric mucosa. NHPH DNA was detected in 18 dogs with gastritis and one with normal gastric mucosa. However, there was no significant correlation between the presence of NHPH DNA and the degree of gastritis. These results show a high prevalence of NHPH DNA in the gastric mucosa of dogs from Venezuela. Further studies are necessary to determine a possible association between a specific NHPH species and the degree of gastritis.

Did transmission of Helicobacter pylori from humans cause a disease outbreak in a colony of Stripe-faced Dunnarts (Sminthopsis macroura)?

Since the discovery that Helicobacter pylori causes a range of pathologies in the stomachs of infected humans, it has become apparent that Helicobacters are found in a diverse range of animal species where they are frequently associated with disease. In 2003 and 2004, there were two outbreaks of increased mortality associated with gastric bleeding and weight-loss in a captive colony of the Australian marsupial, the Stripe-faced Dunnart (Sminthopsis macroura). The presence of gastric pathology led to an investigation of potential Helicobacter pathogenesis in these animals. Histological examination revealed the presence of gastritis, and PCR analysis confirmed the presence of Helicobacter infection in the stomachs of these marsupials. Surprisingly, sequencing of 16S rRNA from these bacteria identified the species as H. pylori and PCR confirmed the strain to be positive for the important pathogenesis factor, cagA. We therefore describe, for the first time, an apparent reverse zoonotic infection of Stripe-faced Dunnarts with H. pylori. Already prone to pathological effects of stress (as experienced during breeding season), concomitant H. pylori infection appears to be a possible essential but not sufficient co-factor in prototypic gastric bleeding and weight loss in these marsupials. The Stripe-faced Dunnart could represent a new model for investigating Helicobacter-driven gastric pathology. Infections from their human handlers, specifically of H. pylori, may be a potential risk to captive colonies of marsupials.

Genetic characterization and epidemiology of Helicobacters in non-domestic animals

BACKGROUND

Novel helicobacter infections and associated disease are being recognized with increasing frequency in animals and people. Yet, the pervasiveness of infection in distantly related animal taxa, genetic diversity of helicobacters, and their transmissability are not known.

AIM

To better understand the ecology of helicobacters, we did a PCR survey and epidemiologic analysis of 154 captive or wild vertebrate taxa originating from 6 continents.

MATERIALS AND METHODS

One hundred twenty nine helicobacter 16s rRNA gene segments were amplified by PCR and sequenced from ninety-three mammalian, reptilian, avian, or amphibian host species. Prevalence estimates were generated, and univariate logistic regression analyses were used to explore relationships between infection status and the health and characteristics of the 220 individual animals.

RESULTS

One hundred and nineteen novel helicobacter DNA sequences were found. No significant relationship between infection and host health was found; however, multi-infection or infections with particular genotypes were associated with mild clinical signs. Phylogenetic and genetic comparisons of helicobacters suggested prolonged co-adaptation and niche-associated divergence as well as periodic inter-species transmission.

CONCLUSION

The genus Helicobacter should accordingly be viewed as a collection of hundreds of organisms that have colonized most tetrapod taxa and have the potential to expand into new hosts as contact among animals and between animals and people increases.

Helicobacter spp. other than Helicobacter pylori

Non-H. pylori Helicobacter species (NHPHS) are associated with several important human and animal diseases. In the past year research into this group of bacteria has continued to gain attention, and novel species have been described in new niches owing to improvements in detection methods. Polymerase chain reaction and/or sequencing remain the gold standard for the detection of this genus. New insights into the pathogenesis of the NHPHS in hepatobiliary, gastric, and intestinal diseases were gained. In particular, data revealed interaction between hepatic steatosis and infectious hepatitis in the development of hepatocellular carcinoma. Evidence of an association between hepatitis C virus and Helicobacter spp. in hepatocarcinoma development was also provided; and male sex hormone signaling appeared to influence infectious hepatitis induced by Helicobacter hepaticus. More findings support an association between Helicobacter heilmannii and gastric adenocarcinoma; and in mice, mucins MUC4 and MUC5 but not MUC1 influence the colonization and pathogenesis of Helicobacter felis. Data indicated that the roles of the adaptive immune system in H. hepaticus-induced intestinal tumorigenesis are different in the small and large intestines, and environmental factors, such as bile acids may modulate H. hepaticus carcinogenic potential. New reports in the prevention and eradication of NHPHS showed a protective response against Helicobacter suis induced by vaccine administration, and a successful cross-foster rederivation method successfully eradicated Helicobacter spp. from contaminated mice litters. Overall, the studies provided insights into the pathophysiology of Helicobacter species other than Helicobacter pylori.