First detection of Helicobacter canis in chronic duodenal ulcerations from a patient with Crohn's disease

Proposal of Helicobacter higonensis sp. nov. isolated from a human clinical specimen, and emended description of Helicobacter valdiviensis Collado, 2014

We have previously isolated a gram-negative microaerophilic strain, PAGU2000T from a patient presenting with a fever in Kumamoto Prefecture, Japan. The present study aimed to comprehensively analyze the taxonomy of the isolated strain using a polyphasic approach. The 16S rRNA gene sequence analysis indicated that the strain was a member of enterohepatic Helicobacter. The strain PAGU2000T shared a 97.5% 16S rRNA gene nucleotide identity with Helicobacter valdiviensis, and this taxonomic position was confirmed by phylogenetic analysis of the GyrA amino acid sequences. The proposed strain PAGU2000T has a 1.482 Mbp chromosome with a DNA G + C content of 31.3 mol% and encodes 1520 predicted coding sequences. The average nucleotide identity between the strain PAGU2000T and type strain of H. valdiviensis was 70.3%, which was lower than the recommended threshold of 95% for species delineation. The strain PAGU2000T was a motile, non-spore-forming, and spiral-shaped bacterium, exhibiting catalase and oxidase activities but not urease and nitrate reduction. This study demonstrates that the isolate represents a novel species within enterohepatic Helicobacter, for which the name Helicobacter higonensis is proposed (type strain: PAGU2000T = GTC 16811T = LMG 33095T). In this study, we describe the phenotypic and morphological features of this strain and propose an emended description of some biochemical traits of H. valdiviensis.

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.

•

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

•

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

•

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.

•

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

•

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

IL-1R8 as Pathoimmunological Marker for Severity of Canine Chronic Enteropathy

Chronic enteropathy (CE) is a severe multifactorial gastrointestinal disease that affects dogs and is driven by poorly characterized inflammatory pathways. Imbalance of pro-inflammatory response regulators, including IL-1R8, may be due to different factors, among which the infection with Helicobacteraceae is known to lead to a vicious circle in which excessive pro-inflammatory signaling and gastrointestinal injury reinforce each other and boost the disease. We investigated the expression of IL-1R8 in large intestine biopsies of dogs with or without clinical signs of CE and with previously assessed enterohepatic Helicobacter spp. colonization status by mean of quantitative real-time PCR. Our study revealed that IL-1R8 is downregulated in both acutely (p = 0.0074) and chronically (p = 0.0159) CE affected dogs compared to healthy controls. The data also showed that IL-1R8 expression tends to decrease with colonization by Helicobacter spp. Interestingly, a negative correlation was detected between the level of expression of IL-1R8 and the severity of macroscopic lesions identified by endoscopy and the crypt hyperplasia score. We further compared the expression levels between males and females and found no statistically significant difference between the two groups. No significant difference was observed in IL-1R8 expression profiles with the age of the animals either. Interestingly, an association was uncovered between IL-1R8 expression level and dog breed. Together, our data advance knowledge on gastrointestinal pathoimmunology in dogs and highlight the potential utilization of IL-1R8 as a diagnostic, prognostic and therapeutic biomarker for canine chronic enteropathy.

Helicobacter canis: A Review of Microbiological and Clinical Features

Helicobacter canis, an enterohepatic Helicobacter, has proven its role in human diseases and has been rediscussed in recent years as its zoonotic potential is increasingly described. Routine microbiological detection of this pathogen is a difficult task as its culture may fail due to fastidious growth. It is therefore supposed that many clinical laboratories under-recognize H. canis infections. A review of all clinical and microbiological literature currently available from previous relevant H. canis human clinical cases, mainly bacteremia, added with a clinical case observed at the Cliniques universitaires Saint-Luc, was performed. Clinical features of H. canis reports show the presence of underlying clinical conditions in 89% of the cases, bacteremia in 83%, associated fever in 58%, and recent close contact with pets in 83%, especially dogs. The observed microbiological trends from 10 cases of bacteremia were a median of 4 days until positive blood culture bottle detection, subcultures showing a thin layer of small colonies under microaerophilic atmosphere at 35–42°C after 3–4 days of growth, and an identification requiring 16S rRNA sequencing given the difficulties observed with MALDI-TOF MS. Low MICs were observed for penicillins, amoxicillin/clavulanic acid, carbapenems, and metronidazole in opposition to high MICs for ciprofloxacin. A frequent association of H. canis and bacteremia in immunocompromised patients with recurrent fever in contact with pets, especially dogs, was identified. Considering the fastidious growing capacities, final identification from blood cultures may not be expected before 7 days. Intravenous ceftriaxone, oral doxycycline, or metronidazole has been suggested as efficient therapeutic choices.

Enterohepatic Helicobacter species - clinical importance, host range, and zoonotic potential

The genus Helicobacter defined just over 30 years ago, is a highly diverse and fast-growing group of bacteria that are able to persistently colonize a wide range of animals. The members of this genus are subdivided into two groups with different ecological niches, associated pathologies, and phylogenetic relationships: the gastric Helicobacter (GH) and the enterohepatic Helicobacter (EHH) species. Although GH have been mostly studied, EHH species have become increasingly important as emerging human pathogens and potential zoonotic agents in the last years. This group of bacteria has been associated with the development of several diseases in humans from acute pathologies like gastroenteritis to chronic pathologies that include inflammatory bowel disease, and liver and gallbladder diseases. However, their reservoirs, as well as their routes of transmission, have not been well established yet. Therefore, this review summarizes the current knowledge of taxonomy, epidemiology, and clinical role of the EHH group.

Helicobacter canis bacteraemia in a rheumatoid arthritis patient treated with tofacitinib: case report and literature review

BACKGROUND

Non-Helicobacter pylori species (NHPS) are newly emerging bacteria that naturally inhabit birds and mammals apart from humans and rarely cause diseases in humans. In recent years, a rise in the number of cases associated with NHPS infections in humans has been observed. Among them, infections with Helicobacter (H.) canis are sporadic and challenging to recognise clinically. To date, ten cases of H. canis infections in mainly immunocompromised humans have been reported in the literature. Transmission pathway is most likely zoonotic via the faecal-oral route during close contacts with dogs and cats or may result from a contaminated sheep milk intake. No clear guidelines for successful antibiotic regimen are known. Important additional risk factor for infection might be biologic agents and Janus kinase inhibitors (JAKi) used in the treatment of rheumatoid arthritis (RA) and other conditions. Herein we present the first case of H. canis bacteraemia in a RA patient treated with novel JAKi tofacitinib.

CASE PRESENTATION

A 65-year-old female patient with RA and rituximab-induced hypogammaglobulinemia treated with tofacitinib, methotrexate, and methylprednisolone came to a planned visit in our outpatient rheumatology clinic. She presented with a history of back pain that significantly worsened 2 days before visit. She had numbness and tingling sensation in both legs and muscle weakness. Neurological examination was within a normal range. The patient was afebrile, had no chills, and was haemodynamically stable. She was in close contact with her pet dogs. Laboratory examination showed increased markers of inflammation. She was found to have H. canis bacteraemia with underlying multilevel degenerative lumbar spinal stenosis. Identification of H. canis was performed by MALDI-TOF MS and 16 S rRNA gene sequence analysis of isolate from subcultured positive aerobic blood culture bottles. Antimicrobial susceptibility testing showed low minimum inhibitory concentrations to amoxicillin-clavulanate, cefotaxime, ceftriaxone, meropenem, and gentamicin. She was treated with combined antibiotic regimen (ceftriaxone, doxycycline) for 14 days, which resulted in total remission of the infection.

CONCLUSIONS

Clinicians should recognise H. canis infection risk in patients with recent pet exposure and predisposing factors such as immunodeficiency disorders or diseases that demand immunosuppressive drug therapy. A minimum of two weeks of antibiotic therapy is suggested.

Exploring the role of healthy dogs as hosts of enterohepatic Helicobacter species using cultivation-dependent and -independent approaches

Enterohepatic Helicobacter (EHH) species have been increasingly associated with acute gastroenteritis, inflammatory bowel disease and hepatobiliary diseases in humans. However, their host range and transmission routes are poorly understood. Therefore, the aim of this study was to determine the presence of EHH in healthy dogs using both cultivation-dependent and -independent methods. Three hundred and ninety faecal samples from domestic dogs without gastrointestinal symptoms were analysed between June 2018 and July 2019 in Valdivia (South of Chile). Samples were inoculated on selective medium and in parallel were filtrated over an antibiotic-free blood agar. Both media were incubated in a microaerobic atmosphere at 37°C for 7 days. Colonies were identified by PCR and phylogenetic analysis. A subset of 50 samples (half of them positive for EHH by cultivation and the remaining half negative) was analysed by PCR-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) for direct detection. Cultivation method detected EHH in 15.4% (60/390) of the samples, being the most prevalent species H. canis (5.8%, 23/390) and H. canicola (5.1%, 20/390), followed by H. bilis (3.6%, 14/390) and 'H. winghamensis' (1.3%, 5/390). In contrast, PCR-DGGE method detected Helicobacter DNA in almost all (96%, 48/50) tested samples. On the other hand, the method used also allowed to isolate other Campylobacterales, in fact 44.3% (173/390) of the samples were positive for Campylobacter upsaliensis (43.3%, 169/390) followed by C. jejuni (2.0%, 8/390). Moreover, two strains that presented Campylobacter-like morphology were finally identified as Anaerobiospirillum succiniciproducens. Our results indicate that healthy domestic dogs commonly carry EHH and other Campylobacter species. However, further studies are needed to determine whether and how these Helicobacter and Campylobacter species can be transmitted to humans.

Immune and microRNA responses to Helicobacter muridarum infection and indole-3-carbinol during colitis

BACKGROUND

Indole-3-carbinol (I3C) and other aryl hydrocarbon receptor agonists are known to modulate the immune system and ameliorate various inflammatory and autoimmune diseases in animal models, including colitis induced by dextran sulfate sodium (DSS). MicroRNAs (miRNAs) are also gaining traction as potential therapeutic agents or diagnostic elements. Enterohepatic Helicobacter (EHH) species are associated with an increased risk of inflammatory bowel disease, but little is known about how these species affect the immune system or response to treatment.

AIM

To determine whether infection with an EHH species alters the response to I3C and how the immune and miRNA responses of an EHH species compare with responses to DSS and inflammatory bowel disease.

METHODS

We infected C57BL/6 mice with Helicobacter muridarum (H. muridarum), with and without DSS and I3C treatment. Pathological responses were evaluated by histological examination, symptom scores, and cytokine responses. MiRNAs analysis was performed on mesenteric lymph nodes to further evaluate the regional immune response.

RESULTS

H. muridarum infection alone caused colonic inflammation and upregulated proinflammatory, macrophage-associated cytokines in the colon similar to changes seen in DSS-treated mice. Further upregulation occurred upon treatment with DSS. H. muridarum infection caused broad changes in mesenteric lymph node miRNA expression, but colitis-associated miRNAs were regulated similarly in H. muridarum-infected and uninfected, DSS-treated mice. In spite of causing colitis exacerbation, H. muridarum infection did not prevent disease amelioration by I3C. I3C normalized both macrophage- and T cell-associated cytokines.

CONCLUSION

Thus, I3C may be useful for inflammatory bowel disease patients regardless of EHH infection. The miRNA changes associated with I3C treatment are likely the result of, rather than the cause of immune response changes.

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

Abstract

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1957989294118782.

Helicobacter canis colonization in sheep: a Zoonotic link

BACKGROUND

Helicobacter canis has been associated with hepatobiliary and gastrointestinal disease in dogs, cats, and humans. Infection has not been documented in other species.

MATERIALS AND METHODS

Sheep feces subjected to microaerobic culture. Isolates were characterized by genus-specific PCR, restriction fragment length polymorphism, biochemical profiling, and 16S rRNA sequence analysis.

RESULTS

Helicobacter canis was isolated from sheep feces and confirmed by the above methods. These isolates are distinct from other sheep-origin enterohepatic Helicobacter species previously isolated.

CONCLUSIONS

This study identifies sheep as H. canis reservoirs potentially important in zoonotic or foodborne transmission.

Helicobacter canis bacteremia in a patient with fever of unknown origin

A 57-year-old woman with common variable immune deficiency and liver failure of unknown etiology presented with recurrent fevers over a 5-month period. She was found to have Helicobacter canis bacteremia. Immunocompromised hosts with exposure to cats or dogs may be at risk for infection with this organism, which may be challenging to diagnose.

Helicobacter spp. other than H. pylori

Significant advances have been made over the last 12 months in the understanding of the biology of non-H. pylori Helicobacter species (NHPH). Several studies have investigated the association between NHPH and human disease, including Crohn's disease, lithiasis, liver disease, coronary disease, gastritis, and pyoderma gangrenosum-like ulcers. Novel Helicobacter taxa were identified in new vertebrate hosts, and new methodologies in the fields of identification of Helicobacter spp. and evaluation of antibiotic resistance were described. The genome of the first human-derived gastric NHPH strain (Helicobacter bizzozeronii CIII-1) was sequenced, and several studies elucidated functions of different genes in NHPH. A number of important investigations regarding pathogenesis and immunopathobiology of NHPH infections have been published including the description of a new urease in Helicobacter mustelae. Finally, the effects of the gut microbiota and probiotics on NHPH infections were investigated.