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.

Review: Other Helicobacter species.

This review covers the most important, accessible, and relevant literature published between April 2019 and April 2020 in the field of non-Helicobacter pylori Helicobacter species (NHPH). The initial part of the review covers new insights regarding the presence of gastric and enterohepatic NHPH in humans and animals, while the subsequent section focuses on the progress in our understanding of animal models, the pathogenicity and omics of these species. Over the last year, the clinical relevance of gastric NHPH infections in humans was highlighted. With regard to NHPH in animals, the ancestral source of Helicobacter suis was further established showing that Cynomolgus macaques are the common ancestor of the pig-associated H. suis population, and 3 novel Helicobacter species isolated from the gastric mucosa of red foxes were described. "Helicobacter burdigaliensis" sp nov. and "Helicobacter labetoulli" sp nov. were proposed as novel enterohepatic Helicobacter species associated with human digestive diseases. An analysis of Helicobacter cinaedi recurrent infections in humans proposed long-term antibiotic therapies. Several studies using rodent models further elucidated the mechanisms underlying the development of NHPH-related disease, as well as intestinal immunity in inflammatory bowel disease models. Omics approaches supported Helicobacteraceae taxonomy and unraveled the transcriptomic signatures of H. suis and Helicobacter heilmannii upon adherence to the human gastric epithelium. With regard to virulence, data showed that the nuclear remodeling promoted by cytolethal distending toxin of Helicobacters involves the MAFB oncoprotein and is associated with nucleoplasmic reticulum formation in surviving cells.

PCR analysis and specific immunohistochemistry revealing a high prevalence of non-Helicobacter pylori Helicobacters in Helicobacter pylori-negative gastric disease patients in Japan: High susceptibility to an Hp eradication regimen.

BACKGROUND: The clinical significance of non-Helicobacter pylori Helicobacter (NHPH) is still unknown. There are many reports of NHPH-infected patients suffering from gastric diseases. Here, we investigated the polymerase chain reaction (PCR) positivity of NHPH infection in gastric disease patients who were negative for H. pylori (Hp) by the rapid urease test and by pathological observation. MATERIALS AND METHODS: We collected the 296 endoscopically obtained gastric mucosal samples of Hp-negative gastric disease patients diagnosed based on a rapid urease test and pathology from 17 hospitals in Japan from September 2013 to June 2019, and we analyzed the existence of Hp and NHPH by PCR. The samples were also treated by indirect immunohistochemistry using an anti-Helicobacter suis VacA paralog antibody and were observed by confocal laser microscopy. RESULTS: Among the 236 non-Hp-eradicated cases, 49 cases (20.8%) were positive for NHPH. Among them, 20 cases were positive for Helicobacter suis, 7 cases were positive for Helicobacter heilmannii sensu stricto/ Helicobacter ailurogastricus (Hhss/Ha), and the other 22 cases could not be identified. The regional differences in the infection rates were significant. Forty percent of the nodular gastritis cases, 24% of the MALT lymphoma, 17% of the chronic gastritis cases, and 33% of the gastroduodenal ulcer cases were NHPH positive. Forty-five patients had been treated with one of the four types of combinations of a proton pump inhibitor and two antibiotics, and in all of these cases, the NHPH diagnosed by PCR was successfully eradicated. Immunohistochemistry using the Helicobacter suis-specific HsvA antibody coincided well with the PCR results. Among the 29 post-Hp eradication cases, three were NHPH positive, including one Hhss/Ha-positive case. Thus, approx. 20% of the Hp-negative non-Hp-eradicated gastric disease patients treated at 17 hospitals in Japan were infected with NHPH.

Helicobacter labacensis sp. nov., Helicobacter mehlei sp. nov., and Helicobacter vulpis sp. nov., isolated from gastric mucosa of red foxes (Vulpes vulpes).

Six Helicobacter-like isolates were recovered from 15 gastric mucosa samples of red foxes (Vulpes vulpes) shot by hunters in the surroundings of Ljubljana, Slovenia. Gram-negative, tightly coiled, intensely motile, 7-15 µm long and ≤1 µm wide bacteria grew on the biphasic blood agar plates. By using a genus-specific polymerase chain reaction (PCR), all isolates were confirmed as Helicobacter sp. and subsequently subjected to whole-genome sequencing (WGS). Five isolates showed a genome-wide average nucleotide identity (ANI) value of <95 % to the previously described Helicobacter species and one isolate was classified as Helicobacter felis. In the five unidentified isolates, the 16S rRNA gene sequence similarity to the type strains of all Helicobacter species ranged from 98.6 to 98.9 %. Their taxonomic status was established using a polyphasic taxonomic approach comprising the core genome-based phylogeny, morphological and phenotypic characteristics, including an analysis of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectra. Phylogeny revealed the existence of three novel and well-supported clusters, with Helicobacter bizzozeronii and Helicobacter baculiformis being the most closely related species. The isolates also differed from the previously described species in their MALDI-TOF profiles and some biochemical characteristics. In conclusion, the data presented herein indicate that the obtained isolates, excluding H. felis isolate, represent three novel Helicobacter species, for which the names Helicobacter labacensis sp. nov., Helicobacter mehlei sp. nov., and Helicobacter vulpis sp. nov. are proposed, with isolates L9T (=DSM 108823T=CRBIP 111719T), L15T (=DSM 108730T=CCUG 72910T) and L2T (=DSM 108727T=CCUG 72909T) as type strains, respectively.

Review: Other Helicobacter species.

This article is a review of the most important, accessible, and relevant literature published between April 2018 and April 2019 in the field of Helicobacter species other than Helicobacter pylori. The initial part of the review covers new insights regarding the presence of gastric and enterohepatic non-H. pylori Helicobacter species (NHPH) in humans and animals, while the subsequent section focuses on the progress in our understanding of the pathogenicity and evolution of these species. Over the last year, relatively few cases of gastric NHPH infections in humans were published, with most NHPH infections being attributed to enterohepatic Helicobacters. A novel species, designated "Helicobacter caesarodunensis," was isolated from the blood of a febrile patient and numerous cases of human Helicobacter cinaedi infections underlined this species as a true emerging pathogen. With regard to NHPH in animals, canine/feline gastric NHPH cause little or no harm in their natural host; however they can become opportunistic when translocated to the hepatobiliary tract. The role of enterohepatic Helicobacter species in colorectal tumors in pets has also been highlighted. Several studies in rodent models have further elucidated the mechanisms underlying the development of NHPH-related disease, and the extra-gastric effects of a Helicobacter suis infection on brain homeostasis was also studied. Comparative genomics facilitated a breakthrough in the evolutionary history of Helicobacter in general and NHPH in particular. Investigation of the genome of Helicobacter apodemus revealed particular traits with regard to its virulence factors. A range of compounds including mulberries, dietary fiber, ginseng, and avian eggs which target the gut microbiota have also been shown to affect Helicobacter growth, with a potential therapeutic utilization and increase in survival.

Cholesterol-α-glucosyltransferase gene is present in most Helicobacter species including gastric non-Helicobacter pylori helicobacters obtained from Japanese patients.

BACKGROUND: Non-Helicobacter pylori helicobacters (NHPHs) besides H. pylori infect human stomachs and cause chronic gastritis and mucosa-associated lymphoid tissue lymphoma. Cholesteryl-α-glucosides have been identified as unique glycolipids present in H. pylori and some Helicobacter species. Cholesterol-α-glucosyltransferase (αCgT), a key enzyme for the biosynthesis of cholesteryl-α-glucosides, plays crucial roles in the pathogenicity of H. pylori. Therefore, it is important to examine αCgTs of NHPHs. MATERIALS AND METHODS: Six gastric NHPHs were isolated from Japanese patients and maintained in mouse stomachs. The αCgT genes were amplified by PCR and inverse PCR. We retrieved the αCgT genes of other Helicobacter species by BLAST searches in GenBank. RESULTS: αCgT genes were present in most Helicobacter species and in all Japanese isolates examined. However, we could find no candidate gene for αCgT in the whole genome of Helicobacter cinaedi and several enterohepatic species. Phylogenic analysis demonstrated that the αCgT genes of all Japanese isolates show high similarities to that of a zoonotic group of gastric NHPHs including Helicobacter suis, Helicobacter heilmannii, and Helicobacter ailurogastricus. Of 6 Japanese isolates, the αCgT genes of 4 isolates were identical to that of H. suis, and that of another 2 isolates were similar to that of H. heilmannii and H. ailurogastricus. CONCLUSIONS: All gastric NHPHs examined showed presence of αCgT genes, indicating that αCgT may be beneficial for these helicobacters to infect human and possibly animal stomachs. Our study indicated that NHPHs could be classified into 2 groups, NHPHs with αCgT genes and NHPHs without αCgT genes.

Analysis of the association between density of Helicobacter spp and gastric lesions in dogs.

OBJECTIVE To evaluate the correlation between the density of native gastric Helicobacter spp and the presence of gastric lesions in dogs. ANIMALS 80 dogs of various breeds, sexes, and ages. PROCEDURES Gastroscopic and histologic examinations were performed for all dogs. Helicobacter spp were detected by combining evaluation of urease activity and results of bacteriologic culture, microscopic observation, and a 16S rRNA PCR assay. The density of Helicobacter-like organisms was evaluated with light microscopy by use of Warthin-Starry modified stain. Correlations were evaluated by use of the Spearman correlation analysis. RESULTS Gastritis was found in 55 of 80 dogs and classified as mild (n = 31), moderate (16), or severe (8). Of these 55 dogs, only 8 had clinical signs. Histologic examination revealed some degree of lymphocytic-plasmacytic infiltrate, mild eosinophilia, and neutrophilic inflammation in the lamina propria. Seventy-six dogs had positive results for Helicobacter spp. Helicobacter pylori DNA was not detected. Low density and homogeneous distribution of Helicobacter spp were observed in all gastric zones. CONCLUSIONS AND CLINICAL RELEVANCE A significant correlation between density of Helicobacter spp and gastroscopic or histologic lesions was not detected. These findings supported the contention that there is no correlation between general Helicobacter spp density or numbers and gastritis in dogs.

Minimal standards for describing new species belonging to the families Campylobacteraceae and Helicobacteraceae: Campylobacter, Arcobacter, Helicobacter and Wolinella spp.

Ongoing changes in taxonomic methods, and in the rapid development of the taxonomic structure of species assigned to the Epsilonproteobacteria have lead the International Committee of Systematic Bacteriology Subcommittee on the Taxonomy of Campylobacter and Related Bacteria to discuss significant updates to previous minimal standards for describing new species of Campylobacteraceae and Helicobacteraceae. This paper is the result of these discussions and proposes minimum requirements for the description of new species belonging to the families Campylobacteraceae and Helicobacteraceae, thus including species in Campylobacter, Arcobacter, Helicobacter, and Wolinella. The core underlying principle remains the use of appropriate phenotypic and genotypic methods to characterise strains sufficiently so as to effectively and unambiguously determine their taxonomic position in these families, and provide adequate means by which the new taxon can be distinguished from extant species and subspecies. This polyphasic taxonomic approach demands the use of appropriate reference data for comparison to ensure the novelty of proposed new taxa, and the recommended study of at least five strains to enable species diversity to be assessed. Methodological approaches for phenotypic and genotypic (including whole-genome sequence comparisons) characterisation are recommended.

Genomic and clinical evidence uncovers the enterohepatic species Helicobacter valdiviensis as a potential human intestinal pathogen.

BACKGROUND: Helicobacter valdiviensis is a recently described enterohepatic species isolated from wild bird's fecal samples. Currently, its pathogenic potential and clinical significance are unknown mainly due to the lack of whole-genome sequences to compare with other helicobacters and the absence of specific screenings to determine its prevalence in humans. MATERIALS AND METHODS: The species type strain (WBE14T ) was whole-genome-sequenced, and comparative analyses were carried out including the genomes from other Helicobacter species to determine the exact phylogenetic position of H. valdiviensis and to study the presence and evolution of virulence determinants. In parallel, stools from diarrheic patients and healthy individuals were screened by PCR to assess the clinical incidence of H. valdiviensis. RESULTS: Helicobacter valdiviensis belongs to a monophyletic clade conformed by H. canadensis, H. pullorum, H. winghamensis, H. rodentium, and H. apodemus. Its predicted genome size is 2 176 246 bp., with 30% of G+C content and 2064 annotated protein-coding genes. The patterns of virulence factors in H. valdiviensis were similar to other enterohepatic species, but evidence of horizontal gene transfer from Campylobacter species was detected for key genes like those coding for the CDT subunits. Positive PCR results confirmed the presence of H. valdiviensis in 2 of 254 (0.78%) stools of patients with acute diarrhea while not a single sample was positive in healthy individuals. CONCLUSIONS: Horizontal gene transfer has contributed to shape the gene repertory of H. valdiviensis, which codes for virulence factors conserved in other pathogens that are well-known human pathogens. Additionally, the detection of H. valdiviensisDNA in diarrheic patients supports its role as a potential emergent intestinal pathogen. Further, sampling efforts are needed to uncover the clinical relevance of this species, which should be accomplished by the isolation of H. valdiviensis from ill humans and the obtention of whole genomes from clinical isolates.

Epidemiological study of gastric Helicobacter spp. in dogs with gastrointestinal disease in Japan and diversity of Helicobacter heilmannii sensu stricto.

Epidemiological and pathological studies of Helicobacter spp. in canine stomachs in Japan were performed to investigate strain specific pathogenicity. Gastric biopsies from 144 dogs with gastrointestinal diseases were evaluated for the presence of Helicobacter spp. using genus and species specific PCRs for Helicobacter felis, Helicobacter bizzozeronii, Helicobacter heilmannii sensu stricto (s.s.) and Helicobacter pylori. PCR indicated that 50/144 (34.7%) dogs were infected with Helicobacter spp. Of the genus positive samples, 21/50 could not be amplified by any of the species specific PCRs. To investigate Helicobacter at the species level, partial ureAB gene sequences from 48/50 genus positive samples were determined; 47 strains were identified. Thirty-five strains from 45 cases were closely related to H. heilmannii s.s. (89-99% sequence similarity), seven strains from seven cases were closely related to H. bizzozeronii (95-99% sequence similarity), three strains from three cases were closely related to Helicobacter felis (86%, 98% and 99% sequence similarity), one strain from one case was closely related to Helicobacter salomonis (99% sequence similarity) and one strain from one case was closely related to H. pylori (99% sequence similarity). Dogs infected with Helicobacter spp. most similar to H. heilmannii s.s. had a higher frequency of moderate to severe gastritis than dogs negative for Helicobacter spp. (P=0.044). In conclusion, the predominant Helicobacter spp. detected in canine stomachs in our study were most closely related to H. heilmannii s.s. and displayed substantial genetic diversity. Infection with Helicobacter spp. may be associated with more severe gastritis in dogs.

Novel urease-negative Helicobacter sp. 'H. enhydrae sp. nov.' isolated from inflamed gastric tissue of southern sea otters.

A total of 31 sea otters Enhydra lutris nereis found dead or moribund (and then euthanized) were necropsied in California, USA. Stomach biopsies were collected and transected with equal portions frozen or placed in formalin and analyzed histologically and screened for Helicobacter spp. in gastric tissue. Helicobacter spp. were isolated from 9 sea otters (29%); 58% (18 of 31) animals were positive for helicobacter by PCR. The Helicobacter sp. was catalase- and oxidase-positive and urease-negative. By electron microscopy, the Helicobacter sp. had lateral and polar sheathed flagella and had a slightly curved rod morphology. 16S and 23S rRNA sequence analyses of all 'H. enhydrae' isolates had similar sequences, which clustered as a novel Helicobacter sp. closely related to H. mustelae (96-97%). The genome sequence of isolate MIT 01-6242 was assembled into a single ~1.6 Mb long contig with a 40.8% G+C content. The annotated genome contained 1699 protein-coding sequences and 43 RNAs, including 65 genes homologous to known Helicobacter spp. and Campylobacter spp. virulence factors. Histological changes in the gastric tissues extended from mild cystic degeneration of gastric glands to severe mucosal erosions and ulcers. Silver stains of infected tissues demonstrated slightly curved bacterial rods at the periphery of the gastric ulcers and on the epithelial surface of glands. The underlying mucosa and submucosa were infiltrated by low numbers of neutrophils, macrophages, and lymphocytes, with occasional lymphoid aggregates and well-defined lymphoid follicles. This is the second novel Helicobacter sp., which we have named 'H. enhydrae', isolated from inflamed stomachs of mustelids, the first being H. mustelae from a ferret.

The First Case Report of Cerebral Cyst Infection Due to Helicobacter cinaedi.

We report the first case of cerebral cyst infection by Helicobacter cinaedi, a fastidious spiral-shaped gram-negative rod bacterium. A 70-year-old man visited Tokyo Medical University Hospital with persisting fever since 2 weeks. He underwent surgery and radiotherapy for parapharyngeal space squamous cell carcinoma 10 years ago. The radiotherapy resulted in a cerebral cyst as a side effect, and an Ommaya reservoir was inserted into the cyst. Blood culture and analysis of the brain cyst fluid revealed the presence of spiral-shaped gram-negative rod bacteria, which were identified as H. cinaedi by polymerase chain reaction. Initially, we administered clarithromycin (400 mg per day). After H. cinaedi infection was confirmed, the treatment was changed to meropenem (MEPM 6 g per day). The patient was treated for 43 days in the hospital with intravenous meropenem, and his clinical course was satisfactory. On the 44th day, he was discharged and prescribed oral minocycline (MINO 200 mg per day). After discharge, the patient's H. cinaedi infection did not recur. Our case illustrated the wide clinical spectrum of H. cinaedi as well as the effectiveness of antibiotic therapy comprising MERM and MINO for treating central nervous system infection by this organism.

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.

Other Helicobacters and gastric microbiota.

This article aimed to review the literature from 2015 dealing with gastric and enterohepatic non-Helicobacter pylori Helicobacter species (NHPH). A summary of the gastric microbiota interactions with H. pylori is also presented. An extensive number of studies were published during the last year and have led to a better understanding of the pathogenesis of infections with NHPH. These infections are increasingly reported in human patients, including infections with H. cinaedi, mainly characterized by severe bacteremia. Whole-genome sequencing appears to be the most reliable technique for identification of NHPH at species level. Presence of NHPH in laboratory animals may influence the outcome of experiments, making screening and eradication desirable. Vaccination based on UreB proteins or bacterial lysate with CCR4 antagonists as well as oral glutathione supplementation may be promising strategies to dampen the pathogenic effects associated with gastric NHPH infections. Several virulent factors such as outer membrane proteins, phospholipase C-gamma 2, Bak protein, and nickel-binding proteins are associated with colonization of the gastric mucosae and development of gastritis. The development of high-throughput sequencing has led to new insights in the gastric microbiota composition and its interaction with H. pylori. Alterations in the gastric microbiota caused by the pH-increasing effect of a H. pylori infection may increase the risk for gastric cancer.

Helicobacter saguini, a Novel Helicobacter Isolated from Cotton-Top Tamarins with Ulcerative Colitis, Has Proinflammatory Properties and Induces Typhlocolitis and Dysplasia in Gnotobiotic IL-10-/- Mice.

A urease-negative, fusiform, novel bacterium named Helicobacter saguini was isolated from the intestines and feces of cotton-top tamarins (CTTs) with chronic colitis. Helicobacter sp. was detected in 69% of feces or intestinal samples from 116 CTTs. The draft genome sequence, obtained by Illumina MiSeq sequencing, for H. saguini isolate MIT 97-6194-5, consisting of ∼2.9 Mb with a G+C content of 35% and 2,704 genes, was annotated using the NCBI Prokaryotic Genomes Automatic Annotation Pipeline. H. saguini contains homologous genes of known virulence factors found in other enterohepatic helicobacter species (EHS) and H. pylori These include flagellin, γ-glutamyl transpeptidase (ggt), collagenase, the secreted serine protease htrA, and components of a type VI secretion system, but the genome does not harbor genes for cytolethal distending toxin (cdt). H. saguini MIT 97-6194-5 induced significant levels of interleukin-8 (IL-8) in HT-29 cell culture supernatants by 4 h, which increased through 24 h. mRNAs for the proinflammatory cytokines IL-1ß, tumor necrosis factor alpha (TNF-α), IL-10, and IL-6 and the chemokine CXCL1 were upregulated in cocultured HT-29 cells at 4 h compared to levels in control cells. At 3 months postinfection, all H. saguini-monoassociated gnotobiotic C57BL/129 IL-10(-/-) mice were colonized and had seroconverted to H. saguini antigen with a significant Th1-associated increase in IgG2c (P < 0.0001). H. saguini induced a significant typhlocolitis, associated epithelial defects, mucosa-associated lymphoid tissue (MALT) hyperplasia, and dysplasia. Inflammatory cytokines IL-22, IL-17a, IL-1ß, gamma interferon (IFN-γ), and TNF-α, as well as inducible nitric oxide synthase (iNOS) were significantly upregulated in the cecal tissues of infected mice. The expression of the DNA damage response molecule γ-H2AX was significantly higher in the ceca of H. saguini-infected gnotobiotic mice than in the controls. This model using a nonhuman primate Helicobacter sp. can be used to study the pathogenic potential of EHS isolated from primates with naturally occurring inflammatory bowel disease (IBD) and colon cancer.

In the Aftermath of Helicobacter pylori: Other Helicobacters Rising Up to Become the Next Gastric Epidemic?

Non-Helicobacter pylori-Helicobacters including H. suis, H. heilmanniisensu stricto and H. felis comprise a group of bacteria that may inhabit the stomach of humans and animals. Human gastric infection has been associated with gastritis, ulcer, MALT lymphoma and cancer. Although the fastidious nature of these organisms has hampered their research, recent advancements in in vitro cultivation and recent reports on in vivo models and prevalence studies in humans suggest this group of bacteria to be of more clinical significance than earlier believed. The present review discusses their history, microbiology and relevance to human health.

Enterohepatic Helicobacter spp. in cats with non-haematopoietic intestinal carcinoma: a survey of 55 cases.

Several enterohepatic Helicobacter spp. (EHS) have been isolated from cats. Despite the reported association between EHS infection and intestinal neoplasia in other species, this association has not been explored in cats. In this study, 55 non-haematopoietic feline intestinal carcinoma cases were histopathologically evaluated. In contrast with prior reports, large intestinal (LI) carcinoma was observed with greater frequency (61 %) relative to small intestinal (SI) carcinoma (35 %). There was a significant association between intestinal location and animal gender. Of males examined, 83 % had LI carcinoma, while no such trend was observed in females. Previously described associations between Siamese breed and intestinal carcinoma could not be definitively confirmed, although the Siamese breed may be predisposed to SI carcinoma location. Of all carcinomas examined in this study, 62 % were classified as adenocarcinoma, although mucinous adenocarcinoma (28 %) and solid carcinoma (11 %) were also identified. Tumours were all moderately or poorly differentiated. When considered by intestinal location and histopathologic classification, LI adenocarcinoma was associated with significantly advanced mean age (13 years) when compared to SI adenocarcinoma and LI mucinous adenocarcinoma (mean, 9 years in both cases), which were also frequently encountered. To determine whether EHS might play a role in feline intestinal neoplasia, Helicobacter genus- and species-specific fluorescence in situ hybridization was performed. Of these carcinoma cases, 56 % were positive for Helicobacter spp. and one or more species-specific assay for Helicobacterbilis, Helicobactercanis or Helicobactermarmotae. The presence of EHS was significantly associated with both LI location (68 %) and mucinous adenocarcinoma (92 %). These findings suggest a role for intestinal bacteria in non-haematopoietic feline intestinal neoplasia.

Helicobacter apri sp. nov., isolated from wild boars.

Three isolates (A19T, C21 and F12) with spiral-shaped cells and one bipolar sheathed flagellum were obtained from gastric mucosa and caecal contents of three different wild boars (Sus scrofa) and subjected to a polyphasic taxonomic study. A genus-specific PCR showed that these isolates belonged to the genus Helicobacter. Phylogenetic analysis based on 16S rRNA, 60-kDa heat-shock protein (HSP60) and atpA genes demonstrated they formed a novel lineage within this genus. Pairwise 16S rRNA, HSP60 and atpA gene sequence comparisons of the three isolates revealed 99.7, 99.4 and 99.9 % similarity, respectively, among the three isolates; the 16S rRNA gene of isolate A19T shared 98.5 % sequence similarity with its nearest validly named neighbouring species, Helicobacter mastomyrinus (to the type strain MIT 97-5577T). The taxonomic uniqueness of the wild boar isolates was confirmed by protein analysis performed by matrix-assisted laser desorption/ionization time-of-flight MS and by a distinctive biochemical profile. These data indicated that isolates A19T, C21 and F12 represent a novel taxon, for which the name Helicobacter apri sp. nov. is proposed, with isolate A19T (=DSM 28990T=LMG 28471T) as the type strain.

Helicobacter Species Identified in Captive Sooty Mangabeys (Cercocebus atys) with Metastatic Gastric Adenocarcinoma.

BACKGROUND: Of all human cancers, gastric carcinoma is the one of the leading causes of death. Helicobacter pylori is considered a major etiologic agent of this disease. Spontaneously occurring gastric carcinoma is a rare diagnosis in nonhuman primates. A 2011 case report documented a high incidence of gastric adenocarcinoma in a closed colony of captive sooty mangabeys (Cercebus atys). However, H. pylori infection was not detected in these animals. MATERIALS AND METHODS: In this study, using archived formalin-fixed, paraffin-embedded stomach sections of these animals alternative methodologies were used to identify H. pylori and other non-H. pylori Helicobacter species. In addition, two additional cases of sooty mangabeys with metastatic gastric carcinoma are characterized. RESULTS: Using fluorescent in situ hybridization, we identified gastric H. suis in 75% of archived and new gastric carcinoma cases. In the two newly reported cases, H. suis and a novel Helicobacter species were detected via PCR and sequence analysis of the 16S rRNA gene. H. pylori was not identified in any of the gastric carcinoma cases via FISH and/or PCR and sequence analysis of Helicobacter spp. in DNA from of available tissues. CONCLUSIONS: This report is the first to characterize Helicobacter species infection in spontaneous gastric carcinoma with metastatic potential in nonhuman primates.

The Other Helicobacters.

In the past year, a substantial number of (putative) novel Helicobacter species have been described, including Helicobacter himalayensis colonizing the Himalayan marmot and Helicobacter apodemus, colonizing the Korean striped field mouse. In addition, a putative novel gastric Helicobacter species was identified in wild gorillas and chimpanzees, for which the name "Candidatus H. homininae" was proposed. A high incidence of gastric non-H. pylori Helicobacter infection was described in China and multiple case reports have described the involvement of enterohepatic Helicobacter species, especially Helicobacter cinaedi, in a wide range of diseases. Several studies in rodent models further elucidated the mechanisms underlying the development of gastric mucosa-associated lymphoid tissue lymphoma during infection with gastric non-H. pylori Helicobacters. The effects of infection with gastric Helicobacters on the development of neuroinflammation were investigated and several enterohepatic Helicobacter species were shown to affect the composition of the gut microbiota, to influence vaccine efficiency as well as the progression of cancer in distant sites of the body.