Flexispira Taxon Research Articles

Helicobacter bilis and Helicobacter trogontum: infectious causes of abortion in sheep.

The aim of our study was to determine the association of Helicobacter spp. that had flexispira morphology with ovine abortion, and to understand the importance of these organisms as a cause of ovine abortion in New Zealand. A retrospective diagnostic survey was carried out on laboratory submissions from ovine abortion outbreaks. A comparison was made of the proportion of laboratory submissions where Helicobacter spp. were detected from flocks that had no other agent identified (group A) with a group that had a known cause of abortion identified (group B). This latter group was considered to be a negative control, given the premise that Helicobacter spp. were not causing abortions and that Helicobacter spp. should be present at a lower rate in the group. Where no diagnosis had been made, aborted material was positive for Helicobacter spp. with flexispira morphology in 8 submissions (20%, 8/40) from 5 of the 31 survey farms (16%, 5/31). Helicobacter spp. were not detected in any of the 18 submissions from the 17 control farms (group B). Helicobacter spp. were confirmed by 16S ribosomal RNA sequencing of 3 of the Helicobacter spp. isolated by culture from the livers of aborted sheep fetuses, and 7 of the 8 where samples were positive in a Helicobacter PCR assay. The Helicobacter spp. were identified as Helicobacter trogontum (Flexispira taxon 5 genotype) and Helicobacter bilis (Flexispira taxon 8 genotype). The findings support Helicobacter spp. being a probable causative agent of ovine abortions in New Zealand.

Co-infection of the Siberian hamster (Phodopus sungorus) with a novel Helicobacter sp. and Campylobacter sp.

We report the isolation of a novel helicobacter isolated from the caecum of the Siberian hamster (Phodopus sungorus). Sequence analysis showed 97% sequence similarity to Helicobacter ganmani. In addition, we report the co-infection of these Siberian hamsters with a Campylobacter sp. and a second Helicobacter sp. with 99% sequence similarity to Helicobacter sp. flexispira taxon 8 (Helicobacter bilis), a species isolated previously from patients with bacteraemia. Gross necropsy and histopathology did not reveal any overt pathological lesions of the liver and gastrointestinal tract that could be attributed to the Helicobacter or Campylobacter spp. infections. This is the first helicobacter to be identified in the Siberian hamster and the first report of co-infection of Helicobacter spp. and Campylobacter sp. in asymptomatic Siberian hamsters.

Could Helicobacter organisms cause inflammatory bowel disease?

The discovery of Helicobacter pylori sparked a revolution in the understanding and management of peptic ulcer disease and gastric cancer. Other Helicobacter species are recognized as important pathogenic agents in colitic diseases of rodents and primates, in particular Helicobacter bilis, Helicobacter fennelliae, Helicobacter hepaticus and Helicobacter trogontum. Helicobacter bilis and H. hepaticus are now routinely used to initiate rodent models of inflammatory bowel disease (IBD), particularly in immunocompromised hosts. Molecular evidence exists linking various non-pylori Helicobacter spp. with human IBD; however, attempts to culture organisms in this disease cohort have proved unsuccessful to date. Attributing causation has therefore proved elusive. Seven enterohepatic, non-pylori Helicobacter organisms have been successfully cultured from humans, namely Helicobacter canadensis, Helicobacter canis, Helicobacter cinaedi, H. fennelliae, Helicobacter pullorum, Helicobacter winghamensis and Helicobacter sp. flexispira taxon 8 (now classified as H. bilis). Of these, H. cinaedi and H. fennelliae are the closest to fulfilling Koch's postulates as causative agents in homosexual proctitis. The possibility that novel Helicobacter organisms have a role in the initiation of human IBD warrants further consideration and targeted investigations.

Pyoderma Gangrenosum–Like Ulcer in a Patient With X-Linked Agammaglobulinemia

Pyoderma gangrenosum-like ulcers and cellulitis of the lower extremities associated with recurrent fevers in patients with X-linked (Bruton) agammaglobulinemia have been reported to be caused by Helicobacter bilis (formerly classified as Flexispira rappini and then Helicobacter strain flexispira taxon 8). Consistent themes in these reports are the difficulty in recovering this organism in blood and wound cultures and in maintaining isolates in vitro. We confirmed the presence of this organism in a patient's culture by using a novel application of gene amplification polymerase chain reaction and electrospray ionization time-of-flight mass spectrometry. An adolescent boy with X-linked agammaglobulinemia presented with indurated plaques and a chronic leg ulcer whose origin was strongly suspected to be an H bilis organism. Histologic analysis demonstrated positive Warthin-Starry staining of curvilinear rods, which grew in culture but failed to grow when subcultured. They could not be identified by conventional techniques. A combination of gene amplification by polymerase chain reaction and electrospray ionization time-of-flight mass spectrometry confirmed the identity of this organism. This novel technology was useful in the identification of a difficult-to-grow Helicobacter organism, the cause of pyoderma gangrenosum-like leg ulcers in patients with X-linked agammaglobulinemia. Correct identification of this organism as the cause of pyoderma gangrenosum-like ulcers in patients with X-linked agammaglobulinemia is of great importance for the early initiation of appropriate and curative antibiotic therapy.

Chronic hepatitis, hepatic dysplasia, fibrosis, and biliary hyperplasia in hamsters naturally infected with a novel Helicobacter classified in the H. bilis cluster.

We recently described helicobacter-associated progressive, proliferative, and dysplastic typhlocolitis in aging (18- to 24-month-old) Syrian hamsters. Other pathogens associated with typhlocolitis in hamsters, Clostridium difficile, Lawsonia intracellularis, and Giardia spp., were not indentified. The presence of Helicobacter genus-specific DNA was noted by PCR in cecal and paraffin-embedded liver samples from aged hamsters by the use of Helicobacter-specific PCR primers. By 16S rRNA analysis, the Helicobacter sp. isolated from the liver tissue was identical to the cecal isolates from hamsters. The six hamster 16S rRNA sequences form a genotypic cluster most closely related to Helicobacter sp. Flexispira taxon 8, part of the Helicobacter bilis/H. cinaedi group. Livers from aged helicobacter-infected hamsters showed various stages of predominantly portocentric and, to a lesser extent, perivenular fibrosis. Within nodules, there was cellular atypia consistent with nodular dysplasia. The livers also exhibited a range of chronic active portal/interface and lobular inflammation, with significant portal hepatitis being present. The inflammation was composed of a mixture of lymphocytes, neutrophils, and macrophages, indicative of its chronic-active nature in these aged hamsters infected with Helicobacter spp. The isolation of novel Helicobacter spp., their identification by PCR from the diseased livers of aged hamsters, and their taxonomic classification as belonging to the Helicobacter bilis cluster strengthen the argument that H. bilis and closely related Helicobacter spp. play an etiological role in hepatobiliary disease in both animals and humans.

Extension of the species Helicobacter bilis to include the reference strains of Helicobacter sp. flexispira taxa 2, 3 and 8 and Finnish canine and feline flexispira strains

The evolution and taxonomy of enterohepatic Helicobacter species with flexispira morphology were studied by a polyphasic approach including phenotypic characterization, analysis of 16S rRNA and ureB gene sequences and dot-blot DNA-DNA hybridization of whole genomic DNA. In addition, available phylogenetic data on the HSP60 gene were used in the analysis. The study included 14 Finnish canine and feline flexispira strains, the reference strains of Helicobacter sp. flexispira taxa 2, 3 and 8 and Helicobacter bilis ATCC 51630(T). Phenotypically, all canine and feline strains were similar to H. bilis. Analysis of 16S rRNA gene sequences of these strains revealed a similarity of 97-99.5 %. Similarity of ureB nucleotide and amino acid sequences within the studied flexispira group was 97-100 % and 99-100 %, respectively, revealing close relatedness. ureB sequences of Helicobacter hepaticus had only 64-66 % similarity to the flexispira group. The similarity to Helicobacter trogontum was 81.5-82.1 %. High levels of DNA-DNA hybridization between the strains were found in dot-blot tests. Polyphasic analysis of the phenotypic and genotypic characteristics of the Finnish flexispira strains and the reference strains of taxa 2, 3 and 8 showed that they differed from other Helicobacter species and are members of the previously described species H. bilis. In addition, canine strain F56 differed in all phylogenetic analyses from the H. bilis group and probably represents a novel Helicobacter species.

Cytolethal distending toxin B gene (cdtB) homologues in taxa 2, 3 and 8 and in six canine isolates of Helicobacter sp. flexispira

The presence of the cytolethal distending toxin B gene (cdtB) was examined in eight Helicobacter sp. flexispira reference strains, Helicobacter trogontum ATCC 700114(T) and 12 Finnish porcine H. trogontum strains and canine flexispira isolates. Part of the cdtB gene was amplified by PCR with degenerate primers VAT2 and DHF1, cloned and sequenced. The presence/absence of the cdtB gene as determined by PCR was confirmed by Southern hybridization and toxin production by HeLa cell-line experiments. PCR amplification resulted in approximately 700 bp fragments from Helicobacter sp. flexispira taxa 2 (ATCC 49314), 3 (ATCC 49320) and 8 (ATCC 43880, ATCC 49308, ATCC 43879), from six canine isolates as well as from the control strains Helicobacter bilis and Helicobacter hepaticus. The hybridization patterns of HaeIII-, HindIII- and AseI-digested chromosomal DNA confirmed the results of the PCR experiments. The cdtB-positive strains had effects ranging from weak to strong on HeLa cell cultures. PCR amplification from the reference strains Helicobacter sp. flexispira taxa 1 (ATCC 43968), 4 (ATCC 49310) and 5 (ATCC 43966) and H. trogontum (ATCC 700114(T)), and also six of the Finnish strains, was unsuccessful. No toxic effect on HeLa cells was evident when bacterial suspensions of PCR-negative strains were used for toxicity assay. Our results are in accordance with previous observations that the cdtB gene is not present in all Helicobacter species. Further, the presence/absence of the cdtB gene in Helicobacter sp. flexispira strains was in accordance with recent taxonomic analysis of the same strains, which suggests that it could serve as a useful marker in Helicobacter taxonomy.

Helicobacter winghamensis sp. nov., a novel Helicobacter sp. isolated from patients with gastroenteritis.

From 1997 to 1999 seven isolates of Campylobacter-like organisms from five patients that were exhibiting symptoms of gastroenteritis, including fever, stomach malaise, and diarrhea, were investigated. The organisms were isolated from stool samples and found to exhibit a diverse colony morphology; hence multiple isolates were submitted from one of the patients. All isolates were found to be identical. The organisms were catalase, urease, alkaline phosphatase, and nitrate negative but oxidase and indoxyl acetate positive. They grew at 37 degrees C but not at 42 degrees C, and three of the isolates from two different patients were sensitive to nalidixic acid and cephalothin. Full 16S rRNA sequence analysis not only grouped these organisms within the Helicobacter genus but also differentiated them from previously identified Helicobacter species. The closest relative by phylogenetic analysis was Helicobacter sp. flexispira taxon 1. Electron microscopy showed that these isolates had one or two bipolar flagella; however, the periplasmic fibers, a characteristic of the known Helicobacter sp. flexispira taxa, were not observed. The present isolates also lacked a flagellar sheath, a trait shared with four other Helicobacter spp., H. canadensis, H. mesocricetorum, H. pullorum, and H. rodentium. On the basis of the unique phenotypic properties of these isolates and 16S rRNA sequence analysis, we propose the classification of a new Helicobacter species, Helicobacter winghamensis sp. nov.

Helicobacter sp. Flexispira Bacteremia in an Immunocompetent Young Adult

A young immunocompetent patient was admitted for a febrile illness with malaise, arthralgias, painful leg swelling, and polyserositis. Shortly prior to becoming ill, the patient had traveled to the Northern African desert. The symptoms disappeared during treatment with antibiotics (doxycycline and ceftriaxone) but recurred twice after stopping therapy. A motile gram-negative fusiform rod was isolated from a blood culture taken on the first admission. Analysis of the 16S rRNA gene of the blood culture isolate revealed close similarity with Helicobacter sp. flexispira taxon 8 (99.9% identity), a species that was previously reported as "Flexispira rappini." This is the first reported case of a recurrent Helicobacter sp. flexispira bacteremia in an adult, immunocompetent patient.