Evidence for a primate origin of zoonotic Helicobacter suis colonizing domesticated pigs.

Helicobacter suis is the second most prevalent Helicobacter species in the stomach of humans suffering from gastric disease. This bacterium mainly inhabits the stomach of domesticated pigs, in which it causes gastric disease, but it appears to be absent in wild boars. Interestingly, it also colonizes the stomach of asymptomatic rhesus and cynomolgus monkeys.

Detection of Helicobacter species in the gastrointestinal tract of ringtail possum and koala: possible influence of diet, on the gut microbiota.

The presence of Helicobacter spp. was examined in the liver and in different regions of the gastrointestinal tract (GIT) including the stomach, 3 cm above ileum, ileum, caecum, colon and rectum of 10 ringtail possums (RTPs) and 3 koalas using a combination of microscopy, culture and PCR. Helicobacter was detected in the distal end of the GIT of 7 of 10 RTPs by direct PCR and in all (10/10) RTPs by nested PCR.

Detection, isolation, and characterization of helicobacter species from the gastrointestinal tract of the brushtail possum.

The presence of Helicobacter species in Australian marsupials was examined systematically using microscopy, culture, and PCR in different regions of the gastrointestinal tract (GIT) and in the liver of brushtail possums (BTPs) (Trichosurus vulpecula), a common Australian marsupial that feeds on eucalyptus leaves. The spatial distribution of Helicobacter species in the GIT sections also was examined microscopically in silver-stained sections and by fluorescent in situ hybridization (FISH) using a Helicobacter genus-specific probe. Helicobacter species were found colonizing the lower bowel of all BTPs studied.

Gene expression profiling in Helicobacter-induced MALT lymphoma with reference to antigen drive and protective immunization.

We have previously shown that long-term infection of BALB/c mice with gastric Helicobacter species results in the development of histopathological lesions that resemble those seen in patients diagnosed with gastric mucosa associated lymphoid tissue (MALT) lymphoma. This paper describes analysis of this disease at the molecular level through the use of microarray technology and immunohistochemical staining. We were able to monitor the genetic changes in the gastric mucosa characterized by distinct transcriptional signatures and correlate these with histological changes as the infection progressed from a chronic inflammatory infiltrate through to MALT lymphoma.

Investigation of the immunomodulatory effects of Lactobacillus casei and Bifidobacterium lactis on Helicobacter pylori infection.

Background: Lactobacillus and Bifidobacterium species have shown beneficial effects in the treatment of Helicobacter pylori infection; however, the mechanisms behind such effects are not fully understood. In this study, we have investigated the immunomodulatory effects of probiotics in a mouse model of H. pylori infection.

Identification and characterisation of ssrA in members of the Helicobacter genus.

Bacterial ssrA encodes tmRNA that functions both as a tRNA and an mRNA to rescue the stalled ribosome on defective mRNAs. In this study, ssrA was identified in four gastric species of Helicobacters and four enterohepatic species of Helicobacters. The tag peptide of 14 amino acids encoded by ssrA showed a pattern of Val(1)Ala(13) in gastric species, a pattern of Ala(1)Val(13 )in enterohepatic species, in contrast to the pattern of Ala(1)Ala(13) in W.

Urea, fluorofamide, and omeprazole treatments alter helicobacter colonization in the mouse gastric mucosa.

Background: Helicobacter pylori is a causative agent of gastric and duodenal ulcers and gastric cancer. Its urease enzyme allows survival in acid conditions and drives bacterial intracellular metabolism. We aimed to investigate the role of urease in determining the intragastric distribution of Helicobacter species in vivo.

The role of antigenic drive and tumor-infiltrating accessory cells in the pathogenesis of helicobacter-induced mucosa-associated lymphoid tissue lymphoma.

Gastric B-cell lymphoma of mucosa-associated lymphoid tissue type is closely linked to chronic Helicobacter pylori infection. Most clinical and histopathological features of the tumor can be reproduced by prolonged Helicobacter infection of BALB/c mice. In this study, we have addressed the role of antigenic stimulation in the pathogenesis of the lymphoma by experimental infection with Helicobacter felis, followed by antibiotic eradication therapy and subsequent re-infection.

Mucispirillum schaedleri gen. nov., sp. nov., a spiral-shaped bacterium colonizing the mucus layer of the gastrointestinal tract of laboratory rodents.

The mammalian gastrointestinal tract is covered by a layer of mucus that can harbour a range of bacterial species specifically adapted to colonize this ecological niche. Examination of 110 bacterial isolates cultivated from the gastrointestinal tract of 23 mice revealed the presence of a subgroup of 30 isolates that did not correspond genetically with genera commonly associated with this site, i.e.

Description of 'Candidatus Helicobacter heilmannii' based on DNA sequence analysis of 16S rRNA and urease genes.

While Helicobacter pylori is accepted as the major bacterial agent of gastric disease in humans, some patients and many animals are infected with a larger, tightly helical-shaped bacterium previously referred to as 'Helicobacter heilmannii' or 'Gastrospirillum hominis'. Taxonomic classification of these bacteria has been hampered by the inability to cultivate them in vitro and by the inadequate discriminatory power of 16S rRNA gene sequence analysis. This study describes the detection and phylogenetic analysis of 26 different gastrospirillum isolates from humans and animals, which incorporates sequence data based on the 16S rRNA and urease genes.

Chronic Helicobacter pylori infection with Sydney strain 1 and a newly identified mouse-adapted strain (Sydney strain 2000) in C57BL/6 and BALB/c mice.

The mouse model of Helicobacter pylori-induced disease using Sydney strain 1 (SS1) has been used extensively in Helicobacter research. Herein we describe the isolation and characterization of a new mouse-colonizing strain for use in comparative studies. One strain capable of persistent mouse colonization was isolated from a total of 110 clinical isolates and is named here SS2000 (Sydney strain 2000).

Comparative chemical and biological characterization of the lipopolysaccharides of gastric and enterohepatic helicobacters.

Background: The lipopolysaccharide of Helicobacter pylori plays an important role in colonization and pathogenicity. The present study sought to compare structural and biological features of lipopolysaccharides from gastric and enterohepatic Helicobacter spp. not previously characterized.

Immunisation against Helicobacter felis infection protects against the development of gastric MALT Lymphoma.

Unlabelled: The formation of mucosa-associated lymphoid tissue (MALT) in response to Helicobacter pylori infection is closely associated with the development of primary gastric MALT lymphoma.

Aim: To examine whether immunisation against Helicobacter felis can protect against development of MALT lymphoma.

Results: The majority of control infected mice demonstrated MALT formation (13/15) and five developed lymphoma.

Protective immunity against Helicobacter is characterized by a unique transcriptional signature.

Immunization with a whole-cell sonicate vaccine of Helicobacter felis in conjunction with cholera toxin as a mucosal adjuvant induces long-term protective immunity in a majority of laboratory mice. We have combined gene expression profiling and immunohistochemical analysis on a set of immunized animals to better understand the mechanism of protection. The stomachs of protected animals exhibited a strikingly different transcriptional profile compared with those of nonprotected or control mice, indicating that vaccination targets the appropriate site and leaves a molecular signature.

Gastric transitional zones, areas where Helicobacter treatment fails: results of a treatment trial using the Sydney strain mouse model.

Current combination therapies cure Helicobacter pylori infection in 75 to 85% of cases. However, many treatment failures are not explained by antibiotic resistance. Our goal was to explore treatment failures under in vivo conditions by using the H.

Animal models of Helicobacter pylori infection and disease.

The acceptance of Helicobacter pylori as a major human pathogen has necessitated the development of animal models to help elucidate the pathogenic mechanisms of this bacterium and aid in the development of improved strategies for the treatment of gastric disease. Appropriate models, utilising a range of animal species, have been developed to examine factors such as the influence of host responses and bacterial factors in disease development and the success of new therapeutic regimens, including vaccination, to cure infection.

Distinct gene expression profiles characterize the histopathological stages of disease in Helicobacter-induced mucosa-associated lymphoid tissue lymphoma.

Long-term colonization of humans with Helicobacter pylori can cause the development of gastric B cell mucosa-associated lymphoid tissue lymphoma, yet little is known about the sequence of molecular steps that accompany disease progression. We used microarray analysis and laser microdissection to identify gene expression profiles characteristic and predictive of the various histopathological stages in a mouse model of the disease. The initial step in lymphoma development is marked by infiltration of reactive lymphocytes into the stomach and the launching of a mucosal immune response.

In vivo behavior of a Helicobacter pylori SS1 nixA mutant with reduced urease activity.

Helicobacter pylori mutants devoid of urease activity fail to colonize the gastric mucosa of mice; however, the effect of decreased levels of urease on colonization has not been examined. The nixA gene, required for full urease activity, encodes a cytoplasmic membrane nickel transporter that imports nickel ions and leads to incorporation of nickel ions into apourease. A nixA mutant of the Sydney strain of H.