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Effect of Helicobacter pylori eradication on extent of duodenal gastric metaplasia and grade of gastritis.

The extent of the regression of duodenal gastric metaplasia (DGM) after the eradication of Helicobacter pylori infection is controversial. Therefore, we decided to assess the degree of DGM before, sex weeks and one year after H. pylori eradication. 105 consecutive Helicobacter pylori positive patients with endoscopically proven duodenal ulcer, with DGM and Helicobacter pylori infection were recruited for this study. The diagnosis of Helicobacter pylori infection was based on CLO-test and histology, and DGM was assessed on four bulb biopsies taken before, sex weeks and one year after Helicobacter pylori eradication. Histological assessment of Helicobacter pylori associated gastritis was performed according to the Sydney classification. Follow up study on 98 patients before, six weeks and one year after the eradication of Helicobacter pylori showed that the mean extent of DGM did not change significantly after eradication and did not differ when compared with 14 patients with persisting infection. Our results show that the inflammatory process related to Helicobacter pylori does not play the main role in the development of DGM.

Duodenal Ulcer↗

The effectiveness of (IgG-ELISA) serology as an alternative diagnostic method for detecting Helicobacter pylori infection in patients with gastro-intestinal bleeding due to gastro-duodenal ulcer.

OBJECTIVES: To establish the sensitivity, specificity, positive predictive value and negative predictive value of serology (IgG ELISA) as an alternative diagnostic method for Helicobacter pylori infection in patients with gastro-duodenal peptic ulcer and digestive hemorrhage. The diagnosis of Helicobacter pylori infection in these patients is difficult due to the low sensitivity of invasive tests and the need to discontinue treatment with proton pump inhibitors to perform a breath test with urea 13C or the detection of Helicobacter pylori antigens in feces. PATIENTS AND METHODS: We included 214 patients (164 men and 50 women) with an average age of 58 +/- 15 years, who were admitted to hospital due to upper gastro-intestinal bleeding caused by a gastro-duodenal peptic ulcer. The presence of Helicobacter pylori was established by means of gastric biopsy (fast urease test histology and/or culture) and a breath test with 13C-labeled urea. Serology was performed with the ELISA method (Pyloriset EIA-G by Orion Diagnostica). Positive Helicobacter pylori infection was accepted with any positive invasive method or breath test, and no infection was established if all invasive tests performed and the breath test with 13C-labeled urea were negative. We calculated the sensitivity, specificity, positive predictive value and negative predictive value of serology in the global series and in different subgroups of patients according to age (> 60 and < 40 years), recent exposure to non-steroidal anti-inflammatory drugs, type of endoscopic wound and history of gastro-duodenal peptic ulcer. RESULTS: 192 patients (89.7%) showed infection due to Helicobacter pylori. In the global series (n = 214) we obtained a sensitivity, specificity, positive predictive value and negative predictive value of 87.5, 54.5, 94.3 and 33.3%, respectively. Specificity was greater in the group not exposed to non-steroidal anti-inflammatory drugs (n = 110) as compared to the exposed group (n = 104), in the < 40 year old group (n = 28) with respect to the > 60 years group (n = 105), in the duodenal ulcer group (n = 141) with respect to the gastric ulcer group (n = 59), and in the group with a history of gastro-duodenal peptic ulcers (n = 92) as compared to the group without any of these past events (n = 122); nevertheless, no significant statistics were reached. CONCLUSIONS: IgG (ELISA) serology shows low specificity and a low negative predictive value in the diagnosis of Helicobacter pylori infection in patients with gastro-intestinal bleeding due to gastro-duodenal peptic ulcer. The diagnostic value of serology did not improve significantly when age, recent exposure to non-steroidal anti-inflammatory drugs, type of endoscopic wound or history of gastro-duodenal peptic ulcer was taken into consideration. We may consider that serology is not a good diagnostic method for the detection of Helicobacter pylori in patients with digestive hemorrhage caused by gastro-duodenal ulcer.

Adolescent↗

Helicobacter pylori infection in hemodialysis patients.

BACKGROUND/AIMS: Studies on the relationship between high serum urea nitrogen, creatinine and Helicobacter pylori infection in hemodialysis patients still give conflicting results. In the present study we investigated the prevalence of Helicobacter pylori positivity in patients with hemodialysis [HD(+)] and without hemodialysis [HD(-)] and assessed the relationship between clinical factors, serum urea nitrogen, creatinine levels and Helicobacter pylori prevalence in these patients. METHODOLOGY: 117 patients with dyspeptic complaints were included in the study. They consisted of 36 HD(+) patients (31%) and 81 HD(-) patients (69%). Endoscopy was performed and gastric antral biopsies were obtained for immunohistochemical analysis for Helicobacter pylori in all patients. RESULTS: Helicobacter pylori was positive in 53(45%) of 117 patients [Hp(+)]. In univariate analysis Hp(+) patients received hemodialysis therapy significantly less often (P = 0.002) and had lower serum urea nitrogen (P = 0.0008) and creatinine (P = 0.003) levels than Hp(-) patients. There was no significant difference in age, gender, endoscopic findings or comorbid conditions (hypertension or diabetes mellitus) between these groups. Multivariate logistic regression analysis revealed that only the serum urea nitrogen level was significantly associated with Helicobacter pylori prevalence (P = 0.008). CONCLUSIONS: These results indicate that high serum urea nitrogen seems to correlate with a low prevalence of Helicobacter pylori infection and hemodialysis patients with high serum urea nitrogen may be protected against Helicobacter pylori infection.

Aged↗

Helicobacter spp. and liver diseases.

To test whether Helicobacter species play a role in the enhancement of liver necro-inflammation and fibrosis and in the development of hepatocellular carcinoma (HCC), we sought DNA sequences of Helicobacter species in liver specimens from patients with viral-related chronic hepatitis, HCC or metastatic liver carcinoma. We enrolled 28 consecutive patients with ultrasound evidence of hepatic nodule(s) on their first liver biopsy: 21 had histological evidence of HCC (Group I) and 7 of metastatic liver carcinoma (Group II). In the same period we observed 27 consecutive patients with chronic hepatitis on their first liver biopsy (Group III). Helicobacter sequences were sought by PCR using primers for the 16S rDNA of Helicobacter spp, designed to amplify a 400 base-pair fragment, and detected by 2% agarose gel and hybridization with a specific biotinylated probe. We used, as positive controls for the DNA extraction from liver tissue, hepatic biopsy sections in which HBV infection was confirmed by HBcAg positivity and in which we amplified HBV-DNA by specific primers; positive controls for the amplification of Helicobacter spp were obtained from gastric biopsy sections in which Helicobacter pylori infection was confirmed by biochemical and histochemical tests. HBV-DNA was found in all five HBcAg positive liver biopsies. Helicobacter spp 16S rDNA was detected in all five biopsy specimens of gastric mucosa and in none of liver specimens from patients in any group. Our data suggest that Helicobacter species were not involved in the pathogenesis of virus-related HCC, chronic hepatitis or liver carcinoma metastasis.

Adult↗

Helicobacter pylori in the etiology of cholesterol gallstones.

GOALS: We aimed to investigate the presence of bacterial structures in cholesterol gallstones and particularly presence of Helicobacter spp/H. pylori in gallstones by microbiologic cultivation, histopathologic staining, and polymerase chain reaction (PCR). BACKGROUND: Many studies suggest that different mechanisms are responsible for the formation of pigmented gallstones and cholesterol gallstones. Recently, studies showed that infection could have an important role in the formation of cholesterol gallbladder stones. STUDY: We examined 77 mixed cholesterol gallstones. After cholecystectomy, gallbladder cultures were done for H. pylori and other bacterium. Gallbladder has also been examined by three histopathologic staining methods (Warthin-Starry, hematoxylin eosin, and gram staining) for Helicobacter spp. In addition, 16S rRNA-PCR amplification was performed for Helicobacter spp in gallstones. Twenty postmortem gallbladders without gallstones were investigated by the same histopathologic and PCR methods for Helicobacter spp. as a control group. RESULTS: Different bacterium were isolated from 22 gallbladder samples (12 Escherichia coli, 8 Pseudomonas, and 2 clostridium) and H. pylori was isolated in 6 gallbladder samples. Helicobacter spp was found in 7 gallstones by PCR amplification. Helicobacter-like organisms were demonstrated in 18 samples by three different histopathologic methods. Helicobacter-like organisms were also found in five samples by the same histopathologic methods (Warthin-Starry, hematoxylin-eosin, and gram staining). Only four samples were found positive for Helicobacter spp/H. pylori by all methods. CONCLUSIONS: Bacterial population including H. pylori could have a possible role in the formation of cholesterol gallstones.

Adolescent↗

Increased risk for Helicobacter pylori recurrence by continuous acid suppression: a randomized controlled study.

BACKGROUND AND AIMS: Acid hyposecretion may enhance Helicobacter pylori colonization. We tested the hypothesis that maintenance therapy with ranitidine after cure of Helicobacter pylori infection increases the risk of recurrence of infection. PATIENTS AND METHODS: Sixty-six patients with duodenal ulcer and cured Helicobacter pylori infection were randomly assigned to 12 months maintenance treatment with ranitidine 150 mg daily (group A) or no treatment (group B). Follow-up consisted of clinical and endoscopic controls with biopsies for histology and rapid urease test every 4 months. RESULTS: Six patients, 3 in each group, were lost to follow up. Helicobacter pylori recurrence occurred in 9 patients in group A and in 2 patients in group B (30% versus 7%; p < 0.05). Duodenal ulcer recurred in one patient in group A and in 2 in group B, all three patients were reinfected with Helicobacter pylori. A corpus-predominant gastritis was observed in all reinfected patients in group A but in none in group B. CONCLUSIONS: Long-term inhibition of gastric acid secretion after eradication of Helicobacter pylori increases the risk of recurrence of infection. Our data imply that gastric acid not only influences the pattern of Helicobacter pylori localization in gastric mucosa, but also plays a key role in preventing recurrence of infection with Helicobacter pylori.

Adult↗

Epithelial-cell apoptosis and proliferation in Helicobacter pylori-related chronic gastritis.

BACKGROUND: Several studies have shown that Helicobacter pylori infection is associated with enhanced gastric epithelial-cell proliferation, which is thought to be involved in its apparent carcinogenicity. This hyperproliferation is believed to be related to the inflammatory effects of the bacterium. The role of Helicobacter pylori in gastric epithelial apoptosis, however, is less clear. AIM: We attempted to identify the effect of Helicobacter pylori infection on apoptosis in the gastric epithelium and its possible relation to epithelial-cell proliferation and mucosal inflammation. PATIENTS AND METHODS: We studied cell proliferation (via bromodeoxyuridine labelling), apoptosis (using in situ TdT-mediated dUTP-biotin nick end labelling of DNA strand breaks) and mononuclear and polymorphonuclear cell infiltrates (computer-assisted image analysis) in gastric antral biopsies obtained from 37 gastritis patients (20 Helicobacter pylori-positive, 17 Helicobacter pylori-negative). RESULTS: Helicobacter pylori-positives displayed significantly enhanced proliferation within the gastric epithelium that was positively correlated with both acute and chronic inflammatory-cell densities. Apoptotic indexes were similar in both groups and showed no correlation with any of the parameters under consideration. CONCLUSIONS: Enhanced epithelial cell proliferation and an altered distribution of cycling cells within the gastric glands are a common feature of chronic superficial gastritis caused by Helicobacter pylori. In vivo immunohistochemically detected apoptosis of gastric epithelial cells does not seem to be affected by Helicobacter pylori infection. Further study is needed to clarify the effect of this infection on programmed cell death within gastric glands.

Adult↗

Detection and effects of helicobacters in healthy dogs and dogs with signs of gastritis.

OBJECTIVES: To determine prevalence, colonization density, and distribution of helicobacters and gastric histologic findings in healthy dogs and dogs with signs of gastritis; to evaluate association of colonization density and gastric inflammation; and to compare the number of Helicobacter spp with degree of inflammation. DESIGN: Cross-sectional prevalence survey. ANIMALS: 25 healthy dogs and 21 dogs with signs of gastritis. PROCEDURE: During endoscopy, gastric mucosal biopsy specimens were obtained from healthy and affected client-owned dogs. Histologic and cytologic evaluation and results of a urease test were used for detecting helicobacters, which were identified definitively by use of transmission electron microscopy and bacterial culture. RESULTS: Helicobacters were detected in all 25 healthy and 20 of 21 affected dogs. Cytologic examination was a more sensitive method than histologic examination or the urease test. Helicobacters were found least frequently and in fewest number in the antrum in both groups of dogs. Gastric inflammation was evident in both groups of dogs and did not differ significantly between groups. A significant association was not detected between colonization density or the number of Helicobacter spp and degree of gastric inflammation. In both groups, H bizzozeronii, H felis, and H salomonis were cultured. CLINICAL IMPLICATIONS: Histologically verified chronic gastritis is common in dogs with signs of gastritis as well as in healthy dogs. Colonization density of helicobacters was not associated with degree of gastric inflammation in the dogs of our study. It remains to be determined whether certain strains of Helicobacter spp can induce gastritis in dogs.

Animals↗

[The attitude of primary health care physicians in the metropolitan area of Barcelona about the diagnosis and treatment of Helicobacter pylori infection in gastroduodenal diseases].

AIM: To evaluate the attitude of primary health care physicians versus the diagnosis and treatment of infection by Helicobacter pylori in patients with dyspepsia and gastroduodenal ulcer. DESIGN: An observational, transversal study was performed by a self administered questionnaire from June to October, 1997. PARTICIPANTS: Primary health care physicians from 38 reformed Medical Centers in the metropolitan area of Barcelona were included in the study. RESULTS: Of the 359 doctors to whom the questionnaire was sent, 283 responded (78.8%). In a patient with dyspepsia 95.4% would first request endoscopy. If they knew of the presence of infection by Helicobacter pylori 96.1% would administer eradication treatment in patients with gastric and duodenal ulcer and 15% would also do so if the endoscopy were normal. If the presence of infection by Helicobacter pylori were unknown in a patient with gastroduodenal ulcer, 65.3% would treat with anti-H2 or proton pump inhibitors associated with a diagnostic test of infection by Helicobacter pylori. If the physician decided to carry out eradication treatment of Helicobacter pylori infection, 98.6% would use one of the regimes recommended by different scientific societies. If confirmation of eradication of Helicobacter pylori infection were requested, 89% would do so one and three months after completion of treatment. In patients with gastric ulcer, 69.3% would request endoscopy on completion of treatment. The percentage of physicians specialized in Family and Community Medicine who would carry out eradication treatment in patients with duodenal ulcer and Helicobacter pylori infection and who would request endoscopies in patients with dyspepsia was found to be statistically significant in comparison with physicians without this specialty. CONCLUSIONS: The attitude of primary care physicians in the metropolitan area of Barcelona with regard to the diagnosis and treatment of infection by Helicobacter pylori in gastroduodenal diseases largely reflects the recommendations recently made by several scientific societies. In general there are no significant differences with respect to this attitude in regard to the age and sex of the physician, although their training was found to influence in some of the responses analyzed.

Adult↗

The rapid detection of low molecular mass proteins differentially expressed under biological stress for four Helicobacter spp. using ProteinChip technology.

Helicobacter pylori is one of the most prevalent human pathogens in the world and is the aetiological agent of gastritis, peptic ulcer disease and gastric malignancies. In addition H. pylori and other novel members of the genus are capable of successfully colonising the bile-rich niche of the upper intestine and are associated with a diverse range of intestinal pathologies. Surface-enhanced laser desorption/ionisation-time of flight mass spectrometry was used to analyse surface extracts from H. pylori, Helicobacter bilis, Helicobacter pullorum and "Helicobacter sp. flexispira" to characterise cell surface changes following bile stress. The system detected two distinct response patterns to bile stress on the cell surface of Helicobacter spp. in vitro. The first involved the increase under bile stress of peaks at 7.6 and 7.9 kDa for H. billis and H. pullorum, respectively. In contrast both "Helicobacter sp. flexispira" and a clinical isolate of H. pylori had similar response profiles to bile stress. Both strains had at least three low mass peaks decreased under bile stress and a single peak induced by bile stress. The present study has established the use of ProteinChip(R) technology to analyse helicobacter-related proteomics. Specifically this study has established that different patterns are generated in response to bile stress among various pathogenic Helicobacter spp. which may give insights into the ability of these strains to colonise different niches.

Bile↗

Detection of Helicobacter species in the gastrointestinal tract of wild rodents from Brazil.

Since we have limited knowledge about the occurrence of Helicobacter in wild animals, we searched for Helicobacter species in the gastrointestinal tract of 75 rodents captured in forest remnants of Minas Gerais, Brazil. Fragments from the antrum and corpus of the stomach and from the colon were taken for PCR assays for Helicobacter detection. Although gastric mucosa was Helicobacter-positive in only one animal, the bacterium was detected in the colonic mucosa of 23 rodents (30.7%). Helicobacter detection was more frequent in the colon of terraced rice rat (56%) and house rat (30%) in contrast to punare and Spix's yellow-toothed cavy, in which the presence of the bacterium was not detected. Helicobacter rodentium, H. marmotae, H. cinaedi, and other species closely related to the murine helicobacters were presumptively identified by DNA sequencing. Wild rodents may serve as a reservoir of these Helicobacter species in nature.

Animals↗

Detection of identical Helicobacter DNA in the stomach and in the non-cirrhotic liver of patients with hepatocellular carcinoma.

OBJECTIVES: Studies have implied the presence of Helicobacter species in the human liver. The possible relationship between the presence of Helicobacter species in the non-cirrhotic liver of patients with hepatocellular carcinoma (HCC) and the detection of Helicobacter species in their stomach was explored. PATIENTS AND METHODS: A 16S rDNA-based polymerase chain reaction (PCR) followed by DNA sequence analysis of the obtained PCR fragments was performed on 51 surgically obtained non-cirrhotic liver specimens and 14 gastric samples. RESULTS: Analysis indicated a significant difference in the presence of Helicobacter-species-specific DNA in the liver of patients with HCC compared with controls. Sequence analysis of these PCR products obtained from HCC patients indicated that they were related most closely to the 16S rDNA sequence of Helicobacter pylori but that they always differed at the same two positions. This same aberrant Helicobacter-species-specific 16S rDNA could be isolated in gastric samples of patients with HCC. CONCLUSION: These data suggest that gastric colonization with a specific subset of Helicobacter strains is associated with the induction of HCC, either directly via colonization of the liver or indirectly, e.g. via secretion of specific toxins by Helicobacter residing in the stomach.

Carcinoma, Hepatocellular↗

Influence of activated charcoal, porcine gastric mucin and beta-cyclodextrin on the morphology and growth of intestinal and gastric Helicobacter spp.

Bile-tolerant Helicobacter spp. are emerging human and animal pathogens. However, due to their fastidious nature, which requires nutrient-rich complex media to grow, infection with these bacteria may be underestimated. The accumulation of toxic metabolites in cultures may be one of the main obstacles for successful culture of these organisms. The present study examined various potential growth-enhancing substances for Helicobacter spp. and, furthermore, how they may affect spiral to coccoid conversion. Five Helicobacter spp. were cultured on agar and in broth media supplemented with activated charcoal, beta-cyclodextrin, or porcine gastric mucin. Growth was determined by estimating the numbers of colony-forming units and colony diameter, as well as bacterial cell mass. Coccoid transformation was estimated every 24 h by both Gram and acridine-orange staining. Activated charcoal was superior in supporting growth and increased cell mass on agar and in broth media. beta-Cyclodextrin delayed spiral to coccoid conversion by Helicobacter pylori and Helicobacter canis, whereas activated charcoal delayed the conversion to coccoid forms of Helicobacter hepaticus and Helicobacter bilis. The progression to coccoid forms by Helicobacter pullorum on agar media was not influenced by any growth supplement. The spiral to coccoid conversion was more rapid in broth media than on agar media. The growth enhancement observed is probably related to the capacity of activated charcoal to remove toxic compounds in culture media.

Animals↗

Detection of Helicobacter ganmani-like 16S rDNA in pediatric liver tissue.

BACKGROUND: To determine the presence of Helicobacter species in the liver biopsy specimens from children with various chronic liver diseases as data in adult literature suggests a possible role of these bacteria in their pathogenesis. MATERIALS AND METHODS: Paraffin sections of 61 liver biopsies of pediatric patients with miscellaneous diseases and autopsy liver tissue from 10 control subjects with no evidence of preexisting liver disease were examined for the presence of Helicobacter species by a genus-specific seminested polymerase chain reaction (PCR) assay. PCR-products of positive samples were further characterized by denaturing gradient gel electrophoresis (DGGE) and DNA-sequence analysis. Based on those results, a seminested PCR assay for H. ganmani was developed and applied to the samples. RESULTS: On analysis, 40/61 patient samples were positive in the genus-specific Helicobacter PCR and 4/10 from the control group. The nucleotide sequences of 16S rDNA fragments were 99-100% similar to mainly Helicobacter sp. 'liver' and H. ganmani. PCR-products similar to H. canis and H. bilis were also found. The 16S rDNAs of control specimens showed similarity to Helicobacter sp. 'liver'. In the H. ganmani-specific PCR analysis 19 patients, but none of the controls, were positive. CONCLUSIONS: Amplified Helicobacter 16S rDNAs were related to Helicobacter sp. 'liver' or H. ganmani in liver biopsy specimens of pediatric patients. The possible significance of Helicobacter species in pediatric liver diseases needs to be evaluated further in prospective studies.

Adolescent↗

[An evaluation of a nutrient medium for isolating and cultivating Helicobacter pylori].

Selective Helicobacter agar containing the selective supplement and blood, adding ex tempore, for the isolation and cultivation of H. pylori was developed. The Helicobacter agar was studied with the use of 5 newly isolated H. pylori strains, 13 bacterial associated cultures, as well as 21 inoculated biopsy specimens of the gastric and duodenal mucosa of patients with peptic ulcer. The study revealed that Helicobacter agar ensured the growth of H. pylori and their isolation from clinical material. The positive results after the inoculation of the specimens of biopsy material on Helicobacter agar and control media was 85%. In addition, the study of Helicobacter agar showed that it also exhibited pronounced selective properties with respect to bacterial associations, not inhibiting the growth of Helicobacter organisms and retaining their main biological properties. It is possible to recommend Helicobacter agar for use in laboratory practice in diagnosing Helicobacter-associated diseases.

Agar↗

Low molecular weight protein of Helicobacter pylori and its relation to gastroduodenal diseases.

BACKGROUND/AIMS: In Taiwan, CagA and VacA cannot be used as markers to evaluate the risk of developing serious gastroduodenal pathogenesis in the hosts. Recent research suggests that the low molecular weight proteins, 35kDa and 19kDa, in Helicobacter pylori may be related to duodenal ulcers and gastric MALToma (mucosa-associated lymphoid tissue lymphoma) respectively. The aims of this study were to examine the sero-prevalence of antibodies against specific Helicobacter pylori antigen in patients with different gastroduodenal diseases and further to find possible virulence factor(s) associated with the development of clinically relevant disease in Helicobacter pylori-infected subjects in Taiwan. METHODOLOGY: Sera were obtained from 108 patients, of which 22 had gastric adenocarcinoma, 31 had non-ulcer dyspepsia and 65 had peptic ulcer disease. The sera were analyzed for specific Helicobacter pylori antigen by using one commercial kit (HelicoBlot 2.0, Genelabs Diagnostic, Singapore, HB2.0). Helicobacter pylori infection was confirmed when the culture was positive or when any two of the other three tests (biopsy CLO test, histology and 13C-urea breath test) were positive. RESULTS: The data showed a high prevalence of CagA and VacA proteins [CagA(+): gastric adenocarcinoma--88.1%, non-ulcer dyspepsia--87.1%, peptic ulcer disease--91%; VacA(+): gastric adenocarcinoma--78.6%, non-ulcer dyspepsia--58.1%, peptic ulcer disease--71.4%] in Taiwan. This is similar to the findings in other Chinese and Taiwanese studies. No significant difference was found among the three groups (P > 0.05) for any Helicobacter pylori protein. We found that antibody responses to the 26.5-kDa and 116-kDa (CagA) antigens were most prevalent in the peptic ulcer disease group. Consequently, we analyzed two special phenotypes, which have simultaneous presence in bands at 116 and 26.5kDa. The phenotype [116-kDa (+) and 26.5kDa(+)] predicted the risk of peptic ulcer disease with 76.7% sensitivity and 62% specificity. CONCLUSIONS: We confirm the universal prevalence of CagA and VacA-positive Helicobacter pylori infection in Taiwan independent of disease. Although we did not find any single specific Helicobacter pylori protein which could act as an indicator of clinical outcome, we found a possible marker of peptic ulcer disease which may be acceptable. This is the phenotype with simultaneous presence in bands at 116kDa and 26.5kDa protein. Our report differs from some previous reports from other regions. This may reflect differences of race and geography.

Adenocarcinoma↗

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. Fifteen gastrospirilla detected in humans, primates and pigs clustered with 'Candidatus Helicobacter suis', thus expanding the host range for this organism. By comparison, based on 16S rRNA data, the remaining 11 gastrospirilla could not be differentiated from Helicobacter felis, Helicobacter bizzozeronii and Helicobacter salomonis. However, urease gene sequence analysis allowed for the discrimination of this latter group into four discrete clusters, three of which contained the above recognized species. The fourth cluster contained isolates from human and feline hosts, and should provisionally be considered a unique bacterial species, for which the name 'Candidatus Helicobacter heilmannii' is proposed.

Adult↗

Visualization of Helicobacter species within the murine cecal mucosa using specific fluorescence in situ hybridization.

BACKGROUND: Members of the genus Helicobacter have been associated with colitis development in a number of immunodeficient animal models. While it is known that these organisms can initiate colitis development, the location and spatial distribution of these bacteria within the intestinal tract is currently unknown. In this study, we developed and optimized fluorescence in situ hybridization (FISH) probes specifically for Helicobacter species. MATERIALS AND METHODS: Based on 16S-RNA gene alignments, two probes specific for the entire family Helicobacteraceae and two probes specific for Helicobacter ganmani and Helicobacter hepaticus were designed. Evaluation of these probes was determined using ATCC reference strains and cecum samples from ten IL-10 knockout mice. The presence of Helicobacter species was determined using FISH and verified using PCR-DGGE and microscopic examination of silver stained sections. RESULTS: Analysis of the ATCC reference strains revealed that the probes HEL274/HEL717 were specific for the family Helicobacteraceae, while HEP642 was specific for H. hepaticus and GAN1237 for H. ganmani. Using these probes, a pattern of spatial localization of the two different Helicobacter species was observed in the cecum tissues of IL-10 knockout mice. This consistently showed that H. ganmani was localized to the lower regions and H. hepaticus to the mid-upper regions of the crypts. CONCLUSION: We have developed FISH probes specific for the family Helicobacteraceae as well as two individual Helicobacter species. This study will allow the future use of the FISH to better understand host-pathogen interactions in vitro.

Animals↗