Helicobacter canis isolated from a dog liver with multifocal necrotizing hepatitis

Helicobacter pylori seroprevalence in patients with cirrhosis of the liver and hepatocellular carcinoma

BACKGROUND

Infection by Helicobacter hepaticus causes chronic hepatitis and hepatocellular carcinoma (HCC) in mice, and Helicobacter pylori (H. pylori) genomic sequences have been demonstrated in the liver of patients with HCC. H. pylori infection reportedly occurs with high frequency in patients with cirrhosis but none of the studies has investigated it in subjects with cirrhosis and superimposed HCC. In this case-control study, we searched for the seroprevalence of H. pylori infection in patients with HCC.

PATIENTS AND METHOD

Forty-six patients (30 males, 16 females, mean age 69 years) with HCC and hepatitis C virus (HCV)-related cirrhosis were compared to 46 sex and age (+/-1 year) matched patients presenting consecutively to the Emergency Department of Molinette Hospital of Torino. All subjects were tested for presence in serum of IgG antibodies against H. pylori and the result was analyzed using the chi-square test.

RESULTS

H. pylori seropositivity was more prevalent among patients with HCC (36/46, 78.2%) than in controls (25/46, 54%) (P<0.05) (OR 3.02, 95% confidence interval ). Twenty-five out of 30 (83.3%) male patients showed seropositivity at a variance with 16/30 (53%) in the controls (P<0.05); 11 out of 16 (68.7%) female patients were seropositive versus 9 out of 16 (56.2%) control subjects (P=n.s.).

CONCLUSION

Seroprevalence of antibodies to H. pylori was found to be higher in patients with HCC than in controls.

Association of the presence of Helicobacter in gallbladder tissue with cholelithiasis and cholecystitis

The presence of Helicobacter DNA species has been investigated in the biliary epithelium of patients with biliary diseases. However, conflicting results have been observed that may have been due to the small number of subjects studied, difficulty in obtaining a healthy control group, absence of controlling for confounding factors, or differences among populations. Therefore, we investigated the presence of Helicobacter species by culture and nested PCR of 16S rRNA genes in gallbladder tissue and bile from 46 Brazilian subjects with and 18 without cholelithiasis. The control group was mainly composed of liver donors and of patients who had submitted to cholecystectomy as part of the surgical treatment for morbid obesity. No Helicobacter species were grown from the bile or gallbladder tissues. Helicobacter DNA was detected in the gallbladder tissue and bile from 31.3 and 42.9% of the patients, respectively. In a logistic regression model, cholelithiasis was positively and independently associated with the female gender (P = 0.02), increasing age (P = 0.002), and the presence of Helicobacter DNA in the gallbladder tissue (P = 0.009). The presence of Helicobacter DNA in the bile was not associated with cholelithiasis (P = 0.8). A significant association between the presence of Helicobacter DNA in the gallbladder epithelium and histological cholecystitis, even after adjusting for gender and age (P = 0.002), was also observed. The sequences of the 16S rRNA genes were >99% similar to that of Helicobacter pylori. In conclusion, our results support the hypothesis that Helicobacter is associated with the pathogenesis of human cholelithiasis and cholecystitis.

Hepatic changes in mice chronically infected with Helicobacter trogontum

We infected NIH germ-free female mice with Helicobacter trogontum, a recently described intestinal bacterium of rats, in order to study the lesions it induced in the liver of this host. Fifteen mice were challenged with a single dose of H. trogontum (test group) and killed 6, 12 and 18 months after inoculation (5 animals/group). Nine animals were challenged with 0.85% saline alone (control group) and killed at the same times. Fragments from the liver, cecum and colon were obtained for microbiologic and histologic examination. Stool samples were also collected. H. trogontum was detected in the cecum, colon and/or stool samples of all test mice. As expected, the bacterium was not isolated from any specimen obtained from the control animals. On the other hand, although we could not cultivate the bacterium from the liver, 13 test animals (86.7%) presented histological changes in this organ. The 6-month group presented infiltration of mononuclear and polymorphonuclear cells in the hepatic parenchyma and the two other groups presented foci of mononuclear cells. The results suggest that H. trogontum can elicit a hepatic inflammatory response in mice since the only difference between control and test animals was the presence of H. trogontum in the latter. This result, together with the growing number of related reports in the literature, reinforces the possible role of Helicobacter infection in the pathogenesis of hepatobiliary diseases.

Helicobacter DNA in bile: correlation with hepato-biliary diseases

BACKGROUND

Helicobacter has been identified in isolated cases of hepato-biliary diseases, but its role in the pathogenesis of these conditions remains unclear.

AIM

To determine whether Helicobacter could be detected in bile obtained at endoscopic retrograde cholangiopancreatography, and to evaluate the prevalence of this infection in patients with hepato-biliary diseases.

METHODS

Bile was collected from 125 patients with various hepato-biliary diseases undergoing endoscopic retrograde cholangiopancreatography. Among them, 75 were diagnosed with biliary stones, 15 with pancreatico-biliary malignancies and four with primary sclerosing cholangitis. The detection of Helicobacter in DNA extracted from these bile samples was performed using Helicobacter genus-specific primers (capable of detecting 100-1000 organisms/mL).

RESULTS

Helicobacter was detected in all positive controls. Only three samples had polymerase chain reaction inhibitors. All remaining bile samples (122 patients with hepato-biliary diseases) were negative for Helicobacter DNA.

CONCLUSIONS

Helicobacter can be detected in bile samples using polymerase chain reaction. This infection, however, was not present in any of our patients diagnosed with gallstones or hepato-biliary malignancies, raising doubt as to the possible association between Helicobacter and these entities. Given the low sample size of patients with primary sclerosing cholangitis, more studies are required to determine whether an association exists with this condition.

A group-specific PCR assay for the detection of Helicobacteraceae in human gut

BACKGROUND

Enterohepatic Helicobacter species are emerging pathogens, which are increasingly isolated from humans with enteric diseases. Nevertheless, current methods to detect Helicobacteraceae in the human gut have significant limitations.

METHODS

Based on 16S-rRNA gene alignments and computer aided primer analysis a set of group-specific PCR primers was designed. The evaluation of the PCR assay was performed using 36 ATCC reference strains and intestinal biopsies from 10 patients with defined gastric Helicobacter pylori status. The amplification products derived from clinical samples were cloned and subsequently analyzed by DNA sequencing. Sensitivity of the PCR-assay was determined by spiking previously negative tested samples with decreasing amounts of Helicobacter DNA.

RESULTS

The analysis of the ATCC reference strains revealed amplification products in all 14 Helicobacter strains and Wolinella succinogenes, 21 other microorganisms representing negative controls did not produce PCR fragments. Four out of the 10 patient-derived samples were positive. Three of them represented H. pylori-derived DNA confirming the gastric H. pylori infection in these patients. In the fourth patient, who was suffering from Crohn's disease, H. pullorum was identified. The sensitivity of the PCR assay was 0.1 pg of Helicobacter-derived DNA representing about 40 bacteria.

CONCLUSION

The novel PCR assay described here is an important new tool in rapid and sensitive assessment for the presence of Helicobacteraceae in human gut.

Helicobacter marmotae sp. nov. isolated from livers of woodchucks and intestines of cats

Woodchucks (Marmota monax) have a high incidence of hepatocellular carcinoma (HCC) associated with chronic infection with woodchuck hepatitis virus (WHV) and serve as a model of hepatitis B virus-associated HCC in humans. Helicobacter hepaticus, an enterohepatic helicobacter in mice, is known to cause hepatocellular adenomas and carcinomas in susceptible mouse strains. In long-term chemical bioassays conducted with B6C3F(1) mice, H. hepaticus has been regarded as a confounding factor because of its tumor-promoting activity. In order to determine if woodchucks harbor a Helicobacter sp. that might play a role in potentiating hepatic inflammation or neoplasia, a study was undertaken to determine whether woodchucks' livers were infected with a Helicobacter sp. Frozen liver samples from 20 (17 WHV-infected and 3 noninfected) woodchucks, 10 with WHV-associated hepatic tumors and 10 without tumors, were cultured by microaerobic techniques and analyzed by using genus- and species-specific helicobacter PCR primers. A 1,200-bp Helicobacter sp.-specific sequence was amplified from 14 liver samples. Southern hybridization confirmed the specific identity of the PCR products. Nine of the 10 livers with tumors had positive Helicobacter sp. identified by PCR, whereas 5 of the 10 livers without tumors were positive. By use of 16S rRNA species-specific primers for H. marmotae, two additional liver samples from the nontumor group had positive PCR amplicons confirmed by Southern hybridization. A urease-, catalase-, and oxidase-positive bacterium was isolated from one liver sample from a liver tumor-positive woodchuck. By 16S rRNA analysis and biochemical and phenotypic characteristics, the organism was classified as a novel Helicobacter sp. Subsequently, four additional bacterial strains isolated from feces of cats and characterized by biochemical, phenotypic, and 16S rRNA analysis were determined to be identical to the woodchuck isolate. We propose the name Helicobacter marmotae sp. nov. for these organisms. Further studies are required to ascertain if this novel Helicobacter sp. plays a tumor promotion role in hepadnavirus-associated tumors in woodchucks or causes enterohepatic disease in cats.

Helicobacter infection in patients with HCV-related chronic hepatitis, cirrhosis, and hepatocellular carcinoma

Chronic hepatitis may progress to cirrhosis and hepatocellular carcinoma (HCC). HCC represents one of the most common human cancers. Incidence rates for this tumor vary widely on a worldwide, suggesting that environmental factors such as infectious microorganisms, carcinogens, or nutrition play a role in its pathogenesis. Several Helicobacter spp. colonize the liver of animals and induce hepatitis. The aim of this study was to determine whether Helicobacter infection was associated with HCV-related liver diseases in humans. Liver tissue samples, including biopsy and surgically excised tissues, were collected from patients positive for hepatitis C viruses (HCV) RNA in the serum. Genomic DNA was extracted from sections of formalin-fixed paraffin-embedded tissues by using the QIAamp Tissue Kit and subjected to polymerase chain reaction (PCR) analysis using two sets of Helicobacter-specific 16S ribosomal RNA primers. To identify positive samples for H. pylori, a set of primers specific for a conserved region in the H. pylori vacA gene were also used. The patients' H. pylori status was determined by ELISA. Forty-one patients (mean age 54.9, range 19-78 years; 24 men) were studied. Thirty patients had chronic viral hepatitis (CH) without (N = 18) or with (N = 12) cirrhosis (CIR), and 11 patients had HCC. Anti-H. pylori IgG was detected in 54%. The expected 422- and 210-bp fragments of Helicobacter 16S rRNA were amplified from 27% of liver samples, including 17% of CH-CIR and 55% of HCC (P = 0.004). The vacA sequence was amplified in 10 of 41(24%) samples (27% of those with HCC). These data confirm the presence of H. pylori DNA sequences in human liver and suggest an association of Helicobacter spp. with HCV-related chronic liver diseases. Further studies are needed to ascertain whether Helicobacter spp. infection plays a role in the development of HCC.

Helicobacter infection in patients with HCV-related chronic hepatitis, cirrhosis, and hepatocellular carcinoma

Chronic hepatitis may progress to cirrhosis and hepatocellular carcinoma (HCC). HCC represents one of the most common human cancers. Incidence rates for this tumor vary widely on a worldwide, suggesting that environmental factors such as infectious microorganisms, carcinogens, or nutrition play a role in its pathogenesis. Several Helicobacter spp. colonize the liver of animals and induce hepatitis. The aim of this study was to determine whether Helicobacter infection was associated with HCV-related liver diseases in humans. Liver tissue samples, including biopsy and surgically excised tissues, were collected from patients positive for hepatitis C viruses (HCV) RNA in the serum. Genomic DNA was extracted from sections of formalin-fixed paraffin-embedded tissues by using the QIAamp Tissue Kit and subjected to polymerase chain reaction (PCR) analysis using two sets of Helicobacter-specific 16S ribosomal RNA primers. To identify positive samples for H. pylori, a set of primers specific for a conserved region in the H. pylori vacA gene were also used. The patients' H. pylori status was determined by ELISA. Forty-one patients (mean age 54.9, range 19-78 years; 24 men) were studied. Thirty patients had chronic viral hepatitis (CH) without (N = 18) or with (N = 12) cirrhosis (CIR), and 11 patients had HCC. Anti-H. pylori IgG was detected in 54%. The expected 422- and 210-bp fragments of Helicobacter 16S rRNA were amplified from 27% of liver samples, including 17% of CH-CIR and 55% of HCC (P = 0.004). The vacA sequence was amplified in 10 of 41(24%) samples (27% of those with HCC). These data confirm the presence of H. pylori DNA sequences in human liver and suggest an association of Helicobacter spp. with HCV-related chronic liver diseases. Further studies are needed to ascertain whether Helicobacter spp. infection plays a role in the development of HCC.

The role of microorganisms in biliary tract disease

The biliary tract is normally sterile, but bile-tolerant bacteria are frequently isolated from patients with cholecystitis. Since the identification of about 25 Helicobacter species, some of which may grow in bile, studies have addressed the role of these organisms in primary biliary cirrhosis, primary sclerosing cholangitis, and cholelithiasis. Most of these bacteria show the presence of Helicobacter DNA or antigens in the bile tract and in liver samples. Altogether, data from studies on biliary and hepatic diseases, as well as pancreatic disorders, suggest that bile-tolerant Helicobacter species may induce a chronic infection with possible malignant transformation.

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.

The non-H pylori helicobacters: their expanding role in gastrointestinal and systemic diseases

The number of species in the genus Helicobacter has rapidly expanded over the past decade. The genus now includes at least 24 formally named species as well as numerous other helicobacters awaiting formal naming. This review highlights the expanding role that other helicobacters, although not as well known as H pylori, play in gastrointestinal and systemic disease in humans.

Classification of a Brevundimonas strain detectable after PCR with a Helicobacter-specific primer pair

In a study for the isolation of new Helicobacter strains, biopsy samples were taken from the gastric mucosa of dogs and subjected to PCR amplification using a Helicobacter-specific primer pair (H276f and H676r, directed to the 16S rDNA) to identify members of this genus in the specimens. From one Helicobacter positive sample, a bacterial strain was isolated which displayed a characteristic band after PCR amplification with the Helicobacter-specific primer pair. The isolate designated H2/98-FUNDUS was motile, oxidase-, catalase- and aminopeptidase-positive and grew only under microaerophilic conditions at 37 degrees C. The bacterium was classified by a polyphasic approach, including analysis of the isoprenoid quinones, fatty acids, polar lipids and partial 16S rDNA sequence. Analysis of the 16S rDNA sequence (1003 bases) indicated that the strain H2/98-FUNDUS is a member of the genus Brevundimonas and most closely related to Brevundimonas aurantiaca DSM 4731T (99.5% sequence similarity). Isolate H2/98-FUNDUS contained a predominant ubiquinone Q-10 and a fatty acid profile with the major compounds C18:1 and C16:0. In the polar lipid extract, phosphatidylglycerol, six unknown phospholipids, one unknown phosphoglycolipid, two unknown glycolipids and two unknown aminolipids were detected. All these results indicate that H2/98-FUNDUS represents a new member of the genus Brevundimonas which gives a positive signal upon PCR employing the Helicobacter-specific primer pair.

Identification of novel Helicobacter species in pig stomachs by PCR and partial sequencing

Evidence of infection with Helicobacter species in pig stomach was investigated by the use of a PCR with Helicobacter genus-specific primers. Forty pig stomachs, each of four different ulcer lesion grades, 0, 1, 2, and 3 in the pars esophagea area, were collected from a slaughterhouse in Minnesota. Of 160 stomach samples examined, 102 (63.8%) were positive by the PCR assay. The 40 samples each of lesion grades 0, 1, 2, and 3 showed 22.5, 52.5, 85.0, and 95.0% PCR-positive results, respectively. There was a significant trend (P < or = 0.01) in the proportions of PCR-positive cases relative to severity of the lesion. About 80% of the 16S rRNA gene was amplified, and PCR-restriction fragment length polymorphism (RFLP) patterns were analyzed. Of 102 PCR-positive samples, the PCR-RFLP patterns resulted in four different types, 32 samples being classified into type MN 1, 16 samples into type MN 2, 43 samples into type MN 3, and 11 samples into type MN 4. When the sequences of each RFLP type were compared to those reported in databases by using BLAST software, types MN 1, MN 2, MN 3, and MN 4 showed homologies of 97.3, 95.4, 96.7, and 99.5% with the 16S ribosomal DNA of Helicobacter flexispira taxon 3, Helicobacter sp. strains MIT 94-022 and MZ 640285, and Helicobacter suis, respectively. None of the 102 samples positive for the Helicobacter genus were positive with a primer set specific for Helicobacter pylori. Attempts to culture the organisms from selected stomachs in vitro were unsuccessful.

Coinfection of enteric Helicobacter spp. and Campylobacter spp. in cats

During a 6-year period, 64 of 227 commercially reared cats had microaerobic bacteria isolated from their feces. All the isolates were initially identified as Campylobacter-like organisms based on biochemical and phenotypic characteristics. DNA extractions from 51 of these isolates were subjected to PCR using primers specific for Helicobacter spp. and Campylobacter spp. Of the isolates, 92% (47 of 51 isolates) were positive for Campylobacter spp., 41% (21 of 51 isolates) were positive for Helicobacter spp., 33% (17 of 51 isolates) were positive for both genera, 59% (30 of 51 isolates) were positive only for Campylobacter spp., and 8% (4 of 51) were positive only for Helicobacter spp. Sixteen of the 47 Campylobacter-positive cultures were positive for more than one Campylobacter spp. Based on a species-specific PCR assay, 83% of the isolates were identified as Campylobacter helveticus, 47% of the isolates were identified as Campylobacter upsaliensis, and 6% of the isolates were classified as Campylobacter jejuni. The 1.2-kb PCR products of the 16S rRNA genes of 19 Helicobacter species isolates were subjected to restriction fragment length polymorphism (RFLP) analysis. Of the five different RFLP patterns obtained, two clustered with Helicobacter ("Flexispira") taxon 8, one clustered with Helicobacter bilis, one clustered with Helicobacter canis, and the remaining pattern was closely related to a novel Helicobacter sp. strain isolated from a woodchuck. The sequence data for the 16S rRNA genes of 10 Helicobacter spp. validated the RFLP-based identification of these isolates. This study demonstrated that biochemical and phenotypic characteristics of microaerobic organisms in cat feces were insufficient to characterize mixed Helicobacter and Campylobacter infections. Molecular structure-based diagnostics using genus- and species-specific PCR, RFLP analysis, and 16S rRNA sequence analysis enabled the identification of multiple microaerobic species in individual animals. The clinical relevance of enteric Helicobacter and Campylobacter coinfection in cats will require further studies.

Emergence of diverse Helicobacter species in the pathogenesis of gastric and enterohepatic diseases

Since Helicobacter pylori was first cultivated from human gastric biopsy specimens in 1982, it has become apparent that many related species can often be found colonizing the mucosal surfaces of humans and other animals. These other Helicobacter species can be broadly grouped according to whether they colonize the gastric or enterohepatic niche. Gastric Helicobacter species are widely distributed in mammalian hosts and are often nearly universally prevalent. In many cases they cause an inflammatory response resembling that seen with H. pylori in humans. Although usually not pathogenic in their natural host, these organisms serve as models of human disease. Enterohepatic Helicobacter species are an equally diverse group of organisms that have been identified in the intestinal tract and the liver of humans, other mammals, and birds. In many cases they have been linked with inflammation or malignant transformation in immunocompetent hosts and with more severe clinical disease in immunocompromised humans and animals. The purpose of this review is to describe these other Helicobacter species, characterize their role in the pathogenesis of gastrointestinal and enterohepatic disease, and discuss their implications for our understanding of H. pylori infection in humans.

[The importance of Helicobacter--beyond the stomach too]

The discovery of H. pylori as causative agent for peptic ulcers was a milestone in gastroenterology. Apart from peptic ulcer, H. pylori may play a role in the pathogenesis of coronary heart disease, rheumatoid arthritis, Sjoegren's syndrome and hepatic encephalopathy. These associations are still controversial and need further studies. Other strains (H. bilis, H. hepaticus, H. rappani, H. pullorum) may cause chronic hepatobiliary diseases or diarrhea. The possible role of such strains in carcinogenesis is very interesting and should be further explored.

A probable new Helicobacter species isolated from a patient with bacteremia

A probable new Helicobacter species was isolated from the blood of a 14-month-old aboriginal child who presented with vomiting, diarrhea, fever, and dry cough. The most similar 16S rRNA gene sequence was that of Helicobacter fennelliae CCUG 18820(T) but the new sequence differed from it by at least 32 base substitutions and by the presence of a large (353-nucleotide) intervening sequence.

Identification of enterohepatic Helicobacter species by restriction fragment-length polymorphism analysis of the 16S rRNA gene

BACKGROUND

Restriction fragment-length polymorphism (RFLP) analysis of a 1,200-bp polymerase chain reaction-amplified DNA fragment of gene coding for 16S rRNA was used to generate restriction profiles of 11 enterohepatic Helicobacter spp. isolated from various animals and humans.

METHODS

The amplicon from each Helicobacter sp. was digested with four restriction endonucleases: Alu I, Hinf I, Hha I, and Dde I. Alu I digestion produced five patterns that were useful for initial differentiation.

RESULTS

Most Helicobacter spp. isolated from rodents had the same RFLP profiles by Alu I digestion (except H. rodentium and H. cholecystus), but they had different RFLP profiles by Hha I digestion. Only H. bilis and "H. rappini" mouse isolates could not be readily distinguished by the polymerase chain reaction-RFLP method. However, these two species can be distinguished using H. bilis specific primers. Some of the Helicobacter spp. have an intervening sequence in their 16S rRNA gene, which changes the RFLP patterns; in these cases, sequencing is the preferred method to make an appropriate diagnosis.

CONCLUSIONS

The RFLP method used in this study was straightforward and rapid and should prove useful as an adjunct for identification and classification of multiple enterohepatic Helicobacter spp.

Bacteriology and taxonomy of Helicobacter pylori

As the scientific community approaches the twentieth anniversary of the first isolation of H. pylori, it appears that despite the wealth of articles published in journals throughout the world every month, there are still many unanswered questions about the microbiology of this bacterium and others in the genus Helicobacter.

Serum antibodies to Helicobacter hepaticus and Helicobacter pylori in patients with chronic liver disease

BACKGROUND

Bile tolerant helicobacter species such as H hepaticus and H bilis have frequently been reported to cause hepatitis in mice and other rodents.

AIMS

To investigate the possible pathogenic role of these and other helicobacter species in chronic liver disease in humans.

METHODS

Serum samples from 144 patients with various chronic liver diseases, 30 patients with primary sclerosing cholangitis (PSC), and 48 healthy blood donors were analysed for antibodies against H hepaticus murine strain CCUG 33637 and H pylori strain CCUG 17874. Cell surface proteins of H hepaticus were extracted by acid glycine buffer and used in an enzyme immunoassay (EIA) and immunoblot (IB).

RESULTS

56 of 144 (39%) patients with chronic liver diseases and six of 30 (20%) with PSC showed increased antibody concentrations in the H hepaticus EIA; in the H pylori EIA the numbers were 58% and 13% respectively. Compared with the healthy blood donors the antibody reactivity against the two helicobacter species was not increased (46% and 48% respectively). Patient serum samples retested by the H hepaticus EIA after absorption with sonicated H pylori cells remained positive in 12 of 37 (33%) serum samples. Distinct antibody reactivity to 55-65 kDa proteins was observed by H hepaticus IB, after the absorption step, and was considered specific for H hepaticus. These 12 serum samples were from patients with chronic alcoholic liver disease.

CONCLUSIONS

Antibodies to H hepaticus, often cross reacting with H pylori, occur frequently in patients with chronic liver diseases, with no clear cut relation to specific diagnostic groups. The pathogenic significance of these findings is not known.

Identification of Helicobacter pylori and other Helicobacter species by PCR, hybridization, and partial DNA sequencing in human liver samples from patients with primary sclerosing cholangitis or primary biliary cirrhosis

Helicobacter pylori was identified in human liver tissue by PCR, hybridization, and partial DNA sequencing. Liver biopsies were obtained from patients with primary sclerosing cholangitis (n = 12), primary biliary cirrhosis (n = 12), and noncholestatic liver cirrhosis (n = 13) and (as controls) normal livers (n = 10). PCR analyses were carried out using primers for the Helicobacter genus, Helicobacter pylori (the gene encoding a species-specific 26-kDa protein and the 16S rRNA), Helicobacter bilis, Helicobacter pullorum, and Helicobacter hepaticus. Samples from patients with primary biliary cirrhosis and primary sclerosing cholangitis (11 and 9 samples, respectively) were positive by PCR with Helicobacter genus-specific primers. Of these 20 samples, 8 were positive with the 16S rRNA primer and 9 were positive with the 26-kDa protein primer of H. pylori. These nine latter samples were also positive by Southern blot hybridization for the amplified 26-kDa fragment, and four of those were verified to be H. pylori by partial 16S rDNA sequencing. None of the samples reacted with primers for H. bilis, H. pullorum, or H. hepaticus. None of the normal livers had positive results in the Helicobacter genus PCR assay, and only one patient in the noncholestatic liver cirrhosis group, a young boy who at reexamination showed histological features suggesting primary sclerosing cholangitis, had a positive result in the same assay. Helicobacter positivity was thus significantly more common in patients with cholestatic diseases (20 of 24) than in patients with noncholestatic diseases and normal controls (1 of 23) (P = <0.00001). Patients positive for Helicobacter genus had significantly higher values of alkaline phosphatases and prothrombin complex than Helicobacter-negative patients (P = 0.0001 and P = 0.0003, respectively). Among primary sclerosing cholangitis patients, Helicobacter genus PCR positivity was weakly associated with ulcerative colitis (P = 0.05). Significant differences related to blood group or HLA status were not found.

Isolation of Helicobacter canis from a colony of bengal cats with endemic diarrhea

On the basis of biochemical, phenotypic, and 16S rRNA analyses, Helicobacter canis was isolated from Bengal cats with and without chronic diarrhea. Because the cats were coinfected with other potential pathogens, including Campylobacter helveticus, and because H. canis was isolated from nondiarrheic cats, the causal role of H. canis in producing the diarrhea could not be proven. Histologically, the colons of the four affected cats were characterized by mild to moderate neutrophilic, plasmacytic, and histocytic infiltrates in the lamina propria. Rare crypt abscesses were also noted for three cats but were a more prominent feature of the colonic lesions noted for the fourth cat. This is the first observation of H. canis in cats and raises the possibility that H. canis, like H. hepaticus and H. bilis in mice, can cause inflammation of the colon, particularly in hosts with immune dysregulation. Further studies are needed to determine the importance of H. canis as a primary enteric pathogen in cats and the role of cats in the possible zoonotic spread of H. canis to humans.

Inflammatory large bowel disease in immunodeficient rats naturally and experimentally infected with Helicobacter bilis

Proliferative and ulcerative typhlitis, colitis, and proctitis were found incidentally in a breeding colony of male athymic nude (Cr:NIH-rnu) rats. Within the crypts of the large intestine, modified Steiner's silver stain revealed spiral organisms that were identified by culture, polymerase chain reaction, and sequencing to be Helicobacter bilis. The large bowel disease was reproduced in H. bilis-free male athymic nude rats that were injected intraperitoneally with a culture of H. bilis from the affected colony. The organism was isolated from the feces and cecum of the experimentally infected rats. H. bilis should be considered a potential pathogen in immunocompromised rats. The infection in immunocompromised rats may serve as an animal model for inflammatory large bowel disease.

Hepatic Helicobacter species identified in bile and gallbladder tissue from Chileans with chronic cholecystitis

BACKGROUND & AIMS

Cancer of the gallbladder is the number one cause of cancer mortality in Chilean women. Incidence rates for this tumor vary widely on a worldwide basis, being approximately 30 times higher in high-risk than in low-risk populations, suggesting that environmental factors such as infectious microorganisms, carcinogens, and nutrition play a role in its pathogenesis. Because several Helicobacter sp. colonize the livers of animals and induce hepatitis, the aim of this study was to determine whether Helicobacter infection was associated with cholecystitis in humans.

METHODS

Bile or resected gallbladder tissue from 46 Chileans with chronic cholecystitis undergoing cholecystectomy were cultured for Helicobacter sp. and subjected to polymerase chain reaction (PCR) analysis using Helicobacter-specific 16S ribosomal RNA primers.

RESULTS

Recovery of Helicobacter sp. from frozen specimens was unsuccessful. However, by PCR analysis, 13 of 23 bile samples and 9 of 23 gallbladder tissues were positive for Helicobacter. Eight of the Helicobacter-specific PCR amplicons were sequenced and subjected to phylogenetic analysis. Five sequences represented strains of H. bilis, two strains of "Flexispira rappini" (ATCC 49317), and one strain of H. pullorum.

CONCLUSIONS

These data support an association of bile-resistant Helicobacter sp. with gallbladder disease. Further studies are needed to ascertain whether similar Helicobacter sp. play a causative role in the development of gallbladder cancer.

Helicobacter bilis sp. nov., a novel Helicobacter species isolated from bile, livers, and intestines of aged, inbred mice

A fusiform bacterium with 3 to 14 multiple bipolar sheathed flagella and periplasmic fibers wrapped around the cell was isolated from the liver, bile, and lower intestine of aged, inbred mice. The bacteria grew at 37 and 42 degrees C under microaerophilic conditions, rapidly hydrolyzed urea, were catalase and oxidase positive, reduced nitrate to nitrite, did not hydrolyze indoxyl acetate or hippurate, and were resistant to both cephalothin and nalidixic acid but sensitive to metronidazole. On the basis of 16S rRNA gene sequence analysis, the organism was classified as a novel helicobacter, Helicobacter bilis. This new helicobacter, like Helicobacter hepaticus, colonizes the bile, liver, and intestine of mice. Although the organism is associated with multifocal chronic hepatitis, further studies are required to ascertain whether H. bilis is responsible for causing chronic hepatitis and/or hepatocellular tumors in mice.