Helicobacter pullorum

Abstract: 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.

Abstract: Campylobacter-like organisms were isolated from the liver, duodenum and caecum of broiler and layer chickens, and from humans with gastroenteritis. They formed a unique DNA homology group and a polyphasic taxonomic analysis was made of 16 strains. Analysis of the nucleotide sequence of the 16S rRNA gene from seven of the strains identified them as belonging to a single species, within the genus Helicobacter. This conclusion was supported by the studies of relative DNA homology and of total protein electrophoretic patterns. The new species could be biochemically differentiated from other helicobacters and its ultrastructure in the electron microscope was typical of the genus except that the flagellum was not sheathed. We propose the name Helicobacter pullorum sp. nov. for this group. Like H. fennelliae or H. cinaedi it represents another non-gastric urease-negative Helicobacter species colonizing the lower bowel. Its isolation from the livers of chickens with vibrionic hepatitis is significant. We describe a species-specific PCR assay for H. pullorum sp. nov. which will facilitate its identification and further studies of its epidemiology.

Abstract: Background and aims: Recent studies have suggested that bacterial coinfection with Helicobacter species in patients already infected with hepatitis C virus (HCV) could be involved in the development of cirrhosis and hepatocellular carcinoma (HCC). A retrospective cross sectional study was performed in order to explore the association between Helicobacter species and HCV associated liver diseases. Methods: The presence of Helicobacter species was tested by polymerase chain reaction on liver samples from four groups of patients. Results: Helicobacter 16S rDNA was found in only 4.2% of liver samples from control patients (n = 24) and in 3.5% of liver samples from patients with non-cirrhotic chronic hepatitis C (n = 29) while it was found in 68.0% of liver samples from patients with HCV positive cirrhosis without HCC (n = 25) as well as in 61.3% of cirrhotic liver samples from patients with HCV positive cirrhosis and HCC (n = 31). In addition, when the HCC tumour tissue was tested (n = 21), 90.5% of samples were positive. DNA from Helicobacter pylori - and Helicobacter pullorum -like organisms was found. Conclusions: There is an association between the presence of Helicobacter species DNA in the liver and hepatitis C cirrhosis, with or without HCC. Indeed, the presence of these bacteria could be the result of structural changes in the liver. Alternatively, Helicobacter species could be a co-risk factor in HCV chronic liver diseases. This result warrants prospective studies to determine the possible causal role of these bacteria in the progression of chronic hepatitis C.

Abstract: We recently analyzed 11 helicobacter isolates cultured from diarrhea patients in Canada. These isolates had been characterized biochemically by restriction fragment length polymorphism (RFLP; Alu I, Hha I) analysis and by fatty-acid analysis as Helicobacter pullorum . However, four of the isolates differed biochemically from H. pullorum by their inability to hydrolyze indoxyl acetate and their resistance to nalidixic acid. Using complete 16S rRNA analysis, we determined that these four strains clustered near H. pullorum but had a sequence difference of 2% and therefore represent a novel helicobacter, Helicobacter canadensis . This novel helicobacter could also be distinguished from H. pullorum by RFLP analysis using Apa LI. The number of novel Helicobacter spp. associated with gastrointestinal disease in humans and animals is rapidly increasing. There are now six Helicobacter spp. isolated from diarrheic humans, the other five being H. pullorum , H. canis , “ H. rappini ,” H. fennelliae , and H. cinaedi . This finding highlights the importance of careful molecular analysis in addition to standard biochemical tests in identifying the increasing number of Helicobacter spp. isolated from humans and animals.