Comparison of isolates of Helicobacter pylori and Helicobacter mustelae.

On the basis of analysis of protein profiles, isolates of Helicobacter pylori and Helicobacter mustelae were less than 40% similar. Cytotoxin produced by H. pylori was not detected in isolates of H. mustelae. Both bacterial species agglutinated human erythrocytes. These results substantiate a taxonomic difference between H. pylori and H. mustelae.     

Protein Hpn: cloning and characterization of a histidine-rich metal-binding polypeptide in Helicobacter pylori and Helicobacter mustelae.

Helicobacter pylori is a human gastrointestinal pathogen involved in gastritis, duodenal ulcers, and gastric neoplasia. This microorganism produces large amounts of a urease which, like all known ureases, has nickel in the active site. We have identified a protein in clinical isolates of H. pylori and an identical protein in the ferret pathogen Helicobacter mustelae that strongly binds Ni2+ and Zn2+. This protein has been named Hpn to emphasize its origins in H. pylori and its affinity for nickel. The encoding hpn gene, cloned and expressed in Escherichia coli ER1793, has an open reading frame (180 bp) that specifies a protein with a calculated molecular mass of 7,077 Da and with the same amino-terminal sequence as that of wild-type Hpn. The deduced sequence of Hpn consists of 60 amino acids, of which 28 (47%) are histidines. The hpn gene does not map with the urease gene cluster on the H. pylori chromosome. An Hpn-negative, isogenic H. pylori strain, generated by hpn gene deletion and grown on blood agar, had the same urease activity that wild-type cells did. Thus, the role of Hpn in helicobacters is unknown.     

Adherence of isogenic flagellum-negative mutants of Helicobacter pylori and Helicobacter mustelae to human and ferret gastric epithelial cells

Isogenic flagellum-negative mutants of Helicobacter pylori and Helicobacter mustelae were screened for their ability to adhere to primary human and ferret gastric epithelial cells, respectively. We also evaluated the adherence of an H. pylori strain with a mutation in the flbA gene, a homologue of the flbF/lcrD family of genes known to be involved in the regulation of H. pylori flagellar biosynthesis. H. pylori and H. mustelae mutants deficient in production of FlaA or FlaB and mutants deficient in the production of both FlaA and FlaB showed no reduction in adherence to primary human or ferret gastric epithelial cells compared with the wild-type parental strains. However, adherence of the H. pylori flbA mutant to human gastric cells was significantly reduced compared to the adherence of the wild-type strain. These results show that flagella do not play a direct role in promoting adherence of H. pylori or H. mustelae to gastric epithelial cells. However, genes involved in the regulation of H. pylori flagellar biosynthesis may also regulate the production of an adhesin.     

Purification and characterization of Helicobacter mustelae urease.

Helicobacter mustelae is a urease-rich bacterium associated with gastritis in ferrets. The ureases of H. mustelae and Helicobacter pylori, a bacterium implicated in human gastritis, share many characteristics. Helicobacter sp. ureases appear to be unique among bacterial enzymes in exhibiting submillimolar Km values and in being composed of two subunits.     

Gastric colonization by Campylobacter pylori subsp. mustelae in ferrets.

Campylobacter pylori subsp. mustelae was cultured from both normal and inflamed gastric mucosa of ferrets. Examination of neonatal, juvenile, and adult ferrets established that the gastric mucosa in the majority of preweanling (age, less than 6 weeks) ferrets sampled were not colonized with C. pylori subsp. mustelae, whereas the gastric mucosa of 100% of adult ferrets were colonized with this gastric organism. C. pylori subsp. mustelae was isolated from the gastric mucosa on a sequential basis from nine ferrets during a several-month period, inferring either persistent colonization or frequent reinfection with C. pylori subsp. mustelae.     

In vitro binding of Helicobacter pylori to human gastric mucin.

The in vitro binding of four Helicobacter pylori strains to human gastric mucin was studied with an enzyme-linked immunosorbent assay. All four strains were found to bind to purified mucin. Neuraminidase treatment and nonspecific oxidation of mucin decreased bacterial adherence to the macromolecule. Mucin preparations were also found to inhibit attachment of H. pylori to HEp-2 monolayers.     

Biochemical studies of Helicobacter mustelae fatty acid composition and flagella.

The fatty acid compositions of Helicobacter mustelae whole cells, isolated phospholipids, and isolated lipopolysaccharides were analyzed by gas-liquid chromatography. Major phospholipid fatty acids were C16:0, C18:0, C18:1, and C19:0 cyc. In isolated lipopolysaccharides, 3-OH-C16:0, 3-OH-C14:0, C14:0, C16:0, and C18:0 were found. The lipid composition of H. mustelae thus showed pronounced differences from that of H. pylori. Flagella were purified by mechanical shearing and centrifugation steps. In all H. mustelae strains, the flagellin had an apparent molecular mass of 53 kDa and was thus the same size as H. pylori flagellin. The flagellin of strain NCTC 12032 was further purified and subjected to N-terminal amino acid sequence analysis. The first 10 amino acids were identical to those of H. pylori flagellin, but the next 5 were different. Significant homology was also found with flagellins of other bacteria.     

Construction and characterization of an isogenic urease-negative mutant of Helicobacter mustelae.

Helicobacter mustelae infects the ferret stomach and provides an opportunity to study pathogenic determinants of a Helicobacter species in its natural host. We constructed an isogenic urease-negative mutant of H. mustelae which produced no detectable urease and showed a reduced acid tolerance. This mutant provides an opportunity to further evaluate the role of urease in the pathogenesis of Helicobacter infection.     

Helicobacter pylori.

Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori. In developed countries, the prevalence of infection is lower. There appears to be no substantial reservoir of H. pylori aside from the human stomach. Transmission can occur by iatrogenic, fecal-oral, and oral-oral routes. H. pylori is able to colonize and persist in a unique biological niche within the gastric lumen. All fresh isolates of H. pylori express significant urease activity, which appears essential to the survival and pathogenesis of the bacterium. A variety of tests to diagnose H. pylori infection are now available. Histological examination of gastric tissue, culture, rapid urease testing, DNA probes, and PCR analysis, when used to test gastric tissue, all require endoscopy. In contrast, breath tests, serology, gastric juice PCR, and urinary excretion of [15N]ammonia are noninvasive tests that do not require endoscopy. In this review, we highlight advances in the detection of the presence of the organism and methods of differentiating among types of H. pylori, and we provide a background for appropriate chemotherapy of the infection.     

Helicobacter pylori AlpA and AlpB bind host laminin and influence gastric inflammation in gerbils

Helicobacter pylori persistently colonizes humans, causing gastritis, ulcers, and gastric cancer. Adherence to the gastric epithelium has been shown to enhance inflammation, yet only a few H. pylori adhesins have been paired with targets in host tissue. The alpAB locus has been reported to encode adhesins involved in adherence to human gastric tissue. We report that abrogation of H. pylori AlpA and AlpB reduces binding of H. pylori to laminin while expression of plasmid-borne alpA or alpB confers laminin-binding ability to Escherichia coli. An H. pylori strain lacking only AlpB is also deficient in laminin binding. Thus, we conclude that both AlpA and AlpB contribute to H. pylori laminin binding. Contrary to expectations, the H. pylori SS1 mutant deficient in AlpA and AlpB causes more severe inflammation than the isogenic wild-type strain in gerbils. Identification of laminin as the target of AlpA and AlpB will facilitate future investigations of host-pathogen interactions occurring during H. pylori infection.     

Adherence of Helicobacter pylori to human gastric epithelial cells in vitro

Gram-negative spiral organisms, currently referred to as Helicobacter pylori, are associated with primary gastritis and duodenal ulceration. The organisms colonise gastric mucus and adhere to epithelial cells of inflamed antra. To further examine the binding of H. pylori to human gastric epithelial cells, we developed and characterised an in-vitro bacterial adherence assay. Scanning electronmicroscopy suggested that spiral-shaped bacteria were adherent to the surface of KATO-III cells which were derived from a human gastric adenocarcinoma. Transmission electronmicroscopy confirmed the attachment of H. pylori to these epithelial cells in tissue culture. Some bacteria were adherent to intact microvilli, others were closely adherent to the plasma membrane in regions where microvilli were effaced. In studies with radiolabelled H. pylori, adherence to epithelial cells in tissue culture contrasted with minimal binding of bacteria to polystyrene wells alone. Incubation of bacteria with gastric cells at 4 degrees C significantly reduced adherence of H. pylori. We conclude that adherence of H. pylori to gastric epithelial cells in tissue culture involved "attachment and effacement mechanisms". This assay could serve as a suitable in-vitro model for the study of the bacterial adhesins and host receptors which mediate attachment of H. pylori to gastric epithelial cell surfaces.     

Helicobacter mustelae isolation from feces of ferrets: evidence to support fecal-oral transmission of a gastric Helicobacter.

Helicobacter mustelae has been isolated from stomachs of ferrets with chronic gastritis and ulcers. When H. mustelae is inoculated orally into H. mustelae-negative ferrets, the animals become colonized and develop gastritis, a significant immune response, and a transient hypochlorhydria. All of these features mimic Helicobacter pylori-induced gastric disease in humans. Because the epidemiology of H. pylori infection is poorly understood and its route of transmission is unknown, the feces of weanling and adult ferrets were cultured for the presence of H. mustelae. H. mustelae was isolated from the feces of 11 of 36 ferrets by using standard helicobacter isolation techniques. H. mustelae was identified by biochemical tests, ultrastructural morphology, reactivity with specific DNA probes, and 16S rRNA sequencing. H. mustelae was not recovered from 20-week-old ferrets which had been H. mustelae positive as weanlings, nor was H. mustelae recovered from 1-year-old ferrets. Isolation of H. mustelae from feces may correspond to periods of transient hypochlorhydria, or H. mustelae may be shed in feces intermittently. The H. mustelae-colonized ferret provides an ideal model for studying the pathogenesis and transmission of H. pylori-induced gastric disease.     

Antigastric autoantibodies in ferrets naturally infected with Helicobacter mustelae

Infection with Helicobacter pylori has been associated with induction of autoantibodies that cross-react with the gastric mucosa. There have been discordant reports as to whether or not these autoantibodies arise due to molecular mimicry between H. pylori and host cell antigens on parietal cells. In this study, we investigated whether molecular mimicry by H. mustelae causes autoantibodies in infected ferrets. Serum from H. mustelae-infected ferrets reacted with parietal cells in the ferret gastric mucosa but not with duodenal or colonic mucosa. These sera did not react with the blood group A epitope on erythrocytes or H. mustelae lipopolysaccharide, and absorption with H. mustelae whole cells or red blood cells did not remove autoantibodies. In conclusion, ferrets naturally infected with H. mustelae generate antibodies that react with parietal cells, but these autoantibodies are not due to molecular mimicry.     

Immunoglobulin A antibodies to Helicobacter pylori.

Serological testing for immunoglobulin G (IgG) antibodies to Helicobacter pylori has proven useful in supporting the diagnosis of infection with this organism, but the clinical value of IgA antibodies in H. pylori-related gastritis remains controversial. The purpose of our study was to determine the frequency of IgA-positive IgG-negative patients with symptoms of gastrointestinal (GI) disorders, thus assessing the clinical utility of IgA testing for H. pylori-related gastritis. It was found previously that the frequency of infected individuals in this category (IgA positive and IgG negative) is about 2%, but a large number of IgG-negative patients with GI disorders suggestive of H. pylori infection have not been investigated until now.     

Antibody to cytotoxin in infection by Helicobacter pylori.

Gastrointestinal disease and colonization by Helicobacter pylori were determined in 36 asymptomatic volunteers and 30 symptomatic individuals undergoing endoscopy and biopsy. Serum antibody immunoglobulin G (IgG) and IgA to H. pylori were measured by enzyme-linked immunosorbent assay. Serum antibody to a cytotoxin produced by H. pylori was detected with a neutralization assay. Serum IgG was 95% predictive of infection by H. pylori, and serum IgA was 88% predictive. Antibody to the cytotoxin was detected in 12 of 18 infected individuals. Antibody to the cytotoxin was a highly specific (96%), but not a very sensitive (67%), indicator of infection by H. pylori. The neutralization assay was 87% predictive of infection. These data confirm the diagnostic value of serum antibody to H. pylori for the detection of infection. The toxin-neutralizing activity of sera from individuals infected with H. pylori suggests that the cytotoxin is produced in vivo. It may therefore contribute to disease associated with H. pylori.     

Evaluation of Helicobacter pylori infection in patients with common migraine headache

Introduction

Migraine can cause headache in different communities so that 12-15% are suffering worldwide. Recently the relationship between infectious diseases such as Helicobacter pylori infection and migraine headache has been the focus of many studies. The current study was designed to evaluate IgG and IgM antibodies to H. pylori in patients suffering from migraine headaches.

Material and methods

Patients who had diagnostic criteria for migraine were chosen as cases compared to some healthy individuals as the control group amongst which immunoglobulin G (IgG), immunoglobulin M (IgM), age, job, gastro-intestinal (GI) disorders, history of migraine, special meals, medications, sleeping disorders, stress, environmental factors etc were analysed.

Results

The prevalence of disease was 38.6%. Household women had the highest prevalence (40%). Among them menstruation was related to high prevalence of migraine. 75.6% of patients had gastrointestinal disorders of which the gastric reflux was the most important sign (47.1%). The mean optical density (OD) value of IgG and IgM antibody to H. pylori was 60.08 ±7.7 and 32.1 ±8.7 for the case group, 21.82 ±6.2 and 17.6 ±9.4 for the control group, respectively.

Conclusions

There was a significant difference in mean OD value of both antibodies to H. pylori amongst the case and control groups. As a result, active H. pylori infection is strongly related to the outbreak and severity of migraine headaches, and H. pylori treatment reduces migraine headaches significantly. Hopefully, the definite treatment and eradication of this infection can cure or reduce the severity and course of migraine headaches significantly if not totally.