Clinical significance of Helicobacter species other than Helicobacter pylori

Acute Peptic Ulcer Disease Caused by Non-Helicobacter pylori-Helicobacter

Human infection by Non-Helicobacter pylori-Helicobacter is rare and most commonly transmitted through direct contact with animals. The clinical presentation in most cases is chronic epigastric abdominal pain and it usually leads to chronic gastritis. We present an uncommon case of a patient with acute onset abdominal pain secondary to acute peptic ulcer disease caused by Helicobacter heilmannii who underwent successful treatment. We also conducted a review of the literature to understand the epidemiology, etiology, clinical presentation, and the best diagnostic and treatment modalities for Non-H. pylori-Helicobacter infections.

Differentiation of Gastric Helicobacter Species Using MALDI-TOF Mass Spectrometry

Gastric helicobacters (Helicobacter (H.) pylori and non-H. pylori Helicobacter species (NHPHs)) colonize the stomach of humans and/or animals. Helicobacter species identification is essential since many of them are recognized as human and/or animal pathogens. Currently, Helicobacter species can only be differentiated using molecular methods. Differentiation between NHPHs using MALDI-TOF MS has not been described before, probably because these species are poorly represented in current MALDI-TOF MS databases. Therefore, we identified 93 gastric Helicobacter isolates of 10 different Helicobacter species using MALDI-TOF MS in order to establish a more elaborate Helicobacter reference database. While the MALDI Biotyper database was not able to correctly identify any of the isolates, the in-house database correctly identified all individual mass spectra and resulted in 82% correct species identification based on the two highest log score matches (with log scores ≥2). In addition, a dendrogram was constructed using all newly created main spectrum profiles. Nine main clusters were formed, with some phylogenetically closely related Helicobacter species clustering closely together and well-defined subclusters being observed in specific species. Current results suggest that MALDI-TOF MS allows rapid differentiation between gastric Helicobacter species, provided that an extensive database is at hand and variation due to growth conditions and agar-medium-related peaks are taken into account.

Helicobacter suis and Helicobacter pylori infection in a colony of research macaques: characterization and clinical correlates

Introduction. Helicobacter suis (Helicobacter heilmannii type 1) commonly infects nonhuman primates but its clinical importance is in question.Aim. To characterize H. suis infection in a colony of rhesus macaques (Macaca mulatta) used in cognitive neuroscience research.Hypothesis/Gap Statement. Inquiries into the nature of Helicobacter suis in nonhuman primates are required to further define the organism's virulence and the experimental animal's gastric microbiome.Methodology. Animals with and without clinical signs of vomiting and abdominal pain (n=5 and n=16, respectively) were evaluated by histology, culture, PCR amplification and sequencing, fluorescent in situ hybridization (FISH) and serology. Three of the five animals with clinical signs, an index case and two others, were evaluated before and after antimicrobial therapy.Results. The index animal had endoscopically visible ulcers and multifocal, moderate, chronic lymphoplasmacytic gastritis with intraglandular and luminal spiral bacteria. Antimicrobial therapy in the index animal achieved histologic improvement, elimination of endoscopically visible ulcers, and evident eradication but clinical signs persisted. In the other treated animals, gastritis scores were not consistently altered, gastric bacteria persisted, but vomiting and abdominal discomfort abated.Nineteen of 21 animals were PCR positive for H. suis and five animals were also PCR positive for H. pylori. Organisms were detected by FISH in 17 of 21 animals: 16S rRNA sequences of two of these were shown to be H. suis. Mild to moderate lymphoplasmacytic gastritis was seen in antrum, body and cardia, with antral gastritis more likely to be moderate than that of the body.Conclusion. No clear association between the bacterial numbers of Helicobacter spp. and the degree of inflammation was observed. H. suis is prevalent in this colony of Macaca mulatta but its clinical importance remains unclear. This study corroborates many of the findings in earlier studies of H. suis infection in macaques but also identifies at least one animal in which gastritis and endoscopically visible gastric ulcers were strongly associated with H. suis infection. In this study, serology was an inadequate biomarker for endoscopic evaluation in diagnosis of H. suis infection.

First report of PCR-based detection of Helicobacter species DNA in Camelus dromedarius in Egypt

Background and Aim:

Helicobacter species infections have epidemiological and zoonotic impacts, and different species of Helicobacter have been implicated in infecting humans and animals. The aim of this study was to investigate Helicobacter species infections in Camelus dromedarius.

Materials and Methods:

Fecal samples were collected from 32 camels from 9 camel farms located at Ismailia Governorate, Egypt. The collected samples were investigated by bacteriological isolation and conventional polymerase chain reaction (PCR) assays targeting the 16S ribosomal RNA gene.

Results:

Although Helicobacter species could not be isolated from all the examined samples, Helicobacter DNA was detected in 2 (22.22%) of the 9 camel farms. Of the 32 camel fecal samples examined, 4 (12.5%) were positive for Helicobacter species as analyzed by the PCR assay.

Conclusion:

To the best of our knowledge, this is the first report of PCR-based detection of Helicobacter species infections in C. dromedarius. Further epidemiological studies are required to clarify Helicobacter species infections in camels.

Role of Th22 cells in Helicobacter pylori-related gastritis and peptic ulcer diseases

Helicobacter pylori (H. pylori) has been shown to be one of the leading causes of peptic ulcer diseases (PUDs) and gastritis. T helper-22 (Th22) cells and its most important cytokine, interleukin-22 (IL-22) are importantly active in inflammation and inflammatory tissues. Since inflammation is one of the main attributes of infection caused by H. pylori and resulting complications (gastritis and gastrointestinal ulcer), this study was designed to evaluate the Th22 cells count and the IL-22 protein expression in people suffering from PUD and gastritis. The present study was conducted on 55 patients with gastritis, 47 patients with PUD and 48 uninfected subjects. After preparation of section and extraction of protein from antral biopsies, immunohistochemistry and western blot methods were used to evaluate the Th22 cells and IL-22 protein expression level, respectively. According to findings, the Th22 cells count and the IL-22 protein expression level in the infected subjects were siginficantly more than in the uninfected subjects. It should be noted that the Th22 cells count and the IL-22 protein expression level in the infected subjects with PUD were significantly greater than those in the infected subjects with gastritis. In addition, the Th22 cells count had positive correlation with the density of H. pylori, chronic inflammation score and acute inflammatory score in the infected subjects with PUD. The Th22 cells count had positive correlation with the Th17 cells count and inverse correlation with the Treg cells count in the infected subjects with PUD and gastritis. Our data demonstrated that abnormal hyper-activation of Th22 cells as well as its correlation with the Th17 cells during infection caused by H. pylori might damage tissues through immunopathological responses.

The Resolution of Helicobacter suis-associated Gastric Lesions after Eradication Therapy

A reddish depressed lesion was found in the corpus of the stomach of a 56-year-old man. Gastric biopsy showed no findings of mucosa-associated lymphoid tissue lymphoma, including lympho-epithelial lesions. A urea breath test, stool antigen test and serum IgG antibody to Helicobacter pylori test were negative. Magnifying endoscopy using narrow-band-imaging showed no malignant structures. Gastric biopsy specimens were subjected to immunohistochemistry and a polymerase chain reaction, which identified Helicobacter suis infection. Triple therapy with esomeprazole, metronidazole, and amoxicillin was administered for 10 days. Three months later, endoscopy showed the significant improvement of the lesion. H. suis infection should be considered in chronic gastritis patients without H. pylori infection.

The Helicobacter cinaedi antigen CAIP participates in atherosclerotic inflammation by promoting the differentiation of macrophages in foam cells

Recent studies have shown that certain specific microbial infections participate in atherosclerosis by inducing inflammation and immune reactions, but how the pathogens implicated in this pathology trigger the host responses remains unknown. In this study we show that Helicobacter cinaedi (Hc) is a human pathogen linked to atherosclerosis development since at least 27% of sera from atherosclerotic patients specifically recognize a protein of the Hc proteome, that we named Cinaedi Atherosclerosis Inflammatory Protein (CAIP) (n = 71). CAIP appears to be implicated in this pathology because atheromatous plaques isolated from atherosclerotic patients are enriched in CAIP-specific T cells (10%) which, in turn, we show to drive a Th1 inflammation, an immunopathological response typically associated to atherosclerosis. Recombinant CAIP promotes the differentiation and maintenance of the pro-inflammatory profile of human macrophages and triggers the formation of foam cells, which are a hallmark of atherosclerosis. This study identifies CAIP as a relevant factor in atherosclerosis inflammation linked to Hc infection and suggests that preventing and eradicating Hc infection could reduce the incidence of atherosclerosis.

Helicobacter apodemus sp. nov., a new Helicobacter species identified from the gastrointestinal tract of striped field mice in Korea

A novel Helicobacter species was identified from the gastrointestinal tract of the Korean striped field mouse (Apodemus agrarius). Biochemical testing, ultrastructure characterization, and 16S rRNA gene sequence analysis suggested that this bacterium represents a distinct taxon. The bacterium was positive for urease activity, susceptible to cephalothin and nalidixic acid, and weakly positive for oxidase and catalase activity. Electron microscopy revealed that the bacterium has spirally curved rod morphology with singular bipolar nonsheathed flagella. Genotypically, the isolated bacterial strains (YMRC 000215, YMRC 000216, and YMRC 000419) were most closely related to a reference strain of Helicobacter mesocricetorum (97.25%, 97.32%, and 97.03% 16S rRNA sequence similarities, respectively). The 16S rRNA sequences of these strains were deposited into GenBank under accession numbers AF284754, AY009129, and AY009130, respectively. We propose the name Helicobacter apodemus for this novel species.

Vertebral Osteomyelitis Caused by Helicobacter cinaedi

Helicobacter cinaedi causes bacteremia, cellulitis, and gastroenteritis. We report the first case of vertebral osteomyelitis caused by H. cinaedi in an elderly man with low back pain and fever. The pathogen was detected in blood and lumbar disc, and the infection was successfully treated with oral doxycycline for 11 weeks.

Epidemiology of Helicobacter pylori infection in dyspeptic Ghanaian patients

Introduction

Helicobacter pylori is a gram-negative urease-producing bacterium causally linked with gastritis, peptic ulcer disease and gastric adenocarcinoma. Infection is more frequent and acquired at an earlier age in developing countries compared to European populations. The incidence of Helicobacter pylori infection in dyspeptic Ghanaian patients was 75.4%. However, epidemiological factors associated with infection vary across populations.

Methods

This study used a cross-sectional design to consecutively sample dyspeptic patients at the Endoscopy Unit of the Korle-Bu Teaching Hospital, Accra between 2010 and 2012. The study questionnaire elicited their epidemiological clinical characteristics. Helicobacter pylori infection was confirmed by rapid-urease examination of antral biopsies at upper Gastro-intestinal endoscopy.

Results

The sample population of dyspeptic patients attending the Endoscopy Unit for upper GI endoscopy yielded 242 patients of which 47.5% were females. The age distribution of H. pylori-infection was even across most age – groups, ranging from 69.2% (61 – 70) years to 80% (21 – 30) years. Helicobacter pylori prevalence decreased across areas mapping to the three residential classes in accordance with increasing affluence with rural areas having the highest prevalence. The unemployed and patients in farming had relatively high Helicobacter pylori infection rates of 92.3% and 91.7% respectively.

Conclusion

Helicobacter pylori is endemic in Ghana but the persistently high prevalence across age groups despite significant community anti-microbial use suggests likely re-crudescence or re-infection from multiple sources in a developing country. Socio-cultural factors such as residential class and farming may be facilitating factors for its continued prevalence.

Beyond the stomach: An updated view of Helicobacter pylori pathogenesis, diagnosis, and treatment

Helicobacter pylori (H. pylori) is an extremely common, yet underappreciated, pathogen that is able to alter host physiology and subvert the host immune response, allowing it to persist for the life of the host. H. pylori is the primary cause of peptic ulcers and gastric cancer. In the United States, the annual cost associated with peptic ulcer disease is estimated to be $6 billion and gastric cancer kills over 700000 people per year globally. The prevalence of H. pylori infection remains high (> 50%) in much of the world, although the infection rates are dropping in some developed nations. The drop in H. pylori prevalence could be a double-edged sword, reducing the incidence of gastric diseases while increasing the risk of allergies and esophageal diseases. The list of diseases potentially caused by H. pylori continues to grow; however, mechanistic explanations of how H. pylori could contribute to extragastric diseases lag far behind clinical studies. A number of host factors and H. pylori virulence factors act in concert to determine which individuals are at the highest risk of disease. These include bacterial cytotoxins and polymorphisms in host genes responsible for directing the immune response. This review discusses the latest advances in H. pylori pathogenesis, diagnosis, and treatment. Up-to-date information on correlations between H. pylori and extragastric diseases is also provided.

Promotion of atherosclerosis by Helicobacter cinaedi infection that involves macrophage-driven proinflammatory responses

Helicobacter cinaedi is the most common enterohepatic Helicobacter species that causes bacteremia in humans, but its pathogenicity is unclear. Here, we investigated the possible association of H. cinaedi with atherosclerosis in vivo and in vitro. We found that H. cinaedi infection significantly enhanced atherosclerosis in hyperlipidaemic mice. Aortic root lesions in infected mice showed increased accumulation of neutrophils and F4/80⁺ foam cells, which was due, at least partly, to bacteria-mediated increased expression of proinflammatory genes. Although infection was asymptomatic, detection of cytolethal distending toxin RNA of H. cinaedi indicated aorta infection. H. cinaedi infection altered expression of cholesterol receptors and transporters in cultured macrophages and caused foam cell formation. Also, infection induced differentiation of THP-1 monocytes. These data provide the first evidence of a pathogenic role of H. cinaedi in atherosclerosis in experimental models, thereby justifying additional investigations of the possible role of enterohepatic Helicobacter spp. in atherosclerosis and cardiovascular disease.

Helicobacter canis bacteremia in a patient with fever of unknown origin

A 57-year-old woman with common variable immune deficiency and liver failure of unknown etiology presented with recurrent fevers over a 5-month period. She was found to have Helicobacter canis bacteremia. Immunocompromised hosts with exposure to cats or dogs may be at risk for infection with this organism, which may be challenging to diagnose.

A case of Helicobacter cinaedi bacteremia in an asplenic patient

Helicobacter cinaedi is an enterohepatic species. It can cause bacteremia, gastroenteritis, and cellulitis, particularly in immunocompromised individuals, such as those with acquired immunodeficiency syndrome, malignancy, or alcoholism. There are no previous reports of H. cinaedi infection in Korea. A 71-yr-old man was admitted to the emergency room because of dyspnea on November 9, 2011. He had undergone splenectomy 3 yr ago because of immune hemolytic anemia. Chest plain radiography revealed bilateral pleural effusion. He developed fever on hospital day (HD) 21. Three sets of blood cultures were taken, and gram-negative spiral bacilli were detected in all aerobic vials. The isolate grew in tiny colonies on chocolate agar after 3-day incubation under microaerophilic conditions. This organism tested positive for catalase and oxidase, and negative for urease. The 16S rRNA gene sequence of this isolate exhibited 99.8% homology with the published sequence of H. cinaedi CCUG 18818^T (GenBank accession no. ABQT01000054) and 98.5% homology with the sequence of Helicobacter bilis Hb1^T (GenBank accession no. U18766). The patient was empirically treated with piperacillin/tazobactam and levofloxacin, and discharged with improvement on HD 31. To our knowledge, this is the first report of H. cinaedi bacteremia in an asplenic patient. Asplenia appears to be a risk factor for H. cinaedi bacteremia.

Refractory chronic pleurisy caused by Helicobacter equorum-like bacterium in a patient with X-linked agammaglobulinemia

We describe a 35-year-old man with X-linked agammaglobulinemia who had refractory chronic pleurisy caused by a Helicobacter equorum-like bacterium. Broad-range bacterial PCR targeting the 16S and 23S rRNA genes and in situ hybridization targeting the 16S rRNA gene of H. equorum confirmed the presence of this pathogen in a human for the first time.

Molecular Characterization of the 16S rRNA Gene of Helicobacter fennelliae Isolated from Stools and Blood Cultures from Paediatric Patients in South Africa

Forty strains of H. fennelliae collected from paediatric blood and stool samples over an 18 year period at a children's hospital in Cape Town, South Africa, were amplified by PCR of the 16S rRNA. Two distinct genotypes of H. fennelliae were identified based on the phylogenetic analysis. This was confirmed by sequencing a portion of the beta subunit of the RNA polymerase (rpoB) gene. All isolates from South Africa clustered with a proposed novel Helicobacter strain (accession number AF237612) isolated in Australia, while three H. fennelliae type strains from the northern hemisphere, NCTC 11612, LMG 7546 and CCUG 18820, formed a separate branch. A large (355bp) highly conserved intervening sequence (IVS) in the 16S rRNA was found in all isolates. Predicted secondary structures of the IVS from the 16S rRNA and 23S rRNA were characterised by a primary stem structure formed by base pairing of the 3′ and 5′ ends and internal loops and stems. This phylogenetic analysis is the largest undertaken of H. fennelliae. The South African H. fennelliae isolates are closely related to an Australian isolate previously reported to be a possible novel species of Helicobacter. This study suggests that the latter is strain of H. fennelliae.

Genetic characterization and epidemiology of Helicobacters in non-domestic animals

BACKGROUND

Novel helicobacter infections and associated disease are being recognized with increasing frequency in animals and people. Yet, the pervasiveness of infection in distantly related animal taxa, genetic diversity of helicobacters, and their transmissability are not known.

AIM

To better understand the ecology of helicobacters, we did a PCR survey and epidemiologic analysis of 154 captive or wild vertebrate taxa originating from 6 continents.

MATERIALS AND METHODS

One hundred twenty nine helicobacter 16s rRNA gene segments were amplified by PCR and sequenced from ninety-three mammalian, reptilian, avian, or amphibian host species. Prevalence estimates were generated, and univariate logistic regression analyses were used to explore relationships between infection status and the health and characteristics of the 220 individual animals.

RESULTS

One hundred and nineteen novel helicobacter DNA sequences were found. No significant relationship between infection and host health was found; however, multi-infection or infections with particular genotypes were associated with mild clinical signs. Phylogenetic and genetic comparisons of helicobacters suggested prolonged co-adaptation and niche-associated divergence as well as periodic inter-species transmission.

CONCLUSION

The genus Helicobacter should accordingly be viewed as a collection of hundreds of organisms that have colonized most tetrapod taxa and have the potential to expand into new hosts as contact among animals and between animals and people increases.

Emerging infections of the gastrointestinal tract

Infections account for significant GI morbidity and mortality worldwide. New organisms are being identified, associated with diarrhoeal illness and some with other gastrointestinal illness as well. Among GI viruses, Sapovirus is now recognised to cause diarrhoea, especially in children. A hypervirulent strain of Clostridium difficile has caused epidemics in many countries. Newly identified bacterial species that may cause diarrhoea include Campylobacter concisus, Arcobacteria, Edwardsiella tarda, Aeromonas, Plesiomonas and Laribacter. Helicobacteria are reviewed, as well as the role of gastric acid suppression in predisposing to enteric infections.

Protective immunization with homologous and heterologous antigens against Helicobacter suis challenge in a mouse model

Helicobacter (H.) suis colonizes the stomach of more than 60% of slaughter pigs and is also of zoonotic importance. Recently, this bacterium was isolated in vitro, enabling the use of pure cultures for research purposes. In this study, mice were immunized intranasally or subcutaneously with whole bacterial cell lysate of H. suis or the closely related species H. bizzozeronii and H. cynogastricus, and subsequently challenged with H. suis. Control groups consisted of non-immunized and non-challenged mice (negative control group), as well as of sham-immunized mice that were inoculated with H. suis (positive control group). Urease tests on stomach tissue samples at 7 weeks after challenge infection were negative in all negative control mice, all intranasally immunized mice except one, and in all and 3 out of 5 animals of the H. cynogastricus and H. suis subcutaneously immunized groups, respectively. H. suis DNA was detected by PCR in the stomach of all positive control animals and all subcutaneously immunized/challenged animals. All negative control animals and some intranasally immunized/challenged mice were PCR-negative. In conclusion, immunization using antigens derived from the same or closely related bacterial species suppressed gastric colonization with H. suis, but complete protection was only achieved in a minority of animals following intranasal immunization.

A Case of Helicobacter cinaedi Bacteraemia in a Previously Healthy Person with Cellulitis

Helicobacter cinaedi is an infrequent, but well recognized cause of gastroenteritis in immunosuppressed patients. Here we report a case of an extra-intestinal infection in a previous healthy 61-year old heterosexual male. Focus for the infection was most likely cellulitis on the lower right leg. The bacterium was cultured from blood twice within one week. Electron microscopy of the isolate visualized bipolar flagella. Partial DNA sequencing of the 16S rRNA gene and phenotypic characterization of the isolate established the species diagnosis. The patient was treated with rifampicin. After end of treatment blood cultures were negative and the cellulitis had disappeared.

Helicobacter pylori infection: further evidence for the role of feco-oral transmission

BACKGROUND

Helicobacter pylori infection is recognized as a major cause of chronic digestive diseases with a major public health impact, yet the knowledge of transmission pathways is limited. We studied the transmission in employees taking care of institutionalized persons with mental disabilities with a documented high prevalence of H. pylori.

MATERIALS AND METHODS

Six hundred and seventy-one health-care workers were screened for H. pylori serology. For each employee, information was collected on age, sex, father's and mother's education level, number of household members and number of children sleeping in the same bedroom during childhood, as well as lifestyle factors such as smoking and tropical journeys and occupational exposure data such as type of contact with inhabitants (changing napkins with stools, washing inhabitants, feeding inhabitants, personal contact) and seniority in the institution.

RESULTS

Seroprevalence for H. pylori increased significantly with age. In univariate analysis, risk factors for H. pylori positivity were (age-adjusted): father's education, mean length of employment, smoking, contact with fecal materials of inhabitants, washing and feeding of inhabitants. Controlling for confounders, in multiple logistic regression analysis, only fecal contact remained as a significant risk factor for H. pylori infection.

CONCLUSIONS

In health-care workers caring for a population with a high prevalence of H. pylori infection, there is an association with fecal transmission. This, however, does not rule out the possibility of other ways of transmission.

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.

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori infection

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Helicobacter species ribosomal DNA in the pancreas, stomach and duodenum of pancreatic cancer patients

AIM: To determine whether gastric and enteric Helicobacter species are associated with pancreatic cancer.

METHODS: Patients with exocrine pancreatic cancer (n = 40), neuroendocrine cancer (n = 14), multiple endocrine neoplasia type 1 (n = 8), and chronic pancreatitis (n = 5) were studied. Other benign pancreatic diseases (n = 10) and specimens of normal pancreas (n = 7) were included as controls. Pancreatic tissue specimens were analyzed by Helicobacter-specific PCR-assay and products were characterized by denaturing gradient electrophoresis and DNA-sequencing. From a subset of the pancreatic cancer patients, gastric and/or duodenal tissue as well as gallbladder and ductus choledochus tissue were analyzed. Gallbladder and choledochus samples were included as controls. Stomach and duodenum samples were investigated to analyze whether a gastric helicobacter might disseminate to the pancreas in pancreatic cancer patients. Pancreatic specimens were analyzed by Bacteroides-specific PCR for detecting the translocation of indigenous gut microbes to the diseased pancreas.

RESULTS: Helicobacter DNA was detected in pancreas (tumor and/or surrounding tissue) of 75% of patients with exocrine cancer, 57% of patients with neuroendocrine cancer, 38% of patients with multiple endocrine neoplasia, and 60% of patients with chronic pancreatitis. All samples from other benign pancreatic diseases and normal pancreas were negative. Thirty-three percent of the patients were helicobacter-positive in gastroduodenal specimens. Surprisingly, H. bilis was identified in 60% of the positive gastroduodenal samples. All gallbladder and ductus choledochus specimens were negative for helicobacter. Bacteroides PCR-assay was negative for all pancreatic samples.

CONCLUSION: Helicobacter DNA commonly detected in pancreatic cancer suggests a possible role of the emerging pathogens in the development of chronic pancreatitis and pancreatic cancer.

Helicobacter heilmanii gastritis in polymyositis

We report the original case of a patient with polymyositis (PM) who developed severe gastritis related to Helicobacter heilmanii. H. heilmanii eradication, using triple therapy with omeprazole, metronidazole and amoxicillin, resulted in the complete disappearance of digestive manifestations. As an association has been found between gastric adenocarcinoma/MALT lymphoma and both polymyositis/dermatomyositis (PM/DM) and H. heilmanii infection, respectively, we suspect that PM/DM patients who develop H. heilmanii infection may have a higher risk of gastric malignancy occurrence. Further studies are warranted to confirm whether Helicobacter species infections do, in fact, increase the risk of gastric adenocarcinoma/MALT lymphoma in patients with PM/DM.

Helicobacter heilmannii gastritis: a case study with review of literature

H. heilmannii belongs to the Helicobacter family and is found in a small number of gastric biopsies. This bacterium is generally found in primates, cats, pigs, and carnivorous mammals. About 0.5% to 6% of human gastric infections have been attributed to H. heilmannii. The bacterium usually induces mild chronic gastritis but may be associated with peptic ulceration, and rare cases were reported in association with gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. We report a case of H. heilmannii chronic gastritis in a 44-year-old man with a history of chronic heartburn, found to have erythema and granularity in the antrum. Antral biopsy showed mild chronic gastritis with prominent lymphoid aggregates, and rare long, thin, spiral bacilli were present adjacent to the surface epithelium. The long tightly coiled morphology suggestive of H. heilmannii was obvious at 1000 x magnification. The lack of information in the literature regarding cross-reactivity of H. heilmannii to commercially available antibodies used for immunohistochemical detection of H. pylori prompted us to evaluate whether commercially available polyclonal anti-H. pylori antibodies show cross-reactivity between the two organisms. The H. pylori immunostain highlighted H. heilmannii organisms and their characteristic morphology, confirming cross-reactivity with the anti-H. pylori polyclonal antibody. This case illustrates the potential contribution of commercially available polyclonal antibodies against H. pylori to help confirm a diagnosis of H. heilmannii gastritis. The use of immunohistochemical stain to identify H. heilmannii may be useful in cases with a paucity of organisms, with suggestive but not diagnostic forms on routine hematoxylin and eosin stain.

Evaluation of antibiotic treatment against "Candidatus Helicobacter suis" in a mouse model

"Helicobacter heilmannii" (proposed name) type 1 colonizes the human stomach. It has been shown to be identical to "Candidatus Helicobacter suis," a Helicobacter species colonizing the stomachs of >60% of slaughter pigs. This bacterium has not been isolated in vitro until now. Antibiotic susceptibility testing of "Candidatus Helicobacter suis" has not been carried out so far. For the present study, a mouse model was adopted to evaluate the antibiotic susceptibility of this organism. Mice infected with "Candidatus Helicobacter suis" were treated with amoxicillin and omeprazole, a therapy which is used to treat H. heilmannii infections in humans. Two different isolates of "Candidatus Helicobacter suis" were tested. The excretion of bacterial DNA was assessed during treatment, using PCR on fecal samples. At the end of the experiment, 8 days after the cessation of treatment, the presence of infection was evaluated using a urease test and a PCR test on stomach samples. A marked decrease in the excretion of bacterial DNA was observed a few days after the onset of treatment, and the level remained low until the end of the experiment. A difference in susceptibility between the two "Candidatus Helicobacter suis" isolates was pointed out. The in vivo mouse model infected with "Candidatus Helicobacter suis" will be useful for further screening of potential therapeutic regimens.

In VitroSusceptibility ofHelicobacter pullorumStrains to Different Antimicrobial Agents

The in vitro activity of 13 antimicrobial agents against 23 Helicobacter pullorum strains from poultry (21) and human (two) origin, and one human H. canadensis strain was tested by the agar dilution method. With the H. pullorum strains, monomodal distributions of Minimum Inhibitory Concentrations (MICs) were seen with lincomycin, doxycycline, gentamicin, tobramycin, erythromycin, tylosin, metronidazole, and enrofloxacin in concentration ranges considered as indicating susceptibility in other bacteria. The normal susceptibility level for nalidixic acid was situated at or slightly above the MIC breakpoints proposed for Campylobacteriaceae. Ampicillin, ceftriaxone, and sulphamethoxazole-trimethoprim showed poor activity against H. pullorum. For the H. canadensis strain, a similar susceptibility pattern was seen, except for nalidixic acid and enrofloxacin, whose MIC of >512 and 8 microg/ml, respectively, indicated resistance of this agent. With spectinomycin, a bimodal distribution of the MICs was noted for the tested strains; eight H. pullorum isolates originating from one flock showed acquired resistance (MIC>512 microg/ml).

Relationship between Helicobacter heilmannii infection and esophageal diseases in Chaoyang, Guangdong Province, China

AIM: To study the relationship of Helicobacter heilmannii (Hh) infection with esophageal diseases in Chaoyang, Guangdong Province, China.

METHODS: A total of 92 cases of endoscopic biopsies and esophagostomies were collected. Hh and Helicobacter pylori (H. pylori) infection were detected by Warthin-Starry silver stain.

RESULTS: Among 92 cases, 43 cases were Hh positive (46.74%), 32 cases were H. pylori positive (37.78%), and mixed infection with Hh and H. pylori were detected in 12 cases (13.04%). Among 43 Hh positive cases, there were 19 cases of esophageal carcinoma, 14 esophagocardiac adenocarcinoma, 3 esophageal ulcers, 4 epithelial hyperplasia, 1 esophagitis and 1 Barrett esophagitis. Following-up data showed that 16 patients had a history of raising dogs, swines or cats, in which Hh infection were found in 10.23 patients denied having a history to contact the animals mentioned above, in which 8 cases were Hh positive.

CONCLUSION: Hh infection has a close connection with esophageal carcinoma, cardiac adenocarcinoma and epithelial hyperplasia, and may be a high risk factor for those diseases in the area. The pathogenesis of the disease may be related to domestic animal raising.

Helicobacter pylori and extragastric diseases -- other helicobacters

The role of Helicobacter pylori infection is explored in more and more extragastric diseases without definite proof in most of the studies, except possibly some hematologic diseases. In cardiovascular diseases, including stroke, the presence of CagA positive strains may be involved. The possible role of helicobacters in hepatobiliary diseases goes beyond that of H. pylori to involve enterohepatic helicobacters. New Helicobacter species are regularly described and molecular methods are developed to improve their detection. Helicobacter felis remains the major species to be used in animal models of Helicobacter infection.