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Toxins Mar 2017colonizes the human stomach and induces inflammation, and in some cases persistent infection can result in gastric cancer. Attachment to the gastric mucosa is the first... (Review)
Review
colonizes the human stomach and induces inflammation, and in some cases persistent infection can result in gastric cancer. Attachment to the gastric mucosa is the first step in establishing bacterial colonization, and outer membrane proteins (OMPs) play a pivotal role in binding to human cells. Some OMP interaction molecules are known in , and their associated host cell responses have been gradually clarified. Many studies have demonstrated that OMPs are essential to CagA translocation into gastric cells via the Type IV secretion system of . This review summarizes the mechanisms through which utilizes OMPs to colonize the human stomach and how OMPs cooperate with the Type IV secretion system.
Topics: Animals; Bacterial Outer Membrane Proteins; Helicobacter pylori; Humans; Virulence Factors
PubMed: 28287480
DOI: 10.3390/toxins9030101 -
Current Microbiology Jul 2017This review aimed to investigate the role of Helicobacter pylori flagella on the pathogenicity of this bacterium in humans. Helicobacter pylori is a flagellated... (Review)
Review
This review aimed to investigate the role of Helicobacter pylori flagella on the pathogenicity of this bacterium in humans. Helicobacter pylori is a flagellated pathogen that colonizes the human gastroduodenal mucosa and produces inflammation, and is responsible for gastrointestinal disease. Its pathogenesis is attributed to colonization and virulence factors. The primary function of H. pylori flagella is to provide motility. We believe that H. pylori flagella play an important role in the colonization of the gastrointestinal mucosa. Therefore, we reviewed previous studies on flagellar morphology and motility in order to explore the relationship between H. pylori flagella and pathogenicity. Further investigation is required to confirm the association between flagella and pathogenicity in H. pylori.
Topics: Animals; Bacterial Proteins; Flagella; Gastric Mucosa; Gene Expression Regulation, Bacterial; Helicobacter Infections; Helicobacter pylori; Humans
PubMed: 28444418
DOI: 10.1007/s00284-017-1256-4 -
World Journal of Gastroenterology Sep 2014Since the discovery of Helicobacter pylori (H. pylori) in 1983, numerous detection methods for the presence of the bacterium have been developed. Each one of them has... (Review)
Review
Since the discovery of Helicobacter pylori (H. pylori) in 1983, numerous detection methods for the presence of the bacterium have been developed. Each one of them has been associated with advantages and disadvantages. Noninvasive tests such as serology, (13)C urea breath test (UBT) and stool antigen tests are usually preferred by the clinicians. Serology has its own limitation especially in endemic areas while (13)C UBT is technically very demanding. The stool antigen detection method, although specific, is usually associated with poor sensitivity. The (13)C UBT is believed to be specific, but with present revelation of the fact that stomach is colonized by many other urease producing bacteria makes it questionable. Histology, culture, rapid urease test and polymerase chain reaction (PCR) are the tests which are carried out on antral biopsies collected by invasive means. Histology has been proposed to be very sensitive and specific but the question is how by simply looking the morphology of the bacteria in the microscope, one can claim that the curved bacterium is exclusively H. pylori. Rapid urease test (RUT), the doctor's test, is also challenged because the presence of other urease producing bacteria in the stomach cannot be denied. Moreover, RUT has been reported with poor sensitivity specially, when density of the bacterium is low. Isolation of H. pylori is essential to investigate its growth requirements, antibiotic susceptibility testing, studying virulence factor to develop vaccine and many more explorations. It has also got several disadvantages i.e., special condition for transporting, media, incubation and few days waiting for the colonies to appear, apart from the speed essentially needed to process the specimens. Till date, majority of the microbiological laboratories in the world are not equipped and trained to isolate such fastidious bacterium. The option left is PCR methods to detect H. pylori's DNA in gastric mucosa, gastric juice, saliva, dental plaques and environmental specimens. There are speculations for false positivity due to detection of non-pylori Helicobacters due to genetic sharing; and false negativity due to low bacterial counts and presence of PCR inhibitors. However, specimen collection, transportation and processing do not require speed and special conditions. PCR based diagnosis may be considered as gold standard by designing primers extremely specific to H. pylori and targeting at least more than one conserved genes. Similarly specificity of PCR may be improved by use of internal Primers. Further, nested PCR will take care of false negatives by countering the effect of PCR inhibitors and low bacterial counts. Therefore, nested PCR based methods if performed properly, may be proposed as gold standard test.
Topics: Antigens, Bacterial; Bacteriological Techniques; Biomarkers; Biopsy; Breath Tests; DNA, Bacterial; Feces; Helicobacter Infections; Helicobacter pylori; Humans; Polymerase Chain Reaction; Predictive Value of Tests; Prognosis; Reproducibility of Results; Serology; Stomach
PubMed: 25278682
DOI: 10.3748/wjg.v20.i36.12847 -
Journal of Microbiology, Immunology,... Jun 2017The genus Helicobacter contains more than 35 species. Helicobacter pylori is the most important in terms of human health. Discovery of these helicobacters gives... (Review)
Review
The genus Helicobacter contains more than 35 species. Helicobacter pylori is the most important in terms of human health. Discovery of these helicobacters gives opportunity to understand the relationship between these bacteria which colonise the animal and human gut and their effect on the host. Infection with Helicobacter spp. and the associated diseases in their hosts allow us to study the pathogenic mechanisms. The potential zoonotic pathway for the transmission of Helicobacter spp. and epidemiology of this genus, deserve more attention to these emerging pathogens.
Topics: Animals; Disease Transmission, Infectious; Helicobacter; Helicobacter Infections; Humans; Zoonoses
PubMed: 28655571
DOI: 10.1016/j.jmii.2016.11.003 -
Helicobacter Sep 2018Helicobacter pylori infection induces a chronic gastric inflammation which can lead to gastric ulcers and cancer. The mucosal immune response to H. pylori is first... (Review)
Review
Helicobacter pylori infection induces a chronic gastric inflammation which can lead to gastric ulcers and cancer. The mucosal immune response to H. pylori is first initiated by the activation of gastric epithelial cells that respond to numerous bacterial factors, such as the cytotoxin-associated gene A or the lipopolysaccharide intermediate heptose-1,7-bisphosphate. The response of these cells is orchestrated by different receptors including the intracellular nucleotide-binding oligomerization domain-containing protein 1 or the extracellular epidermal growth factor receptor. This nonspecific response leads to recruitment and activation of various myeloid (macrophages and dendritic cells) and T cells (T helper-17 and mucosal-associated invariant T cells), which magnify and maintain inflammation. In this review, we summarize the major advances made in the past year regarding the induction, the regulation, and the role of the innate and adaptive immune responses to H. pylori infection. We also recapitulate efforts that have been made to develop efficient vaccine strategies.
Topics: Animals; Bacterial Vaccines; Epithelial Cells; Helicobacter Infections; Helicobacter pylori; Humans; Inflammation; Myeloid Cells
PubMed: 30277626
DOI: 10.1111/hel.12517 -
Arquivos de Gastroenterologia 2023•Clinical studies have shown that hepatobiliary diseases of inflammatory and neoplastic origin are associated with Helicobacter infection. •Translocation and the...
•Clinical studies have shown that hepatobiliary diseases of inflammatory and neoplastic origin are associated with Helicobacter infection. •Translocation and the ascending pathway are putative mechanisms for Helicobacter spp to enter the hepatobiliary system. •H. pylori infection has a systemic effect through the activity of pro-inflammatory cytokines, TNF-α, leukotrienes, interferon-β, interferon-γ, and acute phase proteins. •Histopathological confirmation is needed to present that H. pylori eradication prevents or improves hepatobiliary disease progression. Helicobacter Pylori (H. pylori) is one of the main infectious causes of gastroduodenal diseases, however, its role in developing different extragastric diseases has been proven. The possible involvement of H. pylori in the pathogenesis of cardiovascular, metabolic, neurodegenerative, skin, and hepatobiliary diseases is suggested. The bacterium has been found in tissue samples from the liver, biliary tract, and gallstones of animals and humans. However, the role of H. pylori infection in the pathogenesis of liver and biliary diseases has not been finally established. The histopathological confirmation of the positive effect of H. pylori eradication is needed. In addition, there are discussions on the clinical significance of other Helicobacter species. The review presents the data available for and against the involvement of H. pylori in hepatobi-liary disease development and progression.
Topics: Animals; Humans; Helicobacter; Helicobacter pylori; Liver; Digestive System Diseases; Helicobacter Infections
PubMed: 37556754
DOI: 10.1590/S0004-2803.202302023-15 -
Veterinary Research Jun 2022This article focuses on the pathogenic significance of Helicobacter species naturally colonizing the stomach of dogs, cats and pigs. These gastric "non-Helicobacter (H.)... (Review)
Review
This article focuses on the pathogenic significance of Helicobacter species naturally colonizing the stomach of dogs, cats and pigs. These gastric "non-Helicobacter (H.) pylori Helicobacter species" (NHPH) are less well-known than the human adapted H. pylori. Helicobacter suis has been associated with gastritis and decreased daily weight gain in pigs. Several studies also attribute a role to this pathogen in the development of hyperkeratosis and ulceration of the non-glandular stratified squamous epithelium of the pars oesophagea of the porcine stomach. The stomach of dogs and cats can be colonized by several Helicobacter species but their pathogenic significance for these animals is probably low. Helicobacter suis as well as several canine and feline gastric Helicobacter species may also infect humans, resulting in gastritis, peptic and duodenal ulcers, and low-grade mucosa-associated lymphoid tissue lymphoma. These agents may be transmitted to humans most likely through direct or indirect contact with dogs, cats and pigs. Additional possible transmission routes include consumption of water and, for H. suis, also consumption of contaminated pork. It has been described that standard H. pylori eradication therapy is usually also effective to eradicate the NHPH in human patients, although acquired antimicrobial resistance may occasionally occur and porcine H. suis strains are intrinsically less susceptible to aminopenicillins than non-human primate H. suis strains and other gastric Helicobacter species. Virulence factors of H. suis and the canine and feline gastric Helicobacter species include urease activity, motility, chemotaxis, adhesins and gamma-glutamyl transpeptidase. These NHPH, however, lack orthologs of cytotoxin-associated gene pathogenicity island and vacuolating cytotoxin A, which are major virulence factors in H. pylori. It can be concluded that besides H. pylori, gastric Helicobacter species associated with dogs, cats and pigs are also clinically relevant in humans. Although recent research has provided better insights regarding pathogenic mechanisms and treatment strategies, a lot remains to be investigated, including true prevalence rates, exact modes of transmission and molecular pathways underlying disease development and progression.
Topics: Animals; Cat Diseases; Cats; Cytotoxins; Dog Diseases; Dogs; Gastric Mucosa; Gastritis; Helicobacter; Helicobacter Infections; Helicobacter heilmannii; Helicobacter pylori; Humans; Swine; Swine Diseases; Virulence Factors
PubMed: 35692057
DOI: 10.1186/s13567-022-01059-4 -
World Journal of Gastroenterology Feb 2015Hepatobiliary cancers are highly lethal cancers that comprise a spectrum of invasive carcinomas originating in the liver hepatocellular carcinoma, the bile ducts... (Review)
Review
Hepatobiliary cancers are highly lethal cancers that comprise a spectrum of invasive carcinomas originating in the liver hepatocellular carcinoma, the bile ducts intrahepatic cholangiocarcinoma and extrahepatic cholangiocarcinoma, the gallbladder and the ampulla of Vater (collectively known as biliary tract cancers). These tumors account for approximately 13% of all annual cancer-related deaths worldwide and for 10%-20% of deaths from hepatobiliary malignancies. Cholangiocarcinoma (CCA) is a devastating disease that displays a poor survival rate for which few therapeutic options are available. Population genetics, geographical and environmental factors, cholelithiasis, obesity, parity, and endemic infection with liver flukes have been identified as risk factors that influence the development of biliary tract tumors. Other important factors affecting the carcinogenesis of these tumors include chronic inflammation, obstruction of the bile ducts, and impaired bile flow. It has been suggested that CCA is caused by infection with Helicobacter species, such as Helicobacter bilis and Helicobacter hepaticus, in a manner that is similar to the reported role of Helicobacter pylori in distal gastric cancer. Due to the difficulty in culturing these Helicobacter species, molecular methods, such as polymerase chain reaction and sequencing, or immunologic assays have become the methods of choice for diagnosis. However, clinical studies of benign or malignant biliary tract diseases revealed remarkable variability in the methods and the findings, and the use of uniform and validated techniques is needed.
Topics: Animals; Biliary Tract Neoplasms; Cell Transformation, Neoplastic; Helicobacter; Helicobacter Infections; Host-Pathogen Interactions; Humans; Liver Neoplasms; Prognosis; Risk Assessment; Risk Factors
PubMed: 25663761
DOI: 10.3748/wjg.v21.i5.1414 -
FEMS Immunology and Medical Microbiology Feb 2011The discovery of Helicobacter pylori sparked a revolution in the understanding and management of peptic ulcer disease and gastric cancer. Other Helicobacter species are... (Review)
Review
The discovery of Helicobacter pylori sparked a revolution in the understanding and management of peptic ulcer disease and gastric cancer. Other Helicobacter species are recognized as important pathogenic agents in colitic diseases of rodents and primates, in particular Helicobacter bilis, Helicobacter fennelliae, Helicobacter hepaticus and Helicobacter trogontum. Helicobacter bilis and H. hepaticus are now routinely used to initiate rodent models of inflammatory bowel disease (IBD), particularly in immunocompromised hosts. Molecular evidence exists linking various non-pylori Helicobacter spp. with human IBD; however, attempts to culture organisms in this disease cohort have proved unsuccessful to date. Attributing causation has therefore proved elusive. Seven enterohepatic, non-pylori Helicobacter organisms have been successfully cultured from humans, namely Helicobacter canadensis, Helicobacter canis, Helicobacter cinaedi, H. fennelliae, Helicobacter pullorum, Helicobacter winghamensis and Helicobacter sp. flexispira taxon 8 (now classified as H. bilis). Of these, H. cinaedi and H. fennelliae are the closest to fulfilling Koch's postulates as causative agents in homosexual proctitis. The possibility that novel Helicobacter organisms have a role in the initiation of human IBD warrants further consideration and targeted investigations.
Topics: Animals; Disease Models, Animal; Gastrointestinal Diseases; Helicobacter; Helicobacter Infections; Helicobacter pylori; Humans; Inflammatory Bowel Diseases
PubMed: 20955468
DOI: 10.1111/j.1574-695X.2010.00744.x -
Helicobacter Feb 2022Helicobacter pylori infection is a well-established risk factor for gastric cancer and has been linked to other gastrointestinal diseases, including pancreatic and...
BACKGROUND
Helicobacter pylori infection is a well-established risk factor for gastric cancer and has been linked to other gastrointestinal diseases, including pancreatic and biliary tract cancers; however, the relevance of enterohepatic non-H. pylori helicobacters to the pathophysiology of these diseases remains unclear.
MATERIALS AND METHODS
We estimated the prevalence of two enterohepatic non-H. pylori helicobacters (Helicobacter hepaticus and Helicobacter bilis) in the framework of a hospital-based case-control study involving 121 patients with biliary tract cancer, pancreatic cancer, or other gastrointestinal diseases. Bile and blood samples were collected from the patients undergoing endoscopic retrograde cholangiopancreatography. The presence of H. bilis, H. hepaticus, and other Helicobacter spp. was examined using bacterial culture, PCR-based detection, and serological tests.
RESULTS
Culture of Helicobacter spp. from biliary brush samples was unsuccessful. Approximately 13.0% (15/115) of the bile samples collected from patients with a variety of gastrointestinal cancers, including pancreatic and biliary tract cancers, tested positive for one of the enterohepatic non-H. pylori helicobacter species as determined by PCR. Specifically, H. bilis and H. hepaticus DNA were detected in 11 and 4 bile samples, respectively. Approximately 20%-40% of the patients tested positive for serum non-H. pylori helicobacter IgG antibodies. The seroprevalence of H. bilis and H. hepaticus in the patients without evidence of H. pylori infection appeared to be higher in the pancreatic cancer group than in the control group.
CONCLUSION
Our findings suggest a role for Helicobacter spp., especially H. bilis and H. hepaticus, in the etiology of pancreatic and biliary tract cancers.
Topics: Biliary Tract Neoplasms; Case-Control Studies; Helicobacter; Helicobacter Infections; Helicobacter pylori; Humans; Prevalence; Seroepidemiologic Studies
PubMed: 35005807
DOI: 10.1111/hel.12866