As only few infected humans develop the most severe clinical outcomes, there have been important efforts for identifying and understanding factors predicting bacterial virulence. Confirmation of the proposed mechanism requires elimination of the effect by gene deletion and restoration. Pathogenesis of helicobacter pylori infection clinical. Summary the criteria for a virulence factor include evidence of an association with a disease or a disease surrogate such as the severity of mucosal inflammation, epidemiologic consistency, and biologic plausibility. This discrepancy can be explained in part by the presence of h. There are four species of plasmodium that cause the disease malaria, of which p. Expression of helicobacter pylori virulence factors and. Helicobacter pylori and related virulence factors for. Detection of helicobacter pylori and its virulence genes caga, dupa, and vaca among patients with gastroduodenal diseases in chris hani baragwanath academic hospital, south africa.
This study assessed the significance of possession of both virulence factors in terms of their effect on gastric epithelial cells, using a set of minimally passaged, isogenic vaca, caga and. True virulence factors must therefore have a disease association. Pathogenesis of helicobacter pylori infection maeda. In the past 10 years, tremendous progress has been made in understanding the mechanisms by which h. Molecular mechanisms of helicobacter pylori pathogenesis. Helicobacter pylori colonises the gastric mucosa of humans and causes both antral gastritis and duodenal ulcer disease. In this context, necessary adhesion molecules and significant virulence factors of h. In addition, it explores the epidemiology, diagnosis, treatment with drugs and probiotics, and prophylaxis. Understanding the mechanism of action of the major h. Gram negative pathogenic bateria flashcards quizlet. Despite advances in our understanding of the development of h. Only 15% of those colonized develop disease, and pathogenesis depends upon strain virulence, host genetic susceptibility, and environmental cofactors.
Virulence factors, helicobacter pylori, gastric adenocarcinoma, gastric b cell lymphoma, peptic ulcer disease. Helicobacter pylori in human diseases springerlink. Helicobacter pylori cagapositive strains are much more potent in inducing gastric cancer, and caga can augment the risk of the likelihood of gastric cancer. Helicobacter pylori can survive in the acidic environment of the stomach because it is a spore former and the spores can survive the acid environment. Molecular mechanism of action of major helicobacter pylori. The helicobacter pylori urease virulence factor is. Helicobacter pylori can survive in the acidic environment of the stomach because even though it prefers. Helicobacter pylori, a common human pathogen, which infects about 50% of the worlds population, is associated with duodenal and peptic ulcer diseases. Classification of helicobacter pylori virulence factors.
These bacterial determinants can be distinguished as cellbinding factors, immunoregulatory components, survival factors, toxins, and effector proteins. Hpu is one of the most important virulence factors of h. Helicobacter pylori virulence factors are soluble, cell. Bacterial infection causes an inflammatory response that proceeds through a series of intermediated stages of precancerous lesions gastritis, atrophy, intestinal metaplasia, and dysplasia. Helicobacter pylori do not invade tissues, but the infection causes intense inflammation and immune response. Summary helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the worlds population is colonized with this gramnegative bacterium. The clinical outcome of helicobacter pylori infection is determined by a complex interaction between the bacterium and the host. Mechanisms of the epithelialmesenchymal transition and. Das2 and gauranga mukhopadhyay1 1 special centre for molecular medicine, jawaharlal nehru university.
Confirmation of the proposed mechanism requires elimination of the effect by gene deletion and restoration by complementation. Interplay between helicobacter pylori and immune cells in. This bacterium is closely associated with serious human diseases such as gastric cancer. Yoshio yamaoka department of environmental and preventive medicine, oita university faculty of medicine, idaigaoka, hasamamachi, yufucity, oita 8795593, japan. This book gathers a wealth of contributions on the virulence factors and pathogenic mechanism of helicobacter pylori, prepared by leading international experts. Learn vocabulary, terms, and more with flashcards, games, and other study tools. However, it is still unclear why the pathogenicity of h. However, the influence of these virulence factors on the pathogenesis. Functional association between the helicobacter pylori. The main bacterial factors associated with pathogenicity comprise outer membrane proteins, including baba, saba, oipa, alpa, and alpb, the vacuolating cytotoxin vaca and the products of cagpai.
Radzikowska 6 and piero portincasa 7 1 chair and department of anatomy, medical university of lublin, 20090 lublin, poland. Pdf helicobacter pylori virulence factors exploiting. Helicobacter pylori is one of the most common infectious diseases in humans and causes gastritis, peptic ulcer disease and malignant tumours of the stomach. Virulence factors of helicobacter pylori and their relationship with the development of early and advanced distal intestinal type gastric adenocarcinoma. Helicobacter pylori related gastric carcinogenesis. The multitude of putative virulence factors makes it extremely.
Helicobacter pylori is a bacterium frequently found in the mucus layer of the stomach. Although helicobacter pylori infects 50% of the total human population, only a small fraction of the infected people suffer from severe diseases like pepti. The virulence factors responsible for establishing colonization include urease, flagella, chemotaxis system, and adhesins 2, 3. The helicobacter pylori virulence factors caga and vaca are implicated in the development of gastroduodenal diseases. Detection of helicobacter pylori and its virulence genes. Chronic helicobacter pylori infection increases the risk of gastric cancer and induction of hypoxiainduced factor hif, which is frequently associated with the development and progression of several types of cancer. Abstract helicobacter pylori is the main cause of peptic ulceration, distal gastric adenocarcinoma, and gastric lymphoma. Since its discovery, helicobacter pylori has been identified as the causative agent of various gastric diseases. Helicobacter pylori virulence factors have been suggested to be important in determining the outcome of infection.
Pdf molecular mechanism of action of major helicobacter. Virulence factors include the cag pathogenicity island. Helicobacter pylori virulence factor caga cytotoxinassociated gene a is a 120145kda protein encoded on the 40kb cag pathogenicity island pai. This study aimed at determining the prevalence of h.
Helicobacter pylori is the main cause of peptic ulceration, distal gastric adenocarcinoma, and gastric lymphoma. Yoshio yamaoka, department of environmental and preventive medicine, oita university faculty of medicine, idaigaoka, hasamamachi, yufucity, oita 8795593, japan. Helicobacter pylori pathogenesis and disease outcomes are mediated by a complex interplay between bacterial virulence factors, host, and environmental factors. Helicobacter pylori plays an essential role in the development of various gastroduodenal diseases. Helicobacter pylori a worldwide spread bacteriumis still infecting more than half of humans. Helicobacter pylori is a gramnegative spiralshaped bacterium that colonizes over half of the worlds population. It is the combination of bacterial factors, the genetic background of the individual, and environmental factors that determines disease outcome. Cell envelope characteristics of helicobacter pylori.
Pdf detection of helicobacter pylori and its virulence. Helicobacter pylori virulence factors exploiting gastric colonization and its pathogenicity article pdf available in toxins 1111. These include adhesins, cytotoxins and a range of different enzymes including urease, catalase and superoxide dismutase. The hosts biological changes due to the virulence factors are a valuable pillar of h. Unless treated, colonization usually persists lifelong.
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