Helicobacter pylori is the main cause of peptic ulceration, distal gastric adenocarcinoma, and gastric lymphoma. Frontiers metalloregulation of helicobacter pylori. Helicobacter pylori related gastric carcinogenesis. Helicobacter pylori an overview sciencedirect topics. Cell envelope characteristics of helicobacter pylori. 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. 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. Classification of helicobacter pylori virulence factors. Molecular mechanism of action of major helicobacter pylori.
Pdf detection of helicobacter pylori and its virulence. These include adhesins, cytotoxins and a range of different enzymes including urease, catalase and superoxide dismutase. Detection of helicobacter pylori and its virulence genes. Das2 and gauranga mukhopadhyay1 1 special centre for molecular medicine, jawaharlal nehru university. Most strains possessing caga also possess the more virulent vacuolating form of vaca. Virulence factors, helicobacter pylori, gastric adenocarcinoma, gastric b cell lymphoma, peptic ulcer disease. Gram negative pathogenic bateria flashcards quizlet. Helicobacter pylori plays an essential role in the development of various gastroduodenal diseases.
It is the combination of bacterial factors, the genetic background of the individual, and environmental factors that determines disease outcome. Helicobacter pylori is a spiralshaped gramnegative bacterium that colonizes the human stomach and can establish a longterm infection of the gastric mucosa, a condition that affects the relative risk of developing various clinical disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, mucosaassociated lymphoid tissue malt lymphoma, and gastric. Pathogenesis of helicobacter pylori infection clinical. Understanding the mechanism of action of the major h. Since its discovery, helicobacter pylori has been identified as the causative agent of various gastric diseases.
It is essential for bacterial colonization of human gastric mucosa and is involved in the pathogenesis of gastric and peptic ulcers cellini and donelli, 2000. Helicobacter pylori virulence factor caga cytotoxinassociated gene a is a 120145kda protein encoded on the 40kb cag pathogenicity island pai. This book gathers a wealth of contributions on the virulence factors and pathogenic mechanism of helicobacter pylori, prepared by leading international experts. Helicobacter pylori virulence factors exploiting gastric colonization and its pathogenicity article pdf available in toxins 1111. Mechanisms of the epithelialmesenchymal transition and. Confirmation of the proposed mechanism requires elimination of the effect by gene deletion and restoration by complementation. Helicobacter pylori, a common human pathogen, which infects about 50% of the worlds population, is associated with duodenal and peptic ulcer diseases. Virulence factors of helicobacter pylori and their relationship with the development of early and advanced distal intestinal type gastric adenocarcinoma. This discrepancy can be explained in part by the presence of h. Helicobacter pylori a worldwide spread bacteriumis still infecting more than half of humans. 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.
Xiang z, censini s, bayeli pf, telford jl, figura n, rappuoli r, covacci a 1995 analysis of expression of caga and vaca virulence factors in 43 strains of helicobacter pylori reveals that clinical isolates can be divided into two major types and that caga is not necessary for expression of the vacuolating cytotoxin. Helicobacter pylori pathogenesis and disease outcomes are mediated by a complex interplay between bacterial virulence factors, host, and environmental factors. Helicobacter pylori do not invade tissues, but the infection causes intense inflammation and immune response. Virulence factors include the cag pathogenicity island. Helicobacter pylori and related virulence factors for. In this context, necessary adhesion molecules and significant virulence factors of h. 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. Bacterial infection causes an inflammatory response that proceeds through a series of intermediated stages of precancerous lesions gastritis, atrophy, intestinal metaplasia, and dysplasia. In addition, it explores the epidemiology, diagnosis, treatment with drugs and probiotics, and prophylaxis. Helicobacter pylori cagapositive strains are much more potent in inducing gastric cancer, and caga can augment the risk of the likelihood of gastric cancer. Hpu is one of the most important virulence factors of h. Yoshio yamaoka department of environmental and preventive medicine, oita university faculty of medicine, idaigaoka, hasamamachi, yufucity, oita 8795593, japan. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Recently, the central role of outer membrane vesicles omvs produced by h pylori on the distribution of bacterial antigens was suggested. The virulence factors responsible for establishing colonization include urease, flagella, chemotaxis system, and adhesins 2, 3. Molecular mechanisms of helicobacter pylori pathogenesis. In the past 10 years, tremendous progress has been made in understanding the mechanisms by which h. Functional association between the helicobacter pylori.
Helicobacter pylori is a gramnegative spiralshaped bacterium that colonizes over half of the worlds population. Helicobacter pylori is one of the most common infectious diseases in humans and causes gastritis, peptic ulcer disease and malignant tumours of the stomach. However, the influence of these virulence factors on the pathogenesis. True virulence factors must therefore have a disease association. Yoshio yamaoka, department of environmental and preventive medicine, oita university faculty of medicine, idaigaoka, hasamamachi, yufucity, oita 8795593, japan. This study aimed at determining the prevalence of h. The helicobacter pylori virulence factors caga and vaca are implicated in the development of gastroduodenal diseases. As only few infected humans develop the most severe clinical outcomes, there have been important efforts for identifying and understanding factors predicting bacterial virulence. The hosts biological changes due to the virulence factors are a valuable pillar of h. Pathogenesis of helicobacter pylori infection maeda. Radzikowska 6 and piero portincasa 7 1 chair and department of anatomy, medical university of lublin, 20090 lublin, poland. Helicobacter pylori in human diseases springerlink. The helicobacter pylori urease virulence factor is.
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. This bacterium is closely associated with serious human diseases such as gastric cancer. Helicobacter pylori virulence factors have been suggested to be important in determining the outcome of infection. Interplay between helicobacter pylori and immune cells in. Pdf helicobacter pylori virulence factors exploiting. However, it is still unclear why the pathogenicity of h. Confirmation of the proposed mechanism requires elimination of the effect by gene deletion and restoration. Expression of helicobacter pylori virulence factors and. Only 15% of those colonized develop disease, and pathogenesis depends upon strain virulence, host genetic susceptibility, and environmental cofactors. Helicobacter pylori virulence factors are soluble, cell. The clinical outcome of helicobacter pylori infection is determined by a complex interaction between the bacterium and the host. Although helicobacter pylori infects 50% of the total human population, only a small fraction of the infected people suffer from severe diseases like pepti. There are four species of plasmodium that cause the disease malaria, of which p. Unless treated, colonization usually persists lifelong.
Helicobacter pylori colonises the gastric mucosa of humans and causes both antral gastritis and duodenal ulcer disease. Despite advances in our understanding of the development of h. These bacterial determinants can be distinguished as cellbinding factors, immunoregulatory components, survival factors, toxins, and effector proteins. Helicobacter pylori can survive in the acidic environment of the stomach because even though it prefers. Helicobacter pylori is a bacterium frequently found in the mucus layer of the stomach. Bacterial pathogenic or virulence factors can be grouped into those that are conserved among all strains of h.
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