Helicobacter pylori: a review

Helicobacter pylori is a gram-negative bacterium that was first isolated in 1982. In the years following its discovery, H. pylori infection in humans has been shown to be associated with gastritis, peptic ulcer disease, and gastric carcinoma, as well as other, nongastrointestinal disorders. The epidemiology, transmission, and virulence factors of this bacteria have been an area of intense study. Successful treatment improves cure rates of gastritis and ulceration of the stomach and duodenum. Treatment with antimicrobials also decreases the recurrence rates of these diseases. Clinicians have numerous diagnostic tools and treatment options at their disposal. Vaccination in high-endemic areas may be available in the near future. Here, we review the pharmalogical basis of these treatment options, including their efficacy and economic considerations.     

Helicobacter pylori: 20 years on

Helicobacters are a new genus of bacteria, inhabiting the interface between mucosa and lumen of the gut. Microaerophilic, spiral, flagellated and urease positive, they possess features necessary for colonisation of the juxtamucosal mucus environment. Helicobacter pylori is the major pathogenic species. Once attached to the gastric epithelial cells, it incites an immune response characterised histologically by the development of active gastritis and immunologically by the presence of specific IgG. Persistence of infection is ensured by attachment to tissue antigens (eg Lewis B), a vacuolating toxin (VacA) which assists the free passage of urea through epithelial cells, and a cytotoxin (CagA) which is actually injected into the epithelial cells via a Type IV secretion system. Finally, during the typical lifelong chronic infection, two important diseases occur. H. pylori alters gastric physiology to cause acid hypersecretion and peptic ulcer. Secondly, it damages the acid secreting mucosa leading to atrophic gastritis and gastric cancer risk.     

Helicobacter pylori therapy: a paradigm shift

Helicobacter pylori (H. Pylori) is a leading cause of gastroduodenal disease, including gastric cancer. H. pylori eradication therapies and their efficacy are summarized. A number of current treatment regimens will reliably yield >90% or 95% cure rates with susceptible strains. None has proven to be superior. We show how to predict the efficacy of a regimen in any population provided one knows the prevalence of antibiotic resistance. As with other infectious diseases, therapy should always be susceptibility-based. Susceptibility testing should be demanded. We provide recommendations for empiric therapies when that is the only option and describe how to distinguish studies providing misinformation from those providing reliable and interpretable data. When treated as an infectious disease, high H. pylori cure rates are relatively simple to reliably achieve.     

Helicobacter pylori persistence: biology and disease

Helicobacter pylori are bacteria that have coevolved with humans to be transmitted from person to person and to persistently colonize the stomach. Their population structure is a model for the ecology of the indigenous microbiota. A well-choreographed equilibrium between bacterial effectors and host responses permits microbial persistence and health of the host but confers risk of serious diseases, including peptic ulceration and gastric neoplasia.     

Helicobacter pylori infection: diagnosis and treatment

Helicobacter pylori is one of the most common infections worldwide. Eradication of this important pathogen would lead to virtual elimination of the second most common cancer worldwide - gastric cancer. A variety of accurate diagnostic tests are available but current therapeutic regimens are generally unsatisfactory, with failure rates of between 20 and 40%. Difficulty in curing the infection has led to a three-step approach: diagnosis, therapy and confirmation of cure. Better studies, including head-to-head comparison of different drugs, drug formulations, dosing intervals, dosing in relation to meals, and duration of therapy are needed. The high rates of reinfection and the lack of improvements in standards of living in developing countries makes the development of a vaccine a high priority.     

Helicobacter pylori infection: diagnosis and treatment

Helicobacter pylori is one of the most common infections worldwide. Eradication of this important pathogen would lead to virtual elimination of the second most common cancer worldwide – gastric cancer. A variety of accurate diagnostic tests are available but current therapeutic regimens are generally unsatisfactory, with failure rates of between 20 and 40%. Difficulty in curing the infection has led to a three-step approach: diagnosis, therapy and confirmation of cure. Better studies, including head-to-head comparison of different drugs, drug formulations, dosing intervals, dosing in relation to meals, and duration of therapy are needed. The high rates of reinfection and the lack of improvements in standards of living in developing countries makes the development of a vaccine a high priority.     

Helicobacter pylori: an emerging infectious disease

Helicobacter pylori is the most common chronic bacterial infection in the world, colonizing the stomachs of more than 50% of the human population. The discovery of this bacterium has changed the concept of care and management for peptic ulcer disease, mucosa-associated lymphomas, gastritis, and gastric carcinoma. Although the mode of transmission is not definitively known, person-to-person contact is suspected. This article discusses H. pylori, the associated clinical syndromes and diseases, risk factors, and current pharmacologic management.     

Treatment of Helicobacter pylori infection

Helicobacter pylori infection has been shown to be the principal cause of peptic ulcer disease and has been associated with MALT lymphoma and gastric cancer. Eradication of H. pylori has been shown to change the natural history of peptic ulcer disease by preventing relapse and to reduce health care expenditures when compared with traditional therapy. Two-drug regimens have been superceded by three-drug regimens because they are more effective in eradication. Therapies with the highest efficacy are cost-effective because failed eradication is associated with high costs.     

Helicobacter pylori stool antigen test

In Japan, Helicobacter pylori stool antigen(HpSA) test was opened for diagnosis of H. pylori infection before and after eradication therapy form Nov. 1, 2003. We can use two kinds of HpSA kits, Premier Platinum HpSA(Meridian Bioscience, USA) and Testmate pylori antigen EIA(Wakamoto Pharmaceutical Co., Ltd., Japan). We evaluated the diagnostic accuracy of the HpSA test(Premier Platinum HpSA) compared with diagnosis based on endoscopic biopsy-based methods. In 136 patients, the sensitivity and specificity of the HpSA test before therapy were 98.3% and 95.0%, respectively. In 54 patients, the sensitivity and specificity of the HpSA test after eradication therapy were 90% and 97.7%, respectively. Therefore, it is concluded that the HpSA test is a useful method for the diagnosis of H. pylori infection before and after eradication therapy.     

Helicobacter pylori and hepatobiliary diseases

The aim of this short review is to understand if the Helicobacter pylori could have some sort of importance in the pathogenesis and in the development of not only gastroduodenal diseases, but in particular of those of the liver: a summary of the last researches has been done on the relations between this bacterium and some liver diseases; our intention is to continue this researches.     

Helicobacter pylori vaccine: from past to future

Helicobacter pylori infection is highly prevalent worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma (MALToma), and gastric adenocarcinoma. Infection is usually acquired during childhood and tends to persist unless treated. Because eradication requires treatment with multidrug regimens, prevention of initial infection by a suitable vaccine is attractive. Although immunization with H pylori protein subunits has been encouraging in animals, similar vaccine trials in humans have shown adjuvant-related adverse effects and only moderate effectiveness. Newer immunization approaches (use of DNA, live vectors, bacterial ghosts, and microspheres) are being developed. Several questions about when and whom to vaccinate will need to be appropriately answered, and a cost-effective vaccine production and delivery strategy will have to be useful for developing countries. For this review, we searched MEDLINE using the Medical Subject Heading (MeSH) terms Helicobacter pylori and vaccines for articles in English from 1990 to 2007.     

GENETIC CONTROL OF THE ANTIBODY RESPONSE TO TYPE III PNEUMOCOCCAL POLYSACCHARIDE IN MICE : II. RELATIONSHIP BETWEEN IgM IMMUNOGLOBULIN LEVELS AND THE ABILITY TO GIVE AN IgM ANTIBODY RESPONSE

Serum IgM immunoglobulin levels and antibody responses to an optimally immunogenic dose of Type III pneumococcal polysaccharide (SSS-III) were assessed for F₁, F₂, and backcross progeny derived from crosses between high responding BALB/cAnN (B) and low responding CBA/HN (C) mice. The results obtained confirmed our original hypothesis, namely, that a major component, present on the X chromosome, governs the ability to respond to SSS-III in a decisive manner. Although all low responding C mice had low IgM levels, both intermediate and high responders had high IgM levels of the same magnitude. Treatment with bacterial lipopolysaccharides (LPS) resulted in a significant increase in the IgM levels of low responding C mice. While the IgM levels attained were similar to those of high responding B mice, not given LPS, no antibody specific for LPS appeared to be produced. These findings suggest that C mice are unable to make an IgM antibody response to SSS-III and other polysaccharide antigens, despite the fact that they possess the capacity to synthesize normal amounts of IgM immunoglobulin.     

Eradication of Helicobacter pylori: recent advances in treatment

Helicobacter pylori plays a key role in dyspepsia, peptic ulcer disease, and gastric neoplasia and eradication of the infection has become an important treatment goal in clinical practice. Seven-day proton-pump inhibitor-amoxicillin-clarithromycin triple therapy is the current first-line therapy for H. pylori but eradication rates are compromised by poor compliance and antibiotic resistance. Ten-day sequential treatment may emerge as an alternative first-line therapy. Bismuth-based quadruple therapy is the second-line regimen of choice. Antimicrobial sensitivity testing is not recommended in the routine management of H. pylori infection. Novel triple-therapy regimens containing rifabutin, levofloxacin, or furazolidone may be useful alternatives as second- or third-line therapy.     

Helicobacter pylori: why it still matters in 2005

Despite falling prevalence rates in the developed world, H pylori is still present in the United States and is particularly prevalent among racial minorities and recent immigrants. H pylori infection is clearly associated with an increased risk of peptic ulcer disease, gastric cancer, and MALT lymphoma, and it is associated with some cases of uninvestigated dyspepsia. Identification and eradication of H pylori improves outcomes in patients with peptic ulcer disease and causes tumor regression in patients with MALT lymphoma. It is uncertain whether H pylori eradication will improve outcomes in patients with gastric cancer. Decision analytic models suggest that a test-and-treat strategy for H pylori is rational and cost-effective for patients with uninvestigated dyspepsia.