Gastric Infection by <Emphasis Type="Italic">Helicobacter pylori</Emphasis>

Helicobacter pylori infects half of the world’s population and plays a causal role in ulcer disease and gastric cancer. This pathogenic neutralophile uniquely colonizes the acidic gastric milieu through the process of acid acclimation. Acid acclimation is the ability of the organism to maintain periplasmic pH near neutrality in an acidic environment to prevent a fall in cytoplasmic pH in order to maintain viability and growth in acid. Recently, due to an increase in antibiotic resistance, the rate of H. pylori eradication has fallen below 80% generating renewed interest in novel eradication regimens and targets. In this article, we review the gastric biology of H. pylori and acid acclimation, various detection procedures, antibiotic resistance and the role that gastric acidity plays in the susceptibility of the organism to antibiotics currently in use and propose several novel drug targets that would promote eradication in the absence of antibiotics.     

Low presence of <Emphasis Type="Italic">p53</Emphasis> abnormalities in <Emphasis Type="Italic">H. pylori</Emphasis>-infected gastric mucosa and in gastric adenocarcinoma

Background: Alterations of the p53 gene and/or its abnormal protein accumulation have been observed in gastric cancer and preneoplastic lesions. Our aim was to assess possible associations between different H. pylori strains and p53 abnormalities in patients with dyspepsia and with gastric cancer. Methods: Seventy-five dyspeptic patients and 40 patients with gastric adenocarcinoma entered the study. H. pylori status was determined by the rapid urease test, histology, and polymerase chain reaction (PCR) analysis. Overexpression of the p53 protein was evaluated by immunohistochemistry. Detection of p53 mutations was done by direct DNA sequencing. Results: Fifty-four of the 75 (72.0%) dyspeptic patients and 27 of the 40 (67.5%) gastric cancer patients showed H. pylori infection. Cytotoxin-associated gene (cagA)-positive strains were found in 31 of the 54 (58%) dyspeptic patients and in 25 of the 27 (92.6%) neoplastic patients. As regards vacA, s2 strains showed the highest prevalence among dyspeptic patients (24 of 54 patients; 44.4%), whereas s1 strains were more expressed among cancer patients (23 of 27; 85.2%). Among the dyspeptic patients, 1 patient with duodenal ulcer showed p53 overexpression. Three mutations were identified by DNA sequencing: one in a patient with normal endoscopic findings and two in patients suffering from gastritis. Among the neoplastic patients, 16 subjects (40%) showed p53 overexpression (9 had diffuse-type and 7 intestinal-type cancer). Four mutations (10%) occurred in patients with intestinal-type gastric cancer. No association between p53 abnormalities (overexpression/mutation) and H. pylori infection was found in either group of patients. Conclusions: These results lead us to hypothesize that H. pylori infection does not affect the p53 pattern in gastric mucosa. Moreover, mutations of the p53 gene do not seem to be a predominant event in gastric carcinogenesis, at least in our populations. Received: December 14, 2001 / Accepted: May 17, 2002 RID="*" ID="*"  These authors contributed equally to the work RID="*" ID="*"  These authors contributed equally to the work Acknowledgments. The authors would like to thank Mrs B. D'Attoma and Mrs P. Fiorente for their valuable technical assistance, and Mrs M.V.C. Pragnell, B.A., for her help in revising the English. Reprint requests to: A. Di Leo     

Eradication of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> Infection

Helicobacter pylori infects about 50 % of the world’s population, causing at a minimum chronic gastritis. A subset of infected patients will ultimately develop gastric or duodenal ulcer disease, gastric adenocarcinoma, or MALT (mucosa-associated lymphoid tissue) lymphoma. Eradication of H. pylori requires complex regimens that include acid suppression and multiple antibiotics. The efficacy of treatment using what were once considered standard regimens have declined in recent years, mainly due to widespread development of antibiotic resistance. Addition of bismuth to standard triple therapy regimens, use of alternate antibiotics, or development of alternative regimens using known therapies in novel combinations have improved treatment efficacy in specific populations, but overall success of eradication remains less than ideal. Novel regimens under investigation either in vivo or in vitro, involving increased acid suppression ideally with fewer antibiotics or development of non-antibiotic treatment targets, show promise for future therapy.     

Diagnosis and treatment of <Emphasis Type="Italic">Helicobacter pylori</Emphasis>

Opinion statement Helicobacter pylori infection remains a ubiquitous infection, especially in populations with poor socioeconomic conditions. Severe clinical outcomes of chronic infection include peptic ulcer disease and gastric cancer. Consensus meetings have developed guidelines for diagnosis, treatment, and management of H. pylori infection and related disorders in various populations. Clear benefits are obtained for H. pylori eradication in peptic ulcer disease and gastric mucosa-associated lymphoid tissue lymphoma. Most authorities agree that first-degree relatives of gastric cancer patients should undergo testing for H. pylori infection. H. pylori eradication in dyspepsia remains controversial. Global investigations continue to identify specific host and bacterial factors that are responsible for H. pylori-related inflammatory processes and development of clinical disease. Effective eradication regimens have been identified. The proton pump inhibitor (PPI)-based triple therapies are considered first-line therapy because of high patient compliance and good eradication rates. “Quadruple therapy” with bismuth-metronidazoletetracycline plus a PPI is another first-line therapy with a similar eradication rate. This therapy is preferred in patients with penicillin allergy or prior exposure to clarithromycin. Rescue regimens are being developed because of rising antimicrobial resistance to metronidazole and clarithromycin in H. pylori strains. Emerging rescue combination therapies include furazolidone, rifabutin, and quinolones. These combination regimens are still preliminary and should be reserved for patients who have failed first-line therapies. Vaccine development remains elusive.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> seropositivity in fibromyalgia syndrome

Although there are some studies suggesting relation between different types of infection and fibromyalgia syndrome (FM), there is presently no proof that FM is caused by an infection. Helicobacter pylori (HP) infection may cause extragastric manifestations. Inflammation is an important mediator of increased sympathetic nervous system activity and may lead to pain in fibromyalgia patients. In this study, we aimed to investigate the HP seropositivity in fibromyalgia patients compared with controls for possible role of HP infection in FM. Sixty-seven patients with fibromyalgia were evaluated. Two of them were excluded from the study because of high level of acute phase reactants. Sixty-five female patients with fibromyalgia and 41 randomly selected age-matched female healthy controls were enrolled to study. Serum HP IgA and IgG antibodies were measured by enzyme-linked immunosorbent assay technique. Fibromyalgia Impact Questionnaire was assessed in patients and controls. Seropositivity of HP IgG antibody in the fibromyalgia patients was significantly higher than in the control group. No statistically significant differences were found regarding the clinical features between fibromyalgia patients with HP IgG antibody and patients without IgG antibody. Our study suggests that former HP infection may have a role in the etiopathogenesis of fibromyalgia syndrome or may act as a triggering factor. However, high seroprevalence of HP in general population and prevalent asymptomatic infection make it difficult to interpret these results for the definite role of HP in FM. Highlighting the pathophysiologic mechanisms of FM will result in more effective treatment regimens.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> and gastroesophageal reflux disease

Opinion statement Since the rediscovery of Helicobacter pylori two decades ago, it has become increasingly clear that the true relationships between this organism and diseases of the upper gastrointestinal tract are highly complex. H. pylori colonization is a strong risk factor for peptic ulceration and distal gastric cancer; however, gastritis has no adverse consequences for most hosts, and the prevalence of H. pylori is inversely related to gastroesophageal reflux disease (GERD) and its sequelae, which include Barrett’s esophagus and esophageal adenocarcinoma. One clinical implication stemming from these data is that H. pylori eradication may not be appropriate in certain human populations due to potential beneficial effects conferred by persistent gastric inflammation. However, the majority of published intervention trials indicate that H. pylori treatment neither leads to the development of clinically significant de novo esophagitis nor exacerbates existing reflux disease. Superimposed upon these observations are reports that long-term acid suppression induced by proton-pump inhibitors (PPIs) in conjunction with H. pylori colonization may enhance the development of atrophic gastritis, a well-recognized histologic step in the progression to intestinal-type gastric cancer. Therefore, current evidence-based recommendations regarding management of H. pylori-positive individuals with GERD include the following. H. pylori should not be treated with the intent to either improve reflux symptoms or prevent the development of reflux complications. However, if patients are to receive long-term acid suppressive therapy, they should be tested for H. pylori and treated if positive, due to the potential for PPIs to accelerate atrophy within H. pylori-infected mucosa. Optimal first-line regimens in this country consist of a PPI in combination with clarithromycin and either amoxicillin or metronidazole (triple therapy) for at least 7, but preferably 10, days. Because the most effective second-line regimens contain metronidazole, it is advisable to use amoxicillin instead of metronidazole as first-line therapy in order to optimize results should subsequent therapy be required. If first-line regimens fail to eliminate H. pylori, patients should receive quadruple therapy consisting of a PPI, bismuth subsalicylate, metronidazole, and tetracycline for 14 days. Due to the availability and accuracy of noninvasive diagnostic tests for H. pylori, it is recommended that successful cure be confirmed after intervention.     

Treatment of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in Pediatrics

Opinion statement Helicobacter pylori (H. pylori) is among the most common bacterial infections in humans. In 1982, H. pylori was discovered by Marshal and Warren, demonstrating an association between H. pylori and ulcer disease. H. pylori is a gram-negative, S-shaped rod that produces enzymes like urease, catalase and oxidase. The mechanism of acquisition and transmission of H. pylori is unclear, although the most likely mode of transmission is fecaloral and oral-oral. The mode of transmission is supported by studies that demonstrate viable H. pylori organisms can be cultured from the stool or vomitus of infected patients. Risk factors such as minimal education and low socio-economic status during childhood affect the prevalence. Children infected with H. pylori develop histologic chronic active gastritis despite the fact that they are generally asymptomatic. A small percentage of these children will go on to develop peptic ulcer disease, and even gastric cancer. In contrast, the association of abdominal pain and H. pylori infection remains controversial. In the year 2000, the North American Society of Pediatric Gastroenterology guidelines on H. pylori reported that there is no evidence demonstrating a link between H. pyloriassociated gastritis and abdominal pain, except in rare cases in which gastric or duodenal ulcer disease is present. Currently, treatment with a combination of two antimicrobial agents in conjunction with a proton pump inhibitor (PPI) continues to be recommended for the treatment of H. pylori associated peptic ulcer disease.     

Intestinal-type gastric adenocarcinoma without <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection successfully treated with endoscopic submucosal dissection

A 67-year-old woman was admitted to our hospital for further examination and for treatment of gastric neoplasia located on the posterior wall of the antrum of the stomach, as revealed by screening esophagogastroduodenoscopy. The patient had no history of Helicobacter pylori (H. pylori) eradication. Her serum H. pylori antibody and urea breath test results were negative, histopathological findings revealed no H. pylori bacteria, and endoscopic findings revealed no chronic gastritis. We performed endoscopic submucosal dissection (ESD). Histological examination of the resected tissues revealed the tumor to be composed of a well-differentiated tubular adenocarcinoma with a tubular-type adenoma confined to the mucosa. This adenocarcinoma exhibited immunohistochemical expression of CD10, MUC2, and Cdx2, but not MUC5AC or MUC6. This is an extremely rare case of H. pylori infection-negative, intestinal-type, differentiated gastric adenocarcinoma revealed by detailed immunohistochemical examination that was treated with ESD. The patient has had no recurrence of adenocarcinoma after ESD.     

Isolated granulomatous gastritis successfully treated by <Emphasis Type="Italic">Helicobacter pylori</Emphasis> eradication: a possible association between granulomatous gastritis and <Emphasis Type="Italic">Helicobacter pylori</Emphasis>

We report two cases of granulomatous gastritis that resolved completely with Helicobacter pylori eradication. Two Japanese women, one 61 years old and one 58 years old, presented to our hospital with epigastralgia. Endoscopy revealed multiple shallow ulcerative lesions in the gastric corpus of both patients. Biopsy specimens demonstrated acute and chronic inflammation with multiple small, noncaseating granulomas at the level of the foveolar isthmi—the junction between the pits and the glands. Both specimens were positive for Helicobacter pylori. No other causes of organic granulomatous disease could be found. Both patients were diagnosed as having isolated granulomatous gastritis and were given triple therapy for Helicobacter pylori eradication, with their fully informed consent. The granulomatous gastritis resolved after successful Helicobacter pylori eradication therapy. This report describes a possible association between isolated granulomatous gastritis and Helicobacter pylori infection. To our knowledge, this is the first report describing isolated granulomatous gastritis successfully treated by triple therapy (Helicobacter pylori eradication therapy). Received: November 12, 2001 / Accepted: March 8, 2002 Acknowledgments. We wish to thank Dr. Syoichi Fujika, Dr. Yasuhiko Kitadai, Dr. Toru Hiyama, Dr. Toshiyuki Fukuhara, Dr. Masaru Nakamura, Dr. Chiyuki Watanabe, Dr. Hiroyasu Yamada, and Dr. Masaru Imagawa for their advice and support. Reprint requests to: M. Yoshihara     

Association of <Emphasis Type="Italic">Lewis</Emphasis> and <Emphasis Type="Italic">Secretor</Emphasis> gene polymorphisms and <Emphasis Type="Italic">Helicobacter pylori</Emphasis> seropositivity among Japanese-Brazilians

Background Secretor (Se) and Lewis (Le) genes are involved in the synthesis of Lewis b (Le^b) and type I antigens throughout the body, especially in the epithelial cells of gastric mucosa. Helicobacter pylori can attach to the gastric epithelial cells with the blood group antigen-binding adhesin, which binds to Le^b or H type I carbohydrate structures. In a previous study, a marked association between H. pylori seropositivity and polymorphism of the Se and Le genes was observed among Japanese outpatients of a gastroenterology clinic. The present work aims to investigate the associations between Se and Le gene polymorphisms and H. pylori infection among Japanese-Brazilians.Methods The subjects consisted of 942 healthy volunteer Japanese-Brazilians, who were tested for the presence of anti-H. pylori IgG antibodies and genotyped for Se and Le polymorphisms.Results The sex-age-adjusted odds ratios (aORs) for H. pylori seropositivity were 0.99 for the Sese genotype relative to the SeSe genotype (95% confidence interval [CI], 0.73–1.33), and 1.03 for sese relative to SeSe (95% CI, 0.71–1.48). On the other hand, the aOR for the subjects with the le allele (Lele or lele) relative to the LeLe genotype was 1.48 (95% CI, 1.07–1.79). When the Se and Le genotypes were analyzed in combination according to risk group, no statistically significant association was observed.Conclusions These results are inconsistent with previous work and may have been modulated by an external factor or some other unidentified factor. Japanese-Brazilians are genotypically the same as Japanese, but their lifestyle is adapted to that of Brazil. Further investigations are necessary to clarify this influence on susceptibility to H. pylori infection.     

<Emphasis Type="Italic">cagA</Emphasis> Gene and Protein Status Among Iranian <Emphasis Type="Italic">Helicobacter pylori</Emphasis> Strains

The wide geographic genetic diversity of Helicobacter pylori (Hp) and, in particular, the varying prevalence of cagA in different countries has been documented repeatedly. This study was designed to determine the frequency of cagA in Iranian Hp strains by means of genotyping and assessment of host antibodies. Helicobacter pylori strains from 235 patients, including 174 non-ulcer dyspepsia, 25 peptic ulcer and 36 gastric cancer patients, were studied. The frequencies of the 5′, middle and 3′ terminal regions of the cagA gene were 90.6, 57.6, 89%, respectively, with no correlation to the clinical outcomes. Antibodies against the CagA protein were present in 90.7% of patients. Multiple biopsy sampling in 97 cases revealed multiple infection in 16.5% of the patients. Sequencing of the seven variants of the 3′ end of the cagA gene revealed no clustering and the distribution of the Iranian strains among those of other countries. Our results from the genotyping and serology analyses confirm that the majority of Iranian Hp strains are cagA-positive.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> Infection and Idiopathic Thrombocytopenic Purpura

A treatment strategy for idiopathic thrombocytopenic purpura (ITP) is considered with the aim of cure or management of the bleeding tendency. In 1998, Gasbarrini et al reported a high prevalence of Helicobacter pylori infection in patients with ITP and showed that platelet recovery occurred after eradication therapy in most cases. Since then, many studies were performed to evaluate eradication therapy. This article discusses the incidence of H pylori infection in ITP, characteristic clinical features in H pylori-positive ITP, the effectiveness of eradication on platelet count increase, and the mechanisms of development of ITP by H pylori infection. Overall, there was a positive association between H pylori infection and ITP, and eradication of bacterium was accompanied by a significant increase in platelet counts in more than 50% of H pylori-positive ITP cases. These findings suggest that H pylori infection is involved in the mechanisms of thrombocytopenia in most cases of ITP in middle-aged and older patients. This approach could be beneficial to some ITP patients, but there were some uncertainties raised. To confirm the effectiveness of eradication therapy in H pylori-positive ITP, prospective studies conducted in several countries with a new treatment protocol are required, with a large number of ITP cases and longer follow-up.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> Infection in Anterior Uveitis*

Abstract Background: Despite intensive research, the etiology of acute anterior uveitis (AAU) remains poorly defined. Infection with gram-negative bacteria such as Yersinia, Salmonella, Shigella, and Chlamydia have already been suggested as a possible trigger event for AAU. Helicobacter pylori is also a gram-negative bacterium, shares the lipopolysaccharides, but did not attract the attention of many ophthalmologists until recently. Having in mind the relatively high incidence of H. pylori infection in the population, we propose that H. pylori may also be a trigger factor for AAU. Patients and Methods: The presence of anti-H. pylori antibodies in matching serum and aqueous humor samples of 15 idiopathic AAU patients was determined using a commercial Western blot assay. Control serum and aqueous humor were obtained from five patients undergoing cataract surgery. Results: Six out of 15 AAU patients (40%) were serum-positive for H. pylori, and half of these (n = 3) also had anti-H. pylori antibodies in the aqueous humor. All five aqueous humor and sera controls tested negative for H. pylori infection. Conclusion: These are the first results demonstrating anti-H. pylori antibodies in the aqueous humor of AAU patients. Further studies are needed to demonstrate whether this antibody is indeed locally produced. Our data may provide first evidence for a causative link between H. pylori infection and AAU.*Presented at the 7th Congress of the International Ocular Inflammation Society, Padova, Italy, 2003.     

Gastric adenocarcinoma in a patient re-infected with <Emphasis Type="Italic">H. pylori</Emphasis> after regression of MALT lymphoma with successful anti-<Emphasis Type="Italic">H. pylori</Emphasis>therapy and gastric resection: a case report

Background

Helicobacter pylori (H. pylori) has been etiologically linked with primary gastric lymphoma (PGL) and gastric carcinoma (GC). There are a few reports of occurrence of both diseases in the same patient with H. pylori infection.

Case presentation

We report a patient with PGL in whom the tumor regressed after surgical resection combined with eradication of H. pylori infection. However, he developed GC on follow up; this was temporally associated with recrudescence / re-infection of H. pylori. This is perhaps first report of such occurrence.

Conclusions

Possible cause and effect relationship between H. pylori infection and both PGL and GC is discussed. This case also documents a unique problem in management of PGL in tropical countries where re-infection with H. pylori is supposed to be high.

     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> CagA protein variation associated with gastric cancer in Asia

Recent molecular analysis has provided the pathological actions of CagA on gastric epithelial cells. CagA is injected into epithelial cells via the type IV secretion system and undergoes tyrosine phosphorylation in the cells. In addition, translocated CagA forms a physical complex with SHP-2. There are two major CagA subtypes; the East Asian and the Western type. The East Asian CagA protein possesses stronger SHP-2 binding activity than the Western CagA. The grades of inflammation, activity of gastritis, and atrophy are significantly higher in gastritis patients infected with the East Asian CagA-positive strain than in gastritis patients infected with the cagA-negative or Western CagA-positive strains. The prevalence of the East Asian CagA-positive strain is associated with the mortality rate of gastric cancer in Asia. Endemic circulation of H. pylori populations carrying biologically more active CagA proteins in East Asian countries, where the mortality rate of gastric cancer is among the highest in the world, may be involved in increasing the risk of gastric cancer in these populations.     

Primary Antibiotic Resistance of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> in China

Background and Aims

Antibiotic resistance is the most important factor leading to the failure of eradication regimens; thus, it is important to obtain regional antibiotic resistance information. This review focuses on the prevalence of Helicobacter pylori primary resistance to clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and furazolidone in China.

Methods

We searched the PubMed, EMBASE, the China National Knowledge Infrastructure, and Chinese Biomedical databases from the earliest date of each database to October 2016. The search terms included the following: H. pylori, antibiotic (including clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and furazolidone) resistance with or without China or different regions of China. The data analysis was performed using MedCalc 15.2.2. Each article was weighted according to the number of isolated H. pylori strains. A pooled proportion analysis was performed.

Results

Twenty-three studies (14 studies in English and 9 in Chinese) were included in this review. A total of 6274, 6418, 3921, 5468, 2802, and 275 H. pylori strains were included in this review to evaluate the prevalence of H. pylori primary resistance to clarithromycin, metronidazole, levofloxacin, amoxicillin, tetracycline, and furazolidone, respectively. Overall, the primary resistance rates of clarithromycin, metronidazole, levofloxacin, amoxicillin, tetracycline, and furazolidone were 28.9, 63.8, 28.0, 3.1, 3.9, and 1.7%, respectively.

Conclusions

In China, the prevalence of H. pylori primary resistance to clarithromycin, metronidazole, and levofloxacin was high and increased over time, whereas the resistance rates to amoxicillin, tetracycline, and furazolidone were low and stable over time.