CagA Positivity Research Articles

Association Between Helicobacter pylori Colonization and Glycated Hemoglobin Levels: Is This Another Reason to Eradicate H. pylori in Adulthood?

Helicobacter pylori infection is acquired in early childhood and becomes a chronic infection if left untreated [1]. The majority of infected people remain asymptomatic, and only a small portion develop illness, usually in adulthood [2]. Helicobacter pylori infection causes gastric and duodenal ulcers. It also increases the risk of gastric cancer [2, 3]; the bacterium was classified by the International Agency for Research on Cancer as a group 1 (definite) carcinogen in gastric carcinoma [4]. Helicobacter pylori also increases the likelihood of gastric lymphoma [5]. Moreover, positive associations between H. pylori infection and extragastric manifestations, such as iron deficiency anemia [6] and idiopathic thrombocytopenic purpura, also have been reported [7]. Many of the above-mentioned diseases and conditions are associated with the primary H. pylori virulence factors, cytotoxin-associated gene A (cagA) and vacuolating-associated gene A (vacA). Chronic H. pylori infection causes a continuous activation of the immune system, with a skewed T-helper 1 response [8, 9]. This response has been proposed as a possible mechanism responsible for some potential beneficial effects of H. pylori infection, such as protection against diarrheal diseases [10] and asthma [11]. Type 2 diabetes is an emerging pandemic, with estimates of 3.8 million deaths attributed to the disease in adults globally [12]. Lifestyle (eg, diet, obesity, physical activity), genetic, and socioeconomic factors are among the risk factors for the disease [13, 14]. There are conflicting reports concerning the association between H. pylori infection and the various clinical manifestations of the metabolic or insulin-resistance syndrome [15]. The roles of H. pylori infection in cardiovascular disease and its risk factors [16–18] and in type 2 diabetes are not clear. Although no association was found between H. pylori immunoglobulin G seropositivity and diabetes mellitus [19], a significantly higher prevalence of H. pylori gastritis was reported in patients with type 2 diabetes, compared with age-matched healthy controls (80% vs 56%; P5 .03) [20]. A recent systematic review summarized the epidemiological evidence concerning the association between H. pylori infection and quantitative indexes of insulin resistance and indicated that such an association may exist. The authors of the review concluded, however, that further studies are needed to determine whether this is a causal association [15]. Studying biomarkers of diabetes mellitus, such as glycated hemoglobin levels (HbA1c) and insulin resistance, can contribute substantially to an understanding of the etiologic role of H. pylori infection in diabetes mellitus. In this issue of the Journal, Chen and Blaser report findings of a seroepidemiological study in which they examined the association between seroprevalence of H. pylori infection and the mean levels of HbA1c in 2 large national surveys: the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999–2000. They report that H. pylori seropositivity, and especially H. pylori cagA positivity, was associated with higher mean HbA1c levels, an association that persisted after excluding individuals with a history of diabetes mellitus and controlling for potential confounders. The association was evident mainly in adults aged .18 years. Chen and Blaser also show a synergistic effect of H. pylori and body mass index (BMI) on increased levels of HbA1c in that higher levels were found in H. pylori–infected subjects with BMI $25 but not in those with lower Received and accepted 4 January 2012. Correspondence: Dani Cohen, MPH, PhD, Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel (dancohen@post.tau.ac.il). The Journal of Infectious Diseases The Author 2012. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@ oup.com DOI: 10.1093/infdis/jis110

Association between gastric Helicobacter pylori colonization and glycated hemoglobin levels.

Few studies have evaluated the potential influence of Helicobacter pylori on biomarkers for diabetes. We conducted cross-sectional analyses using data from 7417 participants in the National Health and Nutrition Examination Survey (NHANES) III (aged ≥18 years) and 6072 participants in NHANES 1999-2000 (aged ≥3 years) to assess the association between H. pylori and levels of glycosylated hemoglobin (HbA1c). There was no association between H. pylori and history of self-reported diabetes. Helicobacter pylori seropositivity, especially H. pylori cagA positivity, was positively associated (P < .01, NHANES III; P = .02, NHANES 1999-2000) with HbA1c levels after excluding individuals with history of diabetes and controlling for potential confounders. There was also a synergistic interaction between H. pylori and higher body mass index (BMI), such that increased levels of HbA1c associated with having both H. pylori and higher BMI were greater than the sum of their individual effects (P for interaction < .01). This interaction was observed consistently in both NHANES III and NHANES 1999-2000 and for H. pylori cagA positivity in NHANES III. The findings indicate a role of H. pylori in impaired glucose tolerance in adults that may be potentiated by higher BMI level.

Non‐invasive Genotyping of Helicobacter pylori cagA, vacA, and hopQ from Asymptomatic Children

Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy. H. pylori status of 86 asymptomatic children was assessed by (13) C-urea breath test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced. UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA-positive children. Of the children's DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes (p < 0.0001). Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.

Serological assessment of gastric mucosal atrophy in gastric cancer

BackgroundNon-invasive tools for gastric cancer screening and diagnosis are lacking. Serological testing with the detection of pepsinogen 1 (PG1), pepsinogen 2 (PG2) and gastrin 17 (G17) offers the possibility to detect preneoplastic gastric mucosal conditions. Aim of this study was to assess the performance of these serological tests in the presence of gastric neoplasia.MethodsHistological and serological samples of 118 patients with gastric cancer have been assessed for tumor specific characteristics (Laurén type, localisation), degree of mucosal abnormalities (intestinal metaplasia, atrophy) and serological parameters (PG1, PG2, PG1/2-ratio, G17, H. pylori IgG, CagA status). Association of the general factors to the different serological values have been statistically analyzed.ResultsPatients with intestinal type gastric cancer had lower PG1 levels and a lower PG1/2-ratio compared to those with diffuse type cancer (p = 0.003). The serum levels of PG2 itself and G17 were not significantly altered. H. pylori infection in general had no influence on the levels of PG1, PG2 and G17 in the serum of gastric cancer patients. There was a trend towards lower PG1 levels in case of positive CagA-status (p = 0.058). The degree of both intestinal metaplasia and atrophy correlated inversely with serum levels for PG1 and the PG1/2-ratio (p < 0.01). Laurén-specific analysis revealed that this is only true for intestinal type tumors. Univariate ANOVA revealed atrophy and CagA-status as the only independent factors for low PG1 and a low PG1/2-ratio.ConclusionsGlandular atrophy and a positive CagA status are determinant factors for decreased pepsinogen 1 levels in the serum of patients with gastric cancer. The serological assessment of gastric atrophy by analysis of serum pepsinogen is only adequate for patients with intestinal type cancer.

Clinical Relevance and Sequence Analysis of the Helicobacter pylori dupA Region from Two Areas in Japan with Different Gastric Cancer Risks

Aims: We investigated the virulence and sequences of duodenal ulcer-promoting gene A (dupA) of Helicobacter pylori (H. pylori) isolated from 2 areas in Japan with different gastric cancer risks. Methods: The dupA status of 248 Japanese H. pylori strains (111 from Fukui and 137 from Okinawa) isolated from patients with duodenal ulcers, gastric ulcers, chronic gastritis, or gastric cancer was evaluated by dot-blot hybridization followed by polymerase chain reaction. Sequence analyses of dupA and its upstream region were performed in 15 strains. Results: In both areas, no significant association was observed between dupA and the evaluated clinical outcomes. In a multivariable logistic regression, dupA positivity was independently associated with strains isolated from Okinawa, showing the lowest incidence of gastric cancer in Japan, and with East Asian-type cagA positivity (odds ratio (OR)=2.128, 95% confidence interval (CI) =1.146-3.949 and OR=12.924, 95% CI=1.689-98.901, respectively). Sequence alignment showed dupA was divided into 2 genotypes: a Shi470-type (2499 bp) and a J99-type (1839 bp). Among 60 dupA + Japanese strains, 58 (96.7%) were of the Shi470-type and 2 of the J99-type. The nucleotide sequences of 13 Shi470-type Japanese isolates from both areas were highly homologous (98.9%) to each other and a remote Amazonian strain, Shi470. Of these, 12 (92.3%) carried intact full-length dupA. Conclusion: In Japan, dupA appeared to be associated with East Asian-type cagA and with host residence in Okinawa. The intact genotype of the Shi470-type dupA was the major form in Japan. Immunogastroenterology 2012; 1:127-135

Serological Prevalence of Helicobacter pylori Infection in Saxony-Anhalt, Germany, in 2010

Epidemiological studies from different countries have shown a steady decline of the prevalence of Helicobacter pylori infection. In order to investigate the current seroprevalence of H. pylori infection in the area of Magdeburg, a city of the former East Germany, H. pylori antibodies of patients presenting in our emergency wards were analyzed. In total, 2,318 patients (1,181 males and 1,137 females) enrolled between September 2009 and August 2010 were tested for immunoglobulin G (IgG) against H. pylori and anti-CagA antibodies by specific enzyme immunoassay (EIA). Patients with either anti-H. pylori IgG or anti-CagA antibodies were classified as H. pylori positive, whereas the lack of both antibodies led to the assignment of an H. pylori-negative status. The overall seroprevalence of H. pylori infection was 44.4% (n = 1,029 out of 2,318) and did not differ in relation to sex. The proportion of CagA-positive samples was 43.3% of all H. pylori-positive individuals (446 out of 1,029). The seroprevalence showed a birth cohort effect (0 to 20 years of age, 14.6%; 21 to 30 years, 22.4%; 31 to 40 years, 40.6%; 41 to 50 years, 45.5%; 51 to 60 years, 50.8%) up to the age of 60, while it remained between 40.7% and 50.5% for the following decades. Patients younger than 30 years were significantly less H. pylori positive (21.1%) than those older than 30 years of age (47.7%; P < 0.01), whereas CagA status was similar (44.3 versus 43.3%). Notably, young women (<30 years old) had significantly higher CagA positivity (59.3%) than corresponding men (32.5%; P = 0.016). Taken together, seroprevalence of H. pylori infection shows a significant drop in subjects born after 1980 in Saxony-Anhalt but still remains in the range of 40 to 50% in subjects born earlier.

Extragastric Manifestations of Helicobacter pylori Infection

In the previous year, some extragastric diseases, possibly linked to Helicobacter pylori infection, have been largely investigated. There are, in fact, several studies concerning cardiovascular diseases, lung diseases, hematologic diseases, eye and skin diseases, hepatobiliary diseases, diabetes mellitus, and neurological disorders. Among them, the relationship between bacterial CagA positivity and coronary heart disease is reportedly emphasized. Concerning normal tension glaucoma, new interesting data are playing in favor of the association with H. pylori infection. For other diseases, there are many interesting results, although more studies are needed to clarify the reality of the proposed association.

A study of Helicobacter pylori outer-membrane proteins (hom) A and B in Iraq and Turkey

Helicobacter pylori outer-membrane proteins (hom), especially the homB gene, have been suggested as a novel virulence factor. However, no study has been conducted in Middle Eastern countries regarding the association between these genes and clinical outcome. Gastric biopsies were obtained from 70 and 64 unselected H. pylori+ patients from Iraq and Turkey, respectively. PCR was performed to study the presence of the homA, homB, and cagA. No association was found between homA or homB and clinical outcomes. When Iraqi and Turkish strains were combined as Middle Eastern samples, cagA positivity was significantly higher in patients with peptic ulcer disease (PUD) than those with non-peptic ulcer disease (NPUD) (p=0.003, OR=3.6, CI=1.5-8.8). Two Iraqi strains showed intermediate, non-homA non-homB, length PCR products. The function of such gene is yet to be determined. In conclusion, hom genes might not be a good indicator for disease prediction in the Middle East. More studies are needed to confirm these results and determine the function of intermediate length hom.

Molecular characterization and susceptibility testing of Helicobacter pylori strains isolated in western Argentina

To characterize Helicobacter pylori isolates from western Argentina using virulence markers and antimicrobial susceptibility patterns in order to assess the association between virulent genotypes, antimicrobial resistance, and disease. DNA fingerprinting was also evaluated for the segregation of virulent or resistant strain clusters. Genotyping of 299 H. pylori isolates was performed by PCR using specific primers for the cagA, vacA and iceA genes. Random amplification of polymorphic DNA (RAPD)-PCR and rep-PCR genetic clustering were assessed using five random primers and BOXA1R and ERIC primers, respectively. Resistance to clarithromycin (Cla) and metronidazole (Mtz) was assessed by the agar dilution method. It was observed that 40.8% of the genotypes were cagA-positive; 66.9% were vacA s1m1 genotype and the iceA1 allele was found in 40.8%. A significant correlation (p=0.0000) was observed between cagA positivity and vacA s1m1/iceA1 genotypes. Triple virulent genotypes were statistically associated with peptic ulcer (PU) (p=0.0001) and Cla resistance (p=0.0000). RAPD fingerprints obtained with AO2 primers identified clusters that were strongly associated with PU, virulence markers, and resistance to Cla and Mtz. The H. pylori isolates that harbored two or three virulence markers were more resistant to Cla and Mtz. Combined analysis of virulent genotypes and resistance patterns may permit identification of high-risk patients to prevent PU later in life or to avoid antimicrobial treatment failure.

Diversity of VacA Intermediate Region amongHelicobacter pyloriStrains from Several Regions of the World

Helicobacter pylori is known to be a major cause of gastric carcinoma and peptic ulceration. cagA positivity and vacA's signal regions and mid-regions are well-characterized markers of H. pylori's virulence. Recently, an intermediate region has been identified as another strong marker of H. pylori-associated disease, and its i1 allele has been linked with severe diseases in colonized hosts. The goal of this study was to determine the prevalence of the intermediate alleles in H. pylori isolates from China, Turkey, and Uruguay and from U.S. Africans and to compare their distribution with other well-characterized virulence factors. Originally, 123 H. pylori strains were studied, but 3 were excluded due to the failure to amplify the intermediate region in these samples. Therefore, a total of 120 strains were analyzed: 30 Chinese isolates, 35 Turkish isolates, 30 Uruguayan isolates, and 25 U.S. African isolates. The s type and the m type were determined by PCR amplification. The i type was identified by PCR amplification and DNA sequencing. CagA status was determined by PCR methodology. There was a strong correlation among CagA positivity, s1, and i1 in Chinese, U.S. African, and Uruguayan isolates, but less correlation among these markers in Turkish isolates. A new intermediate variant (i3) was identified in 25.7% of Turkish strains and 3.3% of the Chinese strains. In summary, the distribution of CagA positivity and s1 correlated with the i1 in the three populations, except in the Turkish population, which showed a disproportionate representation of the i3 allele. Phylogenetic mapping confirmed the i-typing method previously defined and adopted for this study. The phylogenetic tree showed country-specific correlation with the intermediate region. Our results showed that the i1 allele is strongly associated with CagA positivity and the vacA s1 allele, suggesting its role as a virulence marker and potential predictor for clinical outcome.

CagA status and VacA subtypes of Helicobacter pylori in relation to histopathologic findings in Iranian population

The aim of this study was to detect dominant cagA/vacA genotypes of Helicobacter Pylori (H. pylori) and determine correlations between different cagA/vacA genotypes and histologic features of chronic gastritis in Iranian patients. Gastric biopsy was taken from 166 patients with nonulcer dyspepsia. The specimens were processed and DNA from each H. pylori isolate was extracted from multiple colony sweeps for identification of glmM gene. The vacA subtypes and cagA gene were tested by PCR . Histopathological features were recorded and graded according to partial Sydney system. Of the 86 strains, 66 (76.7%) were cagA positive. The proportions of vacA gene subtypes s1, s2, m1 and m2 in the 78 strains isolated were 70.5%, 29.5%, 37.2% and 62.8%, respectively. About 83.3% of the vacA-positive strains had s1 allele. Twenty-six strains (33.3%) were positive for both cagA and m1 allele. Positive cagA status and vacA subtypes were not associated significantly with presence of neutrophil infiltration, intestinal metaplasia or H. pylori density. Only vacA s1 was significantly associated with more severe inflammation (P=0.02). The dominant genotype of H. pylori was vacA plus s1/m2. CagA gene positivity rate was not closely associated with severity of the disease. H. pylori strains showing vacA s1 genotype were associated with more severe gastritis. These findings show that vacA genotyping may have clinical relevance in Iran.

Associations of a PTPN11 G/A polymorphism at intron 3 with Helicobactor pyloriseropositivity, gastric atrophy and gastric cancer in Japanese

BackgroundPrevious studies have revealed the significance of Helicobacter pylori (H. pylori) infection as a risk factor of gastric cancer. Cytotoxin-associated gene A (cagA) positivity has been demonstrated to determine the clinical outcome of H. pylori infection in the presence of SHP-2 (src homology 2 domain-containing protein tyrosine phosphatase-2). This study aimed to examine the formerly reported association of G/A PTPN11 (protein-tyrosine phosphatase, nonreceptor-type 11) polymorphism (rs2301756) with gastric atrophy, as well as the association with gastric cancer in a Japanese population using a large sample size.MethodsStudy subjects were 583 histologically diagnosed patients with gastric cancer (429 males and 154 females) and age- and sex-frequency-matched 1,636 non-cancer outpatients (1,203 males and 433 females), who visited Aichi Cancer Center Hospital between 2001–2005. Serum anti-H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and gastric atrophy, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model.ResultsAmong H. pylori seropositive non-cancer outpatients, the age- and sex-adjusted OR of gastric atrophy was 0.82 (95% CI 0.62–1.10, P = 0.194) for G/A, 0.84 (95% CI 0.39–1.81, P = 0.650) for A/A, and 0.83 (95% CI 0.62–1.09, P = 0.182) for G/A+A/A, relative to G/G genotype, and that of severe gastric atrophy was 0.70 (95% CI 0.47–1.04, P = 0.079), 0.56 (95% CI 0.17–1.91, P = 0.356), and 0.68 (95% CI 0.46–1.01, P = 0.057), respectively. Among H. pylori infected subjects (H. pylori seropositive subjects and seronegative subjects with gastric atrophy), the adjusted OR of severe gastric atrophy was further reduced; 0.62 (95% CI 0.42–0.90, P = 0.012) for G/A+A/A. The distribution of the genotype in patients with gastric cancer was not significantly different from that for H. pylori infected subjects without gastric atrophy.ConclusionOur study results revealed that those with the A/A genotype of PTPN11 rs2301756 polymorphism are at lower risk of severe gastric atrophy, but are not associated with a decreased risk of gastric cancer, which partially supported our previous finding that the polymorphism in the PTPN11 gene encoding SHP-2 was associated with the gastric atrophy risk in H. pylori infected Japanese. The biological roles of this PTPN11 polymorphism require further investigation.

Evaluation of a Commercial Immunoblot, Helicoblot 2.1, for Diagnosis of Helicobacter pylori Infection

The best method to diagnose Helicobacter pylori infection in different clinical situations is controversial. The aim of the study was to assess the performance of a commercial immunoblot, Helicoblot 2.1. The study comprised 215 patients, who were grouped according to the presence of H. pylori infection (assessed by two gastroscopies including histology with a median interval of 7.1 years, enzyme immunoassay [EIA]-based serology, and history of previous H. pylori infections and eradication therapies) into four categories: no H. pylori infection ever, previous infection, ongoing infection, and EIA seropositivity as the only marker of a possible previous infection. The sensitivity of Helicoblot 2.1 to show an ongoing or previous H. pylori infection was 100% and 92%, respectively. Helicoblot 2.1 was negative in only 80% of individuals with no evidence of present or previous infection but in 96% of patients 50 years of age or younger. The current infection marker of the immunoblot was positive in 49% of patients with successful H. pylori eradication therapy. After successful eradication therapy, Helicoblot 2.1 sustained positive results in 87% of patients, and CagA positivity was detected in 87% of patients with follow-up samples for more than 10 years after therapy. Helicoblot 2.1 is a sensitive and, among patients of ages 50 years or younger, a specific test in the primary diagnosis of H. pylori infection. However, it does not discriminate between past and current infections. It can be used in epidemiological studies assessing the role of H. pylori in different late sequelae.

High Prevalence of Cag‐A Positive H. pylori Strains in Ischemic Stroke: A Primary Care Multicenter Study

Previous studies suggested an association between CagA-positive H. pylori strains and ischemic stroke. The aim of the present study was to assess the prevalence of Helicobacter pylori infection and CagA status in patients with atherosclerotic stroke in the primary care setting. A total of 106 consecutive patients (age 76.6 +/- 8 years; males 52%) with well-documented history of atherosclerotic stroke and 106 sex-age- (age 76.5 +/- 9 years; males 52%) and social background-matched controls without relevant vascular diseases. Risk factors for ischemic stroke were recorded in all subjects. H. pylori infection was assessed by[13]C-urea breath test. A serologic assay for specific IgG against CagA was performed in infected subjects. A trend toward a higher prevalence of H. pylori was observed in cases (63%) with respect to controls (54%) without reaching a statistical significance. CagA positivity was associated to a higher risk of atherosclerotic stroke (adjusted odds ratio 2.69, 95% confidence interval 1.37-5.30). Our findings suggest that CagA-positive strains of H. pylori are significantly associated to atherosclerotic stroke. This is not a merely confirmative study since it has been performed for the first time in the primary care setting and included only subjects with an active infection.

Prevalence and Risk Factors of Atrophic Gastritis and Intestinal Metaplasia in a Korean Population Without Significant Gastroduodenal Disease

The prevalence of gastric cancer and Helicobacter pylori infection is unacceptably high in Korea. This study was performed to evaluate the prevalence of atrophic gastritis (AG) and intestinal metaplasia (IM) and to identify their risk factors with respect to H. pylori virulence factors, and environmental and host factors, in Korean population without significant gastroduodenal disease. The study cohort consisted of 389 subjects (> or = 16 years). AG and IM were scored histologically using the Sydney classification in the antrum and body, respectively. Prevalences and bacterial factors (i.e. cagA, vacA m1, and oipA), environmental factors (i.e. smoking and alcohol), and host factors (i.e. genetic polymorphisms of IL-1B-511, IL-1RN, TNF-A-308, IL-10-592, IL-10-819, IL-10-1082, IL-8-251, IL-6-572, GSTP1, p53 codon 72, and ALDH2) were evaluated. Prevalences of AG in the antrum and body were 42.5% and 20.1%, and those of IM were 28.6% and 21.2%, respectively. The presences of AG and IM were significantly higher in H. pylori-positive than in the H. pylori-negative subjects. Multivariate analysis showed that the risk factors for AG were H. pylori infection, age > or = 61 years, and cagA and vacA m1 positivity. For IM the risk factors were H. pylori infection, age > or = 61 years, a smoking history (rather than current smoking), strong spicy food, occupation (unemployed or nonprofessional vs. professional), and the presence of IL10-592 C/A as opposed to A/A. In addition, IL6-572 G carrier was found to have a protective effect against IM development as compared with C/C. H. pylori infection was most important risk factor of AG and IM. Bacterial factors were found to be important risk factor for AG but environmental and host factors were more important for IM.

The Relationship Between Virulence Factors of Helicobacter pylori and Severity of Gastritis in Infected Patients

The outcome of Helicobacter pylori infection has been related to specific virulence-associated bacterial genotypes. The best known genotypic virulence factors of H. pylori are cytotoxin-associated gene A (cagA) and vacuolating cytotoxin gene A (vacA). The objective of this study was to assess the relationship between H. pylori cagA and vacA status and histopathological findings. Esophagogastrodoedonoscopy was performed in 80 dyspeptic patients. Antrum and corpus biopsies were obtained for isolation of H. pylori and for histopathological assessment. The polymerase chain reaction was used to detect cagA and vacA genes of H. pylori using specific primers. Biopsy samples were stained with hematoxylin and eosin, and histopathological findings were graded using the "updated Sydney system". H. pylori from 57 of the 80 patients was incubated. Of the 57 patients, 44 were cagA positive. In the corpus biopsy specimens there was a significant relationship between the density of H. pylori colonization (P = 0.02) and chronic inflammation (P = 0.02) and cagA-positive genotypes. In the antrum specimens there was a significant relationship between cagA positivity and neutrophil activity (P = 0.003) and glandular atrophy (P = 0.002), but not with H. pylori density, chronic inflammation, and intestinal metaplasia. The odds ratio of cagA-positive vs. cagA-negative strains for the presence of glandular atrophy, irrespective of grading and of gastric localization, was 4.62 (95% CI, 1.18-18.08, P = 0.041). No significant relationships were observed between vacA s1 and s2 genotypes and histopathological parameters. Corpus neutrophil infiltration was found to be more severe in the m1 group than in the m2 group (P = 0.004). Other histopathological features showed no difference between m1 and m2 genotypes. In conclusion H. pylori strains showing cagA positivity are associated with more severe gastritis in some histological features but virulence factors of H. pylori do not appear to determine the overall pattern of gastritis.

CagA and VacAHelicobacter PyloriAntibodies in Gastric Cancer

Infection with different genotypes of virulent Helicobacter pylori strains (cytotoxin-associated gene A [CagA]- and/or vacuolating cytotoxin A [VacA]-positive) can play a role in the development of atrophic gastritis, duodenal ulcer (DU) and gastric cancer (GC). To determine whether patients with GC and H pylori-negative histological staining had previously been infected with H pylori CagA- and/or VacA-positive virulent strains. Twenty-three GC patients with a mean (+/- SD) age of 68.14+/-9.8 years who tested H pylori-negative on histological staining took part in the study. Three control groups were included. The first group comprised 19 patients with past H pylori infection and DUs eradicated 10 years earlier, with a mean age of 58+/-18.2 years. H pylori-negative status for this group was determined every year with Giemsa staining, and follow-up testing occured 120+/-32 months (mean +/- SD) after therapy. The subsequent control groups included 20 asymptomatic children, with a mean age of 7+/-4.47 years, and with H pylori-negative fecal tests; the final group contained 30 patients without clinical symptoms of H pylori infection, with a mean age of 68+/-11.6 years, who tested H pylori-negative by histological staining. Prevalence of CagA and VacA seropositivity, respectively was 82.6% and 73.91% in GC patients; 84.2% and 84.2% in H pylori-negative DU patients; 25% and 5% in H pylori-negative children; and 36.6% and 16.6% in the patients without clinical symptoms on histological staining. CagA and VacA antibody positivity was not significantly different between GC patients and patients with DUs that had been eradicated 10 years earlier. Significant positivity was found between the children's group and the H pylori-negative (with past DUs) group (P<0.001). A statistically significant difference was found in age between groups (P<0.03). Patients with GC, even when H pylori-negative at the time of the present study, may have been infected by H pylori before the onset of the disease, as confirmed by CagA and VacA seropositivity. These data reinforce the hypothesis that H pylori may be a direct carcinogenic agent of GC.

Influence of Helicobacter pylori genotype on triple eradication therapy

The efficiency of Helicobacter pylori eradication varies geographically, as do many parameters that might affect therapeutic efficiency. The aims of this study were to investigate the relationship between different genotypes of H. pylori and bacterium-related histopathological lesions in patients with duodenal ulcer and to determine the effect of genotype on triple eradication therapy. Helicobacter pylori infections were analyzed in 78 duodenal ulcer patients. The cytotoxin-associated gene (cagA) and vacuolating cytotoxin gene (vacA) subtype status of cultured strains were studied by PCR. Histopathological findings were graded using a described grading system. The patients were treated with triple-therapy regimens consisting of a proton pump inhibitor and two antibiotics twice daily for 7 days. Endoscopy was repeated at 4 weeks post-therapy to monitor ulcer healing and H. pylori eradication. The bacteria were genotyped from 66 patients, 57 of whom had H. pylori eradicated. The absence of cagA was associated with unsuccessful treatment. No difference was found with regard to vacA subtype between the successful and unsuccessful eradication groups. On histopathological examination, high H. pylori colonization density and intestinal metaplasia were associated with low eradication rate, while a high grade of neutrophil infiltration was associated with a significantly higher eradication rate. The data confirm the importance of cagA positivity as a predictor of successful eradication. When high H. pylori colonization density and intestinal metaplasia are present, therapy appears to be less effective. Therefore, these histopathological features may be involved in an unsuccessful therapeutic outcome.

Association of Toll-like receptor–4 (Asp299Gly and Thr399Ileu) gene polymorphisms with gastritis and precancerous lesions

A Toll-like receptor-4 (TLR-4) Asp299Gly and Thr399Ileu substitution reduces responsiveness to Helicobacter pylori (H. pylori) lipopolysaccharide. CagA+ strains of H. pylori are known to be associated with gastroduodenal diseases. Therefore we aimed to evaluate association of TLR-4 substitutions and CagA seropositivity with gastritis and precancerous lesions in a northern Indian population. After upper gastrointestinal endoscopy, 130 rapid urease test (RUT)-positive patients with nonulcer dyspepsia (NUD) were included. Patients with NUD were also screened for H. pylori infection using modified Giemsa staining and anti-CagA IgG enzyme-linked immunoabsorbent assay. All patients and 200 asymptomatic control subjects were genotyped for TLR-4 substitutions using polymerase chain reaction-restriction fragment length polymorphism. We observed that frequencies of TLR-4 Asp299Gly variants were comparable between patients and control subjects, and also between positive and negative groups of precancerous lesions in patients. Frequencies of TLR-4 399Ileu allele (8% vs 3%, p = 0.008) and Asp299-Ileu399 haplotype (6.5% vs 3%, p = 0.022) were higher in patients than in control subjects at risk for gastritis (OR = 2.6 and 2.5, respectively). TLR-4 399Ileu allele carriers had higher risk for plasma cell infiltration (p = 0.023, OR = 10.6) that led to atrophy (p = 0.028, OR = 4.2) and intestinal metaplasia (p = 0.009, OR = 4.7). CagA positivity was more frequently associated with lymphoid follicle formation (p = 0.033, OR = 2.53). In conclusion TLR-4 Thr399Ileu substitution may be a risk factor for gastritis and precancerous lesions. CagA positivity may be a risk factor for lymphoid follicle development but not for other precancerous lesions in a northern Indian population.

Helicobacter pylori and Non‐malignant Diseases

In recent years, the focus of Helicobacter pylori clinical research has been mainly on gastric malignancy. However, the role of H. pylori in non-malignant diseases, such as peptic ulcer, gastroesophageal reflux disease (GERD) and non-ulcer dyspepsia, as well as non-steroidal anti-inflammatory drug consumption, is still of great interest. A 1- to 2-week course of H. pylori eradication therapy is an effective treatment for H. pylori-positive peptic ulcer disease and a positive CagA status is a predictor for successful eradication of H. pylori. Antral prostaglandin-E2-basal levels appear to be critical for the development of aspirin-induced gastric damage in subjects without H. pylori infection. In clinical practice, among patients treated with proton-pump inhibitors, H. pylori status has no effect on the speed or degree of GERD symptom relief. For the management of dyspepsia in primary care, antisecretory therapy confers a small insignificant benefit compared to strategies based on H. pylori testing while these latter strategies may be cost-effective. H. pylori eradication therapy has a small but statistically significant effect on H. pylori-positive non-ulcer dyspepsia. An economic model suggests that this modest benefit may still be cost-effective but more research is needed.