vacA S1m1 Genotype Research Articles

High prevalence of cagA positive Vac A s1m1 Helicobacter pylori strains isolated from patients suffering from various gastroduodenal diseases in Guwahati, Assam, India

Abstract Aim and Background: Genotyping of H. pylori strains was identified on formalin-fixed paraffin wax-embedded tissue (FFPE) sections and correlated with severity grades of gastric mucosal pathologies in biopsies from upper gastrointestinal (UGI) tract from Guwahati, Assam. Materials and Methods: In total, 168 gastric biopsies collected from patients with UGI symptoms underwent histological evaluation as per the updated Sydney system. Result: H. pylori-like organisms were identified with Warthin and Starry stain, and virulent genes were amplified using polymerase chain reaction (PCR) from genomic DNA extracted from FFPE sections by using QIAamp® DNA FFPE Tissue Kit. Histological examination identified H. pylori-like organisms in 100 biopsies, of which 96 were urease + ve. The prevalence of H. pylori infection was high in age groups 71–80 (88.8%) as compared to other age groups, and it was higher in females (78.9%) when compared to males. The prevalence of virulent genes in biopsies was 88.5% cagA and vacA s1m1, 31.2% iceA1, 32.2% iceA2, and 85.2% babA2. The histological parameters mononuclear cell infiltrate (P = 0.04) and atrophy (P = 0.03), showed statistically significant association with iceA2 and intestinal metaplasia with cagA (P = 0.01) vacAs1m1 (P = 0.01) and babA (P = 0.02) genotypes. Gastric erosion due to H. pylori infection and atrophy showed a significant association. A high bacterial density score was seen with the virulent genotypes. Conclusion: Our work reports for the first time a high prevalence (88.5%) of H. pylori cagA vacA s1m1 genotype in Guwahati, Assam. Association of gastric atrophy and intestinal metaplasia was seen with virulent genotypes. Results show the effectiveness of the FFPE kit for DNA extraction in remote areas where transportation and storage of biopsies are otherwise difficult.

Association between the presence and genotype of Helicobacterpylori and periodontitis.

Whether Helicobacter pylori (H. pylori) infection is associated with periodontitis has been contested for decades. The relationship between H. pylori genotypes and periodontitis has not been clarified either. The present study provides a novel perspective to better understand the role of H. pylori in the pathogenesis of periodontitis. A total of 53 volunteers were recruited and divided into 3 groups in this cross-sectional study, namely the periodontally healthy group (15 participants), the stage I/II periodontitis group (20 participants) and the stage III/IV periodontitis group (18 participants). DNA from the subgingival plaque of all participants was extracted and PCR was performed using specific primers for the urease C gene and cytotoxin-associated gene A (cagA)/vacuolating cytotoxin gene A (vacA) to detect the presence and genotype of H. pylori. A χ2 test and one-way ANOVA were performed on the data. There was no significant difference in sex, age or body mass index between the groups. The detection rate of H. pylori was 39.62% in the total population and increased with the deepening of probing depth and clinical attachment loss. There were significant differences in the detection rate of H. pylori among the three groups, with 13.33, 40.00 and 61.11% in the periodontally healthy, stage I/II periodontitis and stage III/IV periodontitis groups, respectively (χ2=8.760, P<0.001). The cagA-/vacAs2m2 genotype was most commonly detected in the periodontally healthy group (100%). In the periodontitis group, cagA+/vacAs1m2 was the most commonly detected genotype in the stage I/II periodontitis group (37.5%) and cagA+/vacAs1m1 in the stage III/IV periodontitis group (36.3%). The results of the present study suggest that the detection rates and genotypes of H. pylori in the subgingival plaque are associated with the status of periodontitis. cagA+/vacAs1m1 and cagA+/vacAs1m2 may be considered virulence markers of periodontitis. However, given the small sample size and lack of correlation analysis of the study, further larger scale and high-quality clinical trials are required to confirm these findings.

Genetic diversity of Helicobacter pylori type IV secretion system cagI and cagN genes and their association with clinical diseases

A number of cagPAI genes in the Helicobacter pylori genome are considered the most evolved genes under a diversifying selection and evolutionary pressure. Among them, cagI and cagN are described as a part of the two different-operon of cagPAI that are involved in the T4SS machinery, but the definite association of these factors with clinical manifestations is still unclear. A total of 70 H. pylori isolates were obtained from different gastroduodenal patients. All isolates were examined for the presence of primary H. pylori virulence genes by PCR analysis. Direct DNA sequence analysis was performed for the cagI and cagN genes. The results were compared with the reference strain. The cagI, cagN, cagA, cagL, vacA s1m1, vacA s1m2, vacA s2m2, babA2, sabA, and dupA genotypes were detected in 80, 91.4, 84, 91.4, 32.8, 42.8, 24.4, 97.1, 84.3, and 84.3% of the total isolates, respectively. The most variable codon usage in cagI was observed at residues 20–25, 55–60, 94, 181–199, 213–221, 241–268, and 319–320, while the most variable codon usage in CagN hypervariable motif (CagNHM) was observed at residues 53 to 63. Sequencing data analysis of cagN revealed a hypothetical hexapeptide motif (EAKDEN/K) in residues of 278–283 among six H. pylori isolates, which needs further studies to evaluate its putative function. The present study demonstrated a high prevalence of cagI and cagN genes among Iranian H. pylori isolates with gastroduodenal diseases. Furthermore, no significant correlation between cagI and cagN variants and clinical diseases was observed in the present study. However, all patients had a high prevalence of cagPAI genes including cagI, cagN, cagA, and cagL, which indicates more potential role of these genes in disease outcome.

Pattern and trends of Helicobacter pylori genotypes in gastric cancer: A Kenyan 8-year study.

Notable geographic and temporal variations in the prevalence and genotypes of Helicobacter pylori, in relation to gastric pathologies, have been observed; however, their significance and trends in African populations is scarcely described. The aim of this study, was to investigate the association of H. pylori and its respective CagA and vacuolating cytotoxin A (VacA) genotypes with gastric adenocarcinoma, and to describe the trends of H. pylori genotypes over an 8-year period (2012-2019). A total of 286 samples of gastric cancer cases and benign controls (one-to-one matching), from three main cities in Kenya, between 2012 and 2019 were included. Histologic evaluation, and CagA and VacA genotyping using PCR, was performed. Distribution of H. pylori genotypes was presented in proportions. To determine association, a univariate analysis was conducted using a Wilcoxon rank sum test for continuous variables, and a Chi-squared test or Fisher's exact test for categorical data. The VacA s1m1 genotype was associated with gastric adenocarcinoma, {odds ratio (OR) = 2.68 [confidence interval (CI) of 95%: 0.83-8.65]; p = 0.108}, whilst VacA s2m2 was associated with a reduced probability of gastric adenocarcinoma [OR = 0.23 (CI 95%: 0.07-0.78); p = 0.031]. No association between cytotoxin associated gene A (CagA) and gastric adenocarcinoma was observed. Over the study period, an increase in all genotypes of H. pylori was seen, and although no predominant genotype was noted, there was significant year-to-year variation, with VacA s1 and VacA s2 showing the greatest variation. VacA s1m1 and VacA s2m2 were associated with increased, and reduced risk of gastric cancer, respectively. Intestinal metaplasia and atrophic gastritis did not appear to be significant in this population.

Clinical relevance of the cagA and vacA s1m1 status and antibiotic resistance in Helicobacter pylori: a systematic review and meta-analysis

BackgroundThe role of Helicobacter pylori (H. pylori) virulence factors of such as vacA s1m1 and cagA in designating clinical outcomes and eradication rate has been deeply challenged in the last decade. The goal of this analysis was to identify the potential relevance between cagA and vacA genotypes with reported antibiotic resistance observed in clinical H. pylori isolates.MethodsThis literature search was conducted in databases such as Clarivate analytics, PubMed, Scopus, EMBASE, DOAJ, and Google Scholar by April 2022, regardless of language restrictions and publication date. Quality of the included studies was assessed by the Newcastle–Ottawa scale. Statistical analysis of retrieved studies was fulfilled using Comprehensive Meta-Analysis software version 2.2. Following quality appraisal of eligible studies, potential association between the status of cagA and vacA genes with resistance to clarithromycin, metronidazole, amoxicillin, tetracycline, and levofloxacin was measured using odds ratio with 95% confidence interval. We also used sensitivity analyses and meta-regression to eliminate the source of heterogeneity from the overall estimates. Publication bias was assessed using funnel plot, Egger’s test, Begg’s test with the trim and fill procedure to assess the presence and magnitude of publication bias in the included studies.ResultsOur findings suggested that a significant relationship between cagA status ‎and increase resistance ‎to metronidazole (OR: 2.69; 95% CI: 1.24–5.83‎‏‎). In subgroup analysis, we ‎found that in the Western ‎population, infection with cagA-positive strains could be led to increase in ‎the resistance to ‎metronidazole (OR: 1.59; 95% CI: ‎0.78–3.21‎‏‎), ‎amoxicillin (OR: ‎19.68‎; 95% CI: 2.74–‎‎141.18), ‎and ‎levofloxacin (OR: ‎11.33; 95% CI: ‎1.39–‎‎91.85). After implementation of trim and fill method, the adjusted OR was not significantly differed from original estimates which in turn represented our subgroup analysis was statistically robust. On the other hand, vacA ‎genotypes usually ‎reduce the antibiotic resistance of this bacterium, so that vacA s1m1 significantly reduces the ‎resistance to ‎metronidazole (OR: 0.41; 95% CI: 0.20–0.86‎‏‎). Surprisingly, resistance of vacA s2m2 strains to antibiotics was low, the reason may be due ‎to the non-inflammatory properties of strains containing vacA s2m2. The meta-regression and sensitivity analyses successfully reduced the effect of heterogeneity from the overall estimates. In addition, although the pooled OR is reduced after trim and fill adjustment but results do not change the conclusion regarding vacA genotypes and antibiotic resistance.ConclusionsAccording to our findings, it was clearly demonstrated that cagA-positive strains are resistance to metronidazole, especially in Western countries. In Western countries, vacA s1m1 increases resistance to amoxicillin and levofloxacin. Based on the present findings, the vacA s1m1 genotype significantly increases resistance to metronidazole, while the vacA s1m2 decreases resistance to clarithromycin and metronidazole. Resistance to antibiotics in less virulent (vacA s2m2) strains is statistically significant lower than others.

Helicobacter pylori genotypes associated with gastric cancer and dysplasia in Colombian patients.

Colombia has high incidence levels of gastric cancer that can be explained by the genetic variability of Helicobacter pylori (H. pylori). Our aim was to establish the relation of the H. pylori CagA and VacA genotypes to dysplasia and gastric cancer, in a high-risk population. A case-control study was conducted on 202 patients from a high-risk cancer zone. Patients with dysplasia and gastric cancer (cases) and patients with nonatrophic gastritis (controls) were included. Endoscopic sampling and histologic classification were carried out according to the Sydney system and the Lauren classification. Genetic information was obtained through polymerase chain reaction on paraffin blocks. The measures of association of the variables of interest were evaluated in bivariate and multivariate models. A P<0.05 was considered statistically significant and the SPSS version 25 program was employed. Age above 50 years (OR: 23.76; CI: 8.40-67.17; P=0.000) and the VacA s1m1 genotype (OR: 6.18; CI: 1.25-30.51; P=0.025) were associated with higher risk for developing dysplasia and gastric cancer. The CagA+ genotype was not found to be a risk factor for developing those pathologies (OR: 1.02; CI: 0.39-2.62; P=0.965). The H. pylori VacA genotypes are markers for the development of gastric cancer. That information could be used to create a risk index in a predictive model to optimize the healthcare of higher-risk patients.

Helicobacter pylori genotypes associated with gastric cancer and dysplasia in Colombian patients

Introduction and aimsColombia has high incidence levels of gastric cancer that can be explained by the genetic variability of Helicobacter pylori (H. pylori). Our aim was to establish the relation of the H. pylori CagA and VacA genotypes to dysplasia and gastric cancer, in a high-risk population. Material and methodsA case-control study was conducted on 202 patients from a high-risk cancer zone. Patients with dysplasia and gastric cancer (cases) and patients with nonatrophic gastritis (controls) were included. Endoscopic sampling and histologic classification were carried out according to the Sydney system and the Lauren classification. Genetic information was obtained through polymerase chain reaction on paraffin blocks. The measures of association of the variables of interest were evaluated in bivariate and multivariate models. A P<0.05 was considered statistically significant and the SPSS version 25 program was employed. ResultsAge above 50 years (OR: 23.76; CI: 8.40-67.17; P=0.000) and the VacA s1m1 genotype (OR: 6.18; CI: 1.25-30.51; P=0.025) were associated with higher risk for developing dysplasia and gastric cancer. The CagA+ genotype was not found to be a risk factor for developing those pathologies (OR: 1.02; CI: 0.39-2.62; P=0.965). ConclusionsThe H. pylori VacA genotypes are markers for the development of gastric cancer. That information could be used to create a risk index in a predictive model to optimize the healthcare of higher-risk patients.

PREX2 gene’s expression in gastric antral epithelial cells of patients with H. pylori infection

The Prex2 protein is a member of the Rac family proteins that belongs to small G proteins with a critical role in cell migration, cell proliferation, and apoptosis through its effects on PI3K cell signaling pathway and phosphatase activity of PTEN protein. The effect of PREX2 gene expression has been shown in some cancer cells. A survey of PREX2 gene expression in gastric antral epithelial cells of gastric cancer patients with Helicobacter pylori various genotypes infection can conduct to better understanding H. pylori infection's carcinogenesis. In a case-control study, PREX2 gene expression was evaluated in gastric antral biopsy samples on four groups of patients referred to Sanandaj hospitals, including gastritis with (n=23) and without (n=27) H. pylori infection and gastric cancer with (n=21) and without (n=32) H. pylori infection. Each gastric biopsy sample's total RNA was extracted and cDNA synthesized by using Kits (Takara Company). The PREX2 gene expression was measured using the relative quantitative real-time RT-PCR method and ΔΔCt formula. The PREX2 gene expression increased in gastric antral biopsy samples of gastritis and gastric cancer patients with H. pylori infection (case groups) than patients without H. pylori infection (control groups) 2.38 and 2.27 times, respectively. The patients with H. pylori vacA s1m1 and sabB genotypes infection showed a significant increase of PREX2 gene expression in gastric cancer antral epithelial cells. H. pylori vacA s1m1 and sabB genotypes have the positive correlations with PREX2 gene expression in gastric antral epithelial cells of gastritis and gastric cancer patients.

Profile of Helicobacter pylori cagA &vacA genotypes and its association with the spectrum of gastroduodenal disease

PurposeGlobally, H. pylori virulence factors cagA and vacA genotypes and its variation is leading to the austere form of the gastroduodenal disease. Our objectives were to detect H. pylori in dyspeptic patients from biopsy samples with the validation of the various existing diagnostic tools and to screen the cagA, vacA genotypes profile from biopsy specimens and how it impacts in progression of gastroduodenal disease in southern India. Methods374 patients who attended endoscopy unit at Kasturba Hospital, Manipal with their consent obtained their biopsies. H. pylori were detected by HPE, Culture, RUT and PCR and its virulence gene were patterned with PCR. ResultsThe positive rate of H. pylori by HPE, RUT, Culture and PCR were 51.33%, 47.1%, 32.4% and 50.3% respectively and comparison by Bayesian LCMs analysis showed PCR is superior among them. The frequency of H. pylori virulence gene viz cagPAI (cagA) were 80.9%, and vacA alleles-s1m1 (42%), s1m2 (33%) and s2m2 (25%) genotypes by PCR respectively. Four combinations of cagA/vacA genotypes were noted, majority of strains harboured cagA+/vacA s1m1 genotypes (42.6%), interestingly this hyper-virulent strain more frequently seen in severe gastroduodenal disease whereas cagPAI negative strains as well as cagA−/vacA s2m2 combinations (19.1%) are seen most commonly in functional dyspepsia cases and depicted significant association by Chi-square test. ConclusionsThis study validates and compares the existing diagnostic methods for detecting H. pylori in biopsies. Also, it reveals some pattern of virulence gene combination will play a vital role in disease progression.

Abstract PO-162: Helicobacter pylori in Native Americans in Northern Arizona

Abstract Background. Helicobacter pylori, one of the most common bacterial infections worldwide. Chronic infections are associated with gastritis, peptic ulcer, and gastric cancer. While H. pylori infections and gastric cancer are going down in the US, certain populations continue to experience high H. pylori prevalence of infection and a significant burden from stomach cancer. For example, in Arizona H. pylori prevalence of infection among the Navajo is 60% and gastric cancer is 3-4 times higher that of the white population. Objective: The aim of this work was to survey the presence of virulence factors (cagA and vacA) in H. pylori in the Navajo reservation and their association with gastric disease. Methods: The presence of the virulence genes, cagA and vacA in H. pylori was investigated in gastric biopsies from 97 patients attending the gastroenterology clinic in Winslow, AZ. Biopsies were collected from the antrum and fundus and used for histological examination and for molecular characterization. Molecular characterization was performed by looking at type and number of EPIYA motifs in cagA and presence of different alleles in the signal (s) and medium (m) regions of the vacA gene. Results: The infection rate in the biopsy samples was 22.9%. The cagA gene amplified in 76.9% of the cases and analysis of the 3′ region of cagA showed the predominant presence of the “Western CagA” type with the EPIYA-ABC motif (70.0%) the most prevalent. The vacA allele s1bm1 was the most prevalent (76.9%) followed by s2m2 (11.5%). CagA negative isolates were associated with gastritis or normal findings while EPIYA motifs ABCC were present in severe gastric disease. vacA s2m2 were associated with normal findings. Conclusions: In this population, we have found H. pylori genotypes with predominant cagA Western-type and ABC EPIYA motifs. The vacA s1m1 genotype was the most prevalent and seemed to be associated with gastritis. American Indian/Native American populations are at higher risk for gastric cancer than the general US population. It is important to better establish and quantify genotypes of H. pylori to identify bacterial factors involved in the high prevalence of H. pylori and associated disease among the Navajo population. Citation Format: Fernando P. Monroy, Heidi E. Brown, Priscilla Sanderson, Gregory Jarrin, Mimi Mbegbu, Shari Kyman, Camenlita Chief, Robin B. Harris. Helicobacter pylori in Native Americans in Northern Arizona [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-162.

Helicobacter pylori Infection, DNA Methylation, and Gastric Carcinogenesis

Helicobacter pylori (H. pylori), the major cause of chronic gastritis, peptic ulcers and gastric cancer, infects about 50% of the world population. Although various host and bacterial factors have been suggested, the detailed pathogenic mechanisms remain to be defined. Increasing evidences have demonstrated that epigenetic dysregulation, such as DNA methylation, plays a critical role in gastric carcinogenesis, and is currently under intensive investigation. H. pylori infection result in aberrant DNA methylation in a number of gene promoters in gastric mucosa, eradication of H. pylori can reverse some hypermethylated genes, but had no effect on others. In some methylated genes, the methylation levels persist even after H. pylori eradication, and the fact suggests that DNA methylation accumulation is associated with molecular irreversibleness and gastric diseases progression. DNA methylome and gastric cancer risk analysis indicate that certain gene promoter methylation may serve as potential biomarkers for gastric cancer predication. In addition, H. pylori cagA and vacA s1m1 genotype are independent variables that is associated with higher methylation level. The levels of methylation can be influenced by the degree and length of infection exposure, and certain host gene polymorphisms are also associated with gene methylation in H. pylori-infected subjects. Continued investigation in these areas will be critical to provide insights into the molecular mechanisms of H. pylori induced gastric diseases and develop strategies for disease prevention and intervention. We review recent progress and discuss future research directions in this important area.

Antibiotic Resistance and Genotypes of Helicobacter pylori Strains in Patients with Gastroduodenal Disease in Southeast Poland.

The aim of this study was to investigate genetic diversity of Helicobacter pylori virulence markers to predict clinical outcome as well as to determine an antibiotic susceptibility of H. pylori strains in Poland. Gastric biopsies from 132 patients with gastrointestinal disorders were tested for presence of H. pylori with the use of rapid urease test, microbial culture, and polymerase chain reaction (PCR) detection. The genetic diversity of 62 H. pylori positive samples was evaluated by detection of cagA and PCR-typing of vacA and iceA virulence-associated genes. Most common H. pylori genotypes were cagA(+)vacAs1m2 (27.4%) and cagA(−)vacAs2m2 (24.2%). In logistic regression analysis, we recognized the subsequent significant associations: gastritis with ureC, i.e., H. pylori infection (p = 0.006), BMI index (p = 0.032); and negatively with iceA1 (p = 0.049) and peptic ulcer with cagA (p = 0.018). Thirty-five H. pylori strains were cultured and tested by E-test method showing that 49% of strains were resistant to at least one of the tested antibiotics. This is the first study that reports the high incidence and diversity of allelic combination of virulence genes in gastroduodenitis patients in Poland. Genotyping of H. pylori strains confirmed the involvement of cagA gene and vacAs1m1 genotype in development and severity of gastric disorder.

Pathogenic potential of Helicobacter pylori strains can explain differences in H. pylori associated diseases rates from Chile and Cuba

Background: The prevalence of Helicobacter pylori-related diseases varies geographically and it is partially determined by the virulence of the circulating strains. Cuba and Chile exhibit different gastric cancer rates, on despite of very similar H. pylori infection rates. We determined if differences in the pathogenic potential of H. pylori isolates from Chile and Cuba could explain the disease outcome in each population.&#x0D; Methods: H. pylori isolates from 78 Chilean and 71 Cuban patients were analyzed using PCR for the presence of cagA, babA2, vacA alleles and the pattern of EPIYA motifs. Results: cagA was detected in 94.9 % of Chilean and 64.7 % of Cuban isolates (P &lt; 0.001) and was significantly associated with duodenal ulcer (DU) in Cuba (P &lt; 0.01) but not in Chile. The presence of cagA with multiple EPIYA-C motifs was 18.2 % higher in Chile than in Cuba (P &lt; 0.05). Also, an association was observed between GU (P ≤ 0.05) and premalignant lesions (P &lt; 0.001) with the multiple EPIYA-C motif status of the strains in Chile, but not in Cuba. The prevalence of vacA s2m2 genotype was predominant in Chile (66.7 %), while in Cuba was prevalent the s1m1 genotype (56.8 %); and the last one was significantly associated with the presence of DU in Cuban patients.&#x0D; Conclusions: The cagA status and the EPIYA pattern found in Chilean and Cuban H. pylori clinical isolates partially explain the differences in disease prevalence between both countries. The high proportion of vacA s2m2 genotype in Chile was an unexpected result, needing further studies.&#x0D; Bangladesh Journal of Medical Science Vol.18(3) 2019 p.577-585

Virulence factor genotyping of Helicobacter pylori isolated from Costa Rican dyspeptic patients

Background and aimsCosta Rica is one of the countries with the highest incidence and mortality rates for gastric cancer. Helicobacter pylori infection rates are high in the whole country. We have previously shown that H. pylori CagA+ is significantly associated with atrophic gastritis (AG) of the antrum in a dyspeptic population. The aim of this work is to determine if other H. pylori virulence factors (vacA, dupA, oipA, iceA and babA2) are associated with atrophic gastritis (AG) or duodenal ulcer (DU). MethodsThe presence of virulence genes in Costa Rican H. pylori isolates was analyzed by PCR in 151 cultured strains from patients with dyspeptic symptoms. Endoscopic and histopathological diagnoses were available. Odds-ratio and 95% confidence intervals for AG patients vs. non-atrophic gastritis (NAG) or DU patients vs. no duodenal ulcer (NDU) patients were calculated. ResultsAmongst the studied isolates, 82% had the cagA+, 76.2% had the vacA s1m1, 97.0% had the oipA+, 21.0% had the icea1, 79.0% had the iceA2, 44.0% had the babA2+ and 76.0% the dupA+ genotypes. Infection with H pylori cagA+, dupA+, oipA+, iceA, babA2+, and vacA s1m1 genotypes was not associated with AG risk. The frequency of the dupA gene was 78.7 and 60.9% in isolates from patients with NDU and DU, respectively, and its presence was significantly associated with decreased risk of duodenal ulcer [odds-ratio: 0.33, p = 0.024, confidence interval 95% (0.11–0.85)]. ConclusionH. pylori dupA genotype is inversely associated with DU risk in this population.

CagA and vacA allelic combination of Helicobacter pylori in gastroduodenal disorders

BackgroundAllelic variation of the virulence genes, vacA and cagA, as the most important virulence associated genes play an important role in the pathogenesis of severe gastrointestinal disease. ObjectiveThe aim of the present study was to identify the diversity of the virulence genes in patients with Gastric Cancer (GC), who were referred to the gastro-endoscopy unit of Imam Khomeini Hospital, Ahvaz Jundishapur University of medical science, Ahvaz, Iran. MethodsGastric biopsy specimens from 301 patients suspected to gastrointestinal disorders, were analyzed for H. pylori using molecular and phenotypical methods (culture, and biochemical test (catalase, oxidase and urease tests)). ResultsAmong 201 PCR positive for H. pylori, using histopathological methods, 22 (10.9%) patients had GC. Presence of vacA gene in our H. pylori strains was 100% (201/201), while the most virulent vacA s1 allele was detected in 82.6% isolates, and the mid region vacA m1 was found in 39.8% isolates. The vacA s1/m1 genotype was the most virulent allelic combination in GC and Peptic Ulcer Disease (PUD) in 68.2% and 50%, respectively. The cagA gene was detected in 66.7% isolates. Among the cagA positive isolates, EPIYA-ABC motif was the most common motif in the GC (66.7%), PUD (55.6%) and Erosive Gastroduodenitis (EG) samples (55.2%), while EPIYA-ABCC was the most common motif (58.7%) in the Non-Ulcer Dyspepsia (NUD) samples. The vacA s1m1/cagA+ combination was detected in GC (73.3%) and PUD (51.9%), while vacA s1m2/cagA+ presented in the NUD and EG samples in 77.8% and 62.1%, respectively. ConclusionIn this work, Western type (EPIYA-ABC and ABCC motifs) cagA, vacA s1m1 combinations have been demonstrated as the dominant genotype in the tested Ahvazian H. Pylori strains. Also the participation of cagA gene and vacA s1m1 genotype in development and severity of gastric disorder was well evident. Therefore, infection with H. pylori strain containing the cagA gene or the vacA s1m1 genotypes could be associated with increased risk of GC. This is the first study in our area that reports the high incidence and diversity of allelic combination of cagA and vacA genes in gastroduodenitis patients.

Genetic diversity and functional analysis of oipA gene in association with other virulence factors among Helicobacter pylori isolates from Iranian patients with different gastric diseases

Helicobacter pylori (H. pylori) is one of the most genetically diverse bacterial pathogens that persistently colonizes the human gastric epithelium. This remarkable genomic plasticity may act as a driving force for successful adaptation and persistence of the bacteria in the harsh gastric environment. Outer inflammatory protein A (OipA) encoded by oipA gene (HP0638/hopH) is a member of the outer membrane proteins (OMPs) of H. pylori involved in induction of IL-8 secretion and is associated with development of peptic ulcer and gastric cancer. Expression of OipA is regulated by phase variation within a CT dinucleotide repeat motif of the oipA gene. In this study we carried out direct DNA sequence analysis of 53 amplified fragments to investigate the oipA “On/Off” status among Iranian H. pylori isolates from patients with various gastric diseases. The prevalence of cagL, cagA, EPIYA motifs, vacA alleles, babA2 and sabA genotypes as well as cagPAI integrity of the isolates were determined by PCR. Our results demonstrated a high prevalence of strains with functional oipA status (79%) and significant associations were found between functional oipA and cagA (P = 0.027) and vacA s1m1 (P = 0.022) genotypes. The vacA s1m2 genotype was also found to be statistically associated with PUD (P = 0.0001). Interestingly, we showed that H. pylori strains with intact cagPAI co-expressed oipA gene in a significant synergistic relationship (P < 0.01). However, no significant association was observed between the functional oipA status and clinical outcomes (P > 0.05). In conclusion, our findings denotes great diversity in the number and pattern of CT dinucleotide repeats of oipA among Iranian H. pylori strains. The synergistic link between functional oipA and other important virulence factors is proposed to be critical in the pathogenesis of H. pylori, which needs further studies with a larger number of samples.

VacA s1m1 genotype and cagA EPIYA-ABC pattern are predominant among Helicobacter pylori strains isolated from Mexican patients with chronic gastritis.

PurposeVirulent genotypes of Helicobacter pylori vacA s1m1/cagA+/babA2+ have been associated with severe gastric diseases. VacA, CagA and BabA are polymorphic proteins, and their association with the disease is allele-dependent. The aims of this work were: (i) to determine the prevalence of H. pylori by type of chronic gastritis; (ii) to describe the frequency of cagA, babA2 and vacA genotypes in strains from patients with different types of chronic gastritis; (iii) to characterize the variable region of cagA alleles.MethodologyA total of 164 patients with chronic gastritis were studied. Altogether, 50 H. pylori strains were isolated, and the status of cagA, babA2 and vacA genotypes was examined by PCR. cagA EPIYA segment identification was performed using PCR and sequencing of cagA fragments of six randomly selected strains.Results/Key findingsThe overall prevalence of H. pylori was 30.5 %. Eighty percent of the isolated strains were vacA s1m1, and the cagA and babA2 genes were detected in 74 and 32 % of the strains, respectively. The most frequent genotypes were vacA s1m1/cagA+/babA2- and vacA s1m1/cagA+/babA2+, with 40 % (20/50) and 28 % (14/50), respectively. In cagA+, the most frequent EPIYA motif was -ABC (78.4 %), and EPIYA-ABCC and -ABCCC motifs were found in 10.8 % of the strains. A modified EPIYT-B motif was found in 66.6 % of the sequenced strains.ConclusionH. pylori strains carrying vacA s1m1, cagA+ and babA2- genotypes were the most prevalent in patients with chronic gastritis from the south of Mexico. In the cagA+ strains, the EPIYA-ABC motif was the most common.

Prevalence of Helicobacter pylori genotypes in patients with gastroduodenal pathology in Kazan

Aim. Investigation of the prevalence of various H. pylori genotypes among children and adult population of Kazan with chronic gastroduodenal pathology.&#x0D; Methods. The study included 107 patients (49 children and 58 adults) with chronic gastritis/gastroduodenitis and gastric and duodenal ulcer who had H. pylori infection confirmed by molecular genetic method. All patients underwent biospy from antral mucosa during endoscopy for H. pylori verification by polymerase chain reaction and genotyping for сagA and babA genes and iceA and vacA allels. &#x0D; Results. CagA gene was found in 19 (32.8%) out of 58 adults and 13 (26.5%) out of 49 children. VacA gene was detected in all patients (100%). VacAs2 genotype in children was nearly 1.6 times as frequent as the vacAs1 genotype (61.2 and 36.7% respectively). In adult patients vacAs2 genotype was detected 2.5 times less frequently than vacAs1 (27.6 and 70.7%, respectively). VacAm2 genotype was revealed in 71.4% (35/49) of children and 77.6% (45/58) of adults. IceA2 genotype was identified in 46.9% (23/49) of children and 44.8% (26/58) of adult patients, iceA1 gene - in 20.4% of children and 55.2% of adult patients. &#x0D; Conclusion. The strains with vacAs2m2 genotype are prevailing in children (42.9%) and determine low toxigenicity of H. pylori strains; vacAs1m2 genotype is predominant among adult patients (53.4%); high prevalence of cagA-negative strains of H. pylori was found both in children and adults (73.5 and 67.2%, respectively).

Advanced non-cardia gastric cancer and Helicobacter pylori infection in Vietnam

BackgroundThe incidence of gastric cancer in the Northern city, Hanoi is higher than in the Southern city, Ho Chi Minh, Vietnam. We previously reported that Helicobacter pylori vacA m1 genotype might be responsible for the difference between the two cities, however, the study only included non-cancer patients. The aim of this study is to investigate the non-cardia gastric cancer characteristics and the role of H. pylori virulence on different non-cardia gastric cancer incidence between two cities in Vietnam.Methods and ResultsWe recruited 282 non-cardia gastric cancer patients that had undergone gastroscopy in two cities, Ho Chi Minh and Hanoi, Vietnam. Characteristics of non-cardia gastric cancer were late age of onset (mean age, 62.5 years), predominance in males (ratio of males/females; 3.9:1), diffuse type (55.3%), and high prevalence of H. pylori infection (79.4%). H. pylori infection and the vacA m1 genotype conferred an increased risk for GC (OR, 2.02; 95% CI 1.4–3.0; P = 0.0003 and OR, 2.7; 95% CI 1.5–4.7; P = 0.001, respectively). Interestingly, the presence of vacA m1 genotype in the gastric cancer group was significantly higher than that in the non-cancer group (68.8% vs 44.9%, P = 0.001) and the significant tendency still observed in Ho Chi Minh (67.6% vs 31.9%, P < 0.0001).ConclusionWe first describe the characteristics of non-cardia gastric cancer in Vietnam. Helicobacter pylori infection was associated with the development of non-cardia GC. vacA m1 genotype might contribute to incidence differences between the two cities.

Two populations of less-virulent Helicobacter pylori genotypes in Bangladesh.

Bangladesh has a population with a low gastric cancer risk but high prevalence of Helicobacter pylori infection. Several studies have examined virulence genes in H. pylori from Bangladesh. We analyzed cagA and vacA subtypes and their association with severe histology phenotypes, and analyzed population types among Bangladeshi strains. We included patients who underwent endoscopy in Dhaka. Sequences of virulence genes and seven housekeeping genes were obtained by next generation sequencing and confirmed by Sanger sequencing. We isolated 56 H. pylori strains from 133 patients, of which 73.2% carried cagA, and all were considered Western-type. Patients infected with cagA-positive strains had more severe histological scores than patients infected with cagA-negative strains. Among vacA s1 and m1 genotypes, the s1a (97.8%, 43/44) and m1c (28/30, 93.3%) genotypes were predominant. All strains containing s1 and m1 (30/56, 53.6%) also had i1, d1, and c1. In contrast, all strains containing the less-virulent genotypes s2 and m2 (12/56, 21.4%) also possessed i2, d2, and c2. Multivariate analysis indicated that subjects infected with vacA m1-genotype strains only had a significantly higher risk of antrum atrophy than patients infected with m2-genotype strains. Of the two main H. pylori populations in this study, hpAsia2 strains were associated with higher activity and inflammation in the antrum compared to hpEurope strains; however, only vacA s1m1i1d1c1 strains, independent of population type, were significantly associated with inflammation in the antrum, unlike the s2m2i2d2c2 genotype. In conclusion, Bangladeshi strains were divided into two main populations of different genotypes. The low incidence of gastric cancer in Bangladesh might be attributable to the high proportion of less-virulent genotypes, which may be a better predictor of gastric cancer risk than the ancestral origin of the H. pylori strains. Finally, the vacA m region may be a better virulence marker than other regions.