cagA Gene Research Articles

EPIYA motifs of Helicobacter pylori cagA genotypes and gastrointestinal diseases in the Iranian population: a systematic review and meta-analysis

Helicobacter pylori is one of the best risk factors for gastric cancer. Recent studies have examined the relationship between virulence factors, in particular CagA toxin, and the development of gastrointestinal diseases. According to the literature, there is a significant relationship between the polymorphism of cagA-EPIYA motifs and progression to severe clinical outcomes. The main goal of our study was to determine the possible association between cagA genotypes and the risk of severe clinical outcomes in the Iranian population. We investigated these ambiguities using a comprehensive meta-analysis study, in which we evaluated data from 1762 Iranian patients for a potential correlation between all cagA gene genotypes and gastrointestinal diseases. According to statistical analysis, the frequencies of cagA genotypes including ABC, ABCC, AB and ABCCC in the Iranian population were estimated at 80.18%, 22.81%, 5.52% and 2.76%, respectively; the ABD genotype was not detected in these PCR-based studies. There was a significant relationship between cagA genotypes ABCC and ABCCC and severe clinical outcomes of infection such as peptic ulcer and gastric cancer. Overall, it can be concluded that there is a positive correlation with the number of copies of EPIYA-C and the increase of gastric cancer. Therefore, according to our results, it seems that the EPIYA-ABCCC motif has a strong positive relationship with gastric cancer in the Iranian population.

High Salt Intake in Helicobacter Pylori Infected Individuals Can Significantly Increase the Risk of Gastric Cancer; a Global Analysis

The odds ratio with 95CIs was used to evaluated the synergistic effects between high salt intake and H. pylori infection among gastric cancer cases. Heterogeneity was assessed by I2 index and Cochrane Q-test; In addition, the presence of publication bias was measured using Beggâ��s p-value and Eggerâ��s p-value test (18). There were 7 studies met our criteria. These studies were conducted during 2003-2019 in Korea, Japan, United states, China, and Portugal. We evaluated data of 8,068 cases. H. pylori infection was confirmed by ELISA and UBT in these eligible studies (Table 1). The frequency of gastric cancer in habitual high salt intakes with positive H. pylori infection was significantly greater than those preference salty food with negative H. pylori infection (Chi-square: 5.33; p-value: 0.02). Our results suggested that there is a positive association between high salt intake and risk of gastric cancer in H. pylori infected-individuals (OR: 1.47; 95CI: 1.01-2.15; p-value: 0.04; I2: 83.6; Q-value: 36.6; Beggâ��s p-value: 0.13; Eggerâ��s p-value: 0.25) (Fig. 1). Gastric cancer is one of the top cause of cancer-related death in the world (1). Unfortunately, gastric cancer has a poor-prognosis and untreated early gastric cancer lesions will progress to advanced gastric cancer during 4-5 years (2). Gastric cancer is a heterogeneous malignancy with multifactorial causes including socio-economic status, diet, environmental condition, genetic polymorphism as well as infectious agents particularly chronic infection by Helicobacter pylori (3). In 1994, the International Agency for Research on Cancer (IARC) announced that H. pylori is considered as class I carcinogens and etiologic cause of human gastric cancer (4). However, a high rate of H. pylori infection in areas with a low incidence of gastric cancer remains an enigma (5). It has been suggested that H. pylori infection alone cannot cause gastric cancer without synergistic effects of lifestyle, diet, etc (6-7). On the other hand, there is evidence that dietary salt has an association with gastric adenocarcinoma (8-9). Therefore, it may that H. pylori infection and high salt intakes have synergistic effects in the development of gastric cancer. the previous studies reveal that salt cause upregulation of H. pylori cagA gene during in vitro experiments (10). We performed a comprehensive literature search in several databases including PubMed, Scopus, Embase, and Google scholar using search terms consisting â��Helicobacter pyloriâ��, â��Saltâ��, â��Gastric cancerâ��, â��Dietaryâ�� and â��Salt intakeâ�� without limitation in time and language. The potential relevant documents were evaluated and the required data such as first author, publication year, country, total cases, the frequency of high salt intake among H. pylori-infected cases with gastric cancer or odds ratio corresponding 95 confidence intervals (95CIs), and H. pylori diagnostic test were summarized in Table 1. The odds ratio with 95CIs was used to evaluate the synergistic effects between high salt intake and H. pylori infection among gastric cancer cases. Heterogeneity was assessed by I2 index and Cochrane Q-test; In addition, the presence of publication bias was measured using Beggâ��s p-value and Eggerâ��s p-value test (18).  There were 7 case-control studies that met our criteria. These studies were conducted during 2003-2019 in Korea, Japan, United states, China, and Portugal. We evaluated data of 8,068 cases. H. pylori infection was confirmed by ELISA and UBT in these eligible studies (Table 1). The sodium concentration was assessed by history, urinary sodium, as well as Food frequency questionnaires (FFQs) in these studies.The frequency of gastric cancer in habitual high salt intakes with positive H. pylori infection was significantly greater than those who preference salty food with negative H. pylori infection (Chi-square: 5.33; p-value: 0.02). Our results suggested that there is a positive association between high salt intake and risk of gastric cancer in H. pylori infected-individuals (OR: 1.47; 95CI: 1.01-2.15; p-value: 0.04; I2: 83.6; Q-value: 36.6; Beggâ��s p-value: 0.13; Eggerâ��s p-value: 0.25) (Fig 1). Tsugane et al, 2004 were suggested that there is a significant relation between salt intake and the subsequent risk of gastric cancer in a Japanese population (19). In addition, Ge et al., 2012 provided a systematic review to show the association between Habitual dietary salt intake and risk of developing to gastric cancer using 11 retrospective single-center studies (20). Â

Transcriptional Profile of Helicobacter pylori Virulence Genes in Patients with Gastritis and Gastric Cancer.

Introduction Numerous molecular epidemiology studies have been performed about the frequency of Helicobacter pylori virulence genes in patients with H. pylori infection so far. This study was conducted to detect transcriptional profile by cDNA of H. pylori virulence genes in gastric biopsy samples of gastritis and gastric carcinoma patients. Materials and Methods In a case-control study, based on the prevalence of gastritis and gastric cancer in Sanandaj city during 2018 and 2019, 23 and 11 gastric antral biopsy samples with H. pylori infection were collected from gastritis and gastric carcinoma patients by the consecutive and available sampling method. Pathological characters, including tumor grades and tumor areas for gastric carcinoma biopsy samples prepared from gastric cancer areas, were determined by the pathologist. Total RNA of gastric antral biopsy samples was extracted, and their cDNA was synthesized by TaKaRa kit. H. pylori virulence genes' cDNA using specific primers and PCR was detected. This study's results were analyzed by SPSS version 25 and statics chi-square tests for determination of relationship and correlation between cDNAs of H. pylori transcriptional profile and clinical outcomes of H. pylori infection, including gastritis, gastric carcinoma, tumor grades, and tumor area. Results The positive statistical correlations were observed between transcripts of cagA, cagA-EPIYAC, cagE, and cagY genes and H. pylori infection clinical outcomes (P < 0.05). Conclusion Detection of the H. pylori virulence genes' cDNA in gastric biopsy samples can help provide the prognosis of clinical outcomes.

MOLECULAR CHARACTERISTICS OF CAGA GENE EPIYA MOTIFS OF HELICOBACTER PYLORI AMONG PATIENTS WITH GASTRODUODENAL DISEASES

Background: cagA gene EPIYA motifs of H. pylori play an important role in the pathogenesis of gastroduodenal disease. This study is aimed at (1) Identify patterns of cagA gene EPIYA motifs ofH. pyloristrains from gastric biopsy specimens; (2) Investigate the association between cagA gene EPIYA motifs and gastroduodenal diseases. Patients and methods: Eighty-nine gastroduodenal disease patients infected with cagA-positive H. pylori were enrolled in this study. The patterns of cagA gene EPIYA motifs were determined by PCR. Result: cagA-positive H. pylori strains with East Asian-type EPIYA motif were predominant (89.9%), whereas strains with Western-type EPIYA motif accounted for only 10.1%. There were two strains with rare East Asian-type EPIYA, as -ABDBD and -AABD. In the duodenal ulcer group, the prevalence of East Asian-type and Western-type EPIYA motifs were 80% and 20%, respectively. Meanwhile, East Asian-type and Westerntype EPIYA motifs accounted for 95.8% and 4.2%, respectively in the gastric cancer group. Conclusion: cagA gene EPIYA motifs of cagA-positive H. pylori were quite diverse with the predominance of East Asian-type EPIYA motif. There were two rare motifs as -ABDBD and -AABD. The frequency of strains with East Asian-type EPIYA motif was highest in the gastric cancer group, whereas it was lowest in the duodenal ulcer group. Key words: Helicobacter pylori, cagA gene, EPIYA motif, gastroduodenal diseases

Prevalence of Helicobacter pylori among residents and their environments in the Nara prefecture, Japan

BackgroundChronic infection with Helicobacter pylori, specifically cagA-positive strains, is associated with gastric cancer. Thus, measures to prevent H. pylori infection are required. This study was conducted to clarify the prevalence of H. pylori in the community to identify the infection source and comprehensively assess the risk of H. pylori infection. MethodsWe collected 90 human faecal samples and 73 environmental samples (water, vegetable, and animal faecal samples) from the residents in an area with a high incidence of gastric cancer in Japan. Polymerase chain reaction assay was performed to detect the glmM housekeeping gene and the cagA virulence gene of H. pylori. A questionnaire survey was conducted, and the responses were analyzed statistically. ResultsThe glmM gene was detected in 18 of 90 (20%) faecal samples obtained from residents; among them, the cagA gene was detected in 33.3% (6/18), and in all who had undergone eradication therapy. H. pylori was not detected in environmental samples. However, contact with dogs (OR 3.89, 95% CI 1.15–13.15, P < 0.05) was associated with higher odds for glmM gene positivity in the questionnaire survey. ConclusionsThe prevalence of H. pylori and cagA-positive strains among the residents was low. However, the study results suggest a correlation between recurrent infection and cagA-positive H. pylori strains. Although H. pylori genes were not detected in living environments, an association between contact with dogs and a glmM positive status was revealed. Further investigations targeting community-dwelling healthy people and their living environments would be required for H. pylori infection control.

Prevalence of East Asian (East CagA) and Western variants of the cagA (Western cagA) gene of Helicobacter pylori in Yakutia

Prevalence of East Asian (East CagA) and Western variants of the cagA (Western cagA) gene of Helicobacter pylori in Yakutia

A Cross-Sectional Study on Molecular Detection of Helicobacter pylori cytotoxin-associated gene A and 16SrRNA Gene from Gastric Biopsy Specimens.

Introduction:The aim of the study is relative proportion of cytotoxin-associated gene A (cagA) virulence marker in Helicobacter pylori isolates and gastric biopsy samples by polymerase chain reaction (PCR).Methods:This cross-sectional study was conducted at a tertiary care hospital setting. Gastric biopsy tissues from 200 patients, suffering from upper gastrointestinal tract disorders, were examined for H. pylori infection using methods, such as hematoxylin and eosin (H and E) staining, 16S rRNA (Ribosomal ribonucleic acid), and cagA gene PCR. Chi-square and kappa statistics were used to find the association and agreement between the tests, respectively; P ≤ 0.05 was considered statistically significant. Screening tests' accuracy was calculated in terms of sensitivity and specificity along with positive and negative predictive values.Results:Out of 200 patients, H. pylori was detected in 14.5%, 48.5%, and 31% patients by H and E staining, 16S rRNA, and cagA PCR, respectively. Sensitivity and specificity of cagA PCR as compared to H and E staining were 89.6% and 78.9%, respectively.Conclusions:CagA detection directly from biopsy specimen by PCR can potentially and rapidly determine the patient's status, especially when at a higher risk of peptic ulcer.

Prevalence of Helicobacter pylori and its cagA gene in patients with gastric cancer or peptic ulcer at an Iranian medical center

Background: Iran has a high incidence rate for gastric cancer among the Middle East countries. In addition to gastric cancer, peptic ulcer is also life-threatening; thus, investigating the prevalence of Helicobacter pylori infection and other risk factors are essential. The present study was aimed to assess the frequency of H. pylori and the cagA-positive strains in patients with gastric cancer or peptic ulcer at a teaching hospital in Qom, one of the most populated cities of Iran. Materials and Methods: The presence of H. pylori was investigated in gastric cancer and peptic ulcer biopsy specimens using the standard culture method. PCR analysis was performed to detect the presence of the cagA gene. Results: The frequency of H. pylori isolates among 86 investigated biopsies was 20 (23.2%). Likewise, the rate of H. pylori was the highest when samples were examined from patients with gastric cancer (25.8%), while it was 21.8% when obtained from peptic ulcer patients. The frequency of the cagA gene in H. pylori isolates was 9 (56.2%), as confirmed by PCR. Conclusion: Our results indicated that H. Pylori infection and its virulent strains are frequent and widely spread in Qom city. The cagA gene was present in almost half of H. pylori isolates from peptic ulcer or gastric cancer patients. Therefore, it is necessary to screen it in all cases with H. pylori infection for early detection of gastric cancer.

Investigation of Clarithromycin Resistance-Associated Mutations and Virulence Genotypes of Helicobacter pylori Isolated from Iranian Population: A Cross-Sectional Study.

Antibiotic resistance has brought into question the efficiency of clarithromycin which is a vital component of eradication therapy for Helicobacter pylori infection. The point mutations within the 23S rRNA sequence of H. pylori isolates which contribute to clarithromycin resistance have yet to be fully characterized. This study was aimed to detect clarithromycin resistance-associated mutations and assess the prevalence of key virulence factors of H. pylori among Iranian patients. Amplification of 16S rRNA and glmM genes were done to identify H. pylori. Minimal inhibitory concentration (MIC) of clarithromycin in 82 H. pylori clinical isolates was determined by agar dilution method. Subsequently, various virulence markers including cagA, vacA, sabA, babA, and dupA of H. pylori were identified by PCR. PCR-sequencing was applied to detect point mutations in the 23S rRNA gene. Based on MIC values, 43.9% of H. pylori isolates showed resistance to clarithromycin. The babA and cagA genes were detected in 92.7% and 82.9% of isolates, assigned to be higher than other virulence factors. No significant relationship was found between the H. pylori virulence genotypes and clarithromycin susceptibility (P > 0.05). Analyzing the 23S rRNA sequences revealed A2143G (4/48, 8.3%) and A2142G (3/48, 6.2%) as the most prevalent mutations in clarithromycin-resistant isolates. Additionally, several novel mutations including G2220T, C2248T, A2624C, G2287A, T2188C, G2710C, C2248T, G2269A, and G2224T were also detected among either resistant or susceptible isolates. Our findings revealed the presence of several point mutations in the 23S rRNA gene of H. pylori isolates which may be associated with resistance to clarithromycin.

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.

ABH and Lewis blood group systems and their relation to diagnosis and risk of Helicobacter pylori infection

BackgroundHelicobacter pylori infection occurs in 50% of the world's population and represents a major risk factor for chronic gastritis, gastroduodenal ulcer and gastric cancer in developed and developing countries. The distribution of H. pylori virulence factors is diverse and varies geographically, such as the CagA and VacA genes, which have revealed association with disease status. Some findings show increased frequencies of these diseases in O Le (a-b +) and A Le (a-b +) blood type individuals, but other studies not found any relationship between these blood groups and H. pylori infection. AimThis study aimed to elucidate probable controversies described in the relationship between the ABH/Lewis blood groups and H. pylori, contributing to the severity of gastric diseases in northern the population of Belém -Pará.-Brazil. MethodsThis cross-sectional study included 288 samples of patients separate into two groups with gastric cancer and chronic gastritis. Blood, saliva, and gastric biopsy were analyzed using modified Gram and hematoxylin-eosin staining techniques, the enzyme immunoassay Elisa and Multiplex PCR. The antigens expression of ABH and Lewis systems was determined through Dot-ELISA and direct hemagglutination. Proportions were compared in univariate analysis, while the relation between putative risk factors including H. pylori status and ABO/Lewis phenotype was performed using multivariable logistic regression analyses, P-value < 0.05 was considered significant. ResultsThe findings of this study demonstrate that the likelihood of developing gastric cancer increases threefold if the individual is from A1 Le (a-b +) blood group, has premalignant changes, and infection with H. pylori virulent strains (cagA+/vacA + s1m1). ConclusionTherefore, this study found a significant association between ABO and Lewis phenotypes and H. pylori cagA status into the relevance of the development of gastric carcinogenesis.

Development of an in-house capture ELISA: An attempt to detect CagA antigen in sera of Helicobacter pylori infected patients

The CagA protein one of the key virulence factors of Helicobacter pylori plays an important role in the pathogenesis of peptic ulcer diseases. Unfortunately the cagA gene status can only be determined by PCR while serology is an alternative approach to detect antigens or antibodies. Our aim is to detect the CagA antigen in sera of infected subjects by the development of an in-house capture ELISA test. Gastric antral biopsies and serum samples were collected from 63 patients. PCR was used to determine the cagA status. Our previously developed recombinant CagA protein and monoclonal antibody were used for setting up the capture ELISA test. H. pylori positive [(38 gastritis, 14 duodenal ulcers (DU), 11 gastric ulcer (GU)] patients were determined by PCR. The cagA gene was detected in 21 (55%) of gastritis, 11 (78%) of DU and 7 (60%) of GU patients. The reagents used in setting up the capture ELISA test following optimization displayed high performance. This study showed that our developed in-house capture ELISA has the potential to detect the CagA antigen at very low concentrations even though not detected in our H. pylori infected patients sera but we are also intended to use it in saliva and stool samples.

Prevalence of Helicobacter pylori vacA, cagA, cagE1, cagE2, dupA and oipA Genotypes in Patients With Gastrointestinal Diseases

Helicobacter pylori (H. pylori) is a bacterium that resides in the human stomach, which is associated with gastroduodenal diseases. We investigate the prevalence of cagA, vacA, oipA, cagE1, cagE2 and dupA genotypes in H. pylori isolated from patients with Gastric ulcer, duodenal ulcer, and Gastric Cancer. Collected 74 samples from the Gastroenterology Unit of the Rasool Akram Hospital were included in this study. Gastric disorders were identified by endoscopy .gastric cancer was further confirmed by histopathology. H. pylori were detected by the urease test. Subsequently, DNA was extracted from gastric tissue of the subjects with the CLO-test yielded positive results. In general, 74 patients with a mean age of 53.45 years (Range 22 to 86-year-old), including 45 men and 29 women, were studied. Among 74 H. pylori-positive patients, 70 (94.5%) patients were positive for the cagA gene. About 95.8% (23/24) of the patients with gastric carcinoma were dupA positive and VacA gene (91.8%). The oipA genotype was detected in 71 (96%) of H.pylori positive samples. This gene was more common in patients with gastritis rather than cancer group. Also, 97.2% of 74 H. pylori isolates were cagE2-positive. In 25 patients with PUD, the occurrence percent of cagA+/VacA+, cagA+/Vac- , cagA- /VacA+ and cagA- /VaxA- genotypes were found 80%, 12%, 4.2% and 4.2 respectively. The results of the present study suggest that a high prevalence of virulent factors could contribute to the risk of developing gastroduodenal diseases.

Prevalence of Helicobacter pylori cagA and vacA Genes and Their Correlation with Gastrointestinal Diseases

Background: Helicobacter pylori (H. pylori) is a gram-negative bacterium, producing gastric ulcer, mild to severe gastritis, gastric carcinoma and lymphoma to the gastric mucosa-associated lymphoid tissue through many virulence influences. Among the virulence factors identified; vacuolating cytotoxin A (vacA) and cytotoxin-associated gene A (cagA) play an important role. Objective: In this study, we try to discover the relation between vacA variant and cagA genes with the clinical illness occurring in H. pylori patients Methodology: One hundred and forty patients were included in our study. Dual biopsy samples were taken from the stomach; one was examined by the urease test, and the other one was stored at −80°C for DNA extraction followed by PCR. The existence of H. pylori in the tissue was recognized by the existence of glmM gene and its detection by PCR. All the positive samples were additionally tested by PCR for the occurrence of cagA and vacA variant genes. Results: Our study demonstrated that cagA and vacA genes were found among 50% and 57% respectively of H. pylori patients complaining from gastrointestinal illnesses and that vacA s1/s2 was the main genotype found in H. pylori persons with gastroduodenal disease. Significant relation between vacA s1 gene and cagA gene was found. Conclusion: vacA s1 genotype has a vital role in upper gastrointestinal illnesses progress.

Association of cagA, cagC, virB2, and vacA Subtypes of Helicobacter pylori with Adenocarcinoma Development in Iranian Patients

Background: Gastric cancer has been introduced as the second cause of cancer death worldwide. Helicobacter pylori infection is considered one of the main risk factors for this type of cancer, so that it has been classified as group I carcinogens. Objectives: The present research intended to examine the prevalence of cagA, cagC, virB2, vacA, and genotype distribution in H. pylori-infected biopsies and adenocarcinoma cases. Methods: Thirty-four H. pylori gastric biopsies taken from Western Iranian patients that were diagnosed as gastritis, gastric ulcers, and adenocarcinoma were used in this study. Two samples were taken from each patient. These samples were selected based on endoscopic observations and histological examinations. The presence of H. pylori was confirmed by the Rapid Urease test (RUT) and the ureC gene by the polymerase chain reaction (PCR) technique. Then, specific primers for vacA and cagPAI were used for genotyping H. pylori by PCR-typing. Results: The obtained results showed that 86.8% of the samples were H. pylori-positive. Moreover, the cagA gene prevalence was 51.50% in the samples. In addition, the adenocarcinoma outcome was significantly related to all selected genes. Likewise, some gastric diseases such as gastric ulcers, duodenal ulcer (DU), gastritis, lymphoid, and gastroesophageal reflux disease (GERD) were observed in adenocarcinoma cases. It was also found that the vacAs1m1i1 genotype plays an important role in gastric malignancies. The most frequent vacA genotype in the H. pylori-infected isolates was s1m1i1, and the observed frequency of vacA and cagA genes in adenocarcinoma was statistically significant. Conclusions: The findings showed that H. pylori vacA and cagA gene virulence factors are associated with adenocarcinoma in Western Iranian patients.

Where to Biopsy to Detect Helicobacter pylori and How Many Biopsies Are Needed to Detect Antibiotic Resistance in a Human Stomach.

This study aims to determine the gastric distribution, density, and diversity of Helicobacter pylori infection. Subtotal resection of the stomachs of three H. pylori-infected and asymptomatic obese patients were collected after a sleeve gastrectomy. Distribution and density of H. pylori were determined using culture and RT-PCR on multiple gastric sites (88, 176, and 101 biopsies per patient). Diversity of H. pylori strains was studied using antibiotic susceptibility testing, random amplified polymorphism DNA (RAPD) typing and cagA gene detection on single-colony isolates (44, 96, and 49 isolates per patient). H. pylori was detected in nearly all analyzed sites (354/365 biopsies, 97%). Antral density was higher in one patient only. The three stomachs were almost exclusively infected by an antibiotic-susceptible strain. One clarithromycin-resistant isolate in one biopsy was detected in two stomachs (1/44 and 1/49 isolates), while in the third one, eight (8/96 isolates) metronidazole-resistant isolates were detected. DNA typing showed infection with cagA-negative strains for one patient, cagA-positive strains for a second patient and the third patient was infected with two different strains of distinct cagA genotypes. Infection with H. pylori is shown to spread to the whole surface of the stomach, but a possibility of minor sub-population of antibiotic-resistant clones, undetectable in routine practice.

Association between human leukocyte antigen gene polymorphisms and multiple EPIYA-C repeats in gastrointestinal disorders

BACKGROUNDPolymorphisms of human leukocyte antigen (HLA) genes are suggested to increase the risk of gastric cancer (GC).AIMTo investigate the HLA allele frequencies of patients with GC relative to a control group in terms of CagA+ multiple (≥ 2) EPIYA-C repeats.METHODSThe patient group comprised 94 patients [44 GC and 50 duodenal ulcer (DU) patients], and the control group comprised 86 individuals [(50 non-ulcer dyspepsia patients and 36 people with asymptomatic Helicobacter pylori (H. pylori)]. Polymerase chain reaction was performed for the amplification of the H. pylori cagA gene and typing of EPIYA motifs. HLA sequence-specific oligonucleotide (SSO) typing was performed using Lifecodes SSO typing kits (HLA-A, HLA-B HLA-C, HLA-DRB1, and HLA-DQA1-B1 kits).RESULTSThe comparison of GC cases in terms of CagA+ multiple (≥ 2) EPIYA-C repeats showed that only the HLA-DQB1*06 allele [odds ratio (OR): 0.37, P = 0.036] was significantly lower, but significance was lost after correction (Pc = 0.1845). The HLA-DQA1*01 allele had a high ratio in GC cases with multiple EPIYA-C repeats, but this was not significant in the univariate analysis. We compared allele frequencies in the DU cases alone and in GC and DU cases together using the same criterion, and none of the HLA alleles were significantly associated with GC or DU. Also, none of the alleles were detected as independent risk factors after the multivariate analysis. On the other hand, in a multivariate logistic regression with no discriminative criterion, HLA-DQA1*01 (OR = 1.848), HLA-DQB1*06 (OR = 1.821) and HLA-A*02 (OR = 1.579) alleles were detected as independent risk factors for GC and DU.CONCLUSIONNone of the HLA alleles were detected as independent risk factors in terms of CagA+ multiple EPIYA-C repeats. However, HLA-DQA1*01, HLA-DQB1*0601, and HLA-A*2 were independent risk factors with no criterion in the multivariate analysis. We suggest that the association of these alleles with gastric malignancies is not specifically related to cagA and multiple EPIYA C repeats.

Characteristics of Helicobacter pylori strains isolated from Mauritanian patients.

Helicobacter pylori (H pylori) is responsible for various diseases including cancer It co-evolved with humans, and human migrations shaped the expansion and the diversity of strains around the world. The risk of developing a disease depends on virulence factors, mainly the cytotoxin-associated gene A protein (CagA). The aim of this study was to determine the cagA status in H pylori strains from Mauritanian patients and to search for a relationship with endoscopic and histologic findings. H pylori was searched in gastric biopsies taken during endoscopy in patients with gastro-duodenal symptoms. RT-PCR was used for the diagnosis and resistance to clarithromycin. The cagA status was determined with PCR and the EPIYA-cagA polymorphism with sequencing. At all, 76/78 (97.4%) biopsies were positive. The rate of clarithromycin resistance was 4/76 (5.26%) due to the A2143G mutation, with a mixed population in 2 cases. The cagA gene was present in 23/76 (30.26%) biopsies, and the EPIYA motif was ABC in 21 (91.3%). High bacterial load and inflammation were significantly associated with cagA-positive status (P<.01). Phylogenetic analysis of the glmM and hspA genes highlighted a mixture of African and European genes in strains of H pylori isolated from patients of Moor origin. We report a high prevalence of H pylori infection in Mauritanian patients, a low rate of clarithromycin resistance (5.26%) and high bacterial load and inflammation associated with cagA-positive status. The phylogenetic analysis highlights the mix of different populations leading to the Moor ethnicity.

VacA genotypes and cagA-EPIYA-C motifs of Helicobacter pylori and gastric histopathological lesions.

Helicobacter pylori infection induces inflammation of the gastric mucosa, which may progress to precancerous lesions and gastric cancer. The gastric histo-pathological damages may be associated with some virulence genes of the bacterium, notably vacA and cagA genes. To establish correlations between these genes and the lesions, biopsies from 1303 adults consenting patients that were previously analyzed by PCR to characterize vacA-s vacA-m, vacA-i regions and cagA 3' region polymorphism, were used. The highest average age was obtained in patients with intestinal metaplasia (53.65 ± 15.26 years) and gastric cancer (53.60 ± 14.32 years). Thus, these lesions are more frequent in elderly and male subjects. Tobacco smoking was significantly associated with neutrophilic activity (P = .02). No significant association was obtained between patients with chronic inflammation and vacA and cagA H. pylori genotypes. However, a significant association has been obtained between this lesion and cagA+ in aged patients (P = .02), while intestinal metaplasia was significantly associated with vacAi1 and vacAm1 separately (P < .01 and .01). Also, a significant association was obtained between intestinal metaplasia and strains with one EPIYA-C motif in young patients (P = .001). Interestingly, a significant association was obtained between gastric cancer and cagA+, vacAi1, vacAm1 H. pylori genotypes and also with two EPIYA-C motifs independently of age groups (all P < .05). The results of our study show that H. pylori vacAi1 could be more potent than the other H. pylori virulent factors for predicting the precancerous gastric lesions, confirming that this gene may be helpful to identify patients at high risk for gastric cancer.

A DNA Sequence Analysis of Helicobacter pylori in Jeddah City, Western Saudi Arabia

Helicobacter pylori are the type of Gram-negative bacteria which colonize the mucous lining of the human stomach. These bacteria have two major virulence factors: (vacuolating cytotoxin A gene) and (cytotoxin-associated A gene). This study aimed to provide data to determine the prevalent virulence factors (vacA and cagA genes) in Jeddah city, western Saudi Arabia, by sequence analysis. This study included 60 patients with symptoms similar to H. pylori infection. H. pylori were identified by using the 16s rRNA sequence. Then, the screening for specific genes in H. pylori (vacA and cagA) was done by using automated DNA sequencing analysis, and the DNA sequences were compared by BLAST and sequence alignment of the vacA nucleotides that are present in all H. pylori strains using those already reported in GeneBank from various studies. Results indicated that H. pylori infection was detected in 13.3%, while 86.7% were negative samples in our study patients. Interestingly, the vacA gene was found in 8.3%, while the cagA gene was not appear in patient. Also, the female prevalence rate was higher than males (11.7% female versus 1.7% males), and the highest infection was between age 40-49 by 6.7%. In conclusion, this study revealed that the vacA gene was spread in the patients infected with H. pylori in Jeddah, while the cagA gene was not appear in any isolate.