vacA S1 Research Articles

Immunodetection of Helicobacter pylori-specific proteins in oral and gastric Candida yeasts.

Human gastric epithelium and immunocytes have been recognized as the sole specialized eukaryotic cells that host Helicobacter pylori (H. pylori). The aim of this study was to provide further evidence for our previous proposal regarding the occurrence of H.pylori inside the yeast vacuole, verifying the viability of the intravacuolar H.pylori by western blotting. Light microscopy and polymerase chain reaction (PCR) were used for primary detection of nonculturable H.pylori in 11 Candida yeasts (six oral and five gastric). Boiling was used for extraction of proteins from yeasts and the control H.pylori. Western blot analysis was recruited to assess the occurrence of H.pylori-specific proteins in protein pool of yeasts, using IgY-Hp raised in hens and IgG1-Hp raised in mice. The fast-moving bacterium-like bodies (BLBs) were identified as H.pylori by amplification of H.pylori 16S rRNA, ureAB, vacA s1, and ahpC genes from the whole DNA of yeasts. Analysis of the sequenced products of 16S rRNA gene amplified from the yeast and H.pylori isolates of patient #2 showed 100 % homology with the corresponding sequences of the reference H. pylori strains in GenBank. According to published data, it was plausible to assign the H.pylori-specific proteins, detected by western blot analysis, as thiol peroxidase (21 kDa), peroxiredoxin (AhpC) (26 kDa), urease-A subunit (UreA) (32 kDa), vacuolating cytotoxin A (VacA) small subunit (36 kDa), and VacA large subunit (56 kDa). Results of this study show that inside yeast, H.pylori expresses proteins and is viable. These proteins appear to serve as powerful tools to help H.pylori to establish in the vacuole of yeast where it can reach nutrients and multiply. The intimate relationship between H.pylori and Candida yeast which began long time ago, could have led to the establishment of H.pylori inside the yeast vacuole before invading human cells.

Characterization of oral Helicobacter pylori strain by 4 methods

The aim of the study was to describe oral Helicobacter pylori strain from a child by 4 methods. The strain was positive by immunofluorescence, ureA− and cagA positive, vacA s1 m2 genotype and resistant to metronidazole and clarithromycin. In conclusion, virulent and antibiotic resistant H. pylori strains can be present in oral cavity from patients with chronic dental and gastroduodenal diseases.

Prevalence of Helicobacter pylori cagA and vacA genes in Cypriot patients

The prevalence of H. pylori varies with geographic locations. To date there are no epidemiological data on its prevalence in Cyprus; therefore, we determined the prevalence and molecular characteristics of H. pylori infection in Cypriot patients. DNA extracted from 103 gastric biopsies was analyzed for the presence of H. pylori by PCR using primers for ureA. H. pylori-positive biopsies were characterized by PCR using specific primers for cagA and vacA genes. The presence of clarithromycin-associated resistant mutations such as A2143G, A2142G, A2142C in 23S rRNA gene of H. pylori-positive patients was determined using a real-time PCR allelic discrimination assay. H. pylori was detected in 41 (39.8%) biopsies and, out of these, 17 (41.5%) tested positive for the cagA gene. The vacA alleles m1, m2, s1a, s1b, and s2 were detected in 7 (17.1%), 34 (82.9%), 12 (29.3%), 2 (4.9%), and 22 (53.7%) isolates, respectively. One (2.4%) biopsy was vacA s1a and s2-positive while one (2.4%) was positive for vacA s1a, s1b, and s2. Three (7.3%) biopsies were untypable for vacA s1, s1b, and s2. The majority (35; 85.4%) of strains were susceptible to clarithromycin while two (4.9%) had the A2143G mutation. Three (7.3%) had a mixture of an A2143G point mutant and susceptible strains while one (2.4%) had a mixture of an A2142G point mutant and susceptible strains. The distribution of the virulence factors cagA and vacA in the Cypriot strains resembled that of strains circulating in Middle Eastern countries geographically close to Cyprus.

Use of the noninvasive entero-test in the detection of Helicobacter pylori in children in an endemic area in Colombia.

Gastric infection with Helicobacter pylori (H pylori), a strong risk factor for gastric cancer, is highly prevalent in children residing in the Colombian Andes. We aimed to validate the use of the Entero-test to culture and genotype H pylori strains from asymptomatic Colombian children. Children (ages 10-15 years, n = 110, 80 of which were H pylori positive by the urea breath test [UBT]) were subjected to the Entero-test, and strings were cultured and/or used for DNA extraction for polymerase chain reaction (PCR). These children had been treated for H pylori in 2007. A second population of children (ages 10-15 years, n = 95),which had not been previously treated, was also subjected to the Entero-test. Of UBT-positive children in the treated group, 29 of 80 (36%) Entero-test samples were H pylori culture positive; 29 additional string extracts were tested by PCR for the H pylori virulence factors cagA and vacA. PCR from cultures and extracts yielded a sensitivity of 74% and specificity of 87%. In the untreated group, 16 of 94 UBT-positive children (17%) produced Entero-tests that were culture positive. Fifty-eight of 94 (62%) string extracts were PCR positive for cagA and/or vacA. In previously treated children, H pylori strains were more often the less virulent vacA s2 (P = 0.001), m2 (P = 0.006), and i2 genotypes (P = 0.039). The Entero-test may be used as a noninvasive test to detect H pylori in asymptomatic children residing in high-risk areas for gastric cancer. Treatment of H pylori in children was associated with less virulent genotypes.

First-degree relatives of early-onset gastric cancer patients show a high risk for gastric cancer: phenotype and genotype profile

First-degree relatives (FDR) of early-onset gastric cancer (EOGC) is presumed to be a population with a distinct molecular and phenotypic profile, regarding the prevalence of gastric premalignant conditions and the association with Helicobacter pylori infection and host proinflammatory gene polymorphisms. A case-control study was conducted with FDR of EOGC patients (n = 103) and age and gender matched controls (n = 101; ranging from spouses to neighbors and dyspeptics). Upper endoscopy was performed, Operative Link on Gastritis Assessment (OLGA) system used for staging and H. pylori (cagA and vacA) and host IL1B-511, IL1RN intron2 VNTR and IFNGR1-56 genotyping. Seventy percent of cases showed atrophy, while 19% presented with high-stage gastritis (OLGA stage III or IV) (p < 0.001); gastric dysplasia was present in seven cases (vs none in controls) (p = 0.007). In cases, H. pylori was present in 82% (vs 62% in controls; p = 0.004) with vacA s1 and vacA m1 + strains significantly associated with the presence of atrophy; individuals homozygous for IL1B-511*T present a significantly higher risk for dysplasia. An increased global prevalence of IFNGR1-56*T/*T polymorphism (37% in cases vs 24% in controls; p = 0.03) was observed with no association with atrophic changes or dysplasia. All trends observed were kept when comparing FDR of EOGC with spouses, neighbors, or dyspeptic controls. We demonstrated that FDR of EOGC patients have an increased prevalence of high-risk OLGA stages and dysplasia that seem to be associated with high virulence H. pylori strains and pro-inflammatory host genotypes, including a possible population-specific risk marker. FDR of EOGC patients may merit specific management through endoscopic and histopathological adequate assessment of gastric mucosa and surveillance.

Helicobacter pylori vacA d1/-i1 genotypes and geographic differentiation between high and low incidence areas of gastric cancer in Iran.

Helicobacter pylori (H. pylori)-specific genotypes have been closely correlated with an increased risk of gastric cancer (GC). The present study aimed to determine the distribution of H. pylori pathogenic genotypes amongst Iranians infected with strains representing European ancestry in areas with different GC incidence. A total of 138 H. pylori isolates from ten districts in Iran were used for genotyping. The following genotypic frequency was observed: vacA s1 (94.9%), s2 (5.1%), m1 (24.6%), m2 (75.4%), d1 (39.9%), d2 (60.1%), i1 (40.6%), i2 (59.4%), iceA1 (76.8%), iceA2 (52.9%), iceA1/2 (29.7%), babA2 (40.6%), and cagA (65.9%). Hierarchical analyses of molecular variance (AMOVA) for the vacA d1, d2, i1, and i2 alleles and iceA1 and iceA1/2 genes found significant levels of genetic differentiation among populations (P < 0.05). Prevalence of the vacA d1, i1, and iceA1/2 (but not iceA1) genes and vacA d1/i1, vacA d1/iceA1, vacA d1/iceA1/2, vacA d1/cagA+, vacA i1/iceA1, vacA i1/iceA1/2, and vacA i1/cagA+ genotypes were significantly higher (>2- or 3-fold) among H. pylori isolates from high incidence GC areas that had age-standardized rates (ASRs) of >20/105 (max. 51.8/105) when compared with those from low incidence (ASRs <10/105) GC areas (P < 0.005, for the latter, P = 0.016). In contrast, the vacA d2/i2, m2/d2, and m2/i2 genotypes were significantly more prevalent in low compared to high incidence GC areas (P < 0.005). The results of Mantel's test only showed a low correlation between genetic and geographic distances for the iceA1 and iceA1/2 (but not vacA alleles, iceA2, babA2, and cagA) genes among ten districts of Iran (r = 0.098 and 0.074, respectively, P < 0.05). We propose that the H. pylori vacA d1/-i1 genotypes, which are new determinants of GC, have tremendous potential for differentiating H. pylori strains from high and low incidence GC areas in Iran.

Genetic Analysis of cagA and vacA Genes in Helicobacter Pylori Isolates and Their Relationship with Gastroduodenal Diseases in the West of Iran

BackgroundHelicobacter pylori have different virulence factors which are associated with several gastroduodenal diseases; however, this association is variable in different geographical regions. Data of genotypes of Iranian H. pylori isolates are few.ObjectivesThe aim of the current study was to investigate the cagA/vacA genotypes of Helicobacter pylori isolates and determine the relationship between these genotypes with respect to different gastric disorders in patients of Chaharmahalo Bakhtiarian.Materials and MethodsIn this cross-sectional study, gastric biopsies were taken from 200 patients with gastrodoudenal diseases. Histopathological features were recognized by specialist. The samples were subjected to PCR for detection and identification of ureC, cagA and vacA genes.ResultsThe frequency of the vacA genotypes, sa1/m1, s1a/m1b, s1a/m2, s1b/m1a, s1b/m1b, s1b/m2, s1c/m1a, s1c/m1b, s1c/m2, s2/m1a, s2/m1b and s2/m2 were 27(6.6%), 8(4.3%), 45(28.04%), 7(3.7%), 5(2.5%), 10 (6.1%), 12 (7.4%), 4 (2.5%), 18(11%), 6(3.7%), 0 and 22(13.5%) respectively. The cagA gene was detected in 92% of strains. Based on our findings, it seemed that cagPAI and vacA s1 genotypes were associated with some gastric disorders in patients with H. pylori. In this region, the isolates carrying s1a/m2 were the most prevalent.ConclusionsWe found considerable relationship between s1a/m1a, s1a/m2, s2/m2 and s1c/m1a and some gastric disorders. Further studies about the role of H. pylori virulence factors and gastric disorders were recommended.

Genotyping of Helicobacter pylori virulence-associated genes shows high diversity of strains infecting patients in western Venezuela

Helicobacter pylori is a major cause of chronic gastritis and an established risk factor for gastric adenocarcinoma. This bacterium also exhibits an extraordinarily high genetic diversity. The genetic diversity of H. pylori strains from Venezuelan patients with chronic gastritis was evaluated by PCR-typing of vacA, cagA, iceA, and babA2 virulence-associated genes using DNA extracted directly from biopsies. The nucleotide sequence and prevalence of size variants of iceA1, iceA2, and babA2 PCR products were introduced in this analysis. The frequency of vacA s1 was associated (p<0.01) with moderate/severe grades of atrophic gastritis. The cagA, iceA1, iceA2, and babA2 genotypes were found in 70.6%, 66.4%, 33.6%, and 92.3% of strains, respectively. The frequency of iceA2 and its subtype iceA2_D were higher (p<0.015) in cases with moderate/severe granulocytic inflammation. The most prevalent combined genotypes were vacA s1m1/cagA/iceA1/babA2 (26.3%), vacA s2m2/iceA1/babA2 (19.5%), and vacA s1m1/cagA/iceA2/babA2 (18.8%). Sequence analysis of iceA1, iceA2, and babA2 PCR-amplified fragments allowed us to define allelic variants and to increase the number of genotypes detected (from 19 to 62). A phylogenetic tree made with iceA1 sequences showed that the H. pylori strains analyzed here were grouped with those of Western origin. Our results show that patients from the western region of Venezuela have an elevated prevalence of infection with H. pylori strains carrying known virulence genotypes with high genetic diversity. This highlights the importance of identifying gene variants for an early detection of virulent genotypes.

English

Helicobacter pylori&nbsp;is associated with the development of a variety of gastroduodenal diseases. In this study, we evaluated the prevalence of&nbsp;H. pylori cagA&nbsp;and&nbsp;vacAgenotypes from a Northeastern Mexico population. DNA was extracted from 135 gastric biopsies from patients with gastric disease: 110 with chronic gastritis (CG) and 25 with intestinal metaplasia (IM). Polymerase Chain Reaction (PCR) was used to detect&nbsp;cagAand&nbsp;vacA&nbsp;(s1, s2, m1, m2) genes of&nbsp;H. pylori. The study showed that the dominant genotypes were&nbsp;cagA vacA s1/m1&nbsp;43 (31.8%), followed by&nbsp;cagA vacA s2/m2&nbsp;18 (13.3%) and&nbsp;cagA vacA s1/m2&nbsp;3 (2.2%).&nbsp; This study did not find any presence of the genotypevacA&nbsp;s2/m1. For the genotype&nbsp;cagA vacA s1/m1, a significant association was found between its presence in patients with IM compared with patient with CG (P Ë‚ 0.05). In conclusion, the results show that the predominant genotype in the Northeastern Mexico population was&nbsp;cagA vacA s1/m1, which was found to be significantly associated with patients with IM. &nbsp;&nbsp; &nbsp; Key words:&nbsp;Gastric biopsies;&nbsp;Helicobacter pylori;&nbsp;cagA; vacA; Chronic Gastritis; Intestinal Metaplasia

Diversity of Helicobacter pylori genotypes in Iranian patients with different gastroduodenal disorders.

To investigate the diversity of Helicobacter pylori (H. pylori) genotypes and correlations with disease outcomes in an Iranian population with different gastroduodenal disorders. Isolates of H. pylori from patients with different gastroduodenal disorders were analyzed after culture and identification by phenotypic and genotypic methods. Genomic DNA was extracted with the QIAamp DNA mini kit (Qiagen, Germany). After DNA extraction, genotyping was done for cagA, vacA (s and m regions), iceA (iceA1 , iceA2 ) and babA with specific primers for each allele using polymerase chain reaction (PCR). All patients' pathologic and clinical data and their relation with known genotypes were analyzed by using SPSS version 19.0 software. χ² test and Fisher's exact test were used to assess relationships between categorical variables. The level of statistical significance was set at P < 0.05. A total of 71 isolates from 177 patients with different gastroduodenal disorders were obtained. Based on analysis of the cagA gene (positive or negative), vacA s-region (s1 or s2), vacA m-region (m1 or m2), iceA allelic type (iceA1 and iceA2 ) and babA gene (positive or negative), twenty different genotypic combinations were recognized. The prevalence of cagA, vacA s1 , vacA s2 , vacA m1 , vacA m2 , iceA1 , iceA2 , iceA1+iceA2 and babA were 62%, 78.9%, 19.7%, 21.1%, 78.9%, 15.5%, 22.5%, 40.8% and 95.8%, respectively. Interestingly, evaluation of PCR results for cagA in 6 patients showed simultaneous existence of cagA variants according to their size diversities that proposed mixed infection in these patients. The most prevalent genotype in cagA-positive isolates was cagA⁺/vacAs1m2 /iceA1 +A2 /babA+ and in cagA-negative isolates was cagA⁻/vacAs1m2 /iceA-/babA+. There were no relationships between the studied genes and histopathological findings (H. pylori density, neutrophil activity, lymphoid aggregation in lamina propria and glandular atrophy). The strains which carry cagA, vacAs1/m1 , iceA2 and babA genes showed significant associations with severe active chronic gastritis (P = 0.011, 0.025, 0.020 and 0.031, respectively). The vacAs1 genotype had significant correlation with the presence of the cagA gene (P = 0.013). Also, babA genotype showed associations with cagA (P = 0.024). In the combined genotypes, only cagA⁺/vacAs1m1 /iceA2 /babA+ genotype showed correlation with severe active chronic gastritis (P = 0.025). This genotyping panel can be a useful tool for detection of virulent H. pylori isolates and can provide valuable guidance for prediction of the clinical outcomes.

Prevalence ofHelicobacter pylorivirulence genotypes among children in Eastern Turkey

To identify the virulence genotypes of Helicobacter pylori (H. pylori) if present in children in Eastern Turkey and if those genotypes are mostly associated with severe clinical presentations. A total of 49 H. pylori positive Turkish children (42 with antral nodularity and 7 with peptic ulcer) who underwent upper gastrointestinal endoscopy with abdominal symptoms during the period from March 2011 to September 2012 were enrolled in this study. Antral nodularity was diagnosed endoscopically by two of the authors. We determined for the presence of cagA, vacA, cagE, iceA and babA2 genotypes of H. pylori isolates in DNA obtained directly from frozen gastric biopsy samples by polymerase chain reaction test using specific primers. Of the 49 H. pylori isolates studied, 61.2%, 91.8%, 22.4%, 28.6%, 57.1% and 40.8% were positive for the cagA, vacA s1, cagE, iceA1, iceA2 and babA2 genes, respectively. We showed that the most common vacA subtype was s1a (79.6%). However, the s2 gene was found less frequently with an isolation rate of 8.2% of the H. pylori isolates. The genotypes iceA2 and vacA s1m2 were the most frequently found types in children with antral nodularity. In addition, the genotypes iceA1, babA2 and vacA s1m1 were found in similar ratios in all the H. pylori isolates obtained from children with peptic ulcer. The genotypes vacA s2m1 and s1c were not observed in any of isolates studied. This study showed that vacA s1m2, cagA and iceA2 were the most common genotypes, and no association between antral nodularity and genotypes was observed.

Prevalence ofHelicobacter pylori cagAandvacAallelic variants and associated disease outcomes in Kenyan patients with dyspepsia

Although Helicobacter pylori has been linked to various gastric disorders in Western countries and Asia, its aetiopathological role in African populations is controversial. The aim of this study was to investigate the role of H. pylori and its virulence genotypes in gastrointestinal diseases in Kenyan patients with dyspepsia. Gastric biopsy specimens were obtained for DNA isolation and histopathological analysis. Amplification was performed using specific oligonucleotide primers. H. pylori positivity was determined by H. pylori stool antigen test, rapid urease test, and histology and molecular diagnostic tools. H. pylori was detected with high frequency in patients with gastritis, peptic ulcer disease (PUD) and gastro-oesophageal reflux disease. This implies a significant risk of the development of these pathologies (p-value = 0.0000 in all cases). H. pylori strains with cagA occurred more frequently in PUD (65.2%). vacA s1a genotype appeared to play a more significant pathological role (82.6% PUD) than the other variants (p-value = 0.0142). The prevalence of vacA m1 was significantly higher in gastritis cases (p-value = 0.0253). vacA m2 was found to be significantly associated with gastritis (p-value = 0.0253). This finding may point to the fact that H. pylori vacA m1 and vacA m2 are independently associated with an increased risk for gastritis. Indications are that H. pylori prevalence in Kenya may be declining. The independently occurring H. pylori genotypes, as opposed to simultaneous carriage, could be the reason for the low distribution of H. pylori pathologies.

Role of Helicobacter pylori cagA EPIYA motif and vacAgenotypes for the development of gastrointestinal diseases in Southeast Asian countries: a meta-analysis

BackgroundInfection with cagA-positive, cagA EPIYA motif ABD type, and vacA s1, m1, and i1 genotype strains of Helicobacter pylori is associated with an exacerbated inflammatory response and increased risk of gastroduodenal diseases. However, it is unclear whether the prevalence and virulence factor genotypes found in Southeast Asia are similar to those in Western countries. Here, we examined the cagA status and prevalence of cagA EPIYA motifs and vacA genotypes among H. pylori strains found in Southeast Asia and examined their association with gastroduodenal disease.MethodsTo determine the cagA status, cagA EPIYA motifs, and vacA genotypes of H. pylori, we conducted meta-analyses of 13 previous reports for 1,281 H. pylori strains detected from several Southeast Asian countries.ResultsThe respective frequencies of cagA-positive and vacA s1, m1, and i1 genotypes among examined subjects were 93% (1,056/1,133), 98% (1,010/1,033), 58% (581/1,009), and 96% (248/259), respectively. Stratification showed significant variation in the frequencies of cagA status and vacA genotypes among countries and the individual races residing within each respective country. The frequency of the vacA m-region genotype in patients infected with East Asian-type strains differed significantly between the northern and southern areas of Vietnam (p < 0.001). Infection with vacA m1 type or cagA-positive strains was associated with an increased risk of peptic ulcer disease (odds ratio: 1.46, 95%CI: 1.01-2.12, p = 0.046 and 2.83, 1.50-5.34, p = 0.001, respectively) in the examined Southeast Asian populations.ConclusionsBoth Western- and East Asian-type strains of H. pylori are found in Southeast Asia and are predominantly cagA-positive and vacA s1 type. In Southeast Asia, patients infected with vacA m1 type or cagA-positive strains have an increased risk of peptic ulcer disease. Thus, testing for this genotype and the presence of cagA may have clinical usefulness.

Prevalence of Helicobacter pylori vacA, cagA and iceA genotypes and correlation with clinical outcome

The aim of this study was to assess the genetic status of cagA, vacA subtype and iceA genotypes of Helicobacter pylori and the relationship with upper gastrointestinal diseases in Northeast China. Gastric biopsies were obtained from 378 patients with upper gastrointestinal diseases and 197 samples were used. The cagA, vacA alleles and iceA genotypes were determined by polymerase chain reaction. CagA was present in 176 (89.3%) of 197 patients. Of the 197 cases, 186 (94.4%) had vacA signal sequence s1c allele, 6 (3%) had s1a and 5 (2.5%) had s1b. The vacA s2 genotype was not detected in our study. VacA middle region sequences, m1 and m2, were found in 20 (10.2%) and 150 (76.1%), respectively. The allelic variant iceA1 (70.1%) was more prevalent than iceA2 (23.4%). The vacA allele s1am2 had a significant relationship with the presence of gastric cancer (p<0.05) and the iceA1 genotype was also associated with gastric cancer (p<0.05). These may be useful risk factors for upper gastrointestinal diseases.

Significance of Helicobacter pylori vacA intermediate region genotyping—a Bulgarian study

The significance of the intermediate (i) region of the Helicobacter pylori vacA gene as a virulence factor associated with the severity of gastric disease is still disputable. The aim of the present study was to evaluate the prevalence and significance of vacA i alleles alone or in combination with other vacA alleles in symptomatic Bulgarian patients and to find out possible associations between vacA i genotype and patients' disease, age, sex, and other H. pylori virulence factors. Unlike vacA s1 and m1, vacA i1 prevalence was significantly higher (75.0%) in strains from peptic ulcer patients than in strains from nonulcer patients with gastric diseases (58.6%) (P = 0.022). Less virulent vacA s1 i2 m2 strains were more prevalent in females (P = 0.03), and cagA+ was associated with vacA i1, s1, m1, and their combinations. In conclusion, vacA i status is a better predictor for the strain virulence than other vacA alleles.

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.

Virulence markers of Helicobacter pylori in patients with diarrhoea-dominant irritable bowel syndrome

Recent studies suggest that irritable bowel syndrome (IBS) is associated with low-grade inflammation. This study aims to determine the distribution of Helicobacter pylori cytotoxin-associated gene A (cagA) and vacuolating cytotoxin A (vacA) alleles (e.g., s1 and s2) in patients with diarrhoea-dominant IBS (IBS-D) as the latter causes vacuolation in colonic epithelial cells in vitro. One hundred and seventy patients meeting Rome III criteria for IBS-D (mean age: 40 ±15 years) were enrolled. Gastric biopsy was assessed histologically and DNA extraction was performed by polymerase chain reaction (PCR) for H. pylori genus 16S ribosomal DNA (16S rDNA), cagA and vacA allele s1 and s2. There was no age- or gender-related difference in H. pylori positivity in IBS-D compared to the control group. H. pylori was positive in 116 (68%) with IBS-D compared to 88 (55%) in the control group (P=0.01). cagA was positive in 73 (63%) with IBS-D compared to 42 (48%) in the control group (P=0.03). vacA s1 was positive in 61 (53%) with IBS-D compared to 32 (36%) in the control group (P=0.02). cagA s1 was positive in 39 (34%) with IBS-D compared to 13 (15%) in the control group (P=0.002).

Detection of Helicobacter pylori in gastric biopsies, saliva and dental plaques of dyspeptic patients from Marília, São Paulo, Brazil: presence of vacA and cagA genes

Helicobacter pylori, a gram-negative bacterium, possesses two important virulence factors: the vacuolating toxin (vacA), and the cytotoxin-associated gene product (cagA). The aim of the present study was to evaluate the presence of H. pylori in the stomach and oral cavity of humans and compare the cagA and vacA genotypes of H. pylori found in different samples (stomach, saliva and dental plaque) from the same patient. Gastric biopsies, saliva and dental plaques were obtained from 62 dyspeptic adults. DNA was extracted and evaluated for the presence of H. pylori and the alleles cagA and vacA. Persons with gastritis had a higher frequency of H. pylori -positive samples in the stomach while positive samples from gastric biopsies were significantly correlated with those from the oral cavity. There was a high H. pylori frequency in patients while the cagA gene was associated with vacA s1 alleles in gastric biopsies. Our results suggest a reservoir of the species in the oral cavity and that, in one patient, more than one H. pylori strain may exist in the saliva, dental plaque and stomach. We found a relationship between gastric infection and the bacterium in the oral cavity, with the cytotoxin genotype varying between saliva and dental plaque.

Association between Helicobacter pylori cagA-related genes and clinical outcomes in Colombia and Japan

BackgroundSpecific genotypes of several virulence factors of Helicobacter pylori (eg, cagA-positive, vacA s1, oipA "on" and babA-positive) have been reported to be predictors of severe clinical outcomes. Importantly, the presence of these genotypes correlates with each other. We hypothesized that novel virulence genes correlate with the presence of cagA. Therefore, we aimed to find novel candidate virulence genes that correlate with cagA and examined the association of these genes with clinical outcomes in Colombian and Japanese populations.MethodscagA-associated genes were selected based on previous H. pylori genome microarray data. A total of 343 strains (174 from Colombia and 169 from Japan) were examined for the status of cagA, vacA, and candidate genes by polymerase chain reaction and dot blot.ResultsMicroarray data showed that 9 genes were significantly correlated with the presence of cagA. Among the 9 genes, the functions of 4 were known, and we selected these 4 genes as candidate genes (hp0967, jhp0045, jhp0046, and jhp0951). The prevalences of cagA, vacA s1/m1 genotype, and hp0967 were significantly higher in Japan than Colombia, whereas those of jhp0045 and jhp0046 were more prevalent in Colombia than Japan. The prevalences of jhp0045 and jhp0046 in cagA-positive cases of gastric cancer were significantly higher than those from gastritis in Colombia (P = 0.015 and 0.047, respectively). In contrast, the prevalence of 4 candidate genes was independent of clinical outcomes in Japan.Conclusionsjhp0045 and jhp0046 might be novel markers for predicting gastric cancer in cagA-positive cases in Colombia, but not in Japan.

Helicobacter pylori oipA genetic diversity and its associations with both disease and cagA, vacA s, m, and i alleles among Bulgarian patients

Prevalence of outer inflammatory protein ( oipA) gene functional status in Helicobacter pylori strains from Southeastern Europe is still unclear. H. pylori strains from 70 symptomatic patients were polymerase chain reaction (PCR) assessed for cagA and vacA types, and oipA gene functional status was evaluated by PCR and sequencing. Our results demonstrated a high prevalence of strains with oipA status “on” genes (81%) and strong association between them and peptic ulcers, cagA, and vacA s1 and s1/m1 genotypes, regardless of the patient gender, place of residence, and age. Importantly, most vacA i1 strains (93%) harbored oipA status “on” versus only 57% of those with vacA i2 type. The vacA i1 genotype was less frequent (66%) than both cagA and vacA s1 types. The virulent strains with cagA + and vacA s1, m1, and i1 were detected in 35% as a predominant genotype and almost all (96%) of these strains harbored oipA status “on”. In conclusion, the high prevalence of in-frame oipA gene strains (81%), associated with peptic ulcers and cagA +, vacA s1, m1, m2, and, importantly, i1 genotypes, indicates a strong synergistic activity of H. pylori virulence factors.