iceA Genes Research Articles

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.

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.

Determination of Helicobacter pylori Virulence Genes in Gastric Biopsies by PCR

Aim. The aim of this study was to identify the presence of H. pylori in biopsy specimens from symptomatic patients by PCR. In addition, the rate of cagA, vacA, iceA1, and iceA2 virulence genes was determined. Materials and Methods. One hundred antral gastric biopsy specimens were collected during endoscopy from patients suffering from gastroduodenal symptoms. The samples were collected by the gastroenterologists in their own clinics in Ramallah, Palestine. DNA was extracted from the biopsies and subsequently used for PCR identification of H. pylori and the virulence genes using specific primers. Results. The rate of positive H. pylori in the collected biopsies was 44%. The rates of the virulence genes in this sample: cagA, vacA, iceA1, and iceA2 were 65.9%, 40.9%, 63.6%, and 84.1%, respectively. Conclusion. The iceA2 gene was the most frequent in this study. Much research is necessary to determine the presence of an association of this gene with gastric pathology. Variation in the rates of the iceA gene in different countries is a strong indication of its geographical distribution. This study would provide important information regarding the prevalence of virulence genes (vacA, cagA, iceA1, and iceA2) in H. pylori strains in the sample tested in this country.

CagE as a biomarker of the pathogenicity of Helicobacter pylori

Helicobacter pylori infection is associated with gastro-duodenal diseases. Genes related to pathogenicity have been described for H. pylori and some of them appear to be associated with more severe clinical outcomes of the infection. The present study investigates the role of cagE as a pathogenicity biomarker of H. pylori compare it to cagA, vacA, iceA and babA2 genes and correlate with endoscopic diagnoses. Were collected biopsy samples of 144 dyspeptic patients at the Hospital of the Federal University of Rio Grande, Rio Grande do Sul, Brazil. After collection, the samples were sent for histological examination, DNA extraction and detection of all putative pathogenicity genes by PCR. Of the 144 patients undergoing endoscopy, 57 (39.6%) presented H. pylori by histological examination and PCR by detection of the ureA gene. Based on the endoscopic diagnoses, 45.6% (26/57) of the patients had erosive gastritis, while 54.4% (31/57) had enanthematous gastritis. The genes cagA, cagE, vacAs1/m1, vacAs1/m2 and iceA1 were related to erosive gastritis, while the genes vacAs2/m2, iceA2 and babA2 were associated to enanthematous gastritis. We found a statistically significant association between the presence of cagE and the endoscopic diagnosis. However, we detect no statistically significant association between the endoscopic diagnosis and the presence of cagA, vacA, iceA and babA2, although a biological association has been suggested. Conclusions Thus, cagE could be a risk biomarker for gastric lesions and may contribute to a better evaluation of the H. pylori pathogenic potential and to the prognosis of infection evolution in the gastric mucosa.

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.

The genetic diversity of Helicobacter pylori virulence genes is not associated with gastric atrophy progression.

Atrophy of the gastric mucosa is a precursor of intestinal-type gastric cancer, and Helicobacter pylori infection causes atrophic gastritis. The aim of this study was to determine whether the genetic diversity of H. pylori virulence genes is associated with the development and progression of gastric atrophy in humans. We isolated and cultured H. pylori strains from patients with gastric ulcer and duodenal ulcer accompanied by atrophic gastritis in background mucosa. H. pylori strains were stored at －80℃ prior to the experiments being carried out. We analyzed iceA, babA, vacA, cagA, and cagE genes by PCR. The cagA gene was analyzed through sequencing of the C-terminal region containing the EPIYA motif, which is related to tyrosine phosphorylation. Severe atrophy was observed in patients with gastric ulcer. The major phenotype of the vacA gene was s1c/m1 (93%). The cagA gene was detected in all strains. The cagE gene was not detected in 2 and 5 strains from the mild cases and severe cases, respectively. The major cagA EPIYA motif, which is amino acids repeat in the C terminus, was the A-B-D type (44 of 58 strains). The virulence genes were not statistically associated with the severity of atrophy in the background gastric mucosa in humans. Not only identification of bacterial virulence factors but also studies of the host response will be necessary to investigate the progression of gastric atrophy and subsequent cancer development in humans.

Prevalence of genotypes in Helicobacter pylori isolates from patients in eastern Turkey and the association of these genotypes with clinical outcome

There is not much information available regarding the prevalence of the genotypes of Helicobacter pylori isolates in Turkey, particularly in eastern Turkey. The aims of this study were to detect the prevalence of different genotypes of H. pylori in Turkish patients with gastrointestinal complaints and to determine the relationship of these genotypes with clinical outcome and sex. One hundred forty H. pylori isolates were examined for the presence of its genotypes by the PCR. We found that the prevalence of vacAs1,vacAs2, cagA, cagE, iceA1, iceA2 and babA2 genes were 88.6%, 11.4%, 71.4%, 35.7%, 41.4%, 58.6%, and 62.1%, respectively. The most predominant vacA subtype was s1a (81.4%). The most vacA allelic combination detected were vacAs1m1 (65.2%) and s1m2 (53.9%) in patients with peptic ulcer and gastritis, respectively. The only vacAs1 isolate was significantly associated with gastritis and peptic ulcer (p<0.05). The vacAs1a, ml, slml and babA2 genes were significantly associated with peptic ulcer (p<0.05), whereas m2 gene was significantly associated with only gastritis (p<0.05). The difference between sex and genotypes was statistically significant among the cagA,vacAs1, iceA2 and babA2 genes. This study reported for the first time the prevalence of H. pylori genotypes in patients with gastrointestinal complaints in eastern Turkey. Further studies are needed to understand epidemiological importance of the genotypes of H. pylori isolates in this region and the association between the virulence genes and clinical outcome in different regions.

Infection with Helicobacter pylori strains carrying babA2 and cagA is associated with an increased risk of peptic ulcer disease development in Iraq

Background and study aimSeveral genes of Helicobacter pylori, such as vacA, cagA, iceA and babA, have been reported to significantly increase the risk of gastrointestinal diseases. The aim of this study was to study the relationship between H. pylori virulence factors and clinical outcomes and identify the independent markers of peptic ulcer disease in Iraq. Patients and methodsDNA was extracted from specimens taken from 154 unselected H. Pylori positive Iraqi patients. Genotyping was performed by the polymerase chain reaction (PCR), using specific primers for cagA, vacA (s, m), iceA and babA2 genes. ResultsA total of 56 (82%) peptic ulcer disease (PUD) patients carried cagA+ strains, significantly more than the 56 (65%) non-ulcer disease (NUD) patients (p=0.017). The difference in the prevalence of babA2 positivity was significant between patients with NUD (33.7%) and PUD (58.8%) (p=0.002). In addition, babA2 was associated as an independent factor, with PUD (p=0.005; odds ratio (OR)=0.4; confidence interval (CI)=0.18–0.68) followed by cagA (p=0.05; OR=0.4; CI=0.18–0.85). Forty-five isolates (29%) were typed as ‘triple positive’ strains, and their presence was significantly associated with PUD (p=0.001). ConclusionThe cagA and babA2 genotypes might be considered as useful markers for PUD patients. However, iceA1 and iceA2 seem not to be good markers for the disease. The presence of H. pylori strains with triple-positive status is of high clinical relevance to H. pylori-associated diseases.

Helicobacter pylori: Detection of iceA1 and iceA2 Genes in the Same Strain in Mexican Isolates

Helicobacter pylori iceA1 and iceA2 gene amplification is usually performed to identify mixed populations as both genes are apparently reportedly exclusive. However, some strains isolated from Mexico show both iceA genes. The aim of this study was to establish the frequency of these genes in Mexican isolates and genomic diversity of the H. pylori strains. One hundred thirty six biopsies were obtained from 68 patients (39 children and 29 adults). The presence of H. pylori was confirmed in 3/18 children and 6/19 adults by culture. There were 93 clinical strains isolated from nine patients. Additionally, we studied 37 strains from a strain collection isolated from 10 patients. The strains were genotyped and dual iceA genes were identified by polymerase chain reaction (PCR) and amplicons were sequenced. In addition, an enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) assay was performed as fingerprinting method. The genotypification of the H. pylori isolates indicated that all strains were vacA+; 86% babA2+, 86% cagA+, 82% vacA s1m1+, 19% iceA1+, 9% iceA2+, and 72% of them carried both iceA1 and iceA2 genes. The ERIC-PCR profiling revealed that the strains clustered in eight genetic groups depending on the presence of iceA1, iceA2 or both. A basic local multiple alignment analysis of the nucleotide sequences revealed that the iceA1 and iceA2 genes exhibited no relevant similarity. The results here showed the presence of triple-positive strains (babA, cagA, vacA) of H. pylori and strains carrying simultaneously both iceA1 and iceA2 genes.

Prevalence of genotypes in Helicobacter pyloriisolates from patients in eastern Turkey and the association of these genotypes with clinical outcome

There is not much information available regarding the prevalence of the genotypes of Helicobacter pylori isolates in Turkey, particularly in eastern Turkey. The aims of this study were to detect the prevalence of different genotypes of H. pylori in Turkish patients with gastrointestinal complaints and to determine the relationship of these genotypes with clinical outcome and sex. One hundred forty H. pylori isolates were examined for the presence of its genotypes by the PCR. We found that the prevalence of vacAs1,vacAs2, cagA, cagE, iceA1, iceA2 and babA2 genes were 88.6%, 11.4%, 71.4%, 35.7%, 41.4%, 58.6%, and 62.1%, respectively. The most predominant vacA subtype was s1a (81.4%). The most vacA allelic combination detected were vacAs1m1 (65.2%) and s1m2 (53.9%) in patients with peptic ulcer and gastritis, respectively. The only vacAs1 isolate was significantly associated with gastritis and peptic ulcer (p<0.05). The vacAs1a, ml, slml and babA2 genes were significantly associated with peptic ulcer (p<0.05), whereas m2 gene was significantly associated with only gastritis (p<0.05). The difference between sex and genotypes was statistically significant among the cagA,vacAs1, iceA2 and babA2 genes. This study reported for the first time the prevalence of H. pylori genotypes in patients with gastrointestinal complaints in eastern Turkey. Further studies are needed to understand epidemiological importance of the genotypes of H. pylori isolates in this region and the association between the virulence genes and clinical outcome in different regions.

Genotypic characterization of Helicobacter pylori isolates among Egyptian patients with upper gastrointestinal diseases

ObjectiveOver 50% of the world populations are infected with Helicobacter pylori (H. pylori). Most subjects are asymptomatic; however, in 1994, H. pylori has been categorized as group I carcinogen. The aim of the study was to investigate the relationship between H. pylori infection and gastric cancer.MethodsThirty gastric cancer patients (GCs) and 30 gastritis patients were enrolled in the study. H. pylori was cultured on non-selective and selective medias, infection density was assessed by quantitative culture. Antibiotic sensitivity testing was performed. PCR was done for the H. pylori 16S rRNA gene in addition to cagA, vacA and iceA genes.ResultsH. pylori could be cultured from 100% of specimens obtained from all patients. The density of H. pylori was higher in cancer cases than in gastritis patients. The 16S rRNA was detected in all GC patients (100%) while it was only detected in 70% of gastritis patients. The cagA gene was found in 53.3% vs 13.3% of GC and gastritis patients, respectively. The vacA gene was present in all GC patients (by at least one of its alleles) while it was only found in 33.3% of gastritis patients. The vacA s1m1 combination was the most predominant genotype in GC patients, while m2 was the commonest allele in gastritis patients (10%). The iceA gene was found in 86.7% vs 40% of GC and gastritis patients, respectively. Simultaneous presence of multiple H. pylori strains was proved, both phenotypically and genotypically.ConclusionThe development of GC is linked to infection with H. pylori harboring certain virulence genes. Higher infection density of H. pylori was found in GC patients. Co-existence of more than one strain of H. pylori in the same patient occurs in both malignant and benign lesions.

Prevalence of cagA, vacA, babA2 and iceA Genes in Helicobacter pylori Strains Isolated from Colombian Patients with Functional Dyspepsia

The clinical outcome of Helicobacter pylori infection has been particularly associated with virulence genotypes. These genotypes are useful as molecular markers in the identification of patients that are infected and at high risk for developing more severe gastric pathologies. Our main objective was to determine the prevalence of virulence genotypes cagA, vacA, iceA and babA2 of H. pylori, in patients with functional dyspepsia who are infected with the bacteria. H. pylori genotypes babA2 and cagA as well as vacA and iceA allelic variants were identified by PCR in 122 isolates resulting from 79 patients with functional dyspepsia. A high prevalence of genes cagA+ (71%), vacAs1am1 (34%), babA2 (57%) and iceA1 (87%) was found. The most frequent combined genotype found were cagA+/vacAs1am1/babA2+/iceA1 and cagA-/vacAs1am1/babA2+/iceA1, regardless of any family history of gastric cancer or MALT lymphoma. The very virulent genotype cagA+/vacAs1am1/babA2+/iceA1 prevailed in the studied patients with functional dyspepsia. Our results provide information about the prevalence of four of the more important virulent factors and constitute new evidence on the prevalence of the most virulent H. pylori genotype in patients with functional dyspepsia.

Relationship Between the Helicobacter pylori Icea Gene and Clinical Outcomes in Western Countries: Meta-Analysis

Background: Although the iceA (induced by contact with epithelium) allelic types of Helicobacter pylori (H. pylori) have been reported to be associated with peptic ulcer, the importance of the iceA gene on clinical outcomes is conflicting in subsequent studies. The aim of this study was to estimate the magnitude of the risk for clinical outcomes associated with iceA gene in Western countries (Europe, North and South America). Methods: A literature search was performed using the PubMed and EMBASE databases for articles published through November 2010, using the following text words: 1) iceA, iceA1 or iceA2, and 2) pylori or Helicobacter. We did not include abstract alone or unpublished articles. The following criteria were applied to select fully published case-control studies examining the relationship between the iceA gene and clinical outcomes (gastritis, peptic ulcer including gastric ulcer and duodenal ulcer, and gastric cancer) in adult population; the presence of the iceA gene was examined by polymerase chain reaction (PCR); original articles published in English. Studies were excluded if raw data were not presented. Subgroup analysis was performed by geographic area. Results: Nineteen studies with a total of 2,218 patients were identified in the search. Infection with the iceA1-positive H. pylori increased the risk for peptic ulcer by 1.27fold (95% confidence interval [CI], 1.01-1.59) overall. However, the test of heterogeneity was significant among these studies. Sensitivity analysis showed that the presence of the iceA1 gene was significantly associated with peptic ulcer (odds ratio [OR] = 1.28, 95% CI = 1.02-1.61) overall. Those of the iceA2 gene was inversely associated with peptic ulcer especially in Europe (OR = 0.55, 95% CI = 0.40-0.76). This trend was the same as in case of duodenal ulcer. There was no association between the presence of the iceA gene and gastric ulcer and gastric cancer. Seven studied examined the correlation with cagA gene, and only two showed the positive correlation. Publication bias did not exist. Conclusion: Our meta-analysis confirmed the importance of the presence of the iceA gene for duodenal ulcer in Western countries, especially in Europe although the significance was small. It is possible that the iceA gene is discriminating factor for peptic ulcer independent on cagA gene.

Genetic diversity in strains of Helicobacter pylori from India and their relatedness to strains from other parts of the world

Helicobacter pylori is predominantly transmitted within families and infection occurs mostly in early childhood, frequently leading to persistent infection lifelong. In the present study, genetic diversity of Helicobacter pylori among North and South Indian isolates was evaluated. 16S rDNA, cagA, vacA and iceA genes were amplified followed by sequencing of respective amplicons for diversity analysis. Result of PCR assay showed that status of pathogenicity genes varied among strains from Varanasi and Hyderabad. Phylogenetic analysis based on 16S rDNA sequences showed clustering of Hyderabad and Varanasi strains in separate groups, pointing to significant diversity. Additionally, phylogenetic analysis revealed that most of the Varanasi strains shared homology with the strains from Taiwan except for two isolates which matched with an isolate from Brazil. On the other hand majority of the Hyderabad strains showed relatedness with strains from Brazil except one which showed homology with one strain from Taiwan. In conclusion our results show that genetic diversity among H. pylori isolates is widely prevalent regardless of the region from which they are isolated. More interestingly, phylogenetic analysis suggests that the Indian strains of H. pylori show close homology to those from Taiwan and/or Brazil.

Molecular and histological detection of Helicobacter pylori and genotyping based on babA2 and iceA in patients with benign gastric pathologies

To investigate the presence of Helicobacter pylori in a Colombian population. Gastric biopsies from 60 patients with benign gastric pathologies were submitted to histopathological examination and genotyped by PCR through amplification of babA2 and iceA genes. The presence of H. pylori was demonstrated in 78.3%, 63.3% and 66.7% of the samples after Giemsa staining, andH. pylori 16S DNAr and iceA gene amplification, respectively. In addition, H. pylori babA2 positive was found infecting 7 patients. Among the iceA positive samples, 35% were identified as iceAl, 47.5% as iceA2 and 17.5% contained iceAl and iceA2 or different iceA2 types. This work allowed detection and genotyping of H. pylori, demonstrating a low proportion of patients carrying strains babA2 positive and an iceA genotype distribution according to previous reports. No association was found between the presence of babA2 and iceA genes and ulcer disease.

Detección histológica y molecular de Helicobacter pylori y genotipificación con base en los genes de virulencia babA2 e iceA en pacientes con patología gástrica benigna

To investigate the presence of Helicobacter pylori in a Colombian population.Gastric biopsies from 60 patients with benign gastric pathologies were submitted to histopathological examination and genotyped by PCR through amplification of babA2 and iceA genes.The presence of H. pylori was demonstrated in 78.3%, 63.3% and 66.7% of the samples after Giemsa staining, andH. pylori 16S DNAr and iceA gene amplification, respectively. In addition, H. pylori babA2 positive was found infecting 7 patients. Among the iceA positive samples, 35% were identified as iceAl, 47.5% as iceA2 and 17.5% contained iceAl and iceA2 or different iceA2 types. This work allowed detection and genotyping of H. pylori, demonstrating a low proportion of patients carrying strains babA2 positive and an iceA genotype distribution according to previous reports. No association was found between the presence of babA2 and iceA genes and ulcer disease.

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

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

Prevalence of Helicobacter pylori vacA, cagA, iceA and oipA genotypes in Tunisian patients

BackgroundDistinct virulence factors of H. pylori have been described: the vaculating cytotoxin (vacA), the cytotoxin associated gene (cagA), the induced by contact with epithelium factor Antigen (iceA gene) and the outer membrane protein oipA. In Tunisia, there are no data regarding the pattern of H. pylori genotypes; therefore, this prospective and multicentre study was the first to be done in Tunisia and aimed to investigate the prevalence of the vacA, cagA, iceA and oipA genotypes of H. pylori isolates from Tunisian patients with peptic ulceration, gastric cancer, MALT lymphoma and gastritis.MethodsH. pylori was cultured from endoscopic biopsies obtained from 281 Tunisian patients. The vacA alleles, cagA, iceA and oipA genotypes were determined by PCR.ResultsThe vacA s1m1, s1m2 and s2m2 were respectively found in 10.7%, 12.5% and 45.6% of strains. The s2m1 genotype was not detected in our study. The cagA was found in 61.6% of isolates. The iceA1 and the iceA2 genotypes were respectively isolated in 60.2% and in 16% of strains. The oipA genotype was detected in 90.8% of strains. Considering the vacA and iceA genotypes, the presence of multiple H. pylori strains in a single biopsy specimen was found respectively in 31.4% and 23.8%. The comparison between strains isolated from antrum and fundus showed that Tunisian patients were infected with two or more strains of different cagA, vacA, iceA and oipA genotypes and the discordance was respectively in 9.6%, 4.6%, 8.9% and 8.5% of strains.ConclusionOur results showed that in 46% (131 strains among 281), the H. pylori strains were highly virulent in relation of the three or four virulent factors they could carry. These finding were described before in the literature. Tunisian patients were colonized by one or multiple strains of H. pylori in the same time in relation of presence of vacA m1/m2 and iceA1/iceA2 in the same biopsy. The discordance between strains isolated from antrum and fundus was high, and it is in favour of multicolonization.

Construction and identification of iceA gene mutant strain of Helicobacter pylori isolated from Chinese patients

Construction and identification of iceA gene mutant strain of Helicobacter pylori isolated from Chinese patients