babA2- and cagA-positive Helicobacter pylori strains are associated with duodenal ulcer and gastric carcinoma in Brazil

Pathogenesis and potential reversibility of intestinal metaplasia - a milestone in gastric carcinogenesis

BACKGROUND

Non-cardia gastric cancer remains a major cause of cancer-related mortality worldwide, despite declining incidence rates in many industrialized countries. The development of intestinal-type gastric cancer occurs through a multistep process in which normal mucosa is sequentially transformed into hyperproliferative epithelium, followed by metaplastic processes leading to carcinogenesis. Chronic infection with Helicobacter pylori is the primary etiological agent that causes chronic inflammation of the gastric mucosa, induces atrophic gastritis, and can lead to intestinal metaplasia and dysplasia. Both intestinal metaplasia and dysplasia are precancerous lesions, in which gastric cancer is more likely to occur. Atrophic gastritis often improves after eradication of Helicobacter pylori; however, the occurrence of intestinal metaplasia has been traditionally regarded as "the point of no return" in the carcinogenesis sequence. Helicobacter pylori eradication heals non-atrophic chronic gastritis, may lead to regression of atrophic gastritis, and reduces the risk of gastric cancer in patients with these conditions. In this article, we discuss the pathogenesis, epigenomics, and reversibility of intestinal metaplasia and briefly touch upon potential treatment strategy.

CONCLUSIONS

Gastric intestinal metaplasia no longer appears to be an irreversible precancerous lesion. However, there are still many controversies regarding the improvement of intestinal metaplasia after Helicobacter pylori eradication.

Prevalence of cagA, cagM, vacA and oipA genes in isolates of Helicobacter pylori obtained from hospital patients in Northeast Brazil

Helicobacter pylori is a major cause of gastrointestinal disorders such as chronic gastritis, peptic ulcers, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. It is estimated that around half of the world's population is infected with this pathogen, with underdeveloped countries reporting the highest frequencies. The genes cagA, cagM, vacA, and oipA are some of the most important virulence factors of H. pylori; however, there are no recent studies from Recife-PE demonstrating their frequency, and their relationship with severe gastric modifications. This work aims to use qualitative PCR to detect the virulence genes cagA, cagM, vacA, and oipA in H. pylori isolates obtained from patients in a public hospital in Recife (PE). We collected samples from the stomach's body and antrum of 147 patients, from which 71 (48%) tested positive for H. pylori. Among positive samples, the most frequently infected gender was female (44/71, 62%), and the most frequently infected age group was those above the age of 46 (31/71, 44%). Histological examination of H. pylori-positive samples revealed alterations other than chronic gastritis, including metaplasia and atrophy. The frequency of cagA, cagM, and oipA genes were identified in 84%, 56%, and 69% of the samples tested, respectively, as well as the vacA-s1m1 allelic combination (77%). However, there was no statistically significant variation in the occurrence of these genes, therefore they cannot be considered unique markers of severity in our setting. New research with larger samples and investigations of other genetic markers can aid uncover local risk factors and lead to a better understanding of H. pylori's pathogenesis.

Helicobacter pylori Outer Membrane Proteins and Virulence Factors: Potential Targets for Novel Therapies and Vaccines

Helicobacter pylori is a gastric oncopathogen that infects over half of the world's human population. It is a Gram-negative, microaerophilic, helix-shaped bacterium that is equipped with flagella, which provide high motility. Colonization of the stomach is asymptomatic in up to 90% of people but is a recognized risk factor for developing various gastric disorders such as gastric ulcers, gastric cancer and gastritis. Invasion of the human stomach occurs via numerous virulence factors such as CagA and VacA. Similarly, outer membrane proteins (OMPs) play an important role in H. pylori pathogenicity as a means to adapt to the epithelial environment and thereby facilitate infection. While some OMPs are porins, others are adhesins. The epithelial cell receptors SabA, BabA, AlpA, OipA, HopQ and HopZ have been extensively researched to evaluate their epidemiology, structure, role and genes. Moreover, numerous studies have been performed to seek to understand the complex relationship between these factors and gastric diseases. Associations exist between different H. pylori virulence factors, the co-expression of which appears to boost the pathogenicity of the bacterium. Improved knowledge of OMPs is a major step towards combatting this global disease. Here, we provide a current overview of different H. pylori OMPs and discuss their pathogenicity, epidemiology and correlation with various gastric diseases.

Infiltration to infection: key virulence players of Helicobacter pylori pathogenicity

PURPOSE

This study aims to comprehensively review the multifaceted factors underlying the successful colonization and infection process of Helicobacter pylori (H. pylori), a prominent Gram-negative pathogen in humans. The focus is on elucidating the functions, mechanisms, genetic regulation, and potential cross-interactions of these elements.

METHODS

Employing a literature review approach, this study examines the intricate interactions between H. pylori and its host. It delves into virulence factors like VacA, CagA, DupA, Urease, along with phase variable genes, such as babA, babC, hopZ, etc., giving insights about the bacterial perspective of the infection The association of these factors with the infection has also been added in the form of statistical data via Funnel and Forest plots, citing the potential of the virulence and also adding an aspect of geographical biasness to the virulence factors. The biochemical characteristics and clinical relevance of these factors and their effects on host cells are individually examined, both comprehensively and statistically.

RESULTS

H. pylori is a Gram-negative, spiral bacterium that successfully colonises the stomach of more than half of the world's population, causing peptic ulcers, gastric cancer, MALT lymphoma, and other gastro-duodenal disorders. The clinical outcomes of H. pylori infection are influenced by a complex interplay between virulence factors and phase variable genes produced by the infecting strain and the host genetic background. A meta-analysis of the prevalence of all the major virulence factors has also been appended.

CONCLUSION

This study illuminates the diverse elements contributing to H. pylori's colonization and infection. The interplay between virulence factors, phase variable genes, and host genetics determines the outcome of the infection. Despite biochemical insights into many factors, their comprehensive regulation remains an understudied area. By offering a panoramic view of these factors and their functions, this study enhances understanding of the bacterium's perspective, i.e. H. pylori's journey from infiltration to successful establishment within the host's stomach.

The Helicobacter pylori cag pathogenicity island as a determinant of gastric cancer risk

Helicobacter pylori strains can be broadly classified into two groups based on whether they contain or lack a chromosomal region known as the cag pathogenicity island (cag PAI). Colonization of the human stomach with cag PAI-positive strains is associated with an increased risk of gastric cancer and peptic ulcer disease, compared to colonization with cag PAI-negative strains. The cag PAI encodes a secreted effector protein (CagA) and components of a type IV secretion system (Cag T4SS) that delivers CagA and non-protein substrates into host cells. Animal model experiments indicate that CagA and the Cag T4SS stimulate a gastric mucosal inflammatory response and contribute to the development of gastric cancer. In this review, we discuss recent studies defining structural and functional features of CagA and the Cag T4SS and mechanisms by which H. pylori strains containing the cag PAI promote the development of gastric cancer and peptic ulcer disease.

Influence of Helicobacter pylori oncoprotein CagA in gastric cancer: A critical-reflective analysis

Gastric cancer is the fifth most common malignancy and third leading cancer-related cause of death worldwide. Helicobacter pylori is a Gram-negative bacterium that inhabits the gastric environment of 60.3% of the world’s population and represents the main risk factor for the onset of gastric neoplasms. CagA is the most important virulence factor in H. pylori, and is a translocated oncoprotein that induces morphofunctional modifications in gastric epithelial cells and a chronic inflammatory response that increases the risk of developing precancerous lesions. Upon translocation and tyrosine phosphorylation, CagA moves to the cell membrane and acts as a pathological scaffold protein that simultaneously interacts with multiple intracellular signaling pathways, thereby disrupting cell proliferation, differentiation and apoptosis. All these alterations in cell biology increase the risk of damaged cells acquiring pro-oncogenic genetic changes. In this sense, once gastric cancer sets in, its perpetuation is independent of the presence of the oncoprotein, characterizing a “hit-and-run” carcinogenic mechanism. Therefore, this review aims to describe H. pylori- and CagA-related oncogenic mechanisms, to update readers and discuss the novelties and perspectives in this field.

HELICOBACTER PYLORI cagA VIRULENCE GENE AND SEVERE ESOGASTRODUODENAL DISEASES: IS THERE AN ASSOCIATION?

BACKGROUND

Helicobacter pylori colonizes approximately half of the world's human population. Its presence in the gastric mucosa is associated with an increased risk of gastric adenocarcinoma, gastric lymphoma, and peptic ulcer disease. In Brazil, the high prevalence of H. pylori infection is a serious health problem. H. pylori virulence factors are associated with an increased risk of serious gastrointestinal disorders. The cagA gene encodes a cytotoxin-A-associated antigen (CagA) that is involved in bacterial pathogenicity. H. pylori strains carrying the cag pathogenicity island (cag-PAI) are significantly associated with severe clinical outcomes and histopathological changes.

OBJECTIVE

The present study aims to investigate the prevalence of the cagA gene among H. pylori isolates from patients with different gastric pathologies. Further, the study hopes to verify its association with clinical outcomes. In addition, phylogenetic analysis was performed on cagA-positive H. pylori strains from patients with severe and non-severe diseases.

METHODS

Gastric specimens were collected through a biopsy from 117 patients with different esogastroduodenal diseases. DNA was extracted from these gastric specimens and the polymerase chain reaction was performed to amplify the gene fragments corresponding to the 16S ribosomal RNA and cagA genes using specific primers. The polymerase chain reaction products of selected samples positive for cagA were sequenced. The sequences were aligned with reference sequences from the National Center for Biotechnology Information (NCBI) (Bethesda/USA), and a phylogenetic tree was constructed.

RESULTS

H. pylori was detected in 65.9% (77/117) of Brazilian patients with different gastroduodenal disorders. Overall, 80.5% (62/77) of the strains were cagA-positive. The ages of patients with cagA-positive strains (15 males and 47 females) ranged from 18 to 74 years. The lesions were categorized as non-severe and severe according to the endoscopic and histopathological reports the most prevalent non-severe esogastroduodenal lesion was gastritis 54/77 (70.12%), followed by esophagitis 12/77 (15.58%) and duodenitis 12/77 (15.58%). In contrast, the most prevalent severe lesions were atrophy 7/77 (9.09%), followed by metaplasia 3/77 (3.86%) and gastric adenocarcinoma 2/77 (2.59%). Phylogenetic analyses performed with the partial sequences of the cagA gene obtained from local strains were grouped in the same clade. No differences in phylogenetic distribution was detected between severe and non-severe diseases.

CONCLUSION

The cagA gene is highly prevalent among H. pylori isolates from gastric lesions in Brazilian patients. The presence of the cagA gene was not considered a marker of the severity of esogastroduodenal lesions in the present study. This is the first study to investigate the phylogenetic population structure of H. pylori strains in a Brazilian capital, which may improve our understanding of the clinical outcome of H. pylori infection.

Association of Helicobacter pylori babA2 gene and gastric cancer risk: a meta-analysis

Background

The association of Helicobacter pylori (H. pylori) babA2 gene with gastric cancer (GC) was reported by several studies, but results were inconsistent. This meta-analysis was performed to investigate the relationship between H. pylori babA2 gene and GC risk.

Methods

Case-control studies involving the association between H. pylori babA2 gene and GC risk were systematically identified from PubMed databases. A meta-analysis was used to pool studies and to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of H. pylori babA2 gene associated with GC risk.

Results

Twenty studies were identified with a total of 1289 GC cases and 1081 controls. H. pylori babA2 gene was associated with an increased risk of GC by 2.05 fold (95% CI, 1.30–3.24, P = 0.002). In subgroup analysis, we found that H. pylori babA2 gene was significantly associated with GC risk in Asian population (OR = 2.63, 95% CI: 1.36–5.09 P = 0.004) but not in South American population (OR = 1.35, 95% CI: 0.69–2.64, P = 0.379).

Conclusions

This meta-analysis indicates that H. pylori babA2 gene may be associated with increased risk of GC, especially in Asian population.

Pathogenesis and clinical management of Helicobacter pylori gastric infection

Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. However, its prevalence varies among different geographic areas, and is influenced by several factors. The infection can be acquired by means of oral-oral or fecal-oral transmission, and the pathogen possesses various mechanisms that improve its capacity of mobility, adherence and manipulation of the gastric microenvironment, making possible the colonization of an organ with a highly acidic lumen. In addition, H. pylori presents a large variety of virulence factors that improve its pathogenicity, of which we highlight cytotoxin associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and gamma-glutamyl transpeptidase. The host immune system, mainly by means of a Th1-polarized response, also plays a crucial role in the infection course. Although most H. pylori-positive individuals remain asymptomatic, the infection predisposes the development of various clinical conditions as peptic ulcers, gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. Invasive and non-invasive diagnostic methods, each of them with their related advantages and limitations, have been applied in H. pylori detection. Moreover, bacterial resistance to antimicrobial therapy is a major challenge in the treatment of this infection, and new therapy alternatives are being tested to improve H. pylori eradication. Last but not least, the development of effective vaccines against H. pylori infection have been the aim of several research studies.

Effects of periodontal therapy on eradication and recurrence of Helicobacter pylori infection after successful treatment

OBJECTIVES

This study aimed to evaluate the effects of periodontal therapy on the efficacy of Helicobacter pylori eradication and on the recurrence of infection after eradication.

METHODS

We conducted a prospective randomized trial on 698 gastric H. pylori-infected patients, of whom 347 received gastric H. pylori treatment alone and 342 received gastric H. pylori treatment plus periodontal therapy. The presence of H. pylori and associated virulence genes were detected by real-time polymerase chain reaction.

RESULTS

After eradication of gastric H. pylori infection, the recurrence of gastric H. pylori was significantly lower in the gastric H. pylori treatment plus periodontal therapy group than in the group receiving gastric H. pylori treatment alone (OR 0.67; 95% CI 0.45 to 0.99), whereas the eradication rate was not significantly different (OR 0.87; 95% CI 0.68 to 0.98). There was a close relationship between the presence of H. pylori in saliva and its presence in the stomach.

CONCLUSIONS

The oral cavity is an important reservoir for gastric H. pylori infection. Adjunctive periodontal therapy could enhance the efficiency of H. pylori treatment and reduce the recurrence of gastric H. pylori infection.

Low Rate of babA2 Genotype among Iranian Helicobacter pylori Clinical Isolates

INTRODUCTION

The Blood Group Antigen-Binding Adhesion (babA), Outer Inflammatory Protein (oipA) and Sialic Acid-Binding Adhesin (sabA) as outer membrane proteins involved in Helicobacter pylori adherence to gastric mucosa have been suggested to have a role in the pathogenesis.

AIM

To investigate the frequency of H. pylori isolates babA2, oipA and sabA genes in Iranian dyspeptic patients.

MATERIALS AND METHODS

DNAs were extracted from H. pylori -positive cultures taken from 100 different dyspeptic patients. Genotyping was performed by Polymerase Chain Reaction (PCR), using the specific primers for babA2, oipA and sabA genes. Chi square test was used to investigate association between variables, p<0.05 was considered statistically significant.

RESULTS

All (100%) isolates possessed oipA and sabA genotypes, whereas babA2 was detected in 22% of isolates. There was no significant relationship between presence of genes with clinical outcome. The combined genotype oipA +/sabA +/ babA2- was correlated with gastritis. The rate of babA2 genotype in our isolates was lower than other Iranian reports.

CONCLUSION

Frequency of babA2 genotype among H. pylori isolates from Southwest of Iran is considerably less than other regions of Iran. Due to heterogeneity of H. pylori strains in different geographic regions, further work will be needed to understand the role of these virulence genes in H. pylori pathogenesis and their possible association with disease outcome.

Helicobacter pylori vacA s1m1 genotype but not cagA or babA2 increase the risk of ulcer and gastric cancer in patients from Southern Mexico

BACKGROUND

The vacA, cagA and babA2 genotypes of Helicobacter pylori are associated with gastric pathology. The objectives were to determine the frequency of infection and distribution of the vacA, cagA and babA2 genotypes of H. pylori in patients with gastric ulcer, chronic gastritis and gastric cancer, and to evaluate the association of virulent genotypes with diagnosis.

METHODS

We studied 921 patients with symptoms of dyspepsia or with presumptive diagnosis of gastric cancer. The DNA of H. pylori and the vacA, cagA and babA2 genes was detected by PCR in total DNA from gastric biopsies. The association of H. pylori and of its cagA, vacA and babA2 genotypes with diagnosis was determined by calculating the odds ratio (OR).

RESULTS

Chronic gastritis was confirmed in 767 patients, gastric ulcer in 115 and cancer in 39. The prevalence of H. pylori was 47.8, 49.6 and 61.5% in those groups, respectively. H. pylori was more frequent in the surrounding tissue (69.2%) than in the tumor (53.8%). The vacA s1m1 genotype predominated in the three groups (45.2, 61.4 and 83.3%, respectively). H. pylori was associated with cancer (OR_adjusted = 2.08; 95% CI 1.05-4.13; p = 0.035) but not with ulcer (OR_adjusted = 1.07; 95% CI 0.71-1.61; p = 0.728). The s1m1 genotype was associated with ulcer and cancer (OR_adjusted = 2.02; 95% CI 1.12-3.62; p = 0.019 and OR_adjusted = 6.58; 95% CI 2.15-20.08; p = 0.001, respectively). babA2 was associated with gastric cancer, and cagA was not associated with the diagnosis.

CONCLUSIONS

In population from Southern Mexico, H. pylori and the s1m1 genotype were associated with gastric cancer and the s1m1/cagA+/babA2+ strains predominated in tumor and adjacent tissue.

Prevalence of Helicobacter pylori vacA, cagA, cagE, oipA, iceA, babA2 and babB genotypes in Iranian dyspeptic patients

There is diversity in clinical outcome of Helicobacter pylori infection in different regions. Microbial, host and environmental factors seem to be reason of such variation. Considering microbial factors, we studied H. pylori genotypes and their association with clinical feature of the infection. Overall 160 H. pylori-positive patients were enrolled in this study. Clinical information and biopsy were collected from each patient. The presence of the major virulence genes were determined by PCR. Regardless to clinical outcomes, vacA, cagA, cagE, oipA, iceA1, babA2 and babB genes was positive in 100%, 69%, 51%, 55%, 26%,78% and 28% of 160 strains respectively. The s1m2 was more common vacA allels and s1a and m1a were predominant s and m regions. In patient with gastric cancer (GC), the oipA was less frequent while the iceA1 was the most common. The babA2 was common in all patient groups. The babB was significantly observed in strains isolated from patients with GC. There were significant association among cagA status with presence of vacAs1, vacAm2, cagE, oipA, iceA1 and babA2. Presence of the babB and oipA was connected with higher and lower risk for GC respectively. There was no association between the cagA, vacA, cagE or iceA status and clinical outcome in patients in Iran. We showed that presence of the babB and iceA1 were significantly connected with higher risk for gastric cancer development in Iranian dyspeptic patients while H. pylori isolates with positive oipA had little threat for leading patients to cancer.

Helicobacter pylori Strains from Duodenal Ulcer Patients Exhibit Mixed babA/B Genotypes with Low Levels of BabA Adhesin and Lewis b Binding

BACKGROUND

BabA is a Helicobacter pylori cell surface adhesin, which binds to the ABO/Le(b) histo-blood group antigens (Le(b)) and serves as a virulence factor.

METHODS

H. pylori single colonies were isolated from 156 [non-ulcer dyspepsia (NUD) = 97, duodenal ulcer (DU) = 34, gastric cancer (GC) = 25)] patients. babA and babB genes were evaluated by gene/locus-specific PCR. BabA protein expression and Le(b) binding activity were determined by immunoblotting and ELISA, respectively.

RESULTS

The combined categorization of H. pylori strains based on high, low or no levels of BabA expression and Le(b) binding, produced 4 groups: (I) BabA-high/Le(b)-high (36 %), (II) BabA-low/Le(b)-low (26 %), (III) BabA-neg/Le(b)-low (30 %) and (IV) BabA-neg/Le(b)-neg (8 %) strains. The majority (63 %) of the BabA-low/Le(b)-low strains exhibited mixed babA/B genotypes as compared to merely 18 % of the BabA-high/Le(b)-high, 15 % of the BabA-neg/Le(b)-neg and 11 % of the BabA-neg/Le(b)-low (P = 0.0001) strains. In contrast to NUD strains, the great majority (70 %) of DU strains were BabA-low/Le(b)-low (11 %, P = 0.0001), which compared to NUD strains, enhanced the risk of DU by 18.8-fold. In parallel, infection with babA/B mixed genotype strains amplified the risk of DU by 3.6-fold (vs. babA-positive: P = 0.01) to 6.9-fold (vs. babA-negative: P = 0.007).

CONCLUSIONS

Here, we show higher prevalence of mixed babA/B genotypes among BabA-low/Le(b)-low clinical strains. Recombination of babA and babB genes across their loci may yield lower BabA expression and lower Le(b) binding activity. We conclude that H. pylori strains with lower Le(b) binding activity are better adapted for colonization of the gastric metaplastic patches in the duodenum and enhance the risk of duodenal ulcers.

Helicobacter pylori strains harboring babA2 from Indian sub population are associated with increased virulence in ex vivo study

Background

The babA2 gene along with the cagA and vacA of Helicobacter pylori has been considered as a risk factor for the disease outcome in certain populations. This study was aimed to understand the role of babA2 of H. pylori with the background of cagA and vacA in disease manifestations in Indian sub population.

Methods

A total of 114 H. pylori strains isolated from duodenal ulcer (DU) (n = 53) and non-ulcer dyspepsia (NUD) patients (n = 61) were screened for the prevalence of these virulence markers by PCR. The comparative study of IL-8 production and apoptosis were done by co-culturing the AGS cell line with H. pylori strains with different genotypes. Adherence assay was performed with babA2 positive and negative strains. Two isogenic mutants of babA2 were constructed and the aforesaid comparative studies were carried out.

Results

PCR results indicated that 90.6 % (48/53), 82 % (50/61) and 73.6 % (39/53) strains from DU patients were positive for cagA, vacA, and babA2, respectively. Whereas the prevalence of these genes in NUD subjects were 70.5 % (43/61); 69.8 % (37/53), and 65.6 % (39/61), respectively. Although adherence to AGS cells was comparable among strains with babA2 positive and negative genotypes, but the triple positive strains could induce highest degree of IL-8 production and apoptosis, followed by the cagA⁻/vacA⁻/babA2⁺ strains and triple negative strains, respectively. The wild type strains showed significantly higher IL-8 induction as well as apoptosis in ex vivo than its isogenic mutant of babA2.

Conclusion

PCR study demonstrated that there was no significant association between the distribution of babA2 genotype or of triple positive strains and disease outcome in this sub population. The adherence assay showed that there was no significant difference in the extent of adherence to AGS cells among babA2 positive and negative strains. But the ex vivo study indicated that the triple positive or even the babA2 only positive strains are involved in increased virulence. The wild type strains also exhibited increased virulence compared to the babA2 mutant strains. This inconsistency demonstrated that bacterial genotype along with host genetic polymorphisms or other factors play important role in determining the clinical manifestation of H. pylori infections.

Review of Research on Routes of Helicobacter pylori Infection

In recent years, many scholars conducted in-depth research onHelicobacter pyloriand identified it as an important pathogen of chronic gastritis and peptic ulcer.H. pylorialso causes also and contributes to precancerous lesions (atrophic gastritis and intestinal metaplasia) and is closely related to occurrence and development of gastric adenocarcinoma and gastric mucosa-associated lymphoma. This study summarizes biological characteristics, epidemic status, and infection route ofH. pyloriand reviews research on roles of natural environments, especially drinking water, during infection.

Infection with CagA-positive Helicobacter pylori strain containing three EPIYA C phosphorylation sites is associated with more severe gastric lesions in experimentally infected Mongolian gerbils (Meriones unguiculatus)

Infection with Helicobacter pylori strains containing high number of EPIYA-C phosphorylation sites in the CagA is associated with significant gastritis and increased risk of developing pre-malignant gastric lesions and gastric carcinoma. However, these findings have not been reproduced in animal models yet. Therefore, we investigated the effect on the gastric mucosa of Mongolian gerbil (Meriones unguiculatus) infected with CagA-positive H. pylori strains exhibiting one or three EPIYA-C phosphorilation sites. Mongolian gerbils were inoculated with H. pylori clonal isolates containing one or three EPIYA-C phosphorylation sites. Control group was composed by uninfected animals challenged with Brucella broth alone. Gastric fragments were evaluated by the modified Sydney System and digital morphometry. Clonal relatedness between the isolates was considered by the identical RAPD-PCR profiles and sequencing of five housekeeping genes, vacA i/d region and of oipA. The other virulence markers were present in both isolates (vacA s1i1d1m1, iceA2, and intact dupA). CagA of both isolates was translocated and phosphorylated in AGS cells. After 45 days of infection, there was a significant increase in the number of inflammatory cells and in the area of the lamina propria in the infected animals, notably in those infected by the CagA-positive strain with three EPIYA-C phosphorylation sites. After six months of infection, a high number of EPIYA-C phosphorylation sites was associated with progressive increase in the intensity of gastritis and in the area of the lamina propria. Atrophy, intestinal metaplasia, and dysplasia were also observed more frequently in animals infected with the CagA-positive isolate with three EPIYA-C sites.  We conclude that infection with H. pylori strain carrying a high number of CagA EPIYA-C phosphorylation sites is associated with more severe gastric lesions in an animal model of H. pylori infection.

Helicobacter pylori vacA i region polymorphism but not babA2 status associated to gastric cancer risk in northwestern Iran

Helicobacter pylori-specific genotypes have been strongly associated with an increased risk of gastric cancer (GC). The aim of the present work was to study the associations of H. pylori virulence factors, vacA i region polymorphisms and babA2 status with GC risk in Azerbaijan patients. The DNA extracted from gastric biopsy specimens was used to access the babA2 and vacA genotypes. Overall, babA2 was present in 85.39 % (76/89) of H. pylori strains: 19 out of 24 (79.16 %) strains from GC, 16 out of 17 (94.14 %) strains from peptic ulcer disease (PUD) and 41 out of 48 (85.14 %) strains from chronic gastritis. No significant association was found between babA2 genotype and clinical outcomes (P > 0.05). i1 vacA polymorphism was detected in 46/89 (51.68 %) strains: in 21/24 (87.5 %), 6/17 (35.29 %) and 19/48 (39.58 %) patients with GC, PUD and chronic gastritis, respectively. i2 allele was detected in 43 (48.31 %) out of all 89 strains examined: 3 (14.28 %) of 24 strains from GC, 11 (64.71 %) of 17 from PUD, and 29 (60.42 %) of 48 strains from chronic gastritis. In this study, multiple linear regression analysis confirmed the strong association of i1 allele with GC (partial regression correlation 0.455 ± 0.101; P = 0). Results of multiple logistic regression analysis showed that vacA i1 genotype was significantly associated with GC compared with a control group (gastritis) (odds ratio 13.142, 95 % CI 3.116-55.430; P = 0). Findings from the measurement of H. pylori babA2 and vacA genotypes indicate a strong correlation between the vacA i1 allele and GC risk in the Azerbaijan area of Iran.

Correlation of ABH blood group antigens secretion with Helicobacter pylori infection in Pakistani patients

OBJECTIVES

A and B blood group antigens are fucosylated carbohydrate present on human erythrocytes and body secretions. Their presence in body secretions depends on the expression of a dominant allele of secretor gene FUT2 and is correlated with susceptibility to various infectious and non-infectious diseases. We investigated the correlation of blood group and ABH antigen secretion with Helicobacter pylori infection and gastroduodenal symptoms and analysed the distribution of babA gene among ABH secretors and non-secretors.

METHODS

Two hundred and ninety patients who underwent gastroduodenal endoscopy during 2011 to 2012 participated. Gastric biopsy, saliva and blood samples were obtained from every patient. Gastric biopsies were subjected to rapid urease test and PCR for the detection of H. pylori and babA gene. Blood grouping and ABH antigens secretions were determined by Lewis blood group phenotyping and haemagglutination inhibition test.

RESULTS

50.34% of patients were ABH antigen secretors and 45.51% non-secretors. Distribution analysis of blood group revealed that 40 blood group B, 67 blood group A 20 blood group O and 19 blood group AB patients secreted ABH antigens in saliva. Fifty-six blood group O, 19 blood group B, 32 blood group A and 17 blood group AB patients were non-secretors. Gastroduodenal complaints were common among non-secretors. Sixty-two percent of patients with a combination of duodenal ulcer and gastro-oesophageal reflux and 54% of patients with gastritis were non-secretors. Of 290 samples, 31.02% were positive for H. pylori. Thirty percent of these tested positive for babA gene; the majority belonged to non-secretor blood group O.

CONCLUSIONS

Our results suggest that the infection of H. pylori is correlated with ABO blood groups and blood group antigens secretion in body fluids.

Occurrence of Helicobacter pylori and Epstein-Barr virus infection in endoscopic and gastric cancer patients from Northern Brazil

BACKGROUND

Helicobacter pylori (HP) and Epstein-Barr virus (EBV) have been associated with cancer development. We evaluated the prevalence of HP, HP CagA+ and EBV infection in gastric cancer (GC) samples from adults and in gastric tissues from patients who underwent upper endoscopy (UE).

METHODS

Samples from UE and GC were collected to investigate the presence of HP infection and the HP virulence factor CagA by a urease test and PCR. The presence of EBV was detected by Eber-1 in situ hybridization.

RESULTS

In UE, 85.5% of juvenile patients showed some degree of gastritis (45.3% of patients with mild gastritis and 54.7% with moderate/severe gastritis) and patients with mild gastritis were younger than patients with moderate/severe gastritis. Among adults, 48.7% presented mild gastritis and 51.3% moderate/severe gastritis. HP infection was detected in 0% of normal mucosa, 58.5% of juvenile gastritis patients, 69.2% of adult gastritis patients and 88% of GC patients. In these same groups, HP CagA+ was detected in 0%, 37.7%, 61.5% and 67.2% of tissue samples, respectively. In juvenile patients, HP infection was more common in those with gastritis than in normal samples (p = 0.004). The patients with either HP or HP CagA+ were older than patients without these pathogens (p < 0.05). In juvenile patients, HP infection was more frequent in cases of moderate/severe gastritis than in cases of mild gastritis (p = 0.026). Moreover, in patients with GC, HP infection was more frequent in males than in females (p = 0.023). GC patients with HP CagA+ were older than patients with HP CagA- (p = 0.027). HP CagA+ was more common in intestinal-type than diffuse-type GC (p = 0.012). HP CagA+ was also associated with lymph-node (p = 0.024) and distal (p = 0.005) metastasis. No association between EBV infection and HP infection or any clinicopathological variable was detected.

CONCLUSIONS

Our results suggest that HP is involved in the pathophysiology of severe gastric lesions and in the development of GC, particularly when CagA+ is present. EBV was not the primary pathogenic factor in our samples.

Diet, microbial virulence, and Helicobacter pylori-induced gastric cancer

Gastric adenocarcinoma is a leading cause of cancer-related death worldwide, and Helicobacter pylori infection is one of the strongest known risk factors for this malignancy. H. pylori strains exhibit a high level of genetic diversity, and the risk of gastric cancer is higher in persons carrying certain strain types (for example, those that contain a cag pathogenicity island or type s1 vacA alleles) than in persons carrying other strain types. Additional risk factors for gastric cancer include specific human genetic polymorphisms and specific dietary preferences (for example, a high-salt diet or a diet deficient in fruits and vegetables). Finally, iron-deficiency anemia is a risk factor for gastric cancer. Recent studies have provided evidence that several dietary risk factors for gastric cancer directly impact H. pylori virulence. In this review article, we discuss mechanisms by which diet can modulate H. pylori virulence and thereby influence gastric cancer risk.

cagE as a biomarker of the pathogenicity of Helicobacter pylori

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

High correlation of babA 2-positive strains of Helicobacter pylori with the presence of gastric cancer

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that is well known in the involvement of chronic inflammation in the gastric mucosa of the human stomach. Several studies have investigated the possible role of H. pylori presence in different gastroduodenal disorders with conflicting results. This study aimed to further investigate such a field. Helicobacter pylori strains were cultured from 160 patients (mean age of 42 years; range 15-75; 90 were male, and 70 were female) [40 gastric cancer (GC), 55 duodenal ulcer (DU) and 65 non-ulcer dyspepsia (NUD)]. In this study, allelic variants of iceA 1, iceA 2 and babA 2 were identified by polymerase chain reaction. The overall prevalence of babA 2 gene was 40.6% (65/160). The prevalence of babA 2 gene was 95% with gastric cancer, 18.1% with duodenal ulcer and 26.1% with non ulcer dyspepsia, respectively. The prevalence of babA 2 in GC patients was significantly higher as compared to either NUD or UD patients (P = 0.0004), while no statistical significance was found between the latter two patient groups. Our study finds that babA 2 and iceA 1 genes are more prevalent in GC compared to either NUD or DU patients in Iran.

Association of Helicobacter pylori babA2 with peptic ulcer disease and gastric cancer

AIM: To investigate the association between babA2 gene and peptic ulcer disease (PUD) and gastric cancer (GC) in Helicobacter pylori-infected populations.

METHODS: We evaluated the relationship between babA2 and clinical outcomes (PUD and GC) using a meta-analysis. A literature search was performed using the PubMed and Web of Science databases for relevant case-control studies that met the defined inclusion criteria. The ORs and 95%CIs were calculated to estimate the association between babA2 genotype and clinical outcomes. A fixed-effect or random-effect model was performed depending on the absence or presence of significant heterogeneity.

RESULTS: A total of 25 articles with 38 studies met the inclusion criteria and were finally included in this meta-analysis. The results showed that the babA2 genotype was significantly associated with an increased risk of PUD (OR = 2.069, 95%CI: 1.530-2.794, P < 0.001) and especially in the subgroup of duodenal ulcer (OR = 1.588, 95%CI: 1.141-2.209, P = 0.006). Moreover, a significant association between babA2 gene and PUD and duodenal ulcer (OR = 2.739, 95%CI: 1.860-4.032, P < 0.001; OR = 2.239, 95%CI: 1.468-3.415, P < 0.001, respectively) was observed in western countries but not in Asian countries.

CONCLUSION: We demonstrated that the presence of babA2 may be associated with increased risks for PUD, especially duodenal ulcer, in western countries.

Helicobacter pylori vacA and cagA genotypes in patients from northeastern Brazil with upper gastrointestinal diseases

Helicobacter pylori causes chronic gastric inflammation and significantly increases the risk of duodenal and gastric ulcer disease and distal gastric carcinoma. In this study, we evaluated the Helicobacter pylori vacA and cagA genotypes in patients from a Brazilian region where there is a high prevalence of gastric cancer. Polymerase chain reaction (PCR) was used to investigate vacA mosaicism and cagA status in the gastric mucosa of 134 H. pylori-positive patients, including 76 with gastritis: 28 with peptic ulcer disease and 30 with gastric cancer. The s1m1 variant was the predominant vacA genotype observed, whereas the s1 allele was more frequently observed in patients with more severe diseases associated with H. pylori infection [p = 0.03, odds ratio (OR) = 5.72, 95% confidence interval (CI) = 1.15-38.60]. Furthermore, all of the s1 alleles were s1b. Mixed vacA m1/m2 strains were found more frequently in patients with gastric cancer and a cagA-positive status was significantly associated with gastric cancer (p = 0.016, OR = 10.36, 95% CI = 1.35-217.31). Patients with gastric cancer (21/21, 100%, p = 0.006) or peptic ulcers (20/21, 95%, p = 0.02) were more frequently colonised by more virulent H. pylori strains compared to gastritis patients (41/61, 67.2%). In conclusion, in the northeastern of Brazil, which is one of the regions with the highest prevalence of gastric cancer in the country, infection with the most virulent H. pylori strains, carrying the cagA gene and s1m1 vacA alleles, predominates and is correlated with more severe H. pylori-associated diseases.

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 AIM

Several 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 METHODS

DNA 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.

RESULTS

A 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).

CONCLUSION

The 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

BACKGROUND AND AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

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.

Virulence attributes of Helicobacter pylori isolates & their association with gastroduodenal disease

BACKGROUND & OBJECTIVES

Certain genotype(s) of Helicobacter pylori strains may play important role in the development of gastric cancer (GC) and peptic ulcer disease (PUD). This study was undertaken to investigate the association of cagA, cagA3/ region subtypes, babA2 and vacA genotypes of H. pylori with GC, PUD and non-ulcer dyspepsia (NUD) as there are no such studies from India.

METHODS

A total of 348 consecutive adult patients (NUD 241, PUD 45, GC 62) undergoing upper gastrointestinal endoscopy between September 2002 and May 2007 in a tertiary referral centre at Lucknow, north India, were enrolled. H. pylori infection was diagnosed by rapid urease test, culture, histopathology and PCR. Genotyping for cagA, cagA3/ subtypes, babA2 and vacA was performed by PCR using sequence specific primers.

RESULTS

H. pylori infection was higher in patients with PUD than with GC (80 vs. 56.5%, P < 0.01) and NUD (80 vs. 55.2%, P= 0.002). cagA positive H. pylori isolates were detected in 80 per cent in GC, 83.3 per cent in PUD and 76.7 per cent in NUD with no significant difference among them. Only A subtype of cagA3/ was detected and its distribution in GC, PUD and NUD was 68.8, 69.4 and 52.6 per cent respectively. Presence of babA2 genotype was 31.4 per cent and it had significant association with PUD when compared with NUD (52.8 vs. 26.3%, P<0.003). On univariate regression analysis, s1a allele was associated with GC (P<0.050) and s1a/m2 vacA genotype with both GC (P=0.014) and PUD (P=0.016).

INTERPRETATION & CONCLUSIONS

H. pylori infection was strongly associated with PUD with a very high proportion of patients with GC have s1a allele and s1a/m2 vacA genotype. Both s1a/m2 vacA genotype and babA2 are associated with PUD. The study shows that different virulence attributes of H. pylori are involved in different gastroduodenal disorders.

Clinical relevance of Helicobacter pylori babA2 and babA2/B in Costa Rica and Japan

AIM: To evaluate the prevalence of Helicobacter pylori (H. pylori) babA2, babB and a recombinant gene between babA2 and babB (babA2/B), and their role in the development of atrophic gastritis in Costa Rican and Japanese clinical isolates.

METHODS: A total of 95 continuous H. pylori-positive Costa Rican (41 males and 54 females; mean age, 50.65 years; SD, ± 13.04 years) and 95 continuous H. pylori-positive Japanese (50 males and 45 females; mean age, 63.43; SD, ± 13.21 years) patients underwent upper endoscopy from October 2005 to July 2006. They were enrolled for the polymerase chain reaction (PCR)-based genotyping of the H. pylori babA2, babB and babA2/B genes. Statistical analysis was performed using the χ² test and the Fisher’s exact probability test and multivariate analysis was performed by logistic regression adjusting for gender and age. P < 0.05 was regarded as statistically significant.

RESULTS: The PCR-based genotyping of 95 Costa Rican and 95 Japanese isolates showed a higher prevalence of babA2 in Japan (96.8%) than in Costa Rica (73.7%), while that of babA2/B was higher in Costa Rica (11.6%) than in Japan (1.1%). In Costa Rican isolates only, babA2 was significantly associated with atrophic gastritis (P = 0.01).

CONCLUSION: These results suggest that the status of babA2 and babA2/B shows geographic differences, and that babA2 has clinical relevance in Costa Rica.

Helicobacter pylori colonization of the human gastric epithelium: a bug's first step is a novel target for us

After Helicobacter pylori enters the stomach, three steps are vital for infection: (i) establishing colonization; (ii) evading host immunity; and (iii) invading gastric mucosa; the last step is what is associated with diverse outcomes. Urease activity and motility mediated by the flagella of H. pylori are important in harboring colonies beneath the gastric mucus in niches adjacent to the epithelium. Several putative adhesins attach the organism to the gastric epithelium and prompt the succeeding processes for evading host immunity and invading the mucosa. Successful colonization is thus the leading and critical step. From another point of view, this can be a novel target to control this common and important infection. This review summarizes the putative adhesins that influence the evasion of host immunity, and how these could determine different clinico-pathologic outcomes. The putative adhesins include the interplay between bacterial and host Lewis antigens (type I: Le(a) and Le(b); type II: Le(x) and Le(y)), the dominant pathway between BabA and Le(b), the SabA adhesin binding to sialylated Le(x) that is upregulated in inflamed gastric tissue or those with weak-Le(b), the CagL apparatus to adapt with the alpha5beta1 integrin to mediate a type IV secretory system for CagA translocation into the epithelium; and other outer membrane proteins as HopZ, AlpA/AlpB, or OipA, without known corresponding receptors. This review implicates the adhesins vital for bugs that could be alternatively provided as novel targets for us to overcome the colonization.

Disease association with two Helicobacter pylori duplicate outer membrane protein genes, homB and homA

Background

homB encodes a Helicobacter pylori outer membrane protein. This gene was previously associated with peptic ulcer disease (PUD) and was shown to induce activation of interleukin-8 secretion in vitro, as well as contributing to bacterial adherence. Its 90%-similar gene, homA, was previously correlated with gastritis. The present study aimed to evaluate the gastric disease association with homB and homA, as well as with the H. pylori virulence factors cagA, babA and vacA, in 415 H. pylori strains isolated from patients from East Asian and Western countries. The correlation among these genotypes was also evaluated.

Results

Both homB and homA genes were heterogeneously distributed worldwide, with a marked difference between East Asian and Western strains. In Western strains (n = 234, 124 PUD and 110 non-ulcer dyspepsia (NUD), homB, cagA and vacA s1 were all significantly associated with PUD (p = 0.025, p = 0.014, p = 0.039, respectively), and homA was closely correlated with NUD (p = 0.072). In East Asian strains (n = 138, 73 PUD and 65 NUD), homB was found more frequently than homA, and none of these genes was associated with the clinical outcome.

Overall, homB was associated with the presence of cagA (p = 0.043) and vacA s1 (p < 0.001), whereas homA was found more frequently in cagA-negative (p = 0.062) and vacA s2 (p < 0.001) strains.

Polymorphisms in homB and homA copy number were observed, with a clear geographical specificity, suggesting an involvement of these genes in host adaptation. A correlation between the homB two-copy genotype and PUD was also observed, emphasizing the role of homB in the virulence of the strain.

Conclusion

The global results suggest that homB and homA contribute to the determination of clinical outcome.

Detection of cytotoxin genotypes of Helicobacter pylori in stomach, saliva and dental plaque

BACKGROUND

The aim of this study was to detect the presence of Helicobacter pylori and its virulent cagA genes in the oral cavity of individuals with upper gastric diseases. Sixty-two individuals (42+/-2.3 years) with dispepsy symptoms, referred for gastroscopy and who were H. pylori positive in the gastric biopsy, were recruited and separated in two groups: case group-individuals with gastric disease (n = 30); control group-individuals with no gastric disease (n = 32); saliva, dental plaque and biopsy samples were collected from all individuals. Oral and biopsy samples were analyzed by PCR using specific primers for H. pylori 16S ribosomal and cagA genes. PCR products were sequenced for DNA homology confirmation. H. pylori was detected neither in dental plaque nor in saliva in the control group. In the case group H. pylori DNA was detected in 16/30 (53.3%) saliva samples and in 11/30 (36.6%) dental plaque samples. The cagA gene was detected in 13/30 (43.3%) gastric biopsies, in 7/16 (43.8%) saliva samples, and in 3/11 (27.3%) dental plaque samples. Eighteen (60.0%) individuals in the case group were H. pylori positive both in oral and biopsy samples, and 8 (26.6%) of those were positive for cagA-H. pylori DNA. H. pylori and its virulent clone showed a higher prevalence in the oral cavity of individuals in the case group than in the control group (p < 0.05). Our results suggest that dental plaque and saliva may serve as temporary reservoir for H. pylori and its virulent cagA variant in individuals with gastric disease.

Frequency of vacA, cagA and babA2 virulence markers in Helicobacter pylori strains isolated from Mexican patients with chronic gastritis

BACKGROUND

Helicobacter pylori has been strongly associated with chronic gastritis, peptic and duodenal ulcers, and it is a risk factor for gastric cancer. Three major virulence factors of H. pylori have been described: the vacuolating toxin (VacA), the cytotoxin-associated gene product (CagA) and the adhesion protein BabA2. Since considerable geographic diversity in the prevalence of H. pylori virulence factors has been reported, the aim of this work was to establish the H. pylori and vacA, cagA and babA2 gene status in 238 adult patients, from a marginal urban area of Mexico, with chronic gastritis.

METHODS

H. pylori was identified in cultures of gastric biopsies by nested PCR. vacA and cagA genes were detected by multiplex PCR, whereas babA2 gene was identified by conventional PCR.

RESULTS

H. pylori-positive biopsies were 143 (60.1%). All H. pylori strains were vacA+; 39.2% were cagA+; 13.3% were cagA+ babA2+ and 8.4% were babA2+. Mexican strains examined possessed the vacA s1, m1 (43.4%), s1, m2 (24.5%), s2, m1 (20.3%) and s2, m2 (11.9%) genotypes.

CONCLUSION

These results show that the Mexican patients suffering chronic gastritis we have studied had a high incidence of infection by H. pylori. Forty four percent (63/143) of the H. pylori strains analyzed in this work may be considered as highly virulent since they possessed two or three of the virulence markers analyzed: vacA s1 cagA babA2 (9.8%, 14/143), vacA s1 babA2 (4.9%, 7/143), and vacA s1 cagA (29.4%, 42/143). However, a statistically significant correlation was not observed between vacAs1, cagA and babA2 virulence markers (chi2 test; P > 0.05).

Prevalence of vacA, cagA and babA2 genes in Cuban Helicobacter pylori isolates

AIM

To investigate the prevalence of vacuolating cytotoxin (vacA), cytotoxin associated gene A (cagA) and blood adhesion binding antigen (babA2) genotypes of Helicobacter pylori (H pylori) isolates from Cuban dyspeptic patients.

METHODS

DNA was extracted from H pylori-positive cultures taken from 130 dyspeptic patients. Genotyping was performed by PCR, using specific primers for vacA (s1, s2, m1, m2), cagA and babA2 genes. Endoscopic observations and histological examinations were used to determine patient pathologies.

RESULTS

vacA alleles s1, s2, m1 and m2 were detected in 96 (73.8%), 34 (26.2%), 75 (57.7%) and 52 isolates (40%), respectively, while the cagA gene was detected in 95 isolates (73.2%). One hundred and seven isolates (82.3%) were babA2-positive. A significant correlation was observed between vacAs1m1 and cagA and between vacAs1m1 and babA2 genotypes (P < 0.001 and P < 0.05, respectively) and between babA2 genotype and cagA status (P < 0.05); but, no correlation was observed between vacAs1 and babA2 genotypes. Eighty five (65.4%) and 73 (56.2%) strains were type 1 (vacAs1-cagA-positive) and "triple-positive" (vacAs1-cagA-babA2-positive), respectively, and their presence was significantly associated with duodenal ulcer (P < 0.01 and P < 0.001, respectively).

CONCLUSION

The distribution of the main virulence factors in the Cuban strains in this study resembled that of the Western-type strains, and the more virulent H pylori isolates were significantly associated with duodenal ulcer, ulcer disease being the worst pathology observed in the group studied.

Prevalence of vacA, cagA and babA2 genes in Cuban Helicobacter pylori isolates

AIM

To investigate the prevalence of vacuolating cytotoxin (vacA), cytotoxin associated gene A (cagA) and blood adhesion binding antigen (babA2) genotypes of Helicobacter pylori (H pylori) isolates from Cuban dyspeptic patients.

METHODS

DNA was extracted from H pylori-positive cultures taken from 130 dyspeptic patients. Genotyping was performed by PCR, using specific primers for vacA (s1, s2, m1, m2), cagA and babA2 genes. Endoscopic observations and histological examinations were used to determine patient pathologies.

RESULTS

vacA alleles s1, s2, m1 and m2 were detected in 96 (73.8%), 34 (26.2%), 75 (57.7%) and 52 isolates (40%), respectively, while the cagA gene was detected in 95 isolates (73.2%). One hundred and seven isolates (82.3%) were babA2-positive. A significant correlation was observed between vacAs1m1 and cagA and between vacAs1m1 and babA2 genotypes (P < 0.001 and P < 0.05, respectively) and between babA2 genotype and cagA status (P < 0.05); but, no correlation was observed between vacAs1 and babA2 genotypes. Eighty five (65.4%) and 73 (56.2%) strains were type 1 (vacAs1-cagA-positive) and "triple-positive" (vacAs1-cagA-babA2-positive), respectively, and their presence was significantly associated with duodenal ulcer (P < 0.01 and P < 0.001, respectively).

CONCLUSION

The distribution of the main virulence factors in the Cuban strains in this study resembled that of the Western-type strains, and the more virulent H pylori isolates were significantly associated with duodenal ulcer, ulcer disease being the worst pathology observed in the group studied.

Helicobacter pylori: phenotypes, genotypes and virulence genes

Helicobacter pylori is a Gram-negative, microaerophilic bacterium that colonizes the gastric mucus overlying the epithelium of the stomach in more than 50% of the world's population. This gastric colonization induces chronic gastric inflammation in all infected individuals, but only induces clinical diseases in 10-20% of infected individuals. These include peptic ulcers, acute and atrophic gastritis, intestinal metaplasia, gastric adenocarcinoma and gastric B-cell lymphoma. Various bacterial virulence factors are associated with the development of such gastric diseases, and the characterization of these markers could aid medical prognosis, which could be extremely important in predicting clinical outcomes. The purpose of this review is to summarize the role of the phenotypes, virulence-related genes and genotypes of H. pylori in the establishment of gastric colonization and the development of associated diseases.

Prevalence of vacA, cagA and babA2 genes in Cuban Helicobacter pylori isolates

AIM: To investigate the prevalence of vacuolating cytotoxin (vacA), cytotoxin associated gene A (cagA) and blood adhesion binding antigen (babA2) genotypes of Helicobacter pylori (H pylori) isolates from Cuban dyspeptic patients.

METHODS: DNA was extracted from H pylori-positive cultures taken from 130 dyspeptic patients. Genotyping was performed by PCR, using specific primers for vacA (s1, s2, m1, m2), cagA and babA2 genes. Endoscopic observations and histological examinations were used to determine patient pathologies.

RESULTS: vacA alleles s1, s2, m1 and m2 were detected in 96 (73.8%), 34 (26.2%), 75 (57.7%) and 52 isolates (40%), respectively, while the cagA gene was detected in 95 isolates (73.2%). One hundred and seven isolates (82.3%) were babA2-positive. A significant correlation was observed between vacAs1m1 and cagA and between vacAs1m1 and babA2 genotypes (P < 0.001 and P < 0.05, respectively) and between babA2 genotype and cagA status (P < 0.05); but, no correlation was observed between vacAs1 and babA2 genotypes. Eighty five (65.4%) and 73 (56.2%) strains were type 1 (vacAs1-cagA-positive) and “triple-positive” (vacAs1-cagA-babA2-positive), respectively, and their presence was significantly associated with duodenal ulcer (P < 0.01 and P < 0.001, respectively).

CONCLUSION: The distribution of the main virulence factors in the Cuban strains in this study resembled that of the Western-type strains, and the more virulent H pylori isolates were significantly associated with duodenal ulcer, ulcer disease being the worst pathology observed in the group studied.

The prevalence of cagA and cagE genes in Helicobacter pylori strains isolated from different patient groups by polymerase chain reaction

The aim of this study was to investigate the prevalence of cagA and cagE genes in H. pylori strains isolated from different patient groups with Non-Ulcer Dyspepsia (NUD), Duodenal Ulcer (DU), Gastric Ulcer (GU) and Gastric Cancer (GC). The patients admitted to the gastroenterology unit at Sharyati hospital in Tehran in 2006 were included in this study. Gastric biopsy specimens were obtained from the antrum of the stomach from each patient then cultured for detection of H. pylori. Identification of H. pylori was performed according to the standard bacteriological methods. Genomic DNA was extracted using a commercially available Qia gene kit. PCR was done using primers cagA-F, cagA-R and cagE-F, cagE-R to detect the target genes cagA and cagE, respectively. Amplified products of target genes were confirmed by sequencing. The cagA and cagE were detected among 85 and 86% of H. pylori isolates, respectively. Prevalence of cagA and cagE genes in the patients with NUD, DU, GU and GC were 22 (64.7%), 28 (100%), 18 (90%), 10 (100%) and 25 (73.5%), 27 (96.4%), 19 (95%), 7 (70%), respectively. The current study demonstrated a significant correlation between peptic ulceration and the presence of H. pylori isolates carrying cagE and cagA genes in Iranian patients.

Roles of Helicobacter pylori BabA in gastroduodenal pathogenesis

Interactions between BabA and Lewis b (Le^b) related antigens are the best characterized adhesin-receptor interactions in Helicobacter pylori (H pylori). Several mechanisms for the regulation of BabA expression are predicted, including at both transcriptional and translational levels. The formation of chimeric proteins (babA/B or babB/A chimeras) seems to play an especially important role in translational regulation. Chimeric BabB/A protein had the potential to bind Le^b; however, protein production was subject to phase variation through slipped strand mispairing. The babA gene was cloned initially from strain CCUG17875, which contains a silent babA1 gene and an expressed babA2 gene. The sequence of these two genes differs only by the presence of a 10 bp deletion in the signal peptide sequence of babA1 that eliminates its translational initiation codon. However, the babA1 type deletion was found only in strain CCUG17875. A few studies evaluated BabA status by immunoblot and confirmed that BabA-positive status in Western strains was closely associated with severe clinical outcomes. BabA-positive status also was associated with the presence of other virulence factors (e.g. cagA-positive status and vacA s1 genotype). A small class of strains produced low levels of the BabA protein and lacked Le^b binding activity. These were more likely to be associated with increased mucosal inflammation and severe clinical outcomes than BabA-positive strains that exhibited Le^b binding activity. The underlying mechanism is unclear, and further studies will be necessary to investigate how the complex BabA-receptor network is functionally coordinated during the interaction of H pylori with the gastric mucosa.

Helicobacter pylori-associated gastritis is related to babA2 expression without heterogeneity of the 3' region of the cagA genotype in gastric biopsy specimens

BACKGROUND

Cytotoxin-associated gene A (cagA) is the major virulence factor of Helicobacter pylori strains and affects the clinical outcome of patients. Blood group antigen binding adhesin (BabA) helps the strains adhere to the epithelial cell layer and is the most important adhesin of H. pylori.

OBJECTIVES

We tried to study the association between the status of babA2 and cagA in H. pylori strains and histological gastritis. methods: Thirty-six patients were included. RNA was extracted from two frozen biopsy samples of the antrum and corpus, respectively, and cagA/babA2 genotypes were analyzed with reverse transcription polymerase chain reaction and direct sequencing. Two gastric specimens of the antrum and corpus, respectively, were also stained with hematoxylin and eosin to analyze H. pylori-related gastritis.

RESULTS

In the antrum, 56% of the specimens were babA2 positive and in the corpus 53%. The gastritis scores of activity and inflammation were associated with the presence of babA2 in antrum specimens but not in corpus specimens. cagA gene encoding in the CagA EPIYA-D region was detected in all samples, and the sequence was completely identical between those from the gastric corpus and antrum.

CONCLUSION

babA2 expression is heterogeneous and correlated with the extent of gastritis in the antrum, but not in the corpus, whereas cagA shows a monotonous genotype.

Prevalence of Helicobacter pylori infection in advanced gastric carcinoma

BACKGROUND

[corrected] There is substantial evidence that infection with Helicobacter pylori plays a role in the development of gastric cancer and that it is rarely found in gastric biopsy of atrophic gastritis and gastric cancer. On advanced gastric tumors, the bacteria can be lost from the stomach.

AIMS

To analyze the hypothesis that the prevalence of H.pylori in operated advanced gastric carcinomas and adjacent non-tumor tissues is high, comparing intestinal and diffuse tumors according to Lauren's classification

METHODS

A prospective controlled study enrolled 56 patients from "Hospital Universitário", Federal University of Rio Grande do Norte, Natal, RN, Brazil, with advanced gastric cancer, treated from February 2000 to March 2003. Immediately after partial gastrectomy, the resected stomach was opened and several mucosal biopsy samples were taken from the gastric tumor and from the adjacent mucosa within 4 cm distance from the tumor margin. Tissue sections were stained with hematoxylin and eosin. Lauren's classification for gastric cancer was used, to analyse the prevalence of H. pylori in intestinal or diffuse carcinomas assessed by the urease rapid test, IgG by ELISA and Giemsa staining. H. pylori infected patients were treated with omeprazole, clarithromycin and amoxicillin for 7 days. Follow-up endoscopy and serology were performed 6 months after treatment to determine successful eradication of H. pylori in non-tumor tissue. Thereafter, follow-up endoscopies were scheduled annually. Chi-square and MacNemar tests with 0.05 significance were used.

RESULTS

Thirty-four tumors (60.7%) were intestinal-type and 22 (39.3%) diffuse type carcinomas. In adjacent non-tumor gastric mucosa, chronic gastritis were found in 53 cases (94.6%) and atrophic mucosa in 36 patients (64.3%). All the patients with atrophic mucosa were H. pylori positive. When examined by Giemsa and urease test, H. pylori positive rate in tumor tissue of intestinal type carcinomas was higher than that in diffuse carcinomas. In tumor tissues, 34 (60.7%) H. pylori-positive in gastric carcinomas were detected by Giemsa method. H. pylori was observed in 30 of 56 cases (53.5%) in tissues 4 cm adjacent to tumors. This difference was not significant. Eradication of H. pylori in non-tumor tissue of gastric remnant led to a complete negativity on the 12th postoperative month

CONCLUSIONS

The data confirmed the hypothesis of a high prevalence of H. pylori in tumor tissue of gastric advanced carcinomas and in adjacent non-tumor mucosa of operated stomachs. The presence of H. pylori was predominant in the intestinal-type carcinoma.

Association between Helicobacter pylori genotypes and gastric disorders in relation to the cag pathogenicity island

Helicobacter pylori is a bacterium associated with upper gastrointestinal diseases in humans. However, only a small proportion of infected people become sick. Although several studies have tried to establish an association between known virulence markers and clinical outcomes, in many cases the results have been conflicting. The aim of this study was to investigate the importance of virulence markers to predict clinical outcome in Brazil. Mixed infections by genetically unrelated strains detected by vacA genotyping were found in 18% of the patients. The cagA and cagE genes and the vacAs1 genotype were associated with the development of peptic ulcer disease (PUD). The cagAvacAs1m1 genotype was associated with PUD and duodenal ulcer (DU). Conversely, jhp947 was not associated with DU or PUD, indicating that this gene is not a universal virulence marker. These results also show that a high proportion of the patients were simultaneously infected by cag-positive and cag-negative H. pylori types. This finding suggests the existence of a dynamic equilibrium between the loss and gain of the cag pathogenicity island, probably depending on the physiologic conditions of the patient's stomach. To the best of our knowledge, this is the first study that has documented this finding in Brazil.

Helicobacter pylori BabA expression, gastric mucosal injury, and clinical outcome

BACKGROUND & AIMS

The blood grou.

METHODS

We compared the ability of published PCR-based methods to assess BabA status with BabA immunoblotting and Lewis b (Le(b)) binding activity assays. We also used immunoblotting to examine the relationship between clinical presentation and levels of BabA expression.

RESULTS

Immunoblotting and Le(b) binding assays for 80 strains revealed 3 levels of BabA expression: BabA high producers (BabA-H) with Le(b) binding activity, BabA low producers (BabA-L) without Le(b) binding activity, and BabA-negative. BabA-negative strains lacked the babA gene. PCR methods to determine BabA status yielded poor results. babA1 sequences were never detected. BabA expression was examined in 250 strains from Western countries and 270 strains from East Asia. The results failed to confirm any relationship between triple-positive status (cagA-positive/vacA s1/BabA-H) and clinical outcome. BabA-negative strains typically were cagA-negative/vacA s2 and were associated with gastritis. BabA-L strains showed a higher level of mucosal injury and were associated more frequently with duodenal ulcer and gastric cancer than the other groups.

CONCLUSIONS

Information gained from currently used PCR-based methods must be interpreted with caution. Le(b) binding activity does not accurately reflect the severity of mucosal damage or the clinical outcome. Quantitation of BabA expression revealed that Le(b)-nonbinding BabA-L strains are associated with higher levels of mucosal injury and clinical outcome.