High prevalence of cagA- and babA2-positive Helicobacter pylori clinical isolates in Taiwan

Detection of the babA2 adhesin protein gene in Helicobacter pylori clinical isolates

The study compared the effectiveness of two different primer sets for detecting and evaluating the prevalence of the babA2 gene in 52 H. pylori clinical isolates from patients with chronic gastritis (n=32), duodenal ulcer (n=16) and stomach cancer (n=4) in St. Petersburg, Russia. The PCR was used for detection of the babA2 gene with 271 bp and 832 bp primer sets followed by sequencing of the PCR-amplicons. The largest proportion of babA2-positive strains - 90.4% (47/52) was detected using a 271 bp PCR primer set. Detection of the 832 bp PCR positive samples was observed only in 51.9% of cases (27/52). The largest proportion of babA2-positive strains - 90.4% (47/52) was detected using 271 bp PCR primer set; detection of 832 bp PCR product was observed only in 51.9% cases (27/52), however, there were no significant differences in the babA2 gene detection rates (p>0.05). Bioinformatic analysis revealed a homology of Sanger sequenced PCR products 271 bp and 832 bp of babA2 gene with regions of the babA2, babA1, and chimeric babA/B genes of H. pylori strains annotated in the NCBI database. Regardless of the primer set used, the presence of babA2 was not significantly associated with duodenal ulcer nor gastric cancer (p>0.05). The combination of the three babA2, cagA, and vacAs1 genes did not reveal any association between the presence of babA2 gene and cagA/vacAs1 genes in H. pylori strains (p>0.05). Thus, none of the two primer sets (271 bp and 832 bp) appears sufficiently informative for detecting the babA2 gene to assess virulence of H. pylori Russian strains.

Rapid Characterization of Virulence Determinants in Helicobacter pylori Isolated from Non-Atrophic Gastritis Patients by Next-Generation Sequencing

Helicobacter pylori is a major human pathogen that causes a wide range of gastrointestinal pathology. Progression of H. pylori induced gastritis to more severe disease has been found to highly correlate with the array of virulence factors expressed by the pathogen. The objective of this study was twofold: first, to characterize the genetic diversity of H. pylori strains isolated from 41 non-atrophic gastritis patients in Switzerland, an issue that has not been investigated to date. And second, to assess the prevalence and sequence variation of H. pylori virulence factors (cagA, vacA, iceA and dupA) and genes encoding outer membrane proteins (OMPs; babA, babB, sabA, sabB, hopZ, hopQ and oipA) by whole genome sequencing (WGS) using an Illumina MiSeq platform. WGS identified high genetic diversity in the analyzed H. pylori strains. Most H. pylori isolates were assigned to hpEurope (95.0%, 39/41), and the remaining ones (5.0%, 2/41) to hpEastAsia, subpopulation hspEAsia. Analysis of virulence factors revealed that 43.9% of the strains were cagA-positive, and the vacA s1 allele was detected in 56.0% of the isolates. The presence of cagA was found to be significantly associated (P < 0.001) with the presence of vacA s1, babA2 and hopQ allele 1 as well as expression of oipA. Moreover, we found an association between the grade of gastritis and H. pylori abundance in the gastric mucosa, respectively and the presence of cagA, vacA s1 and hopQ allele 1. Among our 41 gastritis patients, we identified seven patients infected with H. pylori strains that carried a specific combination of virulence factors (i.e., cagA, vacA s1 allele and babA2 allele), recently implicated in the development of more severe gastrointestinal pathology, like peptic ulcer disease and even gastric cancer. To this end, WGS can be employed for rapid and detailed characterization of virulence determinants in H. pylori, providing valuable insights into the pathogenic capacity of the bacterium. This could ultimately lead to a higher level of personalized treatment and management of patients suffering from H. pylori associated infections.

Gastric juice-based PCR assay: An alternative testing method to aid in the management of previously treated Helicobacter pylori infection

BACKGROUND

Culture of Helicobacter pylori with previous eradication failure has been emphasized in clinical guidelines. The current unmet need to manage previously treated H pylori is one tool with diagnostic accuracy and ability for antibiotics susceptibility. Gastric juice PCR can provide diagnosis and antibiotics susceptibility; however, whether treatment failure affects its accuracy remains uninvestigated. Our study aimed to investigate diagnostic accuracy and antibiotics susceptibility of juice PCR in previously treated H pylori and to compare with the current standard of culture.

METHODS

We categorized all 547 patients into treatment-naïve, post-1st treatment, post-2nd treatment, and post-3rd treatment. Helicobacter pylori infection was confirmed using gold standards. Sensitivity, specificity, positive predictive value, negative predictive value, receiver operating characteristic (ROC) curve and area under ROC curve (AUC) of juice PCR and culture were calculated. Intra-gastric H pylori density was evaluated. Lastly, the antibiotics susceptibility results of gastric juice and culture were compared.

RESULTS

Our findings demonstrated AUC was higher in juice PCR than culture in all patients (96.7% vs 91.3%, P < 0.0001). The superiority of juice PCR was statistically significant in previously treated patients (P < 0.0001) but not in treatment-naïve patients (P = 0.13). Antral H pylori density was less marked in previously treated patients (P = 0.014). The comparisons of PCR-RFLP and E-test for Clarithromycin resistance showed reliable AUC = 89.8%.

CONCLUSION

Compared with the current standard of culture, the gastric juice PCR contains the strengths of performing the antibiotics susceptibility and overcomes the shortcomings of low accuracy. Consequently, gastric juice PCR suits the unmet need to manage previously treated H pylori.

The prognostic role of Helicobacter pylori in gastric cancer patients: A meta-analysis

BACKGROUND

The prognostic value of Helicobacter pylori (H. pylori) infection in gastric cancer patients has been investigated over many years; however, the results remain inconclusive. Thus, we performed a comprehensive review of currently available evidence via a systemic meta-analysis to evaluate the effects of H. pylori infection on the prognosis of gastric cancer patients.

METHODS

Studies that evaluated the prognostic value of H. pylori infection in gastric cancer were extracted in March 2016 by searching PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. We obtained or calculated hazard ratios (HRs) and the associated 95% confidence intervals (CIs) from the identified studies, and conducted random-effects model analyses of overall survival and progression-free survival. Twenty-four studies with a cumulative sample size of 7191 patients were included in our analysis.

RESULTS

Our meta-analysis revealed that H. pylori infection is an indicator of improved overall survival in gastric cancer patients (HR, 0.79; 95% CI, 0.64-0.99); however, this was only true for European patients. The benefits of H. pylori infection were not detected in Asian gastric cancer patients (HR, 1.01; 95% CI, 0.91-1.12) or those in the United States (HR, 0.88; 95% CI, 0.73-1.05). Subgroup analyses revealed that the prognostic significance of H. pylori infection differed with respect to the year of study publication, number of patients, H. pylori detection method, tumor stage, H. pylori-positive rate, and risk of bias. The prognostic value of H. pylori infection on progression-free survival was unclear (HR, 0.84; 95% CI, 0.70-1.01).

CONCLUSIONS

These data provide limited, moderate-quality evidence that H. pylori infection is an indicator of good prognosis in European gastric cancer patients. However, this is not necessarily true for other populations.

Association of host immunity with Helicobacter pylori infection in recurrent gastric cancer

Background

Helicobacter pylori infection is associated with the incidence of gastric cancer. Endoscopic resection has been developed as a proper technique to treat early stage of gastric cancer. However, some patients develop recurrent gastric cancer within 5 years after endoscopic treatment. The aim of the present study is to explore a biomarker for detecting people who has high risk of gastric cancer recurrence.

Methods

We analyzed the Interleukin-10 (IL-10) single nucleotide polymorphism (SNP) and IgG subclass responses to the bacteria in patients with early gastric cancer and recurrent gastric cancer.

Results

Patients with hetero-type in the 1082 SNP and CC genotype in the 592 SNP were at high risk of recurrence of gastric cancer. In patients with genotype carrying high risk of recurrence, IgG1 level tended to be higher than that in patients with other genotypes.

Conclusions

Dominance of T helper 2 (Th2) immunity controlled by IL-10 cytokine may be associated with H. pylori-associated gastric cancer recurrence.

H. pylori isolates with amino acid sequence polymorphisms as presence of both HtrA-L171 & CagL-Y58/E59 increase the risk of gastric cancer

Background

H. pylori CagL-Y58/E59 increase gastric cancer risk by stronger binding with integrin to faciliate type IV secretory system (T4SS). H. pylori can secrete high temperature requirement A (HtrA) to mediate E-Cadherin cleavage for gastric epithelial junction disruption, so H. pylori CagL can adhere to integrin located on basolateral side of epithelium. The study test whether H. pylori HtrA amino acid polymorphisms can increase gastric cancer risk synergistically with CagL-Y58/E59.

Methods

One-hundred and sixty-four H. pylori-positive patients, including 71 with non-ulcer dyspepsia (NUD), 63 with peptic ulcers (PU), and 30 with gastric cancers (GC), were enrolled to receive upper gastrointestinal endoscopy to obtain gastric biopsies for H. pylori culture and histology by the updated Sydney system. Each isolate was screened for htrA & cagL genotype by polymerase chain reaction and HtrA & CagL-Y58/E59 amino acid sequence polymorphisms by sequencing.

Results

The prevalence rates of htrA & cagL gene were both 100%. The HtrA amino acid sequence polymorphisms were not different between NUD and PU. The H. pylori isolates of GC had higher rates of HtrA residue 171 as leucine than those of NUD (73.3% vs. 50.7%, P = 0.036, OR[95%CI] = 2.7[1.1–6.8]). The risk of the H. pylori-infected subjects to get gastric cancer was increased up to 15.4-fold, if the infected isolates had presence of both HtrA-L171 and CagL-Y58/E59 (P < 0.001).

Conclusions

The H. pylori isolates of gastric cancer subjects had a higher rate of HtrA-L171. H. pylori isolates with presence of both HtrA-171 & CagL-Y58/E59 can synergistically increase the risk of gastric cancer.

Electronic supplementary material

The online version of this article (10.1186/s12929-019-0498-9) contains supplementary material, which is available to authorized users.

Blood group antigen-Binding Adhesion2 (BabA2) gene in gastric tissue biopsies as a diagnostic biomarker for Helicobacter pylori infection

BACKGROUND

The Lewis (b) blood group antigen-Binding Adhesion2 (BabA2) has been reported to mediate the attachment of H. pylori to human.

AIM

assessment the diagnostic potential of detection of (BabA2) gene compared with immunostaining of Lewis (b) by specific mouse monoclonal antibodies in gastric biopsies from Egyptian Patients as a diagnostic maker for Helicobacter pylori infection.

MATERIALS AND METHODS

Fifty untreated patients suffering from dyspeptic complaints were enrolled in this study and underwent for upper gastro-duodenal endoscopy. Biopsies were taken for histological examination by (H&E) and immunohistochemical analysis for Lewis b by specific mouse monoclonal antibodies, and scoring of Lewis b expression in gastric tissue biopsy as well as molecular detection of BabA2 gene of H. pylori by PCR. Biochemical analysis was performed to detect the presence of H. pylori urease activity using Rapid Urease Test (RUT).

RESULTS

: Out of 50 gastric biopsies, 41 biopsies were positive for histological, Immunostaining for Lewis b expression and urease activity test (RUT) for H pylori. RUT showed a sensitivity of 87.8%, specificity 88.9%, positive predictive value (PPV) 97.2%, and negative predictive value (NPV) 61.5%. BabA2 gene results revealed that, out of 41 positive biopsied cases, 39 (95.1%) were positive by the PCR test for BabA2 gene. And all 9 negative biopsies (100%) for H pylori negative for BabA2gene so the sensitivity and specificity of BabA2 gene detection in gastric biopsies by PCR were 95.1% and 100%; respectively.

CONCLUSION

: BabA2 gene detection in gastric tissue biopsies could be suggested as a diagnostic biomarker to be included among the other biomarkers routinely performed for clinical diagnosis of H. pylori infection.

A community-based study on the association between Helicobacter pylori Infection and obesity

Helicobacter pylori (H. pylori) infection can induce chronic inflammation and is associated with insulin resistance, metabolic syndrome and body mass index (BMI, kg/m²) changes. This study aimed to evaluate the association between H. pylori infection and overweight/obesity. This research was a cross-sectional study conducted from March 2014 to November 2016, using data from the three districts in the northeastern region of Taiwan. The inclusion criteria were an age >30 years and the absence of pregnancy. Ultimately, 2686 subjects (1713 women) were included in this study. Among the subjects aged less than 50 years, the subjects with H. pylori infection had higher mean BMI values than those without H. pylori infection (40-49 years: 25.7 ± 4.4 vs. 24.7 ± 3.8, P = 0.025; 30-39 years: 24.9 ± 4.4 vs. 24.0 ± 4.1, P = 0.063). H. pylori infection increased the risk of being obese 2 (BMI ≥30) (odds ratio, OR = 1.836, 95% CI = 1.079-3.125, P = 0.025) with adjustments for demographic factors in subjects aged less than 50 years. In conclusions, subjects with H. pylori infection and age less than 50 years may increase a risk of being obesity (BMI ≥30) compared to those without this type of infection.

Mixed Infections of Helicobacter pylori Isolated from Patients with Gastrointestinal Diseases in Taiwan

Background. Persistent Helicobacter pylori infection may induce several upper gastrointestinal diseases. Two major virulence factors of H. pylori, vacuolating cytotoxin A (VacA) and cytotoxin-associated gene A (CagA), are thought to be associated with the severity of disease progression. The distribution of vacA and cag-pathogenicity island (cag-PAI) alleles varies in H. pylori isolated from patients in different geographic regions. Aim. To assess the association between mixed infection of H. pylori clinical isolates from Taiwanese patients and the severity of gastrointestinal diseases. Methods. A total of 70 patients were enrolled in this study. Six distinct and well-separated colonies were isolated from each patient and 420 colonies were analyzed to determine the genotypes of virulence genes. Results. The prevalence of mixed infections of all H. pylori-infected patients was 28.6% (20/70). The rate of mixed infections in patients with duodenal ulcer (47.6%) was much higher than that with other gastrointestinal diseases (P < 0.05). Conclusions. H. pylori mixed infections show high genetic diversity that may enhance bacterial adaptation to the hostile environment of the stomach and contribute to disease development.

Study of the clinical relevance of Helicobacter pylori virulence genes to gastric diseases among Egyptian patients

BACKGROUND AND STUDY AIMS

Helicobacter pylori infection is common in Egypt. It has been associated with gastritis, ulcers and it is a risk factor for gastric cancer. We aimed to study the correlation between the presence of H. pylori virulence factors and the histopathological and endoscopic findings in gastric biopsies.

PATIENTS AND METHODS

Gastric biopsies from thirty seven patients scheduled for diagnostic endoscopy in Cairo University hospital were included in the study. All gastric biopsies were subjected to histopathological examination and PCR assay for detection of 16S rRNA gene to diagnose H. pylori infection, detection of H. pylori virulence factors by PCR for cagA and vacA genotypes and serological analysis of H. pylori (cagA, vacA, P25, and P19) IgG antibodies by immunoblot assay were done.

RESULTS

H. pylori infection was detected in 23 (62.2%) cases by histopathology while 28/37 (75.7%) were positive for H. pylori 16S rRNA gene by PCR. By PCR seventeen samples out of 37 (45.9%) were positive for cagA gene and five (13.5%) for cag empty site gene.

CONCLUSION

The most common vacA genotype identified was vacA s2m2 genotype in 10 (27.02%). No statistical correlation was found between IgG antibodies against different antigens of H. pylori virulence factors (cagA, vacA, p25, and p19) and the degree of gastritis except for IgG antibodies against the UreA antigen.

Helicobacter pylori Diversity and Gastric Cancer Risk

Gastric cancer is a leading cause of cancer-related death worldwide. Helicobacter pylori infection is the strongest known risk factor for this malignancy. An important goal is to identify H. pylori-infected persons at high risk for gastric cancer, so that these individuals can be targeted for therapeutic intervention. H. pylori exhibits a high level of intraspecies genetic diversity, and over the past two decades, many studies have endeavored to identify strain-specific features of H. pylori that are linked to development of gastric cancer. One of the most prominent differences among H. pylori strains is the presence or absence of a 40-kb chromosomal region known as the cag pathogenicity island (PAI). Current evidence suggests that the risk of gastric cancer is very low among persons harboring H. pylori strains that lack the cag PAI. Among persons harboring strains that contain the cag PAI, the risk of gastric cancer is shaped by a complex interplay among multiple strain-specific bacterial factors as well as host factors. This review discusses the strain-specific properties of H. pylori that correlate with increased gastric cancer risk, focusing in particular on secreted proteins and surface-exposed proteins, and describes evidence from cell culture and animal models linking these factors to gastric cancer pathogenesis. Strain-specific features of H. pylori that may account for geographic variation in gastric cancer incidence are also discussed.

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.

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.

Prevalence of Helicobacter pylori vacA, cagA, cagE, iceA, babA2, and oipA genotypes in patients with upper gastrointestinal diseases

BACKGROUND AND OBJECTIVES

Helicobacter pylori has been strongly associated with peptic ulcer diseases, chronic gastritis, ulcers, and reported as a risk factor for gastric cancer, too. The vaculating cytotoxin (vacA), the cytotoxin associated genes (cagA), the induced by contact with epithelium factor antigen (iceA gene), blood adhesion binding antigen (babA2), and outer membrane protein oipA have been described as different virulence factors of H. pylori. The aim of this study was to investigate the prevalence of the vacA, cagA, cagE, iceA, babA2 and oipA genotypes of H. pylori isolates from patients with upper gasterointestinal problem or dyspepsia.

MATERIAL AND METHODS

H. pylori isolated from endoscopic biopsies obtained from 222 studied patients. PCR was done only on cultured positive samples. The vacA alleles, cagA, cagE, iceA, babA2 and oipA genotypes were determined by PCR.

RESULTS

The isolation rate of H. pylori strains from culture of gastric biopsies was 16.7%. The vacA alleles s1, s2, m1 and m2 were detected in 20 (54.1%), 14 (37.8%), 9 (24.3%) and 23 (62.2%) isolates, respectively. VacA s1c genotype was detected in 70.3% of isolates. s1m2 was the most frequent vacA allelic combination in the examined H. pylori strains. The cagA gene was detected in 62.2%, cagE in 40.5%, iceA1 in 48.6%, iceA2 in 16.2%, oipA in 81.1% (95% CI: 0.0902-0.1798) and babA2 in 94.6% (95% CI: 0.113- 0.207). A significant correlation was observed between vacAs1 and cagA genotypes (P<0.008), vacAs1/cagE (P=0.001), vacAs2/cagA (P<0.047), and vacAs2/cagE (P=0.016) with Non-ulcer dyspepsia; but there were not observed any correlation between other virulence markers.

CONCLUSION

No significant correlation was found between the existence of vacA, cagA, cagE, iceA, babA2, and oipA genes with peptic ulcer diseases and non-ulcer dyspepsia groups of studied patients.

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.

Association of IS605 and cag-PAI of Helicobacter pylori Isolated from Patients with Gastrointestinal Diseases in Taiwan

Background. The cag pathogenicity island (cag-PAI) is one of the most important virulent determinants of Helicobacter pylori. An insertion sequence (IS) element of cag-PAI (IS605) has been found to generate H. pylori strains with varying virulence. Aim. To evaluate the impact of IS605 and cag-PAI on H. pylori strains isolated from Taiwanese patients with severity of gastric diseases. Methods. H. pylori isolates were cultured from gastric biopsies from 99 patients with peptic ulcer, chronic gastritis, and gastric carcinoma. Six distinct, well-separated colonies were isolated from each patient and analyzed by genotyping. Results. cagA, cagE, cagM, cagT, orf10, and orf13 were found to be present in 90.0%–100.0% of the H. pylori isolates. A total deletion of cagA, cagE, cagM, cagT, orf10, and orf13 was found in 1 isolate (1.0%). The IS605 element was found to be positive in 15.2% of the isolates. The presence of IS605 was higher in H. pylori isolated from patients with gastric carcinoma (25.0%) than in patients with duodenal ulcer (6.5%) or chronic gastritis (6.3%) (P < 0.001). Conclusions. The majority of the patients examined had intact cag-PAI. IS605 was present in 15.2% and was higher in H. pylori isolated from patients with gastric carcinoma than in those with peptic ulcer.

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.

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

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

Helicobacter pylori CagA-mediated IL-8 induction in gastric epithelial cells is cholesterol-dependent and requires the C-terminal tyrosine phosphorylation-containing domain

Upon infection of the gastric epithelial cells, the Helicobacter pylori cytotoxin-associated gene A (CagA) virulence protein is injected into the epithelial cells via the type IV secretion system (TFSS), which is dependent on cholesterol. Translocated CagA is targeted by the membrane-recruited c-Src family kinases in which a tyrosine residue in the Glu-Pro-Ile-Tyr-Ala (EPIYA)-repeat region, which can be phosphorylated, induces cellular responses, including interleukin-8 (IL-8) secretion and hummingbird phenotype formation. In this study, we explored the role of EPIYA-containing C-terminal domain (CTD) in CagA tethering to the membrane lipid rafts and in IL-8 activity. We found that disruption of the lipid rafts reduced the level of CagA translocation/phosphorylation as well as CagA-mediated IL-8 secretion. By CagA truncated mutagenesis, we identified that the CTD, rather than the N-terminal domain, was responsible for CagA tethering to the plasma membrane and association with detergent-resistant membranes, leading to CagA-induced IL-8 promoter activity. Our results suggest that CagA CTD-containing EPIYAs directly interact with cholesterol-rich microdomains that induce efficient IL-8 secretion in the epithelial cells.

High prevalence of virulence-associated genotypes in Helicobacter pylori clinical isolates in the Region del Maule, Chile

The prevalence of Helicobacter pylori infection and the gastric cancer mortality rate in Chile are remarkably high. This study identified some virulence-associated genes in 78 H. pylori clinical isolates from dyspeptic patients from the Region del Maule, which is the region with the higher gastric cancer mortality rate in the country. The cagA, vacA and babA2 genes were detected in 94.9%, 100% and 97.4%, respectively. Two or more EPIYA C motifs were presented in 48.6% of cagA-positive strains, and this was associated with more severe histopathological findings in the gastric mucosa.

Characterization of Helicobacter pylori cagA and vacA genotypes among Alaskans and their correlation with clinical disease

Helicobacter pylori infection is common in Alaska. The development of severe H. pylori disease is partially determined by the virulence of the infecting strain. Here we present vacA and cagA genotype data for H. pylori strains isolated from Alaskans and their correlation with clinical disease. We enrolled patients scheduled for esophagogastroduodenoscopy and positive for H. pylori infection. Gastric biopsy specimens from the stomach antrum and fundus were cultured. We performed PCR analysis of the H. pylori vacA gene and for the presence of the cagA gene and cagA empty site. We genotyped 515 H. pylori samples from 220 Native and 66 non-Native Alaskans. We detected the cagA gene in 242/286 (85%) persons; of 222 strains that could be subtyped, 95% (212) were non-Asian cagA and 3% (6) were East Asian cagA. After removing mixed infections (n = 17), 83% of H. pylori strains had either the vacA s1m1 (120/269) or s2m2 (103/269) genotype. Sixty-six percent (68/103) of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. Infection with an H. pylori strain having the cagA gene or vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with a decreased risk of esophagitis (P = 0.003 and 0.0003, respectively). Infection with an H. pylori strain having the vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with an increased risk of peptic ulcer disease (PUD) (P = 0.003). The majority of H. pylori strains in this study carried the non-Asian cagA gene and either the vacA s1m1 or s2m2 genotype. A majority of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. There was an association of H. pylori genotype with esophagitis and PUD.

Matrix metalloproteinase-3 promoter polymorphisms but not dupA-H. pylori correlate to duodenal ulcers in H. pylori-infected females

Background

This study investigated if the H. pylori dupA genotype and certain host single nucleotide polymorphisms (SNPs) of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), including MMP-3, MMP-7, MMP-9, TIMP-1 and TIMP-2, might correlate with ulcer risk of H. pylori-infected Taiwanese patients.

Results

Of the 549 H. pylori-infected patients enrolled, 470 patients (265 with gastritis, 118 with duodenal ulcer, and 87 with gastric ulcer) received SNPs analysis of MMP-3_{-1612 6A > 5A}, MMP-7_{-181 A > G}, MMP-9_{exon 6 A > G}, TIMP-1_{372 T > C} and TIMP-2_{-418 G > C} by PCR-RFLP. The 181 collected H. pylori isolates were detected for the dupA genotype by PCR. The rates of dupA-positive H. pylori infection were similar among patients with duodenal ulcer (22.8%), gastric ulcer (20.0%), and gastritis (25.5%) (p > 0.05). Males had higher rates of duodenal ulcer and gastric ulcer than females (p < 0.01). Of H. pylori-infected patients, the MMP-3 6A6A genotype were more common in patients with duodenal ulcers than in those with gastritis (87.7% vs. 74.9%, p < 0.05) in females. This genotype had a 2.4-fold (95% CI: 1.02-5.66) increased risk of duodenal ulcer, compared to those with the 5A carrier. Combining the MMP-3/TIMP-1 genotype as 6A6A/CC, the risk of duodenal ulcer increased up to 3.6 fold (p < 0.05) in H. pylori-infected females.

Conclusions

The MMP-3 promoter polymorphism, but not the dupA-status, may correlate with susceptibility to duodenal ulcer after H. pylori infection in Taiwanese females.

Time trends of endoscopic and pathological diagnoses related to gastroesophageal reflux disease in a Chinese population: eight years single institution experience

The discrepancy between Eastern and Western countries exists regarding the time trends of Barrett's esophagus (BE)/adenocarcinoma. We aimed to elucidate this issue through a retrospective review of the endoscopic and pathological diagnoses of gastroesophageal reflux disease (GERD) over time in a Chinese population. All records were analyzed from 2000 to 2007. Records included demographic data, clinical indication for endoscopy, and endoscopic findings. The total number of endoscopic procedures increased over time. The indications for referral endoscopy secondary to GERD increased from 366 cases (4.9%) in the beginning of the study to 1439 cases (14.1%) at the end. Concomitant GERD symptoms did not significantly change (range, 13-15.1%) in screening endoscopic studies. Endoscopic detection of erosive esophagitis increased in referral populations from 1546 (20.7%) to 5207 cases (51%) and by screening endoscopy from 791 (14.5%) to 1983 cases (23.5%). The prevalence of nonerosive reflux disease and BE did not change over time. BE-associated dysplasia and adenocarcinoma were rare. The detection of Los Angeles class A disease increased with time in referral endoscopy cases with a focus on erosive esophagitis composition. The endoscopic demand for GERD investigation and the GERD endoscopic diagnosis increased in our population. The results were related to a higher prevalence of low-grade erosive disease diagnosed. The incidence of BE-associated dysplasia and adenocarcinoma has been the same and the increased screening did not detect more cancers.

The cag PAI is intact and functional but HP0521 varies significantly in Helicobacter pylori isolates from Malaysia and Singapore

Helicobacter pylori-related disease is at least partially attributable to the genotype of the infecting strain, particularly the presence of specific virulence factors. We investigated the prevalence of a novel combination of H. pylori virulence factors, including the cag pathogenicity island (PAI), and their association with severe disease in isolates from the three major ethnicities in Malaysia and Singapore, and evaluated whether the cag PAI was intact and functional in vitro. Polymerase chain reaction (PCR) was used to detect dupA, cagA, cagE, cagT, cagL and babA, and to type vacA, the EPIYA motifs, HP0521 alleles and oipA ON status in 159 H. pylori clinical isolates. Twenty-two strains were investigated for IL-8 induction and CagA translocation in vitro. The prevalence of cagA, cagE, cagL, cagT, babA, oipA ON and vacA s1 and i1 was >85%, irrespective of the disease state or ethnicity. The prevalence of dupA and the predominant HP0521 allele and EPIYA motif varied significantly with ethnicity (p < 0.05). A high prevalence of an intact cag PAI was found in all ethnic groups; however, no association was observed between any virulence factor and disease state. The novel association between the HP0521 alleles, EPIYA motifs and host ethnicity indicates that further studies to determine the function of this gene are important.

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.

Inhibition of Helicobacter pylori-induced inflammation in human gastric epithelial AGS cells by Phyllanthus urinaria extracts

AIM OF THE STUDY

Helicobacter pylori is linked to a majority of peptic ulcers and to some types of gastric cancer, and its resistance to antibiotic treatment is now found worldwide. This study is aimed at evaluating the antimicrobial activity of Phyllanthus urinaria Linnea (Euphorbiaceae), chloroform (PUC) and methanol (PUM) extracts, and its eight isolates on H. pylori-infected human gastric epithelial AGS cells.

MATERIALS AND METHODS

The in vitro anti-bacterial activity of P. urinaria chloroform (PUC) and methanol (PUM) extracts, and its eight isolates were determined. Additional experiments were also performed to know the PUC and PUM ability to inhibit the H. pylori adhesion to and invasion of AGS cells, in addition to the effect of PUC on NF-kappaB activity as well as IL-8 synthesis during H. pylori infection of AGS cells.

RESULTS

The results revealed that crude extracts PUC and PUM showed potent antimicrobial activity against H. pylori than pure isolates. On the other hand, in vitroH. pylori-infection model revealed that the inhibition of bacterial adhesion and invasion to AGS cells has dramatically reduced by treatment of extract PUC, while PUM has the same moderate effect. Furthermore, H. pylori-induced nuclear factor (NF)-kappaB activation, and the subsequent release of interleukin (IL)-8 in AGS cells were also inhibited by the extract PUC.

CONCLUSIONS

These results open the possibility of considering P. urinaria a chemopreventive agent for peptic ulcer or gastric cancer, but this bioactivity should be confirmed in vivo in the future.

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.

Cholesterol depletion reduces Helicobacter pylori CagA translocation and CagA-induced responses in AGS cells

Infection with Helicobacter pylori cagA-positive strains is associated with gastritis, ulcerations, and gastric cancer. CagA is translocated into infected epithelial cells by a type IV secretion system and can be tyrosine phosphorylated, inducing signal transduction and motogenic responses in epithelial cells. Cellular cholesterol, a vital component of the membrane, contributes to membrane dynamics and functions and is important in VacA intoxication and phagocyte evasion during H. pylori infection. In this investigation, we showed that cholesterol extraction by methyl-beta-cyclodextrin reduced the level of CagA translocation and phosphorylation. Confocal microscope visualization revealed that a significant portion of translocated CagA was colocalized with the raft marker GM1 and c-Src during infection. Moreover, GM1 was rapidly recruited into sites of bacterial attachment by live-cell imaging analysis. CagA and VacA were cofractionated with detergent-resistant membranes (DRMs), suggesting that the distribution of CagA and VacA is associated with rafts in infected cells. Upon cholesterol depletion, the distribution shifted to non-DRMs. Accordingly, the CagA-induced hummingbird phenotype and interleukin-8 induction were blocked by cholesterol depletion. Raft-disrupting agents did not influence bacterial adherence but did significantly reduce internalization activity in AGS cells. Together, these results suggest that delivery of CagA into epithelial cells by the bacterial type IV secretion system is mediated in a cholesterol-dependent manner.

Comparison of stool enzyme immunoassay and immunochromatographic method for detecting Helicobacter pylori antigens before and after eradication

The objective of this study is to compare the performance of enzyme immunoassay (Premier Platinum HpSA) and immunochromatographic method (ImmunoCard HpSA STAT) in detecting stool Helicobacter pylori antigen before and after eradication therapy. Two hundred forty dyspeptic patients (143 men and 97 women; mean age, 53.2 years old; range, 19-79 years old) volunteered to participate in this study. Those who delivered improper stool samples, including diarrhea, inadequate amount, or delayed delivery after collection, were excluded. All of the participants received endoscopy, biopsy-based tests, and noninvasive tests, including (13)C-urea breath test ((13)C-UBT) and 2 stool antigen tests. Fifty-eight patients completed all the above tests before and after eradication therapy, and each contributed to 2 person-times. In total, there were 176 person-times in the preeradication group and 100 in the posteradication group that were analyzed for comparison. Follow-up endoscopic examinations were done 2 to 4 months after completion of eradication therapy, and stool samples were collected within 3 days after endoscopy. Positive H. pylori infection was established when either culture was positive or any 2 of the histology, rapid urease test, and UBT were positive. In the preeradication group (n = 176), 99 (56.3%) were H. pylori positive and 77 were Hp negative. In the posteradication group (n = 100), the treatment was successful in 67 (67.0%) of them. In the preeradication group, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were 95.2%, 87.0%, 90.4%, 93.1%, and 91.5%, respectively, for ImmunoCard HpSA STAT, and 83.8%, 90.9%, 92.2%, 81.4%, and 86.9%, respectively, for Premier Platinum HpSA. In the posteradication group, the sensitivity, specificity, PPV, NPV, and accuracy were 100%, 91.0%, 84.6%, 100%, and 94.0%, respectively, for ImmunoCard HpSA STAT, and 84.9%, 92.5%, 84.8%, 92.5%, and 90.0%, respectively, for Premier Platinum HpSA. There were no statistically significant differences between these 2 stool tests. ImmunoCard HpSA STAT is a rapid, simple, and accurate in-clinic test for preeradication diagnosis of H. pylori and posteradication follow-up.

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.

Prevalence of Helicobacter pylori cagA, iceA and babA2 alleles in Brazilian patients with upper gastrointestinal diseases

Helicobacter pylori is an important human pathogen associated with gastrointestinal diseases such as gastritis, gastric and duodenal ulcer (peptic ulcer disease, PUD), and gastric cancer. A number of pathogenic factors have been described for this bacterium, and some of them have been proposed as markers for the prediction of the clinical outcome. However, with the exception of the cag and vacA status, there is no universal consensus regarding the importance of the other virulence factors. Therefore, the aim of this study was to investigate the status of H. pylori strains regarding the babA and iceA alleles, as well as the cagA genotype, to reveal any association between these genotypes and clinical outcomes in Brazilian patients. The great majority (92.6%) of the strains were typed as iceA1, while 40.4% were found to possess the babA2 allele. The cagA gene was detected in 73.4% of the strains. The iceA2 and cagA genotypes were associated with PUD, while iceA1 was negatively correlated with PUD. However, considering the high percentage of strains typed as iceA1, these associations must be treated with caution. No clinical entity was associated with the babA2 allele. These results suggest that iceA1 is not a good marker for the diseases associated with H. pylori infection in Brazil. Further studies are needed in order to elucidate the relevance of the babA status, because other studies performed in Brazil have associated the babA2 allele with clinical outcomes. These results also indicate the existence of regional differences in the H. pylori genotypes and their association with clinical outcomes.

Prevalence of Helicobacter pylori vacA, cagA, cagE, iceA, babA2 genotypes and correlation with clinical outcome in Turkish patients with dyspepsia

BACKGROUND

Distinct virulence factors of Helicobacter pylori have been associated with clinical outcome of the infection; however, considerable variations have been reported from different geographic regions and data on genotypes of Turkish H. pylori isolates are sparse.

AIM

To determine the prevalence of specific genotypes of H. pylori in Turkish patients with dyspepsia.

MATERIALS AND METHODS

Ninety-three H. pylori-positive patients [30 with non-ulcer dyspepsia (NUD), 30 with duodenal ulcer (DU), and 33 with gastric cancer (GC)] who were admitted to our endoscopy unit due to dyspepsia were enrolled in the study. H. pylori infection was confirmed in all patients by histology and rapid urease test (RUT). The presence of vacA alleles, cagA, cagE, iceA, and babA2 genotypes were determined by polymerase chain reaction (PCR). Chi-squared test and Fisher's exact test were used for statistical comparisons and multivariate regression analysis was performed to find out independent predictors of different clinical outcomes.

RESULTS

Turkish strains examined predominantly possessed the vacA s1,m2 (48.4%) and s1,m1 (40.7%) genotypes. The vacA s1a genotype was detected in 66.7, 96.4, and 87.9% of isolates from patients with NUD, DU, and GC, respectively, and its presence was significantly associated with that of DU (p = .004), GC (p = .043), and cagA gene (p = .021). None of the cases was found to harbor the s1c genotype. The frequencies of the cagA and cagE genes among studied isolates were 73.6 and 59.3%, respectively. The cagA gene was significantly associated with the presence of DU (p = .004) and GC (p = .003), and the cagE gene, too, was significantly associated with the presence of DU (p = .002) and GC (p = .000). All H. pylori isolates possessed the iceA gene. In all, 68 isolates (74.7%) were positive for iceA1 and 23 (25.3%) for iceA2. The frequency of icea1 gene was significantly higher in cases with GC (85%) than in cases with NUD (60%) (p = .026). The frequency of babA2 gene was 23.3, 46.4, and 87.9% in isolates of patients with NUD, DU, and GC, respectively. When compared to cases with NUD (p = .000) and DU (p = .000), the presence of babA2 gene was significantly higher in cases with GC. Multivariate regression analysis disclosed cagE (p = .006) and vacA s1a (p = .027) genotypes to be independent predictors of DU and babA2 (p = .000) and cagE (p = .013) genotypes to be independent predictors of GC.

CONCLUSIONS

H. pylori vacA s1a, cagA, cagE genotypes have significant relations with the presence of DU and GC, and iceA1, babA2 with GC in Turkish patients with dyspepsia, whereas cagE and vacA s1a genotypes are independent predictors of DU, and babA2 and cagE genotypes are independent predictors of GC.

Association of antibiotic resistance and higher internalization activity in resistant Helicobacter pylori isolates

OBJECTIVES

Helicobacter pylori resistance to antibiotics is the main factor for therapy failure, while other features remain largely unknown. The aims of this study are to investigate the relationship of antibiotic resistance and in vitro internalization activity between cure and failure isolates and to determine whether failures are associated with persistence of the same predominant strain.

METHODS

Fifty-three isolates from forty-seven patients (cure group, n = 31; failure group, n = 16) receiving one of two lansoprazole-based therapies before and/or after therapy were investigated. Antibiotic susceptibility was determined by Etest. Genotyping was determined by cagA, babA, vacA and RAPD analyses. Target cells of internalization assay were AGS cells.

RESULTS

Five of six paired pre- and post-treatment isolates had the same predominant genetic profiles and exhibited similarly high internalization activities. The A2143G point mutation of the 23S rRNA gene conferred clarithromycin resistance. Moreover, increased antibiotic resistance after therapy was found for these five cases. Pre-treatment isolates from the failure group (n = 11) had higher level of internalization activity than those from the cure group (n = 31) (P = 0.00005). Antibiotic-resistant strains were significantly associated with higher internalization activity than were susceptible strains (metronidazole, P < 0.005; clarithromycin, P < 0.005).

CONCLUSIONS

Our results suggest that resistant H. pylori strains are associated with antibiotic resistance and superior internalization activity, protecting them against antibiotic treatment.

No correlation of babA2 with vacA and cagA genotypes of Helicobacter pylori and grading of gastritis from peptic ulcer disease patients in Brazil

BACKGROUND

The babA2 gene, which encodes a blood-group antigen-binding adhesin that mediates attachment of Helicobacter pylori to human Lewis(b) antigens on gastric epithelial cells, has been associated with a higher risk of peptic ulcer and gastric cancer. The purpose of this study was to ascertain the frequency of babA2 genotype in H. pylori strains of patients with peptic ulcer and to correlate with other virulence factors.

MATERIALS AND METHODS

vacA, cagA, and babA2 genotypes of H. pylori were determined by using polymerase chain reaction (PCR). DNA was extracted from positive urease test gastric samples of 150 patients with peptic ulcer. Antrum and corpus biopsies were taken for histologic examination according to the updated Sydney system classification.

RESULTS

babA2 genotype was present in 104 (69.3%) and cagA in 113 (75.3%) gastric samples. No significant correlation was observed between babA2 and vacAs1 genotype or between babA2 and cagA status. The correlation of vacAs1 genotype with positive cagA was statistically significant ( p < .001). The babA2-positive strain was more frequently found from the gastric samples of men, than of women (p = .01). Strains harboring cagA, vacAs1, and babA2 genotypes had no association to the grading of gastritis, presence of glandular atrophy, or intestinal metaplasia. The simultaneous presence of cagA, vacAs1, and babA2 was found in 32.6% of the H. pylori strains.

CONCLUSIONS

babA2 genotype is frequently found in H. pylori strains from peptic ulcer disease in Brazil, although it has no significant correlation to the worsening of the gastritis and to other virulence markers such as vacAs1 and cagA.

Lower prevalence of Helicobacter pylori infection with vacAs1a, cagA-positive, and babA2-positive genotype in erosive reflux esophagitis disease

BACKGROUND

Increased prevalence of esophagitis has been recognized in the West. Helicobacter pylori infection, particularly virulent strains, is proposed as a protective factor against the development of gastroesophageal reflux disease. To evaluate the relationship of reflux esophagitis with virulent H. pylori infection, we studied the prevalence of reflux esophagitis among H. pylori-infected and -uninfected patients and the genotype of isolates in Taiwan.

METHODS

Patients who had routine physical examination were investigated. The severity of esophagitis was evaluated using the Los Angeles grading system. H. pylori status was assessed by histology, rapid urease test, and bacterial culture. Genotyping of vacA, cagA, and babA2 was determined by polymerase chain reaction (PCR). Risk factors for severe esophagitis were evaluated.

RESULTS

Reflux esophagitis was found in 21.2% of 1622 patients. The prevalence of H. pylori infection was found in 33.0% of 276 patients with reflux esophagitis compared with 67.5% of 378 patients with normal esophagus (p < .001). Esophagitis occurred in a significantly lower rate among H. pylori-positive patients with peptic ulcer than those without peptic ulcer. cagA, babA2, and vacAs1a were detected in 100% of 143 isolates. Factors that predicted severe esophagitis included age, gender, and hiatus hernia but not H. pylori infection.

CONCLUSIONS

Our study suggests significantly lower incidence of H. pylori infection with the triple-positive virulent genotype in patients with reflux esophagitis in Taiwan.

cagA genotype and variants in Chinese Helicobacter pylori strains and relationship to gastroduodenal diseases

Previous studies have implicated CagA [encoded by cytotoxin-associated gene A (cagA)] in Helicobacter pylori-associated gastroduodenal pathology and distinct subgenotypes of cagA may circulate in different pathological manifestations of cagA-positive H. pylori infection. To investigate cagA genotype and variants in Chinese H. pylori strains and explore their relationship with gastroduodenal diseases, the cagA status of 82 Chinese H. pylori strains was examined and variation in size of the 3' region of cagA in 71 of these strains was analysed by PCR. cagA was detected in 28 (100%) of 28 strains from peptic ulcer patients, two (100%) of two strains from gastric cancer patients, 32 (94.1%) of 34 strains from chronic gastritis patients and 17 (94.4%) of 18 strains from healthy volunteers. PCR products of the cagA 3' variable region were obtained from 71 (92.2%) of 77 Chinese H. pylori strains and could be classified into subgenotypes I, II and III, which gave PCR products of around 825, 900 and 950 bp, respectively. Subgenotype I cagA predominated in Chinese H. pylori strains (67/71), whereas subgenotype II cagA presented in two isolates from patients with chronic gastritis and subgenotype III presented in two isolates from healthy volunteers. Therefore, neither cagA nor its 3' region variants can be used as a sole marker for the presence of particular H. pylori-related gastroduodenal diseases in the Chinese population.

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

The babA2 and cagA genes were investigated in 208 Brazilian Helicobacter pylori strains. A strong association between babA2 and duodenal ulcer or gastric carcinoma was observed, even after adjusting for confounding factors, such as age, gender, and cagA status. cagA-positive strains were also independently associated with H. pylori-related diseases.