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

Helicobacter pylori BabA-SabA Key Roles in the Adherence Phase: The Synergic Mechanism for Successful Colonization and Disease Development

Helicobacter pylori is a pathogenic microorganism that successfully inhabits the human stomach, colonizing it by producing several virulence factors responsible for preventing host self-defense mechanisms. The adherence mechanism to gastric mucosal tissue is one of the most important processes for effective colonization in the stomach. The blood group antigen-binding adhesion (BabA) and sialic acid-binding adherence (SabA) are two H. pylori outer membrane proteins able to interact with antigens in the gastroduodenal tract. H. pylori possesses several mechanisms to control the regulation of both BabA and SabA in either the transcriptional or translational level. BabA is believed to be the most important protein in the early infection phase due to its ability to interact with various Lewis antigens, whereas SabA interaction with sialylated Lewis antigens may prove important for the adherence process in the inflamed gastric mucosal tissue in the ongoing-infection phase. The adherence mechanisms of BabA and SabA allow H. pylori to anchor in the gastric mucosa and begin the colonization process.

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.

Analysis of babA, cagE and cagA Genes in Helicobacter pylori from Upper Gastric Patients in the North of Iran

OBJECTIVE

Helicobacter pylori is a Gram-negative bacterium which has a serious effect on up to half of the world's population and has been related to different gastric diseases. The goal of this study was to assess the frequency of babA, cagE and cagA genotypes among H. pylori strains isolated from gastric biopsies of endoscopic patients in the north of Iran.

METHODS

The present study was performed on 90 strains of H. pylori isolated from patients with gastric diseases (Gastric ulcer (GU), Duodenal ulcer (DU), Gastritis (G), Non-ulcer dyspepsia (NUD) and Gastric adenocarcinoma (GC)). DNA was extracted from all isolated strains and PCR method was performed to detect the prevalence of babA2, cagE and cagA genes using specific primers.

RESULTS

Among 90 samples of H. pylori, babA2, cagE, and cagA genes were detected in 42.2%, 30% and 82.2% of strains respectively. The statistical analysis showed that the prevalence of cagA gene in GU, G, DU, and NUD was significantly higher than other genes. Moreover, cagA, and babA2 genes were significantly more prevalent in GC patients compared to cagE gene. Our isolates exhibited 8 distinct arrangements of virulence patterns. The occurrence of cagA (35.6%) was the most prevalent pattern followed by cagA/babA2 (20%) and cagA/babA2/cagE (14.4%).

CONCLUSION

In summary, as first report from Guilan province in the north of Iran, we showed significant association between the presence of babA2, cagE, and cagA genes in different types of gastric disorders.

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 BabA in adaptation for gastric colonization

Helicobacter pylori (H. pylori) as a causative agent of gastric complications, is well adapted for the colonization of gastric mucosa. Although the infectious process depends on several factors, the adhesion to the gastric mucosa is the first and important step. Among several outer membrane proteins, BabA is one of the significant protein involving in many inflammatory processes in addition to its role in the attachment for the persistent colonization. We performed a PubMed search using the key words: “babA”, “pylori”, “gastric complications”, “homologous recombination”, “slipped strand mispairing”; a total of 249 articles were displayed. Of these we mainly focused on articles with the full text in English and published between 2005 and 2016. H. pylori BabA is involved in binding with receptors; however, its synthesis is regulated by phase variation. In this review we confirm that H. pylori babA can be modulated at the molecular and functional levels to adapt to the stress within the gastro-intestinal tract.

Relationship between histopathological status of the Helicobacter pylori infected patients and proteases of H. pylori in isolates carrying diverse virulence genotypes

Helicobacter pylori is the main cause of several gastroduodenal diseases in Humans. Among various virulence factors of H. pylori, proteases may also be involved in its pathogenicity. In this study, relationship between proteolytic activity of H. pylori strains and histopathological changes of the stomach was investigated in the patients infected with strains carrying diverse virulence factors. H. pylori strains were isolated from the biopsies of 116 patients who referred to hospital for their gastroduodenal disorders, in Tehran, Iran. Biopsies were sent to microbiology and pathology laboratories for further analysis. All the suspected grown colonies were characterized by both biochemical tests and polymerase chain reaction (PCR). Presence of seven protease genes, htrA, clpP, hp0169, hp1012, hp0382, hp1350 and hp1435, and distinct allelic variants of H. pylori virulence factors, cagA, vacA, iceA, babA2 and sabA, were analyzed in each strain. Protease activity of the strains was assessed using spectrophotometric assay. Furthermore, association between diversity in protease genes and virulence genes, protease activity, as well as pathological changes was estimated statistically. Proteases genes, htrA, clpP, hp0169, hp1012, hp0382, hp1350, hp1435, were detected among 100%, 100%, 98%, 98%, 98%, 98%, and 8% of fifty H. pylori strains isolated from the patients, respectively. Status of cagA, vacA s1, vacA s2, vacA m1, vacA m2, iceA1, iceA2, babA2 and sabA genes in isolates were 64%, 68%, 30%, 26%, 74%, 48%, 52%, 100%, and 96%, respectively. Predominant (84%) combined status for protease genes was: htrA/clpP/hp0169/hp1012/hp0382/hP1350/hp1435, while the prevalent combined status (16%) for virulence genes was: cagA+/vacA s1m2/iceA1⁺/sabA⁺/babA2⁺. Although most of the strains (91.4%) presented moderate protease activity in vitro, lowest activity was measured in strains isolated from the patients with chronic gastritis (4.25%). Present study provide the new data on diversity of protease genes in H. pylori, as well as the proteolytic activity of these genes in H. pylori strains from the sick patients. Presence of significant association between lower protease activity of the strains and mildness of the pathological changes propose involvement of these proteases in the pathogenesis of H. pylori in vivo.

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.

Association of Helicobacter pylori infection with the Lewis and ABO blood groups in dyspeptic patients

Background:

Helicobacter pylori infection is a basic risk factor for chronic gastritis, and gastric carcinoma. Based on some studies, the reason is binding of H. pylori to H and Le^b antigens in gastric mucosa. However, some other findings have not determined any association between the infection and these antigens. Because of this controversy and the fact that H. pylori infection and gastric adenocarcinoma are common diseases in Iran, the assessment of the association of H. pylori infection with these blood groups could be valuable.

Materials and Methods:

In a cross sectional study on 135 adult dyspeptic patients in Mashhad, Iran, from 2009 to 2010, H. pylori infection was evaluated by using the Heliprobe ¹⁴C-urea breath test and the ABO and Lewis blood group antigens were determined by the tube method. Association between the Lewis and ABO phenotypes with H. pylori infection were analysed by Fisher's exact test. A P ≤ 0.05 was considered to be significant.

Results:

68 (50.4%) patients were positive for H. pylori infection. The frequencies of the ABO, Lewis and secretion phenotypes were not significant in the infected and non-infected patients. We also did not find a significant association between Le^a and Le^b antigens and this infection.

Conclusion:

We could not establish a significant association between the Lewis, ABO and secretion phenotypes with H. pylori infection. Diversity of sequences of blood group antigen b-binding adhesion (babA gene) of H. pylori may be a reason why our findings are different from other studies in other geographic areas.

Serum pepsinogen II is a better diagnostic marker in gastric cancer

AIM

To investigate screening makers for gastric cancer, we assessed the association between gastric cancer and serum pepsinogens (PGs).

METHODS

The subjects comprised 450 patients with gastric cancer, 111 individuals with gastric atrophy, and 961 healthy controls. Serum anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG), PGI and PG II were detected by enzyme-linked immunosorbent assay. Gastric atrophy and gastric cancer were diagnosed by endoscopy and histopathological examinations. Odds ratios and 95%CIs were calculated using multivariate logistic regression.

RESULTS

Rates of H. pylori infection remained high in Northeastern China. Rates of H. pylori IgG positivity were greater in the gastric cancer and gastric atrophy groups compared to the control group (69.1% and 75.7% vs 49.7%, P < 0.001). Higher levels of PG II (15.9 μg/L and 13.9 μg/L vs 11.5 μg/L, P < 0.001) and lower PGI/PG II ratio (5.4 and 4.6 vs 8.4, P < 0.001) were found in patients with gastric cancer or gastric atrophy compared to healthy controls, whereas no correlation was found between the plasma PGI concentration and risk of gastric cancer (P = 0.537). In addition, multivariate logistic analysis indicated that H. pylori infection and atrophic gastritis were independent risk factors for gastric cancer. Lower plasma PGI/PG II ratio was associated with higher risks of atrophy and gastric cancer. Furthermore, plasma PG II level significantly correlated with H. pylori-infected gastric cancer.

CONCLUSION

Serum PG II concentration and PGI/PG II ratio are potential biomarkers for H. pylori-infected gastric disease. PG II is independently associated with risk of gastric cancer.

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.

Role of the Lewis and ABO Blood Group Antigens in Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori infection is a major risk factor for chronic gastritis and gastric cancer. Some findings show increased frequencies of these diseases in individuals with type O blood and in secretors (expressing Le(b) antigen), but other studies have not found any relationship between blood groups and this infection. Given that H. pylori infection and gastric cancer are common in Iran, the assessment of the pathogenesis of this infection in relation to these blood groups could be valuable.

METHODS

In a cross-sectional study, we determined the ABO and Lewis blood groups of participants using the tube method and evaluated the level of anti-H. pylori immunoglobulin G using an enzyme-linked immunosorbent assay. This study included 171 Iranian blood donors from Mashhad, Iran, during 2010. The significance of the differences in the frequencies of the Lewis and ABO phenotypes between individuals infected with and without H. Pylori infection were tested using the Chi-square test. A P-value < 0.05 was considered significant.

RESULTS

H. pylori infection was found in 76.6% of the study subjects (n = 131). The most common ABO blood group was O (33.9%), and the most common Lewis blood group was Le(a-b+) (54.7%). The frequencies of the ABO, Lewis, and secretion phenotypes were not significantly different between the infected and uninfected subjects.

CONCLUSION

We did not find any significant relationship between the Lewis, ABO, and secretion phenotypes and H. pylori infection.

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.