Genetic differences between Helicobacter pylori strains isolated from patients with chronic mild and severe gastritis

Background. Helicobacter pylori-associated chronic gastritis (CG), being a very heterogeneous group, still does not have a divisin based on Helicobacter pylori (Hp) genotyping data, which could predict the clinical form of CG.The aim of the study is to search for the prevalence of the cagA gene or any allelic combination of the vacA gene, or stable combinations of cagA and any allelic combination of vacA genes in Hp isolates from patients with mild and severe CG, as well as patients with peptic ulcer disease (PUD).Methods. Hp isolates from gastrobiopsy specimens were genotyped for cagA and vacA allelic combinations (s1m1, s2m1, s1m2, s2m2). The difference in the occurrence of vacA allelic combinations was assessed by Mann–Whitney U test; the conjunction of cagA and vacA allelic combinations was assessed by the Spearman's rank correlation coefficient (rs).Results. The cagA gene was found in more than half of all cases, both in patients with ulcer and in patients with CG (mild and severe). The incidence of vacAs1m1 (the most virulent allelic combination) showed no significant differences in all forms of gastritis and in PUD; the correlation between cagA and vacAs1m1 was significant in all groups of patients, rs ranged from 0.57 to 0.72. In patients with mild CG, an abundance of non-virulent allelic combination vacAs2m2 was observed, which was significantly different from its occurrence both in patients with severe CG and in patients with ulcer; the joint occurrence of vacAs2m2 and cagA in patients with mild CG was chaotic (rs=-0.13; P=0.40).Conclusion. In mild CG, despite the absence of significant differences in cagA and vacAs1m1 (when compared with severe CG and ulcer disease), strains with a non-virulent allelic combination vacAs2m2 were significantly dominant; therefore, the detection of this particular allelic combination of vacA speaks in favor of a mild course of CG.

Serodiagnosis and Bacterial Genome of Helicobacter pylori Infection

The infection caused by Helicobacter pylori is associated with several diseases, including gastric cancer. Several methods for the diagnosis of H. pylori infection exist, including endoscopy, the urea breath test, and the fecal antigen test, which is the serum antibody titer test that is often used since it is a simple and highly sensitive test. In this context, this study aims to find the association between different antibody reactivities and the organization of bacterial genomes. Next-generation sequences were performed to determine the genome sequences of four strains of antigens with different reactivity. The search was performed on the common genes, with the homology analysis conducted using a genome ring and dot plot analysis. The two antigens of the highly reactive strains showed a high gene homology, and Western blots for CagA and VacA also showed high expression levels of proteins. In the poorly responsive antigen strains, it was found that the inversion occurred around the vacA gene in the genome. The structure of bacterial genomes might contribute to the poor reactivity exhibited by the antibodies of patients. In the future, an accurate serodiagnosis could be performed by using a strain with few gene mutations of the antigen used for the antibody titer test of H. pylori.

New genotypes of Helicobacter Pylori VacA d-region identified from global strains

Background Pathogenesis of Helicobacter Pylori (HP) vacuolating toxin A (vacA) depends on polymorphic diversity within the signal (s), middle (m), intermediate (i), deletion (d) and c-regions. These regions show distinct allelic diversity. The s-region, m-region and the c-region (a 15 bp deletion at the 3′-end region of the p55 domain of the vacA gene) exist as 2 types (s1, s2, m1, m2, c1 and c2), while the i–region has 3 allelic types (i1, i2 and i3). The locus of d-region of the vacA gene has also been classified into 2 genotypes, namely d1 and d2. We investigated the “d-region”/“loop region” through bioinformatics, to predict its properties and relation to disease. One thousand two hundred fifty-nine strains from the NCBI nucleotide database and the dryad database with complete vacA sequences were included in the study. The sequences were aligned using BioEdit and analyzed using Lasergene and BLAST. The secondary structure and physicochemical properties of the region were predicted using PredictProtein. Results We identified 31 highly polymorphic genotypes in the “d-region”, with a mean length of 34 amino acids (9 ~ 55 amino acids). We further classified the 31 genotypes into 3 main types, namely K-type (strains starting with the KDKP motif in the “d-region”), Q-type (strains starting with the KNQT motif), and E-type (strains starting with the ESKT motif) respectively. The most common type, K-type, is more prevalent in cancer patients (80.87%) and is associated with the s1i1m1c1 genotypes (P < .01). Incidentally, a new region expressing sequence diversity (2 aa deletion) at the C-terminus of the p55 domain of vacA was identified during bioinformatics analysis. Conclusions Prediction of secondary structures shows that the “d-region” adopts a loop conformation and is a disordered region.

Prevalence of Helicobacter pylori vacA, cagA, cagE1, cagE2, dupA and oipA Genotypes in Patients With Gastrointestinal Diseases

Helicobacter pylori (H. pylori) is a bacterium that resides in the human stomach, which is associated with gastroduodenal diseases. We investigate the prevalence of cagA, vacA, oipA, cagE1, cagE2 and dupA genotypes in H. pylori isolated from patients with Gastric ulcer, duodenal ulcer, and Gastric Cancer. Collected 74 samples from the Gastroenterology Unit of the Rasool Akram Hospital were included in this study. Gastric disorders were identified by endoscopy .gastric cancer was further confirmed by histopathology. H. pylori were detected by the urease test. Subsequently, DNA was extracted from gastric tissue of the subjects with the CLO-test yielded positive results. In general, 74 patients with a mean age of 53.45 years (Range 22 to 86-year-old), including 45 men and 29 women, were studied. Among 74 H. pylori-positive patients, 70 (94.5%) patients were positive for the cagA gene. About 95.8% (23/24) of the patients with gastric carcinoma were dupA positive and VacA gene (91.8%). The oipA genotype was detected in 71 (96%) of H.pylori positive samples. This gene was more common in patients with gastritis rather than cancer group. Also, 97.2% of 74 H. pylori isolates were cagE2-positive. In 25 patients with PUD, the occurrence percent of cagA+/VacA+, cagA+/Vac- , cagA- /VacA+ and cagA- /VaxA- genotypes were found 80%, 12%, 4.2% and 4.2 respectively. The results of the present study suggest that a high prevalence of virulent factors could contribute to the risk of developing gastroduodenal diseases.

Effects of Multi-Strain Probiotics on Immune Responses and Metabolic Balance in Helicobacter pylori-Infected Mice

Chronic inflammation caused by Helicobacter pylori infection increases the risk of developing gastric cancer. Even though the prevalence of H. pylori infection has been decreased in many regions, the development of antibiotic resistance strains has increased the difficulty of eradicating H. pylori. Therefore, exploring alternative approaches to combat H. pylori infection is required. It is well-known that probiotic therapy can improve H. pylori clearance. In this study, H. pylori-infected mice were treated with Lactobacillus fermentum P2 (P2), L. casei L21 (L21), L. rhamnosus JB3 (JB3), or a mixture including the aforementioned three (multi-LAB) for three days. All the lactic acid producing bacteria (LAB) treatments decreased H. pylori loads in the stomach and vacA gene expression, H. pylori specific immunoglobulin (Ig) A, and IgM levels in stomach homogenates, as well as serum levels of interferon-gamma and interleukin-1 beta. The multi-LAB and JB3 treatments further restored the superoxide dismutase and catalase activities suppressed by H. pylori infection. Furthermore, H. pylori infection decreased serum concentrations of 15 kinds of amino acids as well as palmitic acid. The multi-LAB treatment was able to recover the serum levels of alanine, arginine, aspartate, glycine, and tryptophan, which are all important in modulating immune functions. In addition, butyric acid, valeric acid, palmitic acid, palmitoleic acid, stearic acid, and oleic acid levels were increased. In this study, multi-LAB revealed its ability to adjust the composition of metabolites to improve health. To date, the mechanisms underlying how LAB strains crosstalk with the host are not fully understood. Identifying the mechanisms which are regulated by LABs will facilitate the development of effective therapies for infection in the future.

A DNA Sequence Analysis of Helicobacter pylori in Jeddah City, Western Saudi Arabia

Helicobacter pylori are the type of Gram-negative bacteria which colonize the mucous lining of the human stomach. These bacteria have two major virulence factors: (vacuolating cytotoxin A gene) and (cytotoxin-associated A gene). This study aimed to provide data to determine the prevalent virulence factors (vacA and cagA genes) in Jeddah city, western Saudi Arabia, by sequence analysis. This study included 60 patients with symptoms similar to H. pylori infection. H. pylori were identified by using the 16s rRNA sequence. Then, the screening for specific genes in H. pylori (vacA and cagA) was done by using automated DNA sequencing analysis, and the DNA sequences were compared by BLAST and sequence alignment of the vacA nucleotides that are present in all H. pylori strains using those already reported in GeneBank from various studies. Results indicated that H. pylori infection was detected in 13.3%, while 86.7% were negative samples in our study patients. Interestingly, the vacA gene was found in 8.3%, while the cagA gene was not appear in patient. Also, the female prevalence rate was higher than males (11.7% female versus 1.7% males), and the highest infection was between age 40-49 by 6.7%. In conclusion, this study revealed that the vacA gene was spread in the patients infected with H. pylori in Jeddah, while the cagA gene was not appear in any isolate.

vacA genotypes and EPIYA motifs of Helicobacter pylori in patients with atrophic and non-atrophic gastritis

Summary Background Helicobacter pylori is the main microorganism causing gastrointestinal diseases, such as chronic gastritis, peptic ulcer, MALT lymphoma, among others. The presence of the s1/m1 genotype of the vacA gene and EPIYA phosphorylation motifs of the cagA gene have been linked to the production of prolonged gastric inflammation. This study determines the presence of these virulence genotypes and their relationship with atrophic gastritis. Methods We included 231 patients with a history of dyspepsia undergoing upper gastrointestinal endoscopy. Samples of gastric tissue were taken to establish, through molecular techniques, the presence of H. pylori by amplifying the ureA and flaA2 housekeeping genes; in addition, the alleles of signal (s) and of the middle region (m) present in the vacA gene were amplified; and by sequencing the repeating patterns of the tyrosine phosphorylation motifs within the Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs of the cagA gene were also amplified. A chi-square test was performed in order to establish the relationship between the virulence genes and the degrees of gastric injury. Results A total of (91/231) samples were positive for H. pylori, of which (57/91) amplified the cagA gene and (66/91) the vacA gene. 81.8% (54/66) of the positive samples for the vacA gene showed the combination of the s1/m1 alleles, associated mostly with atrophic gastritis (AG). The most frequent EPIYA motifs were ABC and ABCC, with 54.4% (31/57) and 40.4% (23/57) respectively. A relation of the genes with AG and its injury severity with a p>0.05 value was observed. The cagA +/vacA s1/m1+/EPIYA ABC pattern is found in most samples. A p=0.02 relationship was found between the presence of the vacA gene and the cagA gene. Conclusions The results show a higher proportion of gastric atrophy in patients infected with H. pylori. The sum of the pathogenicity factors such as the cagA+/vacA s1/m1+/EPIYA ABCC genotype increases the virulence potential of the microorganism, suggesting that the coexistence of these genes could result in an increase in the severity of the progression of inflammation that leads to precancerous lesions.

Prevalence of Helicobacter pylori genotypes in patients with gastroduodenal pathology in Kazan

Aim. Investigation of the prevalence of various H. pylori genotypes among children and adult population of Kazan with chronic gastroduodenal pathology. Methods. The study included 107 patients (49 children and 58 adults) with chronic gastritis/gastroduodenitis and gastric and duodenal ulcer who had H. pylori infection confirmed by molecular genetic method. All patients underwent biospy from antral mucosa during endoscopy for H. pylori verification by polymerase chain reaction and genotyping for сagA and babA genes and iceA and vacA allels. Results. CagA gene was found in 19 (32.8%) out of 58 adults and 13 (26.5%) out of 49 children. VacA gene was detected in all patients (100%). VacAs2 genotype in children was nearly 1.6 times as frequent as the vacAs1 genotype (61.2 and 36.7% respectively). In adult patients vacAs2 genotype was detected 2.5 times less frequently than vacAs1 (27.6 and 70.7%, respectively). VacAm2 genotype was revealed in 71.4% (35/49) of children and 77.6% (45/58) of adults. IceA2 genotype was identified in 46.9% (23/49) of children and 44.8% (26/58) of adult patients, iceA1 gene - in 20.4% of children and 55.2% of adult patients. Conclusion. The strains with vacAs2m2 genotype are prevailing in children (42.9%) and determine low toxigenicity of H. pylori strains; vacAs1m2 genotype is predominant among adult patients (53.4%); high prevalence of cagA-negative strains of H. pylori was found both in children and adults (73.5 and 67.2%, respectively).