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

Molecular Characterization of Antimicrobial Resistance and Virulence Genotyping among Helicobacter pylori-Positive Dyspeptic Patients in North Iran

BACKGROUND

Iran has a relatively high prevalence of H. pylori, which correlates with high-risk areas for gastric cancer worldwide.

METHODS

Our study aimed to investigate the underlying genetic mechanisms associated with resistance to metronidazole (frxA, rdxA), clarithromycin (23S rRNA), tetracycline (16S rRNA), and fluoroquinolone (gyrA) in H. pylori-positive dyspeptic patients using PCR and sequencing. We further examined the potential correlation between resistance profiles and various virulence genotypes.

RESULTS

The rates of genetic mutations associated with resistance to metronidazole, fluoroquinolone, clarithromycin, and tetracycline were found to be 68%, 32.1%, 28.4%, and 11.1%, respectively. Well-documented multiple antibiotic resistance mutations were detected, such as rdxA and frxA (with missense and frameshift alterations), gyrA (Asp91, Asn87), 23S rRNA (A2142G, A2143G), and 16S rRNA (triple-base-pair substitutions AGA926-928→TTC). The cagA+ and vacA s1/m1 types were the predominant genotypes in our study. With the exception of metronidazole and tetracycline, no significant correlation was observed between the cagA+ and cagL+ genotypes and resistance-associated mutations.

CONCLUSION

The prevalence of antibiotic resistance-associated mutations in H. pylori was remarkably high in this region, particularly to metronidazole, ciprofloxacin, and clarithromycin. By conducting a simultaneous screening of virulence and resistance genotypes, clinicians can make informed decisions regarding the appropriate therapeutic regimen to prevent the escalation of antibiotic resistance against H. pylori infection in this specific geographical location.

Genomic analysis of Helicobacter pylori in Australia: Antimicrobial resistance, phylogenetic patterns, and virulence factors

BACKGROUND AND AIM

Rates of antimicrobial-resistant Helicobacter pylori infection are rising globally, but little is known about contemporary resistance patterns, virulence factors, and phylogenetic patterns of isolates within Australia. We aimed to characterize antimicrobial resistance and genetic mutations associated with adverse clinical outcomes.

METHODS

Whole genome sequencing, culturing, and antibiotic sensitivity data for refractory H. pylori isolates at Australian centers were collected between 2013 and 2022. Phylogenetic origins, antibiotic resistance mutations, and virulence factors were examined with phenotypic resistance profiles.

RESULTS

One hundred thirty-five isolates underwent culture, with 109 of these undergoing whole genome sequencing. Forty-three isolates were isolated from patients in South Australia and 66 from Western Australia. Isolates originated primarily from hpEurope (59.6%), hpEastAsia (25.7%), and hpNEAfrica (6.4%). Antimicrobial resistance to clarithromycin was seen in 85% of isolates, metronidazole in 52%, levofloxacin in 18%, rifampicin in 14%, and amoxicillin in 9%. Most isolates (59%) were multi-drug resistant. Resistance concordance between genetically determined resistance and phenotypic resistance was 92% for clarithromycin and 94% for levofloxacin. Analysis of virulence factors demonstrated cag pathogenicity island (cagPAI) in 67% of isolates and cagA in 61%, correlating with isolate genetic origin. The most virulent s1m1 vacuolating cytotoxin A genotype was present in 26% of isolates.

CONCLUSION

Refractory H. pylori isolates in Australia emanate from multiple global origins. Strong concordance between genetic and phenotypic antibiotic resistance profiles raises the possibility of utilizing genetic profiling in clinical practice. The dynamic landscape of H. pylori in Australia warrants the establishment of a national database to monitor H. pylori resistance and evolving virulence.

Global incidence and prevalence of gastritis and duodenitis from 1990 to 2019: A systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND AND AIM

Gastritis and duodenitis, prevalent diseases of the digestive system, impose a significant global burden. This study aimed to examine their incidence and prevalence patterns worldwide, including changes over the past 30 years.

METHODS

The age-standardized incidence rate (ASIR) and age-standardized prevalence rate (ASPR) of gastritis and duodenitis, stratified by age, sex, geographical region, and sociodemographic index (SDI), were obtained from the Global Burden of Disease 2019. The dynamic trends were captured by calculating the average annual percentage changes (AAPC).

RESULTS

In 2019, the global ASIR and ASPR of gastritis and duodenitis were 379.88/100 000 (95% uncertainty interval [UI]: 312.42/100 000-448.12/100 000) and 518.11/100 000 (95% UI: 420.62/100 000-631.66/100 000), respectively. The highest rates were observed among the 50-69 age group (ASIR: 856.48/100 000; ASPR: 1158.04/100 000) and in low SDI regions (ASIR: 443.33/100 000; ASPR: 631.22/100 000). From 1990 to 2019, there was a significant decrease in global ASIR (AAPC = -0.34%, 95% confidence interval [CI]: -0.36% to -0.31%) and ASPR (AAPC = -0.34%, 95% CI: -0.37% to -0.31%) of gastritis and duodenitis. However, ASIR (AAPC = 0.47%, 95% CI: 0.42%-0.52%) and ASPR (AAPC = 0.51%, 95% CI: 0.47%-0.52%) of gastritis and duodenitis experienced a significant increase in low SDI regions.

CONCLUSIONS

Despite a significant decrease in the global incidence and prevalence of gastritis and duodenitis, these conditions continue to impose a burden on individuals aged 50-69 years and low SDI regions. Targeted interventions for those specific populations and regions are necessary.

Potentialities of Dandelion (Taraxacum Mongolicum Hand.-Mazz.) Flower Extracts on Gastric Protection against Helicobacter Pylori and Characterization of its Bioactive Constituents

OBJECTIVES

Dandelion has been shown to exert anti-inflammatory and anti-bacterial effects. Our study aimed to identify the effect and mechanism of dandelion flower extracts on H. pylori-induced gastritis and screen for novel antimicrobial substances.

METHODS

Anti-H. pylori activities of water extracts(WEDF) and ethanol extracts (EEDF) of dandelion flowers were performed with disk diffusion method assay, MIC, and MBC. The H. pylori-induced model was constructed to examine the gastroprotective of EEDF using RUT, pathological analysis, and ELISA.

RESULTS

EEDF exhibited better anti- H. pylori and urease inhibition activities than WEDF. In vivo studies, EEDF can reduce the adhesion of H. pylori to the gastric mucosa, alleviate gastric damage, and concurrently reduce the levels of TNF-α and IL-6 in gastric tissues. The six phenolic compounds showed urease inhibition effect (IC50: 2.99±0.15 to 66.08±6.46 mmol/mL). Among them, chlorogenic acid, caffeic acid, and luteolin also had anti-H. pylori activity (MIC: 64-256 μg/mL).

CONCLUSION

EEDF exhibited anti-H. pylori, gastroprotective and anti-inflammatory effects. Chicoric acid and luteolin may be the main active compounds of dandelion flowers to exert anti-H. pylori, and worthy of further investigation.

The Helicobacter pylori single nucleotide polymorphisms SNPs associated with multiple therapy resistance in Colombia

The eradication of Helicobacter pylori (H. pylori) using multiple therapies is used as a prevention strategy. However, its efficacy has been compromised by the emergence of single nucleotide polymorphisms in genes associated with H. pylori's resistance to multiple antibiotics. To estimate antibiotic resistance rates associated with mutations in H. pylori genes in the high-cancer-risk population in Colombia, we included 166 H. pylori whole genome sequences from a cohort of individuals with a high risk of gastric cancer. By using the reference strain ATCC 26695, we identified mutations in specific genes to evaluate resistance rates for different antibiotics: 23S rRNA for clarithromycin, 16S rRNA for tetracycline, pbp1A for amoxicillin, gyrA for levofloxacin, and rdxA for metronidazole. The phylogenomic analysis was conducted using the core genome consisting of 1,594 genes of H. pylori-ATCC 26695. Our findings revealed that the resistance rate of H. pylori to clarithromycin was 3.62%, primarily associated with mutations A2143G and A2142G in the 23S rRNA gene. For tetracycline, the resistance rate was 7.23%, with mutations A926G, A926T, and A928C observed in the 16S rRNA gene. Amoxicillin resistance was found in 25.9% of cases, with observed mutations in the pbp1A gene, including T556S, T593, R649K, R656P, and R656H. In the gyrA gene, mutations N87K, N87I, D91G, D91N, and D91Y were identified, resulting in a resistance rate of 12.04% to levofloxacin. The most common mutations in the rdxA gene associated with metronidazole resistance were a stop codon, and mutations at D59N and D59S, resulting in a resistance rate of 99.3%. The high resistance rate of H. pylori to metronidazole indicated that this drug should be excluded from the eradication therapy. However, the resistance rates for tetracycline and clarithromycin did not exceed the established resistance threshold in Colombia. The increased resistance rate of H. pylori to levofloxacin and amoxicillin may partially explain the observed therapeutic failures in Colombia. The phylogenomic tree showed that the H. pylori isolate belongs to its own lineage (hspColombia). These findings offer valuable insights to enhance the characterization of treatment protocols for the specific H. pylori lineage (hspColombia) at the local level.

A Genetic and Immunohistochemical Analysis of Helicobacter pylori Phenotypes and p27 Expression in Adenocarcinoma Patients in Jordan

Stomach (gastric) cancer is one of the most prevalent and deadly cancers worldwide and most gastric cancers are adenocarcinomas. Based on prior research, there is an association between Helicobacter pylori (H. pylori) infection together with the frequency of duodenal ulcer, distal gastric adenocarcinoma, mucosa-associated lymphoid tissue (MALT) lymphoma, and antral gastritis. Helicobacter pylori virulence and toxicity factors have been identified before that significantly influence the clinical outcomes of H. pylori infection and gastric adenocarcinoma. However, it remains unclear exactly how different strains of H. pylori affect gastric adenocarcinoma. Current research suggests this involves tumor suppressor genes, like p27 but also H. pylori toxic virulence proteins. Therefore, we quantified known H. pylori genotypes within adenocarcinoma patients to establish the prevalence of known toxins that include cytotoxin-associated gene A (cagA) as well as vacuolating cytotoxin A (vacA) within patients of variable adenocarcinoma diagnosis. This analysis used gastrectomy samples validated for DNA viability. The incidence of H. pylori in adenocarcinoma patients in Jordan was established to be 54.5% positive (ureA gene positive) with cagA genotype occurrence at 57.1%, but also in this population study vacA gene ratios found to be 24.7%:22.1%:14.3%:14.3%. (vacAs1:vacAs2:vacAm1:vacAm2). Using immunohistochemistry (IHC), we confirmed with statistical significance that p27 was dysregulated and suppressed, within nearly all H. pylori vacA genotypes. In addition, within 24.6% of H. pylori samples analyzed was a different bacterial genotype, and curiously that p27 protein expression was retained in 12% of tested adenocarcinoma H. pylori samples. This is suggestive that p27 could be used as a prognostic indicator but also that an unknown genotype could be contributing to the regulatory effects of p27 protein within this bacterial and cellular environment that may include other virulence factors and unknown immune system regulatory changes.

Helicobacter pylori Virulence Factors and Clarithromycin Resistance-Associated Mutations in Mexican Patients

Persistent infection with Helicobacter pylori (H. pylori) is an important factor in gastric diseases. The vacA and cagA virulence factors of H. pylori contribute to the development of these diseases. Triple therapy containing clarithromycin has been used to eradicate this infection. Unfortunately, resistance to this antibiotic is the primary cause of treatment failure. This study aimed to determine the prevalence of clarithromycin resistance-associated mutations and to assess the relationship between virulence factors and Mexican patients infected with H. pylori. The cagA and vacA genotypes were determined by multiplex PCR. Furthermore, a qPCR was used to identify mutations of the 23S rRNA gene. This study reported a prevalence of 84.3% of H. pylori among patients with gastric diseases, and the vacA s1m1/cagA+ genotype was the most frequent (44.8%) in antrum and corpus. Analysis of the 23S rRNA gene revealed a 19.8% prevalence of clarithromycin resistance-associated mutations. The most prevalent mutations were A2143G (56%) and A2142C (25%). A significant association (p < 0.05) between the A2142G and the vacA s1m1/cagA+ genotype was detected. In conclusion, we report a high prevalence (>15%) of clarithromycin resistance-associated mutations, and we found an association between the genotypes of virulence factors and a mutation in the 23S rRNA gene.

Urolithin A Attenuates Helicobacter pylori-Induced Damage In Vivo

Urolithin A (UA) is a metabolite produced in the gut following the consumption of ellagic acid (EA) rich foods. EA has shown anti-inflammatory, antioxidant, and anticancer properties. Because EA is poorly absorbed in the gastrointestinal tract, urolithins are considered to play a major role in bioactivity. Helicobacter pylori (H. pylori) infection is the most common chronic bacterial infection all over the world. It is potentially hazardous to humans because of its relationship to various gastrointestinal diseases. In this study, we investigated the effect of UA on inflammation by H. pylori. The results indicated that UA attenuated H. pylori-induced inflammation in vitro and in vivo. UA also reduced the secretion of H. pylori virulence factors and tissue injuries in mice. Furthermore, UA decreased the relative abundance of Helicobacteraceae in feces of H. pylori-infected mice. In summary, taking UA effectively inhibited the injury caused by H. pylori.

Nrf2 Downregulation Contributes to Epithelial-to-Mesenchymal Transition in Helicobacter pylori-Infected Cells

Simple Summary

Gastric cancer is mainly linked to Helicobacter pylori infection. It is therefore important to decipher the mechanisms involved in H. pylori-induced gastric carcinogenesis, and especially the early events. We have previously demonstrated that the infection leads to an epithelial-to-mesenchymal transition (EMT) favoring gastric carcinogenesis. H. pylori infection is also associated with high levels of oxidative stress. In this work, we aimed at investigating the modulation of Nrf2, a major regulator of cellular antioxidant response to oxidative stress, upon infection with H. pylori and to decipher its implication in EMT. We demonstrated that H. pylori-induced Nrf2 downregulation may participate in gastric cells’ EMT, one crucial tumorigenic event in gastric cancer. These results could pave the way for new therapeutic strategies using Nrf2 modulators to reduce gastric carcinogenesis associated with H. pylori infection.

Abstract

Background: Gastric cancer, the fifth most common cancer worldwide, is mainly linked to Helicobacter pylori infection. H. pylori induces chronic inflammation of the gastric mucosa associated with high oxidative stress. Our study aimed at assessing the implication of Nrf2, a major regulator of cellular redox homeostasis, in H. pylori-induced gastric carcinogenesis. Methods: Using three different gastric epithelial cell lines, a non-cancerous (HFE-145) and two different subtypes of gastric cancer (AGS and MKN74), we analyzed the modulation of Nrf2 expression over time. After invalidation of Nrf2 by CRISPR-cas9, we assessed its role in H. pylori-induced epithelial-to-mesenchymal transition (EMT). Finally, we evaluated the expression of Nrf2 and ZEB1, a central EMT transcription factor, in human gastric tissues. Results: We first demonstrated that the Nrf2 signaling pathway is differentially regulated depending on the infection stage. Rapidly and transiently activated, Nrf2 was downregulated 24 h post-infection in a VacA-dependent manner. We then demonstrated that Nrf2 invalidation leads to increased EMT, which is even exacerbated after H. pylori infection. Finally, Nrf2 expression tended to decrease in human patients’ gastric mucosa infected with H. pylori. Conclusions: Our work supports the hypothesis that Nrf2 downregulation upon H. pylori infection participates in EMT, one of the most important events in gastric carcinogenesis.

Targeting microbiota-host interactions with resveratrol on cancer: Effects and potential mechanisms of action

Resveratrol (RSV) is a natural polyphenolic compound detected in grapes, berries, and red wine. The anticancer activities of RSV have been observed in vivo and in vitro studies. However, the pharmacology mechanism of RSV is confusing due to its low bioavailability. According to studies of the metabolic characteristics of RSV, the gut intestine is a crucial site of its health benefits. Dietary RSV exhibits a profound effect on the gut microbiota structure and metabolic function. In addition, emerging evidence demonstrates a protective effect of RSV metabolites against carcinogenesis. Therefore, to better understand the anticancer mechanisms of dietary RSV, it is vital to evaluate the role of RSV-microbiota-host interactions in cancer therapy. In this review, we summarized significant findings on the anticancer activities of RSV based on epidemiological, experimental and clinical studies involved in investigating the metabolic characteristics and the traditional anticancer mechanisms of RSV. Special attention is given to the putative mechanisms involving microbiota-host interactions, such as the modulation of gut microecology and the anticancer effects of RSV metabolites. The changes in microbiota-host interactions after RSV supplementation play vital roles in cancer prevention and thus offering a new perspective on nutritional interventions to treat cancer.

CagA and VacA inhibit gastric mucosal epithelial cell autophagy and promote the progression of gastric precancerous lesions

Cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) are the keys to the pathogenic role of Helicobacter pylori and the high-risk factors for the progression of gastric precancerous lesions. Autophagy can stabilize the intracellular environment, resist Helicobacter pylori infection, prevent the accumulation of damaged DNA, and inhibit the proliferation of gastric precancerous variant cells. However, CagA and VacA can inhibit the activation of upstream signals of autophagy and the maturation of autophagy-lysosomes in various ways, thus inhibiting the autophagy of gastric mucosal cells in precancerous lesions of gastric cancer. This change can cause Helicobacter pylori to be unable to be effectively cleared by autophagy, so CagA and VacA can persist and promote the inflammation, oxidative stress, apoptosis of gastric mucosal tissue cells, and the glycolytic activity and proliferation of variant cells in gastric precancerous lesions and a series of malignant biological processes. In recent years, the research on drugs specifically inhibiting the activities of CagA and VacA has become a new direction for the prevention and treatment of Helicobacter pylori-related severe gastric diseases, and a variety of drugs or components that can precisely and effectively regulate the factors for the treatment of gastric precancerous lesions are emerged, which opens a new strategy for the treatment of gastric precancerous lesions in the future.

Helicobacter pylori in Native Americans in Northern Arizona

Background: In Arizona Helicobacter pylori prevalence of infection among Navajo adults is about 62% and gastric cancer incidence rate is 3–4 times higher than that of the non-Hispanic White population. Aim: The aim of this study was to estimate the prevalence of specific H. pylori virulence factors (cagA and vacA) among Navajo patients undergoing and their association with gastric disease. Methods: Virulence genes, cagA and vacA, in H. pylori were investigated in gastric biopsies from 96 Navajo patients over age 18 who were undergoing esophagogastroduodenoscopy. Biopsies from the antrum and fundus were used for molecular characterization to determine cagA type and number of EPIYA motifs and presence of alleles in the signal (s) and medium (m) regions of the vacA gene. Results: H. pylori infection was found in 22.9% of the biopsy samples. The cagA gene amplified in 57.6% of samples and showed a predominant “Western cagA” type, with the EPIYA-ABC motif (45.4%), most prevalent. The vacA allele s1bm1 was the most prevalent (54.5%). Conclusions: H. pylori genotypes were predominantly cagA Western-type and ABC EPIYA motifs. The vacA s1bm1 genotype was the most prevalent and seemed to be associated with gastritis. American Indian/Alaska Native populations are at higher risk for gastric cancer. It is important to identify genotypes of H. pylori and virulence factors involved in the high prevalence of H. pylori and associated disease among the Navajo population.

Potential Non-invasive Biomarkers of Helicobacter pylori-Associated Gastric Cancer

BACKGROUND

Gastric cancer (GC) remains the fifth most common incident cancer with the highest incidence in East Asian countries and the third leading cause of cancer death worldwide. The causal association between non-cardia GC and Helicobacter pylori (H. pylori) has been firmly documented by clinical and epidemiological studies. According to the guidelines for diagnosis and treatment of H. pylori infection, eradication therapy is strongly recommended. Early detection of GC is critical and can save lives through rapid technological advancement. At present, endoscopy remains the most efficient technique. However, it is invasive and costs highly.

METHODS

An extensive bibliographic search was performed via PubMed/Medline, Web of Science, and EBSCO host databases to select studies conducted within the past 8 years. Forty-six relevant analyses were encompassed in this review.

RESULTS

Several non-invasive candidate biomarkers associated with H. pylori, divided into virulence markers, transcriptome markers, genomic markers, and inflammatory markers, have been shown to be potential predictors of GC at an early stage.

CONCLUSION

The discovery of non-invasive biomarkers offers new perspectives for screening, early detection, and monitoring of individuals at risk.

Association of toll-like receptor 4, 5 and 10 polymorphisms with Helicobacter pylori-positive peptic ulcer disease in a center in Jordan

BACKGROUND

Helicobacter pylori infection is widespread, affecting about 50% of the global population. Polymorphisms in host genes such as the toll-like receptor 4 (TLR4) might affect the susceptibility and severity of infection and treatment success.

OBJECTIVE

Investigate the susceptibility and severity of H pylori infection with host TLR4 (rs11536889, rs4986790, rs200109652, rs10759932), TLR5 (rs5744174, rs2072493, rs746250566), TLR10 (rs559182335, rs10004195) polymorphisms.

DESIGN

Analytical, cross-sectional.

SETTING

Endoscopy clinic at tertiary care center.

PATIENTS AND METHODS

Genomic DNA was extracted from formalin-fixed paraffin-embedded tissues collected from H pylori-infected patients and healthy individuals. The single nucleotide polymorphisms (SNPs) within the targeted TLR genes were genotyped to assess the genetic association of various SNPs with disease severity.

MAIN OUTCOME MEASURES

Effect of genotype distribution on H pylori infection.

SAMPLE SIZE

250 peptic ulcer patients and 217 controls.

RESULTS

The TLR10 genotype showed no significant association with H pylori infection except for rs10004195 (T>A) (P=.002). The genotype frequency of Rs5744174 in TLR5 had a significant association with the presence of H pylori infection (P=.046, OR=0.52). Except for gender (P=.022), there were no significant associations between clinical and demographic variables and SNPs relating to the severity of the H pylori infections.

CONCLUSIONS

Our findings are consistent with differences in severity of H pylori infection due to TLR SNPs in different ethnic groups. Understanding differences in genetic susceptibility could help in classifying patients and matching patients with various treatment options on a genetic basis.

LIMITATIONS

Lack of H pylori pathogenicity features assessment.

CONFLICTS OF INTEREST

None.

Helicobacter pylori prevalence in healthy Mexican children: comparison between two non-invasive methods

Background

Helicobacter pylori detection in asymptomatic children with suspected infection or with symptoms that suggest gastric pathology is problematic, since most of the methods depend on the endoscopic study, an invasive and expensive method. Non-invasive methods can be a feasible alternative but must be validated. The purpose of this study was to evaluate the concordance between H. pylori DNA detection in saliva and dental plaque by PCR, with antigen detection in stool by immunochromatography, among asymptomatic children in the state of Guerrero, Mexico.

Methods

Dental plaque, saliva, and stool samples were obtained from 171 children between 6 and 12 years old. H. pylori detection in saliva and dental plaque was performed by PCR using specific primers for the 16S rRNA gene, while the detection in stool samples was performed by immunochromatography using the CerTest kit.

Results

We found an overall H. pylori prevalence of 59.6% (102/171). Of the H. pylori positive children 18% (20/111) were positive in saliva samples, 28.1% (34/121) in dental plaque samples, and 50.4% (71/141) in stool samples. A higher prevalence was found in girls (64.7%, p = 0.002). Although some of the children declared some dyspeptic symptoms, these were no related to H. pylori. In conclusion, we found a high prevalence of H. pylori in asymptomatic children and the highest proportion was detected by stool antigen test, which was the most feasible method to detect H. pylori infection.

Diagnosis of Helicobacter pylori Infection in a Routine Testing Workflow: Effect of Bacterial Load and Virulence Factors

Reliable diagnostic methods are mandatory for effective management of Helicobacter pylori infection. Histology and culture are the most common invasive methods in current practice, even if molecular methods are gaining in importance. The performance of these conventional methods varies significantly. We conducted a retrospective study of 1540 adults and 504 children with gastric biopsies taken during endoscopy to assess the impact of bacterial load and the cagA virulence factor on the performance of H. pylori infection testing. The association between virulence and histology findings was also investigated. With 23S rRNA qPCR confirmed by glmM amplification as the gold standard, culture and histology had lower sensitivity, 74.4% and 73.3%, respectively. However, their sensitivity was enhanced (>90%) in biopsies with high bacterial load (qPCR Ct < 30). Positive cagA status of the strain was associated with high bacterial load (94.9%), thus resulting in more frequent positive culture (94.3%) and H. pylori histology detection (91.7%) and more severe lesions on histology (p < 0.001). Conversely, the cagA status of the strains was negative in 110/119 (92.4%) of biopsies with low bacterial load (qPCR Ct < 30), 82/90 (91.1%) with negative H. pylori histology detection and 119/131 (90%) with negative culture findings (p < 0.001). This study highlights the low sensitivity of conventional culture and histology that may lead to false negative diagnosis if used alone. H. pylori quantification associated with cagA genotyping in routine workflow are essential for a sensitive and reliable diagnosis, to identify patients at high risk and to manage eradication therapies.

Cancer-fighting potentials of algal polysaccharides as nutraceuticals

Cancer has been listed as one of the world's five incurable diseases by the World Health Organization and causes tens of thousands of deaths every year. Unfortunately, anticancer agents either show limited efficacy or show serious side effects. The algae possess high nutritional value and their polysaccharides have a variety of biological activities, especially anti-cancer and immunomodulatory properties. Algal polysaccharides exert anti-cancer effects by inducing apoptosis, cell cycle arrest, anti-angiogenesis, and regulating intestinal flora and immune function. Algal polysaccharides can be combined with nanoparticles and other drugs to reduce the side effects caused by chemotherapy and increase the anticancer effects. This review shows the signal pathways related to the anti-cancer mechanisms of algal polysaccharides, including their influence on intestinal flora and immune regulation, the application of nanoparticles, and the effects on combination therapy and clinical trials of cancer treatments.

Genotyping Helicobacter pylori antibiotic resistance - and virulence-associated genes in patients with gastric cancer in Wenzhou, China

BACKGROUND AND STUDY AIMS

Helicobacter pylori infection affects approximately 50% of the global population and has become a serious health concern related to gastric cancer, gastritis, and peptic ulcers. This organism acquires drug resistance through gene mutations, and its increasing resistance to antibiotics has severely influenced the effectiveness of eradication efforts. Therefore, we designed this study to determine the prevalence of H. pylori virulence- (cagA and vacA) and antibiotic resistance - associated genotypes in patients with gastric cancer infected with H. pylori in Whenzhou, China.

PATIENTS AND METHODS

We used polymerase chain reaction (PCR) to confirm H. pylori in cancerous and paracancerous tissue specimens from 225 patients. Then we tested the prevalence of virulence- and antibiotic resistance - associated genotypes in H. pylori using a PCR-based DNA-sequencing assay.

RESULTS

We observed H. pylori DNA in 222 of the 225 patients and found the most prevalent virulence-associated genotypes in cagA⁺ (97.75%) and vacAs1m1 (93.25%). Metronidazole resistance - associated gene mutation was G616A in rdxA; levofloxacin resistance - associated gene mutations were N87K, N87I, and D91G in gyrA; clarithromycin resistance - associated gene mutations were A2143G and A2142G in 23SrRNA; and amoxicillin resistance - associated gene mutation was T556S in pbp1. The most prevalent mutation related to antibiotic resistance was present in rdxA (97.30%), followed by gyrA (41.44%) and 23SrRNA (16.67%); the least prevalent was in pbp1 (2.25%). We observed single-gene mutations in 102 patients (45.95%) and found mutations in multiple genes (≥2 genes) in 116 patients (52.25%).

CONCLUSION

Patients with gastric cancer in Wenzhou, China, have high incidence infection caused by H. pylori with high-toxicity virulence genotypes. The frequency of gene mutations associated with metronidazole, levofloxacin, and clarithromycin resistances was high and that associated with amoxicillin resistance was relatively low. The mutation patterns were diverse, and the rates of multiple gene mutations were high.

Evaluation of Helicobacter pylori Genotypes in Obese Patients with Gastric Ulcer, Duodenal Ulcer, and Gastric Cancer: An Observational Study

INTRODUCTION

Obesity is a well-known risk factor for a variety of gastrointestinal disorders (GID). Helicobacter pylori is associated with different GID, such as gastric cancer and chronic gastritis. In this study, we investigated the prevalence of dominant genotypes in H. pylori isolated from obese patients diagnosed with gastric ulcer, duodenal ulcer, and gastric cancer.

METHODS

A total of 222 H. pylori-positive samples were collected from patients with obesity. GID and gastric cancer were identified by endoscopy and histopathology, respectively. Three biopsy specimens from the gastric antrum were obtained from each patient for culture tests, histological examination, and identification of vacuolating cytotoxin A (vacA) (vacA s1, vacA s2, vacA m1, vacA m2, vacA s1m1 vacA s1m2, vacA s2m1, and vacA s2m2), cagA, cagE, iceA1, oipA, dupA, and babA2 using polymerase chain reaction.

RESULTS

vacA, cagE, cagA, iceA1, oipA, dupA, and babA2 genes were detected in 222 (100%), 171 (77%), 161 (72.5%), 77 (34.6%), 77 (34.6%), 137 (61%), and 69 (31%) patients with obesity, respectively. Our findings revealed that vacA, iceA1, oipA, and babA2 were significantly associated with a higher risk of GID, while cagE, cagA, and dupA indicated no correlation with the development of GID. Also, in the combination of s- and m-region genotypes, s1m2 (79%) was the most frequently identified genotype in patients with obesity. A significant association was also found between cagA and the presence of vacA genotypes (except for vacA m1 and babA2).

CONCLUSIONS

This study indicated the high prevalence of different virulence genes in H. pylori isolated from obese patients and supported the significant role of H. pylori in the development of GID.

Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment

Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.

Association of cagA, cagC, virB2, and vacA Subtypes of Helicobacter pylori with Adenocarcinoma Development in Iranian Patients

Background: Gastric cancer has been introduced as the second cause of cancer death worldwide. Helicobacter pylori infection is considered one of the main risk factors for this type of cancer, so that it has been classified as group I carcinogens. Objectives: The present research intended to examine the prevalence of cagA, cagC, virB2, vacA, and genotype distribution in H. pylori-infected biopsies and adenocarcinoma cases. Methods: Thirty-four H. pylori gastric biopsies taken from Western Iranian patients that were diagnosed as gastritis, gastric ulcers, and adenocarcinoma were used in this study. Two samples were taken from each patient. These samples were selected based on endoscopic observations and histological examinations. The presence of H. pylori was confirmed by the Rapid Urease test (RUT) and the ureC gene by the polymerase chain reaction (PCR) technique. Then, specific primers for vacA and cagPAI were used for genotyping H. pylori by PCR-typing. Results: The obtained results showed that 86.8% of the samples were H. pylori-positive. Moreover, the cagA gene prevalence was 51.50% in the samples. In addition, the adenocarcinoma outcome was significantly related to all selected genes. Likewise, some gastric diseases such as gastric ulcers, duodenal ulcer (DU), gastritis, lymphoid, and gastroesophageal reflux disease (GERD) were observed in adenocarcinoma cases. It was also found that the vacAs1m1i1 genotype plays an important role in gastric malignancies. The most frequent vacA genotype in the H. pylori-infected isolates was s1m1i1, and the observed frequency of vacA and cagA genes in adenocarcinoma was statistically significant. Conclusions: The findings showed that H. pylori vacA and cagA gene virulence factors are associated with adenocarcinoma in Western Iranian patients.

Association of Helicobacter pylori vacA genotypes and peptic ulcer in Iranian population: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is accounted as the most etiologic agent for digestive disorders, in particular, the most important of them i.e. peptic ulcer and gastric cancer. In the recent years, association of vacA genotypes and gastrointestinal disorders has attracted a lot of attention. In present study, we assessed the correlation between vacA genotypes (s1, s2, m1, m2, s1m1, s1m2, s2m1 and s2m2) and development to peptic ulcer in Iranian population.

METHODS

In our study, first, 24 original articles containing of information of 3328 patients were evaluated. Statistical analysis was done by Comprehensive Meta-Analysis version 2.0 software (Biostat, Englewood, NJ, USA). In this regards, we used from fixed-effects model for analysis of data with low heterogeneity, while for analysis of data with high heterogeneity (I2 statistic index > 25%, Cochrane Q statistic p value < 0.05), random-effects model was used.

RESULTS

Abundance of each of s1, s2, m1, m2, s1m1, s1m2, s2m1, and s2m2 was estimated 36.24, 28.32, 42.90 29.86, 27.88, 32.34, 15.70, and 25.94%, respectively. According to the results, the m1, s1, and s1m2 genotypes were among the most prevalent genotypes among the Iranian patients, whereas, s2m1 genotype had the lowest frequency.

CONCLUSIONS

Overall, 24 articles (total participants = 3328) were included in this comprehensive analysis. H. pylori infection rate were 90.26% in these cases, so that 33.65% of whom had peptic ulcer. Moreover, the abundance of each vacA genotypes including s1, s2, m1, m2, s1m1, s1m2, s2m1, and s2m2 was estimated as 36.24, 28.32, 42.90 29.86, 27.88, 32.34, 15.70, and 25.94% respectively. We demonstrated that there is a significant relationship between infection of stomach with m1, s1m1, and s2m1 genotypes and development to peptic ulcer disease.

Women with chronic follicular gastritis positive for Helicobacter pylori express lower levels of GKN1

In women, serum levels of CTSB, GKN2, LIPF, LIPFG, AZGP1, TOP2A and PGA4 are proposed as predictive markers of gastric cancer. It is unknown whether GKN1 expression varies with the sex of patients with chronic gastritis or gastric cancer. We studied 36 patients with histopathological diagnosis of chronic gastritis from the state of Guerrero, Mexico. PCR was performed for H. pylori detection and GKN1 expression was determined by RT-qPCR and western blot. GKN1 mRNA expression was significantly lower in patients with chronic follicular gastritis than in those with chronic chemical gastritis (p = 0.00071). The mRNA and protein level of expression of GKN1 were significantly lower in women with chronic follicular gastritis than in men with the same condition (p = 0.0279 and p = 0.0014, respectively); the lowest levels of GKN1 were detected in women with H. pylori-positive follicular gastritis (p = 0.0175 and p = 0.0111, respectively). Through a bioinformatic analysis, estrogen response elements were identified in the GKN1 promoter.

Helicobacter pylori-related risk predictors of gastric cancer: The latest models, challenges, and future prospects

Helicobacter pylori is known as an important determinant of preneoplastic lesions or gastric cancer (GC) risk. The bacterial genotypes may determine the clinical outcomes. However, the evidence for these associations has varied between and within continents, and the actual effect of each gene and corresponding allelic variants are still debatable. In recent years, two new models have been proposed to predict the risk of GC; the phylogeographic origin of H. pylori strains and a disrupted co-evolution between H. pylori and its human host, which potentially explain the geographic differences in the risk of H. pylori-related cancer. However, these models and earlier ones based on putative virulence factors of the bacterium may not fully justify differences in the incidence of GC, reflecting that new theories should be developed and examined. Notably, the new findings also support the role of ancestry-specific germline alteration in contributing to the ethnic/population differences in cancer risk. Moreover the high and low incidence areas of GC have shown differences in transmission ecology, largely affecting the composition of H. pylori populations. As a new hypothesis, it is proposed that any high-risk population may have its own specific risk loci (or variants) as well as new H. pylori strains with national/maybe regional gene pools that should be considered. The latter is seen in the Americas where the rapid evolution of distinct H. pylori subpopulations has been occurred. It is therefore proposed that the deep sequencing of both H. pylori and its human host is simultaneously performed in GC patients and age-sex-matched controls from high-risk areas. The expression and functional activities of the identified new determinants of GC must then be assessed and matched with human and pathogen ancestry, because some of risk loci are ancestry-specific. In addition, potential study-level covariates and moderator variables (eg physical conditions, life styles, gastric microbiome, etc) linked to causal relationships, and their impact, should be recognized and controlled.

An improved quantitative real-time polymerase chain reaction technology for Helicobacter pylori detection in stomach tissue and its application value in clinical precision testing

BACKGROUND

Helicobacter pylori (H. pylori) infection is a serious human health threat. The empiric H. pylori treatment paradigm guided by traditional testing technologies has led to antibiotic resistance. Here, we improved the qPCR method to provide technical support for precision H. pylori diagnosis and treatment.

METHODS

Two pairs of primers and probes targeting the glmM gene were designed to detect H. pylori, and a multiplex qPCR method was established for virulence factor detection. Then, a rapid urease test (RUT), culturing and qPCR were performed on 141 specimens collected from Xinqiao Hospital of China in 2017 to evaluate the qPCR detection capability. Finally, the H. pylori infectious amount and virulence genes were detected by qPCR.

RESULTS

1. The improved qPCR method which used two pairs of primers had a higher detection rate (100%) and better accuracy (p = 0.000), compared with the qPCR using a pair of primers. It also had better consistency with the bacterial culture than with RUT (Kappa =0.440, p < 0.001). 2. The H. pylori infectious amount was significantly positively associated with gastritis in corpus (p = 0.003) and gastric erosion (p = 0.043). The H. pylori infectious amount in gastric precancerous patients was significantly lower than that in H. pylori-positive patients (p < 0.05), and the infectious H. pylori-vacA s1+ amount was significantly greater than that of H. pylori-vacA s1- (p < 0.05). 3. The vacA s1 frequency was significantly higher than that of vacA m1/cagA+/babA2+ in chronic superficial gastritis (p = 0.000), peptic ulcer (p = 0.037) and gastric erosion (p = 0.009). The H. pylori-vacA+/cagA+/babA2+ frequency showed a significant positive correlation (p < 0.05).

CONCLUSIONS

The H. pylori infectious amount and presence of H. pylori virulence factors showed complex correlations with gastric disease occurrence and development. The improved qPCR with good detection performance can be used for quantitative H. pylori detection and testing for the virulence genes vacA s1, vacA m1, cagA and babA2 simultaneously. These findings will provide valuable information for disease diagnosis and treatment.

Microbiome and host crosstalk: A new paradigm to cancer therapy

The commensal microbiome of humans has co-evolved for thousands of years. The microbiome regulates human health and is also linked to several diseases, including cancer. The advances in next-generation sequencing have significantly contributed to our understanding of the microbiome and its association with cancer and cancer therapy. Recent studies have highlighted a close relationship of the microbiome to the pharmacological effect of chemotherapy and immunotherapy. The chemo-drugs usually interfere with the host immune system and reduces the microbiome diversity inside the body, which in turn leads to decreased efficacy of these drugs. The human microbiome, specifically the gut microbiome, increases the potency of chemo-drugs through metabolism, enzymatic degradation, ecological differences, and immunomodulation. Recent research exploits the involvement of microbiome to shape the efficacy and decrease the toxicity of these chemo-drugs. In this review, we have highlighted the recent development in understanding the relationship of the human microbiome with cancer and also emphasize on various roles of the microbiome in the modulation of cancer therapy. Additionally, we also summarize the ongoing research focussed on the improved efficacy of chemotherapy and immunotherapy using the host microbiome.

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

Background

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

Methods

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

Results

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

Conclusions

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

Epigenetic changes in gastric cancer induction by Helicobacter pylori

Epigenetic disorder mechanisms are one of the causes of cancer. The most important of these changes is the DNA methylation, which leads to the spread of Helicobacter pylori and inflammatory processes followed by induction of DNA methylation disorder. Mutations and epigenetic changes are the two main agents of neoplasia. Epithelial cells infection by H. pylori associated with activating several intracellular pathways including: MAPK, NF-κB, Wnt/β-catenin, and PI3K are affects a variety of cells and caused to an increase in the production of inflammatory cytokines, changes in apoptosis, proliferation, differentiation, and ultimately leads to the transformation of epithelial cells into oncogenic. The arose of free radicals impose the DNA cytosine methylation, and NO can increase the activity of DNA methyltransferase. H. pylori infection causes an environment that mediates inflammation and signaling pathways that probably caused to stomach tumorigenicity. The main processes that change by decreasing or increasing the expression of various microRNAs expressions include immune responses, apoptosis, cell cycle, and autophagy. In this review will be describe a probably H. pylori roles in infection and mechanisms that have contribution in epigenetic changes in the promoter of genes.

Prevalence of Helicobacter pylori Infection, Its Virulent Genotypes, and Epstein-Barr Virus in Peruvian Patients With Chronic Gastritis and Gastric Cancer

PURPOSE

Helicobacter pylori (HP) and Epstein Barr virus (EBV) infections induce chronic gastritis (CG) and are accepted carcinogenics of gastric cancer (GC). Our objective for this study was to determine the prevalence of these agents and clinicopathological features of GC and CG associated with the infection.

PATIENTS AND METHODS

A single-center cohort of 375 Peruvian patients with GC and 165 control subjects with CG were analyzed. Evaluation of HP and EBV genes was performed through quantitative polymerase chain reaction.

RESULTS

Prevalence of HP was 62.9% in the whole population and 60.8% in the GC subset. The cagA gene was detected in 79.9%; vacAs1 and vacAm1 alleles in 41.6% and 60.7%, respectively; and concurrent expression of vacAs1 and vacAm1 in 30.4% of infected patients in the whole series. The prevalence of EBV was 14.1% in the whole population and was higher in GC (P < .001). Coinfection of HP and EBV was found in 7.8% and was also higher in GC in univariate (P < .001) and multivariate (P = .011) analyses. Infection rates of HP and EBV were not associated with a geographic location in the whole series. Few clinicopathological features have been associated with infectious status.

CONCLUSION

Prevalence of HP infection and virulent strains are high in the Peruvian population. Infection by EBV was more frequent in patients with GC.

CagL polymorphisms D58/K59 are predominant in Helicobacter pylori strains isolated from Mexican patients with chronic gastritis

Background

Helicobacter pylori is a Gram-negative bacterium that colonizes the gastric mucosa in humans. One of the main virulence factors of H. pylori is the cag pathogenicity island (cagPAI), which encodes a type 4-secretion system (T4SS) and the cytotoxin CagA. Translocation of CagA through the T4SS triggers host-signaling pathways. One of the T4SS proteins is CagL, which is necessary for CagA translocation. CagL is a 26-kDa protein that contains a hypervariable motif, which spans residues 58 to 62. Several polymorphisms in this region have been associated with different disease outcomes, e.g. in Mexico, N58 is associated with a higher risk of gastric cancer. The aim of this work is to analyze the sequence of the hypervariable motif (residues 58 to 62) of clinical isolates from Mexican patients with chronic gastritis, and to correlate these polymorphisms with the vacA genotype.

Results

Of the 164 biopsies analyzed, only 30.5% (50/164) were positive for H. pylori. Thirty-six of the 50 clinical isolates (72%) were cagA positive, and 40 (80%) had the most virulent vacA genotype (s1/m1). Of the cagA positive strains, 94.4% were vacA s1/m1. All the cagA⁺ strains contained the cagL gene. The most prevalent sequence in the polymorphic region (residues 58–62) was DKMGE (75.8%, 25/33), followed by NKMGQ and NEIGQ (6.1%, 2/33), and DEIGQ, NKMGE, DKIGE, and DKIGK (3%, 1/33). Regarding polymorphisms in positions 58 and 59, the most common were D58/K59 (81.8%, 27/33), followed by N58/K59 (9.1%, 3/33), and D58/E59 (3%, 1/33). Only two isolates (6.1%) contained residues N58/E59, which correspond to those found in H. pylori strain ATCC 26695. 92.6% of the clinical isolates having polymorphism D58/K59 had the genotype vacA s1/m1, considered to be the most virulent, while 7.4% had the genotypes vacA s1/m2 and s2/m2.

Conclusions

In Mexican patients, CagL polymorphisms D58, K59, M60, E62, K122, and I134 are more common in patients with chronic gastritis.

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.

Tipping the Scale Toward Gastric Disease: A Host-Pathogen Genomic Mismatch?

PURPOSE OF REVIEW

Chronic infection with Helicobacter pylori infection is necessary but not sufficient to initiate development of intestinal-type gastric adenocarcinoma. It is not clear what additional factors tip the scale from commensal bacteria towards a pathogen that facilitates development of gastric cancer. Genetic variants in both the pathogen and host have been implicated, but neither alone explains a substantial portion of disease risk.

RECENT FINDINGS

In this review, we consider studies that address the important role of human and bacterial genetics, ancestry and their interactions in determining gastric disease risk. We observe gaps in the current literature that should guide future work to confirm the hypothesis of the interacting roles of host and bacterial genetics that will be necessary to translate these findings into clinically relevant information.

SUMMARY

We summarize genetic risk factors for gastric disease in both H. pylori and human hosts. However, genetic variation of one or the other organism in isolation insufficiently explains gastric disease risk. The most promising models of gastric disease risk simultaneously consider the genetic variation of both the H. pylori and human host, under a co-evolution model.

Prevalence of CagA and antimicrobial sensitivity of H. pylori isolates of patients with gastric cancer in Egypt

BACKGROUND

Helicobacter pylori (H. pylori) infection has been recognized as a significant threat for gastric cancer. However, studies that investigated the oncogenic factors and antimicrobial resistance of H. pylori in Egyptian isolates with gastric cancer are rare. The current study aimed to examine: (1) The pattern of antimicrobial resistance of H. pylori isolates of Egyptian gastric cancer patients, and (2) the prevalence of Cytotoxin-associated gene A (CagA).

METHODS

Samples were collected from patients with gastric cancer. Isolation of H. pylori was performed using Columbia blood agar supplemented with 10% horse blood, and selective supplement of H. pylori for 3 to 5 days at 37 °C under microaerophilic condition. Isolates were identified by biochemical traits of H. pylori: oxidase, urease and catalase tests. Antimicrobial susceptibility of H. pylori isolates was examined against five antimicrobial agents using disc diffusion method. After that, extraction of DNA and Polymerase Chain Reaction (PCR) were performed to amplify the target genes.

RESULTS

Twelve samples were collected from six males and six females Egyptian patients with cancer with an age range from 22 to 65 years. These cases are scarce and samples were collected over a period of almost eleven months. All isolates were confirmed as positive H. pylori through colony morphology and biochemical tests. The most effective antibiotic found was ciprofloxacin whereas all isolates showed resistance to metronidazole and erythromycin. The target CagA oncogene gene with expected product size was reported and seven (out of twelve) isolates (58%) were identified as CagA positive.

CONCLUSION

The current study is unique in two main aspects. First, it reported the pattern of antimicrobial susceptibility and prevalence of CagA gene in H. pylori from Egyptian patients. Second, it exclusively recruited isolates from gastric cancer patients which were confirmed by clinical and laparoscopic examination. The moderately high prevalence of CagA gene in Egyptian cancer patients calls for more vigilance against that oncogene.

Primary antibiotic resistance and its relationship with cagA and vacA genes in Helicobacter pylori isolates from Algerian patients

The epidemiology of Helicobacter pylori resistance to antibiotics is poorly documented in Africa and especially in Algeria. The aim of our study was to determine the antibiotic resistance rates, as well as its possible relationship with VacA and CagA virulence markers of isolates from Algerian patients. One hundred and fifty one H. pylori isolate were obtained between 2012 and 2015 from 200 patients with upper abdominal pain. Antimicrobial susceptibility testing was performed for amoxicillin, clarithromycin, metronidazole, ciprofloxacin, rifampicin and tetracycline. Molecular identification of H. pylori and the detection of vacA and cagA genes were performed using specific primers. We found that H. pylori was present in 83.5% of collected biopsies, 54.9% of the samples were cagA positive, 49.67% were vacA s1m1, 18.30% were vacA s1m2 and 25.49% were vacA s2m2. Isolates were characterized by no resistance to amoxicillin (0%), tetracycline (0%), rifampicin (0%), a high rate of resistance to metronidazole (61.1%) and a lower rate of resistance to clarithromycin (22.8%) and ciprofloxacin (16.8%). No statically significant relationship was found between vagA and cagA genotypes and antibiotic resistance results (p > 0.5) except for the metronidazole, which had relation with the presence of cagA genotype (p = 0.001).

Prevalence of Helicobacter pylori vacA Genotypes and cagA Gene in Dental Plaque of Asymptomatic Mexican Children

The variability in Helicobacter pylori vacA and cagA genes has been related to the progression of the gastrointestinal disease; also the presence of H. pylori in the oral cavity has been associated with periodontal disease in adults, but, in children without dyspeptic symptoms, little is known about this. We evaluated the prevalence of H. pylori and the presence of vacA/cagA genotypes in the oral cavity of Mexican children without dyspeptic symptoms. The gingival status was measured, and dental plaque samples (n = 100) were taken. 38% of children were positive for H. pylori 16S rRNA gene by qPCR. A significant association between H. pylori oral infection and gingival status was observed (P < 0.001). In 34.6% (9/26) of mild gingivitis cases, s1m2 genotype was found, while s1m1 was typed in 50% (3/6) of moderate gingivitis. The cagA prevalence among H. pylori-positive children was 80.8% (21/26), 83.3% (5/6), and 16.7% (1/6) of cases of mild gingivitis, moderate gingivitis, and nongingivitis, respectively (P < 0.001). The s1m1/cagA+ combinational genotype was the most detected in children with gingivitis. Our results suggest that the prevalence of H. pylori and detection of vacA/cagA genotypes-associated gastrointestinal disease in the oral cavity could be related to the progression of gingivitis in asymptomatic children.