The endemic Helicobacter pylori population in Southern Vietnam has both South East Asian and European origins

Helicobacter pylori cagA, vacA, and iceA genotypes and clinical outcomes: a cross-sectional study in central Vietnam

Helicobacter pylori is the most common cause of gastroduodenal diseases. The concept that cagA-positive H. pylori is a risk factor for gastric cancer appears to be true only for H. pylori strains from Western countries. Other virulent genes may have a synergistic interaction with cagA during pathogenesis. This study aims to investigate H. pylori cagA, vacA, and iceA prevalence, genotypes, and their association to clinical outcomes in Vietnamese patients. The cagA status and vacA and iceA genotypes were determined using the PCR technique on DNA extracted from gastric biopsies of 141 patients with gastroduodenal diseases. After performing molecular analysis for cagA, vacA, and iceA genes, samples with mixed H. pylori strains, positivity, or negativity for both cagA and cagPAI-empty site, or unidentified genotypes were excluded. Finally, 107 samples were examined. The presence of the cagA, vacA, and iceA genes were detected in 77.6%, 100%, and 80.4% of cases, respectively. Notably, cagA( +) with EPIYA-ABD, vacA s1i1m1, vacA s1i1m2, iceA1, and iceA2 accounted for 73.8%, 44.9%, 33.6%, 48.6%, and 31.8% of cases, respectively. Four iceA2 subtypes (24-aa, 59-aa, 94-aa, and 129-aa variants) were found, with the 59-aa variant the most prevalent (70.6%). The cagA( +)/vacAs1i1m1/iceA1 and cagA( +)/vacAs1i1m2/iceA1 combinations were found in 26.2% and 25.1% of cases, respectively. A multivariable logistic regression analysis was performed, after adjusting for age and gender, with the gastritis group was used as a reference control. Statistically significant associations were found between the vacA s1i1m2 genotype, the iceA1 variant, and the cagA( +)/vacAs1i1m2/iceA1 combination and gastric cancer; the adjusted ORs were estimated as 18.02 (95% CI: 3.39-95.81), 4.09 (95% CI: 1.1-15.08), and 16.19 (95% CI: 3.42-76.66), respectively. Interestingly, for the first time, our study found that vacA s1i1m2, but not vacA s1i1m1, was a risk factor for gastric cancer. This study illustrates the genetic diversity of the H. pylori cagA, vacA, and iceA genes across geographical regions and contributes to understanding the importance of these genotypes for clinical outcomes.

Genomic and vaccine preclinical studies reveal a novel mouse-adapted Helicobacter pylori model for the hpEastAsia genotype in Southeast Asia

Introduction. Helicobacter pylori infection is a major global health concern, linked to the development of various gastrointestinal diseases, including gastric cancer. To study the pathogenesis of H. pylori and develop effective intervention strategies, appropriate animal pathogen models that closely mimic human infection are essential.Gap statement. This study focuses on the understudied hpEastAsia genotype in Southeast Asia, a region marked by a high H. pylori infection rate. No mouse-adapted model strains has been reported previously. Moreover, it recognizes the urgent requirement for vaccines in developing countries, where overuse of antimicrobials is fuelling the emergence of resistance.Aim. This study aims to establish a novel mouse-adapted H. pylori model specific to the hpEastAsia genotype prevalent in Southeast Asia, focusing on comparative genomic and histopathological analysis of pathogens coupled with vaccine preclinical studies.Methodology. We collected and sequenced the whole genome of clinical strains of H. pylori from infected patients in Vietnam and performed comparative genomic analyses of H. pylori strains in Southeast Asia. In parallel, we conducted preclinical studies to assess the pathogenicity of the mouse-adapted H. pylori strain and the protective effect of a new spore-vectored vaccine candidate on male Mlac:ICR mice and the host immune response in a female C57BL/6 mouse model.Results. Genome sequencing and comparison revealed unique and common genetic signatures, antimicrobial resistance genes and virulence factors in strains HP22 and HP34; and supported clarithromycin-resistant HP34 as a representation of the hpEastAsia genotype in Vietnam and Southeast Asia. HP34-infected mice exhibited gastric inflammation, epithelial erosion and dysplastic changes that closely resembled the pathology observed in human H. pylori infection. Furthermore, comprehensive immunological characterization demonstrated a robust host immune response, including both mucosal and systemic immune responses. Oral vaccination with candidate vaccine formulations elicited a significant reduction in bacterial colonization in the model.Conclusion. Our findings demonstrate the successful development of a novel mouse-adapted H. pylori model for the hpEastAsia genotype in Vietnam and Southeast Asia. Our research highlights the distinctive genotype and pathogenicity of clinical H. pylori strains in the region, laying the foundation for targeted interventions to address this global health burden.

Helicobacter pylori Infection and Peptic Ulcer Disease in Symptomatic Children in Southern Vietnam: A Prospective Multicenter Study

BACKGROUND

Helicobacter pylori (H. pylori) remains a major cause of gastroduodenal diseases. We aimed to evaluate the burden of this infection, particularly peptic ulcer disease in Vietnamese children.

METHODS

We enrolled consecutive children referred for esophagogastroduodenoscopy at two tertiary children's hospitals in Ho Chi Minh City, from October 2019 to May 2021. Children treated with proton pump inhibitors during the last two weeks or antibiotics for four weeks, and those having a previous or interventional endoscopy were excluded. H. pylori infection was diagnosed with either a positive culture or positive histopathology combined with a rapid urease test, or with a polymerase chain reaction of the urease gene. The study was approved by the Ethics Committee and written informed consent/assent was obtained.

RESULTS

Among 336 enrolled children aged 4-16 (mean: 9.1 ± 2.4 years; 55.4% girls), H. pylori infection was positive in 80%. Peptic ulcers were detected in 65 (19%), increasing with age, and 25% with anemia. cagA+ strains were detected at a higher rate in children with ulcers.

CONCLUSIONS

Prevalence of H. pylori and peptic ulcers is high among symptomatic Vietnamese children. It is crucial to have a program for early detection of H. pylori to reduce ulcer risk and gastric cancer later.

Effect of Helicobacter pylori on non-homologous end joining-mediated repair of proximal DNA double-strand breaks in GCV6 cells

Infection with Helicobacter pylori is the strongest known risk factor for gastric cancer, which is one of the leading causes of cancer-related mortality worldwide. H. pylori can contribute to carcinogenesis by inducing the genomic instability of infected cells through increasing accumulation of DNA double-stranded breaks (DSBs) and deregulating DSB repair systems. However, the mechanism of this phenomenon is still being elucidated. This study aims to investigate the impact of H. pylori on the efficacy of non-homologous end joining (NHEJ)-mediated repair of DSB. In this study, we used a human fibroblast cell line bearing a single copy of an NHEJ-reporter substrate stably inserted into the genome, which provides a quantitative measurement of NHEJ. Our results indicated the potential abilities of H. pylori strains to alter the NHEJ-mediated repair of proximal DSB in infected cells. In addition, we found an association between the alteration in the NHEJ efficiency, and the inflammation responses of infected cells caused by H. pylori.

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.

Antibiotic Resistance of Helicobacter pylori in Patients with Peptic Ulcer

Background and Objectives: To determine the antibiotic resistance rate of H. pylori among patients with peptic ulcer. Materials and Methods: A cross-sectional monocentric study was conducted from January to December 2021 among patients aged from 16 years with gastrointestinal symptoms and esophagogastroduodenoscopy. Gastric mucosa biopsies were collected at the edges of the ulcer or at lesion sites for H. pylori culture. Five antibiotics (amoxicillin (AMX), clarithromycin (CLR), metronidazole (MTZ), levofloxacin (LEV), and tetracycline (TET)) were selected for antibiotic susceptibility testing. Results: One hundred and twenty-five patients were included, and the sex ratio was 0.6. Their mean age was 47.3 ± 14.2 years. All of the participants had gastritis, and 24.0% had duodenitis. A total of 21.6% of patients had a duodenal ulcer, and 12.8% had an antral ulcer. A total of 40 specimens have grown in H. pylori culture. The proportion of resistance to AMX, CLR, MTZ, LEV, and TET was 27.5%, 50%, 67.5%, 35%, and 5%, respectively. The proportion of multidrug resistance was 22.5%. The proportion of double resistance to AMX + CLR was 20.0%, AMX + MTZ was 15.0%, AMX + LEV was 2.5%, CLR + MTZ was 32.5%, and TET + MTZ was 5.0%. Conclusions: Our research results show that the treatment with MTX-TET or LVX-AMOX has the highest sensitivity rate. Therefore, practitioners should refer to these regimes to eradicate H. pylori in patients with gastric and duodenal ulcers. The reports on H. pylori eradication from different geographic areas show heterogeneous results. Therefore, continuous monitoring of antibiotic resistance of H. pylori in each population is very important. Having evidence helps clinicians to treat patients most effectively, reduce treatment costs, and limit the rate of antibiotic resistance.