Effect of bacterial and host factors on Helicobacter pylori eradication therapy

Unveiling Novel Urease Inhibitors for Helicobacter pylori: A Multi-Methodological Approach from Virtual Screening and ADME to Molecular Dynamics Simulations

Helicobacter pylori (Hp) infections pose a global health challenge demanding innovative therapeutic strategies by which to eradicate them. Urease, a key Hp virulence factor hydrolyzes urea, facilitating bacterial survival in the acidic gastric environment. In this study, a multi-methodological approach combining pharmacophore- and structure-based virtual screening, molecular dynamics simulations, and MM-GBSA calculations was employed to identify novel inhibitors for Hp urease (HpU). A refined dataset of 8,271,505 small molecules from the ZINC15 database underwent pharmacokinetic and physicochemical filtering, resulting in 16% of compounds for pharmacophore-based virtual screening. Molecular docking simulations were performed in successive stages, utilizing HTVS, SP, and XP algorithms. Subsequent energetic re-scoring with MM-GBSA identified promising candidates interacting with distinct urease variants. Lys219, a residue critical for urea catalysis at the urease binding site, can manifest in two forms, neutral (LYN) or carbamylated (KCX). Notably, the evaluated molecules demonstrated different interaction and energetic patterns in both protein variants. Further evaluation through ADMET predictions highlighted compounds with favorable pharmacological profiles, leading to the identification of 15 candidates. Molecular dynamics simulations revealed comparable structural stability to the control DJM, with candidates 5, 8 and 12 (CA5, CA8, and CA12, respectively) exhibiting the lowest binding free energies. These inhibitors suggest a chelating capacity that is crucial for urease inhibition. The analysis underscores the potential of CA5, CA8, and CA12 as novel HpU inhibitors. Finally, we compare our candidates with the chemical space of urease inhibitors finding physicochemical similarities with potent agents such as thiourea.

Application of a WeChat-based mini-app as a patient reminder in Helicobacter pylori eradication: a prospective multi-center randomized controlled study

BACKGROUND

To improve the eradication rate of H. pylori, researchers have investigated the role of WeChat-based mini-app as an electronic reminding system in H. pylori treatment.

METHODS

Subjects from three medical centers were divided into two groups. Patients in the daily mini-app-based notification system group received daily notifications via the WeChat mini-app. Patients in the control group received one-time verbal education on the first clinical visit. Both groups received a 14-day quadruple therapy to eradicate H. pylori infection. Eradication rate, compliance, adverse events and satisfaction were evaluated.

RESULTS

Both intention-to-treat (ITT) and per-protocol (PP) analyses were conducted. The eradication rate in the daily mini-app-based notification system group was slightly higher compared with the control group (ITT analysis: 76.70% vs. 70.73%, p = 0.312; PP analysis: 85.87% vs. 82.86%, p = 0.562). The compliance was significantly higher in the daily mini-app-based notification system group (ITT analysis: 85.52% vs. 70.48%, p = 0.028; PP analysis: 92.39% vs. 81.90%, p = 0.030). The adverse event rates were similar between the two groups (PP analysis: 36.96% vs. 40.95%, p = 0.566). No significant difference in eradication rate was seen in each subgroup analysis by age, place of residence, grade of education, or endoscopic findings.

CONCLUSION

The study showed that daily mini-app-based notification improved patient compliance but not H. pylori eradication rate. Trial registration The research was registered in the Chinese Clinical Trial Registry (ChiCTR2000031011, 21/03/2020).

[Prospects for personalized Helicobacter pylori eradication therapy. Pro et contra]

The article is devoted to debatable aspects of Helicobacter pylori eradication therapy. The eradication cancer-preventive effects are considered. A negative comorbidity between H. pylori infection and such diseases as gastroesophageal reflux disease, inflammatory bowel disease and bronchial asthma has been described. The perspectives of populational, individualized and personalized strategies for H. pylori eradication therapy assessment are given. Recommendations for individualized H. pylori eradication strategy implementation in practical healthcare are proposed.

Involvement of Helicobacter pylori in Preoperative Gastric Findings on a Bariatric Population

The prevalence of Helicobacter pylori (Hp) in bariatric patients is common and related to gastric pathology. With preoperative upper gastrointestinal endoscopy (UGE), these pathologies and the presence of Hp are diagnosed. The histopathological study of the UGE biopsies is classified based on the Sydney System, a scoring system that stages chronic gastritis (CG) and precancerous gastric lesions. The objective is to assess the histological findings of gastric biopsies during routine UGE and to determine the involvement of Hp in gastric disorders in patients undergoing bariatric surgery. A multicenter retrospective review of prospectively collected databases was performed. The presence of CG, gastric atrophy (GA), and gastric intestinal metaplasia (GIM) in the study of the biopsies was assessed and correlated with Hp infection. The incidence of Hp among our bariatric population was 36.1%, and it increases with age. The percentage of patients with severe Hp infection is higher in patients with GA or GIM. The Hp eradication rate is also reduced when GA and GIM are present. A histological examination of all the biopsies did not show features of malignancy in any of the cases. Hp is not the only factor involved in the development of gastric pathology in bariatric patients.

Helicobacter pylori Eradication Efficacy of Therapy Based on the Antimicrobial Susceptibility in Children with Gastritis and Peptic Ulcer in Mekong Delta, Vietnam

Background: The efficacy of Helicobacter pylori (H. pylori) eradication therapy for children is currently low, and antibiotic resistance is a significant cause of treatment failure. The purpose of this study was to evaluate the H. pylori eradication efficacy of therapy based on antimicrobial susceptibility in pediatric patients with gastritis and peptic ulcer. Methods: This study was conducted at Can Tho Children’s Hospital and Can Tho University of Medicine and Pharmacy Hospital between March 2019 and April 2022. We performed an upper gastrointestinal endoscopy, cultured H. pylori from biopsies of gastric mucosa, determined antibiotic sensitivities to H. pylori by the E-test method, and treated eradication based on the antibiotic susceptibilities of bacteria. After at least 4 weeks of eradication therapy, we assessed the effectiveness of treatment with a breath test. Results: Among 237 children recruited in this study, 48.9% were boys and 51.1% were girls, and the mean age was 10.03 ± 2.53 years. We determined that 80.6% of H. pylori were resistant to clarithromycin, as well as amoxicillin, metronidazole, levofloxacin, and tetracycline, at 71.7%, 49.4%, 45.1%, and 11.4%, respectively. The overall eradication rate of H. pylori was 83.1% (172/207). Among therapies tailored to antimicrobial susceptibility, the bismuth quadruple regimen achieved the greatest success, but the efficacy of triple therapy with esomeprazole + AMX + CLR/MTZ was low. Conclusions: Tailored eradication therapy was highly successful in our study but did not achieve over 90%. We recommend that in countries with a high prevalence of antibiotic resistance in H. pylori strains, particularly where the amoxicillin-resistance rate of H. pylori is high, therapy tailored to antimicrobial susceptibility should be used as first-line therapy, and bismuth and tetracycline should be added to enhance the eradication efficacy in children.

Failure to eradicate Helicobacter pylori infection is more frequent among HIV-positive patients

OBJECTIVES

Helicobacter pylori is a worldwide infection, but little is known about the efficacy of treatment for H. pylori infection in HIV-positive patients. The goal of this work was to evaluate outcomes after first-line H. pylori treatment and identify risk factors for failure in HIV-positive patients.

METHODS

This registry study of unmatched H. pylori-infected HIV-positive patients and HIV-negative obese pre-bariatric surgery controls was performed in a tertiary university hospital. Cases were enrolled from 2006 to 2017, controls from 2007 to 2014, and both received standard of care. An additional 'optimal' subgroup of cases was enrolled prospectively from 2017 to 2019 which was treated only on the basis of antibiogram, drug interaction search and additional support by one referent physician. Helicobacter pylori eradication failure rates were compared according to clinical, microbiological and pathological parameters and treatment.

RESULTS

We analysed 258 HIV-positive patients and 204 HIV-negative control patients. Helicobacter pylori eradication failure rates were markedly greater in cases (24.1%) than in controls (8.8%). The proportions of levofloxacin and metronidazole resistance were greater in cases than in controls (P < 0.05). Among cases treated with H. pylori triple therapy (S3T), the 'optimal' subgroup experienced a 9.5% failure rate vs. 28.6% with other strategies (P = 0.01). Risk factors for failure were H. pylori treatment strategy, exposure to antiretroviral treatment, and alcohol status. Overall, positive HIV status was a risk factor for S3T eradication failure.

CONCLUSIONS

Patients co-infected with H. pylori and HIV frequently failed to eradicate H. pylori and this was related to treatment strategy, antiretroviral exposure and lifestyle.

Helicobacter pylori treatment in the post-antibiotics era-searching for new drug targets

Abstract

Helicobacter pylori, a member of Epsilonproteobacteria, is a Gram-negative microaerophilic bacterium that colonizes gastric mucosa of about 50% of the human population. Although most infections caused by H. pylori are asymptomatic, the microorganism is strongly associated with serious diseases of the upper gastrointestinal tract such as chronic gastritis, peptic ulcer, duodenal ulcer, and gastric cancer, and it is classified as a group I carcinogen. The prevalence of H. pylori infections varies worldwide. The H. pylori genotype, host gene polymorphisms, and environmental factors determine the type of induced disease. Currently, the most common therapy to treat H. pylori is the first line clarithromycin–based triple therapy or a quadruple therapy replacing clarithromycin with new antibiotics. Despite the enormous recent effort to introduce new therapeutic regimens to combat this pathogen, treatment for H. pylori still fails in more than 20% of patients, mainly due to the increased prevalence of antibiotic resistant strains. In this review we present recent progress aimed at designing new anti-H. pylori strategies to combat this pathogen. Some novel therapeutic regimens will potentially be used as an extra constituent of antibiotic therapy, and others may replace current antibiotic treatments.

Key points

• Attempts to improve eradication rate of H. pylori infection.

• Searching for new drug targets in anti-Helicobacter therapies.

Analysis of Correlation between the Seven Important Helicobacter pylori (H. pylori) Virulence Factors and Drug Resistance in Patients with Gastritis

The aim of this study is to evaluate the association between seven important H. pylori virulence factors and antibiotic resistance in patients with gastritis. H. pylori strains isolated from 33 patients with gastritis were examined. Antimicrobial susceptibilities were tested by GenoType® HelicoDR (Hain Life Science, Germany) test kit and RT-PCR. The virulence-factors were determined using conventional PCR. 39% of patients were resistant for clarithromycin and 27% of patients were resistant for fluoroquinolone. 15% of patients were resistant to both clarithromycin and fluoroquinolone. The H. pylori vacA m1/s2 genotype was the most frequent allelic combination. Patients were possessed the vacA s1, m1 (6.1%); s1, m2 (6.1%); s2, m1 (15.1%); and s2, m2 (3.0%) genotypes. 94% of patients with gastritis were positive for H. pylori napA gene. Also, there were no dupA gene-positive gastritis patients. There was no significant correlation between the vacA, cagA, oipA, hpaA, babA, napA, dupA, ureA, ureB virulence genes, clarithromycin, and fluoroquinolone resistance. Herein, we report that the relationship between the H. pylori napA gene and gastritis. Although we found a correlation between H. pylori virulence factor and clinical outcome, there is a need for further studies to enlighten the relation between H. pylori virulence genes and antibiotic resistance.

Clarithromycin-Susceptible But Virulent Helicobacter pylori Strains Infecting Iranian Patients' Stomachs

Introduction

Helicobacter pylori was discovered first in the stomachs of patients with gastritis and ulcers by Marshall and Warren in 1982. This discovery majorly affected many research areas of gastroenterology. Since then, the main aim has been to eradicate this microaerophilic bacterium from the stomachs of infected subjects.

Methods

We studied symptomatic cases by endoscopic surgery and examined the prevalence of cagA-vacA genotypes among the H. pylori isolates. H. pylori isolated from antral biopsies of patients with gastritis and duodenal ulcer were subjected to antimicrobial susceptibility testing and PCR genotyping by using routine bacterial cultures. Clarithromycin-susceptibility profiling was done by the E-test. DNA was extracted using standard manufacturer protocols with minor modifications and cagA and vacA genotyping was done PCR.

Results

In our study, all strains identified as H. pylori in culture (61/81) were confirmed by PCR by amplifying a fragment of the glmM gene. Totally, 61 patients were confirmed to be positive for H. pylori and they were included in the genotyping and antibiotic-susceptibility testing. Thirteen H. pylori strains were determined to be resistant to clarithromycin.

Discussion

Current accumulating data indicate that both clarithromycin-resistant and susceptible isolates of H. pylori need to be screened and tracked in populations.

[The efficacy and safety of quadruple therapy without bismuth (concomitant therapy) in the treatment of patients with Helicobacter pylori - associated gastric and duodenal peptic ulcer disease]

AIM

Evaluation of the efficacy and safety of quadrupletherapy without bismuth (concomitant therapy) in patients with Helicobacter pylori - associated gastric ulcer and duodenal ulcer in the framework of a comparative research in the population of patients in Russia.

MATERIALS AND METHODS

A prospective randomized trial was conducted, which included 210 patients with H. pylori - associated gastric/duodenal ulcer without complications. During the process of randomization, the patients were divided into three equal groups (n=70) depending on the prescribed 10-day scheme of eradication therapy (ET): the first group received the classic triple scheme (Omeprazole 20 mg 2 times a day, Amoxicillin 1000 mg 2 times a day and Clarithromycin 500 mg 2 times a day); the second group received quadruple therapy with bismuth drugs (Omeprazole 20 mg 2 times a day, Tetracycline 500 mg 4 times a day, Metronidazole 500 mg 3 times a day, Bismuth subcitrate potassium 120 mg 4 times a day); the third group received quadruple therapy without bismuth - concomitant therapy (Omeprazole 20 mg 2 times a day, Amoxicillin 1000 mg 2 times a day, Clarithromycin 500 mg 2 times a day and Metronidazole 500 mg 2 times a day). Diagnostics of H. pylori infection during screening and control of eradication was carried out via the fast urease biopsy sample test and urea breath test system. Control of the effectiveness of ET of the microorganism was carried out not earlier than 4 weeks after the end of the treatment. During the course of therapy, the frequency of development of side effects was assessed using a special questionnaire.

RESULTS AND DISCUSSION

The effectiveness of triple therapy was 72.8% (ITT; 95% CI of 62.17-83.54) and 78,4% (PP; 95% CI 68.19-88.72); quadruple therapy with the preparation of bismuth - 80.0% (ITT; 95% CI 70.39-89.6) and 84,8% (PP; 95% CI, 75.96-93.73); quadruple therapy without bismuth - concomitant therapy - 84.2% (ITT; 95% CI 75.54-93.02) and 92.1% (PP; 95% CI 85.43-98.94). Quadruple therapy without bismuth was reliably more effective than the classical triple therapy in the PP selection (p=0.044883). Statistical analysis showed a tendency to poorer effectiveness of ET in patients who had previously used antibiotic therapy (OR 0.4317; 95% CI 0.1776-1.049), and in individuals with a rapid metabolism genotype - CYP2C19*1/*1 (OR 0.12; 95% CI 0.005848-2.4624). The frequency of development of side effects during the use of triple therapy was 18.5% (95% CI of 9.23-27.91), when using quadruple therapy with bismuth - 20.0% (95% CI 10.39-29.6), and with the use of quadruple therapy without bismuth - concomitant therapy - 24.2% (95% CI 13.98-34.58).

CONCLUSION

This prospective randomized study demonstrated the high efficiency of quadruple therapy without bismuth (concomitant therapy) in the framework of eradication of H. pylori infection in Russia.

The antibiotic resistance of Helicobacter pylori to five antibiotics and influencing factors in an area of China with a high risk of gastric cancer

Background

H. pylori exhibits antibiotic resistance with regional differences. In this paper, we explored antibiotic resistance of H. pylori to five antibiotics in an area with a high risk of gastric cancer.

Results

H. pylori resistance rates to metronidazole, levofloxacin, clarithromycin, amoxicillin, and tetracycline were 78.0, 56.0, 31.0, 9.0, and 15.0%, respectively. Double, triple, quadruple, and quintuple resistance rates were 23, 20, 6, and 4%, respectively. The clarithromycin and multidrug resistance rates were significantly higher in males than females (clarithromycin: 44.4% vs 15.2%, respectively, P = 0.002; multidrug: 75.5% vs 37.2%, respectively; P < 0.001). During the three periods of 1998–1999, 2002–2004 and 2016–2017, the resistance rates to levofloxacin and amoxicillin were increasing (OR: 2.089, 95%CI: 1.142–3.821, P = 0.017; and OR: 5.035, 95%CI: 1.327–19.105, P = 0.018, respectively). The antibiotic resistance rates were unassociated with the host disease state. Metronidazole resistance was lower in the vacAs1m1/m2 group than the vacAs1m1m2 group (65% vs 85.7%, respectively; P = 0.026). As for levofloxacin resistance, it was higher with cagA⁺ than cagA⁻ (60.9% vs 23.1%, respectively; P = 0.020) but lower with slyD⁺ than slyD⁻ (41.4% vs 68.5%, respectively; P = 0.009). Clarithromycin had a lower resistance rate with iceA⁺⁺ than iceA⁻⁺ (19.7% vs 52.4%, respectively; P = 0.017). For amoxicillin, the iceA⁺⁺ group had a lower resistance rate than the iceA⁻⁻ group (1.6% vs 27.8%, respectively; P = 0.009).

Conclusions

The total resistance rates of H. pylori to metronidazole, levofloxacin, clarithromycin, amoxicillin, and tetracycline were high in Zhuanghe. The resistanc rates to levofloxacin and amoxicillin increased over time. Clarithromycin resistance was associated with male and iceA. The resistance of metronidazole was related to vacA. Levofloxacin resistance was concerned with cagA and slyD and amoxicillin resistance was concerned with iceA. While, the antibiotic resistance of H. pylori had nothing to do with the status of gastric disease.

Efficacy and safety of the use of rebamipide in the scheme of triple eradication therapy of Helicobacter pylori infection: a prospective randomized comparative study

Purpose of the study. To evaluate the effectiveness and safety of the use of rebamipide as part of the triple eradication therapy (ET) scheme of Helicobacter pylori infection. Materials and methods. A prospective, randomized comparative study included 94 patients with uncomplicated H. pylori-associated stomach / duodenal ulcer. In the process of randomization, patients are divided into three groups depending on the intended therapy. The first group (n=36) received a classical triple scheme of the first-line ET (omeprazole 20 mg twice a day, amoxicillin 1000 mg twice a day, clarithromycin 500 mg twice a day) for 10 days. Patients of the second group (n=33) were assigned a classical triple scheme of ET with the inclusion of rebamipide (omeprazole 20 mg twice a day, amoxicillin 1000 mg twice a day, clarithromycin 500 mg twice a day, rebamipide 100 mg 3 times a day day) for 10 days. Patients of the third group (n=25) were assigned a classical triple scheme of ET with the inclusion of rebamipide (omeprazole 20 mg twice a day, amoxicillin 1000 mg twice a day, clarithromycin 500 mg twice a day, rebamipide 100 mg 3 times a day) in for 10 days, with the prolongation of the administration of rebamipide for the next 20 days. The effectiveness of ET was determined by the respiratory test after 6 weeks after the end of treatment. Adverse events were recorded by patients in specially developed diaries. All patients with gastric ulcer at the 6th week underwent a histological examination of the biopsy specimens of the antrum and the body of the stomach, assessing the inflammatory activity of the process on a point system in accordance with the updated Sydney system. Results and discussion. Efficiency of H. pylori eradication in the first group was 77.7% (ITT), 82.3% (PP), in the second group - 81.8% (ITT), 84.4% (PP), and in the third group - 84% (ITT), 87.5% (PP). The use of rebamipide in the triple ET regimen was associated with an increase in H. pylori eradication efficiency, both with simultaneous use with the scheme [odds ratio (OR) 1.16; 95% confidence interval (CI) 0.32-4.24], and with subsequent prolonged admission (OR 1.5, 95% CI 0.34-6.7). A somewhat more pronounced dynamics of the epithelization of erosive and ulcerative changes in the mucous membrane of the stomach and duodenum to the 21st and 28th days in the third group of patients was noted. The incidence of adverse events between the groups was comparable: 22.2% in the first group, 24.2% in the second group and 20% in the third group. In the pathomorphological evaluation of biopsy specimens of patients with gastric ulcer at the 6th week after the treatment, significant differences were revealed between the first and third groups in terms of the inflammatory activity in the antrum stomach (2±0.63 vs. 1.4±0.52; p=0,0399). The conclusion. The inclusion of rebamipide in the classical triple scheme of H. pylori ET increases the effectiveness of treatment and does not affect the safety profile. In the post-eradication period, it is advisable to continue the use of rebamipide to potentiate the repair of the gastric mucosa and regress the inflammatory processes.

Fifth Chinese National Consensus Report on the management of Helicobacter pylori infection

BACKGROUND

Since the 'Fourth Chinese National Consensus Report on the management of H. pylori infection' was published in 2012, three important consensuses (Kyoto global consensus report on H. pylori gastritis, The Toronto Consensus for the Treatment of H. pylori Infection in Adults and Management of H. pylori infection-the Maastricht V/Florence Consensus Report) have been published regarding the management of H. pylori infection.

MATERIALS AND METHODS

A Delphi method was adopted to develop the consensus of relevant 'statements'. First, the established 'statements' were sent to experts via email. Second, after undergoing two rounds of consultation, the initial statements were discussed face to face and revised in the conference item by item on 16 December 2016. Finally, 21 core members of conferees participated in the final vote of statements. Voting for each statement was performed using an electronic system with levels of agreements shown on the screen in real time.

RESULTS

Consensus contents contained a total of 48 "statements" and related 6 parts, including indications for H. pylori eradication, diagnosis, treatment, H. pylori and gastric cancer, H. pylori infection in special populations, H. pylori and gastrointestinal microbiota.

CONCLUSIONS

Recommendations are provided on the basis of the best available evidence.

Can bacterial virulence factors predict antibiotic resistant Helicobacter pylori infection?

AIM

To evaluate the association between virulence factor status and antibiotic resistance in Helicobacter pylori (H. pylori)-infected patients in Ireland.

METHODS

DNA was extracted from antral and corpus biopsies obtained from 165 H. pylori-infected patients. Genotyping for clarithromycin and fluoroquinolone-mediating mutations was performed using the Genotype HelicoDR assay. cagA and vacA genotypes were investigated using PCR.

RESULTS

Primary, secondary and overall resistance rates for clarithromycin were 50.5% (n = 53/105), 78.3% (n = 47/60) and 60.6% (n = 100/165), respectively. Primary, secondary and overall resistance rates for fluoroquinolones were 15.2% (n = 16/105) and 28.3% (n = 17/60) and 20% (n = 33/165), respectively. Resistance to both antibiotics was 12.4% (n = 13/105) in treatment-naïve patients, 25% (n = 15/60) in those previously treated and 17% (n = 28/165) overall. A cagA-positive genotype was detected in 22.4% (n = 37/165) of patient samples. The dominant vacA genotype was S1/M2 at 44.8% (n = 74/165), followed by S2/M2 at 26.7% (n = 44/165), S1/M1 at 23.6% (n = 39/165) and S2/M1 at 4.8% (n = 8/165). Primary clarithromycin resistance was significantly lower in cagA-positive strains than in cagA-negative strains [32% (n = 8/25) vs 56.3% (n = 45/80) P = 0.03]. Similarly, in patients infected with more virulent H. pylori strains bearing the vacA s1 genotype, primary clarithromycin resistance was significantly lower than in those infected with less virulent strains bearing the vacA s2 genotype, [41% (n = 32/78) vs 77.8% (n = 21/27) P = 0.0001]. No statistically significant association was found between primary fluoroquinolone resistance and virulence factor status.

CONCLUSION

Genotypic H. pylori clarithromycin resistance is high and cagA-negative strains are dominant in our population. Less virulent (cagA-negative and vacA S2-containing) strains of H. pylori are associated with primary clarithromycin resistance.

The association between vacA or cagA status and eradication outcome of Helicobacter pylori infection: A meta-analysis

Background

H. pylori virulence factors, especially vacA and cagA are important in gastroduodenal disease pathogenesis and affect cure rates. This meta-analysis aimed to clarify the association between vacA or cagA status and eradication outcome of H. pylori infection.

Methods

A literature search was performed using electronic databases to identify studies. Twenty-six prospective studies were determined eligible. Meta-analytical techniques were conducted to calculate eradication rates and pooled relative ratios (RR).

Results

The eradication rate was greater approximately 10% in vacA s1 compared with vacA s2 infected patients, and the pooled RR was 1.164 (95%CI: 1.040–1.303, P = 0.008). A significant association existed between vacA s1 and higher eradication rates in Europe (RR: 1.203, 95%CI: 1.003–1.442, P = 0.046) and Asia (RR: 1.187, 95%CI: 1.028–1.371, P = 0.020), in triple therapy patients (RR: 1.175, 95%CI: 1.012–1.365, P = 0.035). Eradication rates were similar for vacA m1 and m2 genotypes (RR: 0.981, 95%CI: 0.891–1.080, P = 0.690), whereas they were higher by approximately 8% in cagA-positive compared with cagA-negative infected patients, with a pooled RR of 1.094 (95%CI: 1.025–1.168, P = 0.007). A significant association existed between cagA-positive and increased eradication rates in Europe (RR: 1.138, 95%CI: 1.000–1.295, P = 0.049) and Asia (RR: 1.118, 95%CI: 1.051–1.190, P<0.001), in using PCR (RR: 1.232, 95%CI: 1.142–1.329, P<0.001) and protein chips (RR: 1.200, 95%CI: 1.060–1.359, P = 0.004), in triple therapy patients (RR: 1.090, 95%CI: 1.006–1.181, P = 0.034).

Conclusions

Evidence indicates that infection with vacA s1, cagA-positive strains, but not vacA s2, cagA-negative, is more conducive to H. pylori eradication.

The Bifunctional Enzyme SpoT Is Involved in the Clarithromycin Tolerance of Helicobacter pylori by Upregulating the Transporters HP0939, HP1017, HP0497, and HP0471

Clarithromycin (CLA) is a commonly recommended drug for Helicobacter pylori eradication. However, the prevalence of CLA-resistant H. pylori is increasing. Although point mutations in the 23S rRNA are key factors for CLA resistance, other factors, including efflux pumps and regulation genes, are also involved in the resistance of H. pylori to CLA. Guanosine 3′-diphosphate 5′-triphosphate and guanosine 3′,5′-bispyrophosphate [(p)ppGpp)], which are synthesized by the bifunctional enzyme SpoT in H. pylori, play an important role for some bacteria to adapt to antibiotic pressure. Nevertheless, no related research involving H. pylori has been reported. In addition, transporters have been found to be related to bacterial drug resistance. Therefore, this study investigated the function of SpoT in H. pylori resistance to CLA by examining the shifts in the expression of transporters and explored the role of transporters in the CLA resistance of H. pylori. A ΔspoT strain was constructed in this study, and it was shown that SpoT is involved in H. pylori tolerance of CLA by upregulating the transporters HP0939, HP1017, HP0497, and HP0471. This was assessed using a series of molecular and biochemical experiments and a cDNA microarray. Additionally, the knockout of genes hp0939, hp0471, and hp0497 in the resistant strains caused a reduction or loss (the latter in the Δhp0497 strain) of resistance to CLA. Furthermore, the average expression levels of these four transporters in clinical CLA-resistant strains were considerably higher than those in clinical CLA-sensitive strains. Taken together, our results revealed a novel molecular mechanism of H. pylori adaption to CLA stress.

[Possibilities for optimization of eradication therapy for Helicobacter pylori infection in modern clinical practice]

A steady decline in the effectiveness of standard eradication therapy (ET) regimens for Helicobacter pylori infection necessitates a search for ways of their optimization, by enhancing the efficiency of treatment protocols and by improving their safety and tolerability. The review systematizes the data available in the literature on main accessible methods for optimizing ET regimens. Among the optimization methods that can considerably enhance the efficiency of ET regimens, one may identify their addition of a bismuth agent (by 10-20%), the use of rebamipide (by 11.9%), adjuvant therapy with probiotics (by 8.1-13%), or double-dose proton pump inhibitors (by 8%). Only adjuvant therapy with probiotics results in a significant decrease in the incidence of side effects from ET. In posteradication period, rebamipide should be used to potentiate gastric mucosal repair and to regress inflammatory processes.

[Molecular genetic predictors of resistance to anti-Helicobacter pylori therapy]

In current clinical practice, there is no optimal empirical therapy for Helicobacter pylori (H. pylori) infection and there is a progressive decrease in the efficiency of classical eradication therapy (ET) regimens. The variability in the efficiency of ET in a specific patient is largely due to the heterogeneous molecular genetic mechanisms underlying the resistance of the microorganism to the components of the treatment regimens. The basis of the mechanisms for antibiotic resistance in H. pylori is mainly the point mutations in some genes, which determine alterations in the mechanisms of action of drugs, such as clarithromycin (domain V of 23S rRNA), metronidazole (rdxA, frxA), amoxicillin (pbp1A), tetracycline (16S rRNA), and levofloxacin (gyrA). The predictors of resistance to ET are also the CagA-negative status of the microorganism and the presence of the vacA s2 allele. There are a number of host genetic determinants (the CYP2C19 genotype (*1/*1, *1/*17, *17/*17) and the MDR1 3435 T/T genotype (in an Asian population)) that reduce the efficiency of ET, by altering the pharmacokinetics of proton pump inhibitors. In addition, the IL-1β-511 C/C polymorphism that affects gastric acid secretion is a predictor of the inefficiency of ET.

Update on prevention and treatment of Helicobacter pylori infection

From the first isolation of Helicobacter pylori (H. pylori) from the gastric mucosa by Marshall and Warren in 1983, 33 years have passed. H. pylori has been found to be closely associated not only with chronic gastric diseases but also with multiple system diseases. Advances in research of H. pylori infection has led to a better understanding of the pathogenicity of H. pylori and the prevention and treatment of related disease. In 2015, Professor Zou's team developed oral recombinant H. pylori vaccine, which is promising in the prevention of H. pylori infection. Japan aims to reduce the risk of H. pylori infection in the whole population in 2014 to reduce the incidence of gastric cancer, which has caused widespread concern. H. pylori infection is a kind of infectious disease, and the infection rate in China is about 56%.Therefore, it is of great clinical importance to strengthen the research on bacteriology and pathogenesis of H. pylori, improve the prevention and treatment related diseases, and seek antibacterial regimens with better efficacy and lower drug resistance.