Role of Bismuth in the Eradication of Helicobacter pylori

The antibacterial activity and selectivity of bismuth(III) tris(8-hydroxyquinolinates)

The series of bismuth(III) tris(8-hydroxyquinolinates); [Bi(Q")3] (1), [Bi(Q'Cl)3] (2), [Bi(QCl2)3] (3), [Bi(QBr2)3] (4), and [Bi(QI2)3] (5) (where Q"-H = C9H7NO; Q'Cl-H = C9H6NOCl, QCl2-H = C9H5NOCl2; QBr2-H = C9H5NOBr2; and QI2-H = C9H5NOI2) were synthesised, fully characterised, and evaluated for their antibacterial activity towards three Gram-positive bacteria (vancomycin-resistant E. faecalis, S. aureus, methicillin-resistant S. aureus), and four Gram-negative bacteria (A. baumannii, P. aeruginosa, K. pneumoniae, and E. coli) and also their cytotoxicity towards mammalian cells. New crystallographic data on 4 indicates it is dimeric in the solid state through 'Bi2O2' bridging which is consistent with data previously reported for 5. The five complexes (1-5) all exhibited good but variable antibacterial activity and selectivity. Complexes 2 and 5 showed significant activity towards Gram-positive bacteria with MIC (minimum inhibitory concentration) values ranging from 0.78 μM - 3.13 μM and selectivity indices of 6.2 - ≥16.0. For Gram-negative species, complexes 3 and 4 exhibited highly selective activity towards multi-drug resistant strains of A. baumannii with a range of MIC values 0.39-1.56 μM and selectivity indices of 3.14-7.23 respectively. While some of the 8-hydroxyquinolines themselves show reasonable antibacterial activity this is generally enhanced through complexation to bismuth(III).

Efficacy and safety of vonoprazan-amoxicillin dual therapy versus bismuth-containing quadruple therapy for patients with Helicobacter pylori infection: a meta-analysis

Introduction

This meta-analysis aims to compare the efficacy and safety of vonoprazan-amoxicillin (VA) dual therapy in comparison to bismuth-containing quadruple therapy (BQT) for patients with Helicobacter pylori (H. pylori) infection.

Materials and methods

Four databases (PubMed, Embase, Web of Science, and Cochrane Library) were searched published from establishment of database to June 1, 2024, for articles studying VA dual therapy compared to BQT for patients with H. pylori infection. Meta-analyses of eradication rates, adverse events, compliance and cost were preformed.

Results

A total of 17 studies were included for meta-analysis. Compared with BQT, VA increased the incidence of H. pylori eradication rate, with significant difference under the ITT analysis (86.9% vs. 80.4%, RR = 1.07, 95% CI: 1.01-1.12, p = 0.01) but there no significant difference under the PP analysis (90.7% vs. 86.5%, RR = 1.03, 95% CI: 0.99-1.08, p = 0.13). Besides, VA significantly increased compliance (RR = 1.03, 95% CI: 1.01-1.05, p < 0.01) and decreased the occurrence of total adverse events (27.0% vs. 11.5%, RR = 0.43, 95% CI: 0.37-0.51, p < 0.01). Furthermore, VA has lower cost compared to BQT.

Conclusion

Our findings indicated that VA dual therapy provided a higher eradication rate, enhanced compliance, decreased adverse events, and lowered cost relative to BQT for patients with H. pylori infection.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024576738, identifier CRD42024576738 (PROSPERO).

Overcoming antibiotic-resistant Helicobacter pylori infection: Current challenges and emerging approaches

Recent studies have shown a noticeable increase in global Helicobacter pylori (H. pylori) resistance, with clarithromycin resistance surpassing 15% in various areas. However, inadequate epidemiological monitoring, especially in developing countries, and the absence of uniform testing methods lead to discrepancies between regions and a possible underestimation of resistance levels. The complexity of treating H. pylori is driven by its highly dynamic genome, which is prone to frequent mutations contributing to phenotypical resistance. The usual course of action in empirical treatment involves using a combination of various drugs simultaneously, leading to significant resistance selection pressure and potential side effects. The emergence of H. pylori strains resistant to multiple drugs is closely tied to failures in first-line treatment, highlighting the need to prevent further resistance by using optimal initial empirical therapy or regimens guided by antibiotic susceptibility testing, requiring a collection of mixed samples and multiple isolates for accurate assessment. The emergence of new treatments like potassium-competitive acid blockers offers a hopeful approach to decrease antimicrobial usage while still ensuring effectiveness in comparison to traditional therapies with proton pump inhibitors. Additionally, the use of probiotics is under investigation to identify specific strains and formulations that may mitigate therapy-associated adverse effects.

The Effect of the Combination of Probiotics and Heavy Metals From Various Aspects in Humans: A Systematic Review of Clinical Trial Studies

Background and Aims

Probiotics usually have beneficial effects on the absorption of trace elements and detoxification of toxic metals in human. Hence, the aim of the systematic review was to evaluate various aspects of the effect of the combination of probiotics and heavy metals in human clinical trial studies.

Methods

Nine databases were searched for clinical trials up to June 2024 investigating probiotics for heavy metal exposure in humans. Two reviewers independently screened records and extracted data on study characteristics, interventions, outcomes, and results. Risk of bias was assessed.

Results

The analysis included 31 clinical trials with a total of 4,611 participants, focusing on the effects of probiotics, prebiotics, and synbiotics. Among the trials, 23 investigated probiotics, five looked at prebiotics, and three explored synbiotics, with probiotic doses ranging from 107 to 2.5 × 1010 CFU/day. Results indicated that probiotics combined with zinc significantly reduced the time to resolution of vomiting and diarrhea compared to zinc alone, improved the treatment efficacy of antibiotic-associated diarrhea linked to pneumonia, and shortened hospital stays relative to probiotics alone. Probiotics did not show significant effects on blood parameters compared to placebo; however, prebiotic galactooligosaccharides enhanced iron absorption in women and children. The addition of probiotics to bismuth quadruple therapy did not improve Helicobacter pylori eradication rates but reduced side effects like diarrhea and vomiting. One trial reported a decrease in toxic metal levels in pregnant women due to probiotics, but no similar effects were observed in children.

Conclusions

Probiotics are one of the new methods employed to improve or eliminate the adverse effects of heavy metals in the body. Although many studies have investigated the effects of probiotics on heavy metals, there is still a need for more in-depth and extensive studies.

Rapid diagnosis and precision treatment of Helicobacter pylori infection in clinical settings

Helicobacter pylori is a gram-negative bacterium that colonizes the stomach of approximately half of the worldwide population, with higher prevalence in densely populated areas like Asia, the Caribbean, Latin America, and Africa. H. pylori infections range from asymptomatic cases to potentially fatal diseases, including peptic ulcers, chronic gastritis, and stomach adenocarcinoma. The management of these conditions has become more difficult due to the rising prevalence of drug-resistant H. pylori infections, which ultimately lead to gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. In 1994, the International Agency for Research on Cancer (IARC) categorized H. pylori as a Group I carcinogen, contributing to approximately 780,000 cancer cases annually. Antibiotic resistance against drugs used to treat H. pylori infections ranges between 15% and 50% worldwide, with Asian countries having exceptionally high rates. This review systematically examines the impacts of H. pylori infection, the increasing prevalence of antibiotic resistance, and the urgent need for accurate diagnosis and precision treatment. The present status of precision treatment strategies and prospective approaches for eradicating infections caused by antibiotic-resistant H. pylori will also be evaluated.

Should Metronidazole Be Included in Second-Line Treatment After Standard Triple Therapy for Helicobacter pylori?: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND AIM

Although standard triple therapy remains the first-line eradication treatment for H. pylori worldwide, it is unclear whether metronidazole should be included empirically in second-line eradication treatments. The aim of this study was to compare the efficacy of metronidazole-containing regimens with that of metronidazole-free regimens after failure of first-line eradication using standard triple therapy.

METHODS

PubMed, the Cochrane Library, and the Igaku-Chuo-Zasshi database were searched to identify RCTs eligible for inclusion in this systematic review and meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Thirteen eligible RCTs were included, with a total of 2039 patients assigned to metronidazole-containing (975 patients) or metronidazole-free (1064 patients) regimens. Metronidazole-containing regimens had significantly lower eradication failure rates than regimens without metronidazole (OR 0.55; 95% CI, 0.39-0.78). Subgroup analysis based on the regional risk of metronidazole resistance demonstrated that metronidazole-containing regimens had lower eradication failure rates not only in low-risk regions but also in high-risk regions (OR, 0.29; 95% CI, 0.11-0.74 and OR, 0.66; 95% CI, 0.49-0.91, respectively).

CONCLUSION

After failure of standard triple therapy, secondary eradication treatment regimens containing metronidazole demonstrate higher eradication rates than those without metronidazole.

Immunobiological effects of lipopolysaccharide derived from Helicobacter pylori and influence of a proton pump inhibitor lansoprazole on human polymorphonuclear leukocytes

Helicobacter pylori colonizes the human gastric mucosa of more than half of the human population and has a unique lipopolysaccharide (LPS) structure. LPS is the most dominant and suitable pathogen-associated molecular pattern that is detected via pattern recognition receptors. Although the priming effect of H. pylori LPS on reactive oxygen species (ROS) production of PMNs is lower than that of Escherichia coli O111:B4 LPS, LPS released from H. pylori associated with antibiotics eradication therapy may activate PMNs and increase ROS production. In addition, we describe the effects of H. pylori and E. coli O111:B4 LPSs on gene expression and the anti-inflammatory effect of lansoprazole (LPZ) in human polymorphonuclear leukocytes. LPS isolated from H. pylori and E. coli O111:B4 alters toll-like receptor 2 (TLR) and TLR4 expressions similarly. However, LPS from E. coli O111:B4 and H. pylori caused a 1.8-fold and 1.5-fold increase, respectively, in CD14 expression. All LPS subtypes upregulated TNFα and IL6 expression in a concentration-dependent manner. Although E. coli O111:B4 LPS upregulated IL8R mRNA levels, H. pylori LPS did not (≦ 100 ng/mL). Gene expression levels of ITGAM demonstrated no significant change on using both LPSs. These different effects on the gene expression in PMNs may depend on variations in LPS structural modifications related to the acquired immunomodulatory properties of H. pylori LPS. Proton pump inhibitors, i.e., LPZ, are used in combination with antibiotics for the eradication therapy of H. pylori. LPZ and its acid-activated sulphenamide form AG-2000 suppress ROS production of PMNs in a dose-dependent manner. These results suggest that LPZ combination with antibiotics for H. pylori eradication reduces gastric inflammation by suppressing ROS release from PMNs.

Comparison of vonoprazan bismuth-containing triple therapy with quadruple therapy in Helicobacter pylori-infected treatment-naive patients: a prospective multicenter randomized controlled trial

BACKGROUND AND AIM

Helicobacter pylori infection is linked to various gastrointestinal conditions, such as chronic active gastritis, peptic ulcers, and gastric cancer. Traditional treatment options encounter difficulties due to antibiotic resistance and adverse effects. Therefore, the aim of this study was to explore the effectiveness of a new treatment plan that combines vonoprazan (VPZ), amoxicillin, and bismuth for the eradication of H. pylori.

METHODS

A total of 600 patients infected with H. pylori were recruited for this multicenter randomized controlled trial. Patients treated for H. pylori elimination were randomly assigned at a 1:1 ratio to receive 14 days of vonoprazan-based triple therapy (vonoprazan + amoxicillin + bismuth, group A) or standard quadruple therapy (esomeprazole + clarithromycin + amoxicillin + bismuth, group B). Compliance and adverse effects were tracked through daily medication and side effect records. All patients underwent a 13C/14C-urea breath test 4 weeks after treatment completion.

RESULTS

Intention-to-treat (ITT) and per-protocol (PP) analyses revealed no substantial differences in H. pylori eradication rates between groups A and B (ITT: 83.7% vs 83.2%; PP: 90.9% vs 89.7%). However, significant differences were observed in the assessment of side effects (13.7% vs 28.6%, P < 0.001). Specifically, group A had significantly fewer "bitter mouths" than group B did (3.7% vs 16.2%, P < 0.001).

CONCLUSION

Triple therapy comprising vonoprazan (20 mg), amoxicillin (750 mg), and bismuth potassium citrate (220 mg) achieved a PP eradication rate ≥90%, paralleling standard quadruple therapy, and had fewer adverse events and lower costs (¥306.8 vs ¥645.8) for treatment-naive patients.

In Vitro Susceptibility and Synergistic Effect of Bismuth Against Helicobacter pylori

Background/objectives: Bismuth is commonly used in Helicobacter pylori (H. pylori) eradication therapy. However, few studies have examined the in vitro susceptibility of H. pylori to bismuth. Moreover, the exact mechanism of action of bismuth on H. pylori remains unclear. The aim of this study was to identify the anti-bacterial effect of bismuth as well as to evaluate potential synergistic effects between bismuth and various antibiotics. Methods: The minimum inhibitory concentrations (MICs) of three bismuth preparations, bismuth subsalicylate, bismuth potassium citrate, and colloidal bismuth subcitrate (CBS, De-Nol) were determined for H. pylori strains using the agar dilution technique. Agar plates of varying pH values from 5.0 to 8.0 were used to investigate whether acidity influences the anti-bacterial effect of bismuth. A checkerboard assay was performed to assess the synergism between CBS and antibiotics (amoxicillin, clarithromycin, and metronidazole). Results: Twelve H. pylori strains, including three reference strains (H. pylori 26695, J99, and ATCC 43504), and nine clinically isolated strains were tested. The MICs for bismuth subsalicylate, bismuth potassium citrate, and CBS ranged from 4 to 32 μg/mL, 2 to 16 μg/mL, and 1 to 8 μg/mL, respectively. The bismuth MICs for the reference strains were similar at pH 5-8. In the checkerboard assay, no interactions between CBS and any of the antibiotics were observed in the reference H. pylori strains. Conclusions: Bismuth showed in vitro susceptibility against H. pylori. The enhanced eradication efficacy of bismuth-containing regimens appears to be due to mechanisms other than direct synergy with antibiotics.

Bismuth-based drugs sensitize Pseudomonas aeruginosa to multiple antibiotics by disrupting iron homeostasis

Pseudomonas aeruginosa infections are difficult to treat due to rapid development of antibiotic drug resistance. The synergistic combination of already-in-use drugs is an alternative to developing new antibiotics to combat antibiotic-resistant bacteria. Here we demonstrate that bismuth-based drugs (bismuth subsalicylate, colloidal bismuth subcitrate) in combination with different classes of antibiotics (tetracyclines, macrolides, quinolones, rifamycins and so on) can eliminate multidrug-resistant P. aeruginosa and do not induce development of antibiotic resistance. Bismuth disrupts iron homeostasis by binding to P. aeruginosa siderophores. Inside cells, bismuth inhibits the electron transport chain, dissipates the proton motive force and impairs efflux pump activity by disrupting iron-sulfur cluster-containing enzymes, including respiration complexes. As a result, bismuth facilitates antibiotic accumulation inside bacteria, enhancing their efficacy. The combination therapy shows potent antibacterial efficacy and low toxicity in an ex vivo bacteraemia model and increases the survival rate of mice in in vivo mouse lung-infection models. Our findings highlight the potential of bismuth-based drugs to be repurposed to combat P. aeruginosa infections in combination with clinically used antibiotics.

Efficacy of Bismuth Therapy in Eradicating Helicobacter pylori in Children-Data From the RENIHp Registry

OBJECTIVES

To evaluate the efficacy of colloidal bismuth subcitrate (CBS) therapy for the eradication of H. pylori in patients from a national pediatric registry of H. pylori infection.

METHODS

The Spanish Registry of Children with H. pylori Infection (RENIHp) is a national, multi-center, prospective, non-interventional registry that includes children aged 5-18 years with H. pylori infection diagnosed by endoscopy. All patients in the registry who were treated with CBS between the period 2020 and 2023 were included in this study. The primary outcome was the eradication rate, which was assessed using a 13C-urea breath test or monoclonal antigen in the stool 6-8 weeks post-treatment.

RESULTS

The registry included 682 patients, 38 (5.6%) of whom underwent treatment with CBS. Fifty percent (19/38) of patients had previously undergone unsuccessful eradication treatment. In 78.9% (30/38) of patients, treatment was guided by an antibiotic sensitivity test. In the remaining patients, an empirical approach was employed. The CBS therapies used were as follows: quadruple therapy with proton pump inhibitors (PPIs), CBS, amoxicillin, and metronidazole (MET) [18/38 (47.3%)]; quadruple therapy with PPIs, CBS, tetracycline, and MET [13/38 (34.2%)]; and other therapies [7/38 (18.4%)]. Thirty-two patients (84.2%) treated with CBS were followed-up with eradication monitoring. The overall eradication rate in patients treated with CBS was 93.8% (30/32, [95% CI: 85.4%-100%]), whereas it was 86.7% in patients in the registry who were not on CBS treatment (430/496, [95% CI: 83.3%-89.5%], p = 0.208). In the six patients with dual resistance to clarithromycin (CLA) and MET who were treated with quadruple therapy with CBS, the eradication rate was 100% (n = 6/6, [95% CI: 61.0%-100%]).

CONCLUSION

CBS therapies in our registry, although only used in selected cases and at lower than recommended levels, were very effective and showed an eradication rate of > 90%.

Bismuth add-on improves the efficacy of 2-week tegoprazan-based triple therapy for first-line Helicobacter pylori eradication: a real-world evidence study

BACKGROUND

This study aimed to investigate the efficacy of bismuth added to a 2-week triple therapy consisting of tegoprazan (TPZ), amoxicillin, and clarithromycin for first-line Helicobacter pylori eradication.

RESEARCH DESIGN AND METHODS

We reviewed the retrospective data of patients who received a 2-week TPZ-based triple therapy with or without 300 mg bismuth twice daily. The primary endpoint was the H. pylori eradication rate of adding bismuth to the TPZ-based triple regimen (TAC-B group), compared to no bismuth added (TAC group).

RESULTS

In total, 306 and 256 patients were included in the intention-to-treat (ITT) and per-protocol (PP) analyses, respectively. The eradication success rates were significantly higher in the TAC-B group than in the TAC group (ITT, 82.9% vs. 71.8%, p = 0.029; PP, 95.8% vs. 87.5%, p = 0.027, respectively). The adherence rate to the eradication regimen was 100% in the TAC-B group and 97.0% in the TAC group. The adverse drug event rate in the TAC-B group was comparable to that in the TAC group (29.2% vs. 27.3%, p = 0.742). No use of bismuth was significantly associated with eradication failure (p = 0.038).

CONCLUSIONS

The bismuth add-on increased the first-line H. pylori eradication rate of 2-week TPZ-based triple therapy.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT05453994.

Systematic Review and Meta-Analysis: Bismuth Enhances the Efficacy for Eradication of Helicobacter pylori

BACKGROUND

In the eradication of Helicobacter pylori, the efficacy of bismuth remains inconclusive. We aimed to compare the efficacy of bismuth on various H. pylori eradication regimens.

METHODS

Randomized controlled trials were collected to compare the efficacy of bismuth to nonbismuth regimens in H. pylori eradication. We pooled information to study eradication, adverse events, and drug compliance. In addition, subgroup analyses for eradication efficacy were performed according to high or low clarithromycin-resistance area, bismuth drug form, and amount of bismuth element.

RESULTS

Records for a total of 2506 patients in 15 trials from 13 randomized controlled studies were included. The eradication of H. pylori was superior when bismuth compared to nonbismuth regimen (odds ratio [OR] = 1.63, 95% confidence interval [CI], 1.33-2.00 in intention-to-treat [ITT]; OR = 2.05, 95% CI, 1.58-2.68 in per-protocol [PP] analyses), without significant difference in drug compliance or adverse events. Bismuth regimens in the high clarithromycin resistance area tend to enhance the eradication rate (OR = 1.66, 95% CI, 1.34-2.05 in ITT; OR = 2.22, 95% CI, 1.67-2.95 in PP analyses). Bismuth potassium citrate and bismuth subcitrate were more effective drug forms in regard to eradication rate. Bismuth at a dosage of < 500 mg/day was significantly higher for the eradication rate.

CONCLUSIONS

Bismuth to the H. pylori eradication regimens achieve a higher eradication rate, especially in the high clarithromycin resistance area. It could be an eradication option achieving sufficient resistance rates without increasing antibiotic resistance, side effects, or poor compliance.

The second Irish Helicobacter pylori Working Group consensus for the diagnosis and treatment of Helicobacter pylori infection in adult patients in Ireland

BACKGROUND

There has been an increase in resistance to many of the antimicrobials used to treat Helicobacter pylori ( H. pylori ) nationally and internationally. Primary clarithromycin resistance and dual clarithromycin and metronidazole resistance are high in Ireland. These trends call for an evaluation of best-practice management strategies.

OBJECTIVE

The objective of this study was to revise the recommendations for the management of H. pylori infection in adult patients in the Irish healthcare setting.

METHODS

The Irish H. pylori working group (IHPWG) was established in 2016 and reconvened in 2023 to evaluate the most up-to-date literature on H. pylori diagnosis, eradication rates and antimicrobial resistance. The 'GRADE' approach was then used to rate the quality of available evidence and grade the resulting recommendations.

RESULTS

The Irish H. pylori working group agreed on 14 consensus statements. Key recommendations include (1) routine antimicrobial susceptibility testing to guide therapy is no longer recommended other than for clarithromycin susceptibility testing for first-line treatment (statements 6 and 9), (2) clarithromycin triple therapy should only be prescribed as first-line therapy in cases where clarithromycin susceptibility has been confirmed (statement 9), (3) bismuth quadruple therapy (proton pump inhibitor, bismuth, metronidazole, tetracycline) is the recommended first-line therapy if clarithromycin resistance is unknown or confirmed (statement 10), (4) bismuth quadruple therapy with a proton pump inhibitor, levofloxacin and amoxicillin is the recommended second-line treatment (statement 11) and (5) rifabutin amoxicillin triple therapy is the recommend rescue therapy (statement 12).

CONCLUSION

These recommendations are intended to provide the most relevant current best-practice guidelines for the management of H. pylori infection in adults in Ireland.

A Highly Stable Multifunctional Bi-Based MOF for Rapid Visual Detection of S2- and H2S Gas with High Proton Conductivity

Metal organic frameworks (MOFs) constructed with bismuth metal have not been widely reported, especially multifunctional Bi-MOFs. Therefore, developing multifunctional MOFs is of great significance due to the increasing requirements of materials. In this work, a 3D Bi-MOF (Bi-TCPE) with multifunctionality was successfully constructed, demonstrating high thermal stability, water stability, a porous structure, and strong blue fluorescence emission. We evaluated the properties of Bi-TCPE in detecting anions (S2-, Cr2O72-, and CrO42-) in aqueous solution, along with the rapid visual detection of H2S gas and proton conduction. In terms of anion detection, Bi-TCPE achieved the rapid detection of trace S2- in aqueous solutions, while the Ksv value was 1.224 × 104 M-1 with a limit of detection (LOD) value of 1.93 μM through titration experiments. Furthermore, Bi-TCPE could sensitively detect Cr2O72- and CrO42-, with Ksv values of 1.144 × 104 and 1.066 × 104 M-1, respectively, while LOD reached 2.07 and 2.18 μM. Subsequently, we conducted H2S gas detection experiments, and the results indicated that Bi-TCPE could selectively detect H2S gas at extremely low concentrations (2.08 ppm) and with a fast response time (<10 s). We also observed significant color changes under both UV light and sunlight. Therefore, we developed a H2S detection test paper for the rapid visual detection of H2S gas. Finally, we evaluated the proton conductivity of Bi-TCPE, and the experimental results showed that the proton conductivity of Bi-TCPE reached 4.77 × 10-2 S·cm-1 at 98% RH and 90 °C, achieving an excellent value for unmodified and encapsulated MOFs. In addition, Bi-TCPE showed high stability in proton conduction experiments (it remained stable after 21 consecutive days of testing and 12 cycles of testing), demonstrating relatively high application value. These results indicate that Bi-TCPE is a multifunctional MOF material with great application potential.

Bismuth interaction with plants: Uptake and transport, toxic effects, tolerance mechanisms - A review

Bismuth (Bi) is a minor metal whose abundance on Earth is estimated at 0.025 ppm. Known since ancient times for its medical properties, its use in many industrial applications has increased significantly in recent years due to its physical and chemical properties. Considered less toxic than other metals, Bi has been defined as a "green metal" and has been suggested as a replacement for lead in many industrial processes. Although the occurrence of Bi in the environment is predicted to increase, there is still a lack of information on its interaction with biota. Even though it is absorbed by many organisms, Bi has not been directly implicated in the regulation of fundamental metabolic processes. This review summarises the fragmentary knowledge on the interaction between Bi and plants. Toxic effects at the growth, physiological and biochemical levels have been described in Bi-treated plants, with varying degrees and consequences for plant vitality, mostly depending on the chemical formulation of Bi, the concentration of Bi, the growth medium, the time of exposure, and the experimental conditions (laboratory or outdoor conditions). Bismuth has been shown to be readily absorbed and translocated in plants, interfering with plant growth and development, photosynthetic processes, nutrient uptake and accumulation, and metal (especially iron) homeostasis. Like other metals, Bi can induce an oxidative stress state in plant cells, and genotoxic effects have been reported in Bi-treated plants. Tolerance responses to the excess presence of Bi have been poorly described and are mostly referred to as the activation of antioxidant defences involving enzymatic and non-enzymatic molecules. The goal of this review is to offer an overview of the present knowledge on the interaction of Bi and plants, highlighting the gaps to be filled to better understand the role of Bi in affecting key physiological processes in plants. This will help to assess the potential harm of this metal in the environment, where its occurrence is predicted to increase due to the growing demand for medicinal and industrial applications.

Effect of mouthwash containing poly l-Lysine and glycerol monolaurate on oral Helicobacter pylori relating to biofilm eradication, anti-adhesion, and pro-inflammatory cytokine suppression

BACKGROUND/PURPOSE

Helicobacter pylori has been found to be related to periodontitis, and the oral cavity has been considered a reservoir for H. pylori gastritis infection. Thus, this study evaluated the effect of mouthwash containing poly l-Lysine and glycerol monolaurate on inhibiting H. pylori growth, biofilm formation, cell cytotoxicity, adhesion ability, cagA mRNA expression, and pro-inflammatory cytokines stimulated by H. pylori.

MATERIALS AND METHODS

Nineteen H. pylori strains were isolated from the oral cavity. The effectiveness of mouthwash containing poly l-Lysine and glycerol monolaurate was examined for its ability to inhibit H. pylori growth and biofilm formation and was tested for cell viability in oral epithelial cells (H357), gastric adenocarcinoma cells (AGS), and periodontal ligament cells (PDL). Additionally, the mouthwash was tested for reducing cagA mRNA expression, adhesion ability to H357 and AGS cells, and pro-inflammatory cytokines stimulated with H. pylori in AGS and PDL cells.

RESULTS

The mouthwash containing poly l-Lysine and glycerol monolaurate could eradicate the biofilm by 14.9-19.9% after incubation at 5 min, and cell viability revealed 77.2, 79.8, and 100.0% for AGS, H357, and PDL cells, respectively. Moreover, the mouthwash containing poly l-Lysine and glycerol monolaurate could down-regulate cagA mRNA expression, reduce adhesion of H. pylori by approximately 9.5-47.8% for H357 cells and 24.5-62.9% for AGS cells, and decrease pro-inflammatory cytokines, especially interleukin-8, stimulated with H. pylori.

CONCLUSION

Mouthwash containing poly l-Lysine and glycerol monolaurate could inhibit H. pylori growth and reduce their virulence expression. The mouthwash also revealed low cytotoxicity to oral and gastric cells.

Helicobacter pylori antibiotic resistance profile in Chinese children with upper gastrointestinal symptoms and a literature review for developing personalized eradicating strategies

Background: H. pylori (Helicobacter pylori) infections typically occur in early childhood. Although the prevalence of H. pylori in children is lower than that in adults, the eradication rate of this infection in children is relatively low because of resistance. In this study, we analyzed personalized treatment strategies to achieve treatment goals based on H. pylori resistance characteristics. This retrospective single-center study was conducted between January 2019 and December 2022 and enrolled 1,587 children who presented with upper gastrointestinal symptoms and underwent endoscopy. H. pylori culturing and antimicrobial susceptibility testing were performed. Results: Culture-positive results for H. pylori were obtained in 535 children. The resistance rates to clarithromycin (CLA), metronidazole (MET), and levofloxacin (LEV) were 39.8%, 78.1%, and 20.2%, respectively. None of the isolates were resistant to tetracycline (TET), amoxicillin (AMO), or furazolidone (FZD). Double resistance rates to CLA + MET, CLA + LEV, and MET + LEV were 19.1%, 3.0%, and 5.8%, respectively. Notably, triple-resistant to CLA + MET + LEV was 9.7%. Based on susceptibility tests, individualized triple therapy [proton pump inhibitor (PPI) +AMO + CLA/MET] was selected for 380 children with H. pylori sensitive to MET and/or CLA. In 155 children resistant to CLA and MET, bismuth-based quadruple therapy was recommended; for unable to receive bismuth, concomitant therapy was recommended for 14 children (<8 years of age); triple therapy with TET was recommended for 141 children (>8 years of age), with 43 children (>14 years of age) requiring FZD rather than TET. Conclusion: Resistance to H. pylori in Chinese children was relatively poor. Personalized therapy regimens should be based on susceptibility tests and avoided factors associated with treatment failure.

Bi(III) Binding Stoichiometry and Domain-Specificity Differences Between Apo and Zn(II)-bound Human Metallothionein 1a

Bismuth is a xenobiotic metal with a high affinity to sulfur that is used in a variety of therapeutic applications. Bi(III) induces the cysteine-rich metallothionein (MT), a protein known to form two-domain cluster structures with certain metals such as Zn(II), Cd(II), or Cu(I). The binding of Bi(III) to MTs has been previously studied, but there are conflicting reports on the stoichiometry and binding pathway, which appear to be highly dependent on pH and initial metal-loading status of the MT. Additionally, domain specificity has not been thoroughly investigated. In this paper, ESI-MS was used to determine the binding constants of [Bi(EDTA)]- binding to apo-MT1a and its individual αMT fragment. The results were compared to previous experiments using βMT1a and βαMT3. Domain specificity was investigated using proteolysis methods and the initial cooperatively formed Bi2MT was found to bind to cysteines that spanned across the traditional metal binding domain regions. Titrations of [Bi(EDTA)]- into Zn7MT were performed and were found to result in a maximum stoichiometry of Bi7MT, contrasting the Bi6MT formed when [Bi(EDTA)]- was added to apo-MT. These results show that the initial structure of the apo-MT determines the stoichiometry of new incoming metals and explains the previously observed differences in stoichiometry.

Consumption of non-antibacterial drugs may have negative impact on Helicobacter pylori colonization in the stomach

Background

Nineteen non-antibacterials were examined to show that their consumption for treatment of other diseases may inhibit Helicobacter pylori. Four antibiotics were used for comparison.

Materials and methods

Agar dilution method was used to examine the susceptibility of 20 H. pylori isolates to 4 antibiotics; metronidazole (MTZ), clarithromycin (CLR), amoxicillin (AMX), tetracycline (TET) and 19 non-antibacterials; proton pump inhibitors (PPIs), H2-blockers, bismuth subsalicylate (BSS), antifungals, statins, acetaminophen (ACE), aspirin (ASA), B-vitamins (B-Vits; Vit B1, Vit B6 and Vit Bcomplex) and vitamin C (Vit C). Blood agar plates were prepared with different concentrations of drugs and spot-inoculated with bacterial suspensions. Plates were incubated at 37 °C under microaerobic conditions and examined after 3-5 days. The isolate #20 that was mucoid and resistant to 19 drugs, including MTZ and SMV was tested against combined MTZ (8 μg/mL) and SMV (100 μg/mL). Results were analyzed statistically.

Results

Minimum inhibitory concentrations (MICs, μg/mL) of drugs and the frequency of susceptible H. pylori were determined as MTZ (8, 80%), CLR (2, 90%), AMX (1, 100%), TET (0.5, 70%), PPIs (8-128, 80%), H2-blockers (2000-8000, 75-80%), BSS (15, 85%), antifungals (64-256, 30-80%), statins (100-250, 35-90%), ACE (40, 75%), ASA (800, 75%), B-Vits (5000-20000, 80-100%) and Vit C (2048, 85%). Susceptibility of H. pylori isolates to 16 out of 19 non-antimicrobials (75-100%) was almost similar to those of antibiotics (70-100%) (P-value >0.05). The highest susceptibility rate (100%) belonged to Vit B1, Vit B6 and AMX. Out of 20 H. pylori isolates, 17 (85%) were susceptible to ≥13 non-antimicrobials and 3 (15%) were susceptible to < 13 (P-value <0.05). Mucoid H. pylori showed susceptibility to combination of MTZ and SMV.

Conclusions

Most of non-antibacterials inhibited H. pylori isolates, similar to antibiotics but their MICs exceeded those of antibiotics and their plasma concentrations. At low plasma concentration, non-antimicrobials may act as weak antibacterials, antibiotic adjuvants and immunostimulators.

Helicobacter pylori infection in humans and phytotherapy, probiotics, and emerging therapeutic interventions: a review

The global prevalence of Helicobacter pylori (H. pylori) infection remains high, indicating a persistent presence of this pathogenic bacterium capable of infecting humans. This review summarizes the population demographics, transmission routes, as well as conventional and novel therapeutic approaches for H. pylori infection. The prevalence of H. pylori infection exceeds 30% in numerous countries worldwide and can be transmitted through interpersonal and zoonotic routes. Cytotoxin-related gene A (CagA) and vacuolar cytotoxin A (VacA) are the main virulence factors of H. pylori, contributing to its steep global infection rate. Preventative measures should be taken from people's living habits and dietary factors to reduce H. pylori infection. Phytotherapy, probiotics therapies and some emerging therapies have emerged as alternative treatments for H. pylori infection, addressing the issue of elevated antibiotic resistance rates. Plant extracts primarily target urease activity and adhesion activity to treat H. pylori, while probiotics prevent H. pylori infection through both immune and non-immune pathways. In the future, the primary research focus will be on combining multiple treatment methods to effectively eradicate H. pylori infection.

Efficacy comparison of 7- and 14-day P-CAB based bismuth-containing quadruple regimen with PPI based bismuth-containing quadruple regimen for Helicobacter pylori infection: rationale and design of an open-label, multicenter, randomized controlled trial

BACKGROUND

Owing to its strong acid inhibition, potassium-competitive acid blocker (P-CAB) based regimens for Helicobacter pylori (H. pylori) eradication are expected to offer clinical advantages over proton pump inhibitor (PPI) based regimens. This study aims to compare the efficacy and adverse effects of a 7-day and a 14-day P-CAB-based bismuth-containing quadruple regimen (PC-BMT) with those of a 14-day PPI-based bismuth-containing quadruple regimen (P-BMT) in patients with high clarithromycin resistance.

METHODS

This randomized multicenter controlled clinical trial will be performed at five teaching hospitals in Korea. Patients with H. pylori infection who are naive to treatment will be randomized into one of three regimens: 7-day or 14-day PC-BMT (tegoprazan 50 mg BID, bismuth subcitrate 300 mg QID, metronidazole 500 mg TID, and tetracycline 500 mg QID) or 14-day P-BMT. The eradication rate, treatment-related adverse events, and drug compliance will be evaluated and compared among the three groups. Antibiotic resistance testing by culture will be conducted during the trial, and these data will be used to interpret the results. A total of 366 patients will be randomized to receive 7-day PC-BMT (n = 122), 14-day PC-BMT (n = 122), or 14-day P-BMT (n = 122). The H. pylori eradication rates in the PC-BMT and P-BMT groups will be compared using intention-to-treat and per-protocol analyses.

DISCUSSION

This study will demonstrate that the 7-day or 14-day PC-BMT is well tolerated and achieve similar eradication rates to those of 14-day P-BMT. Additionally, the 7-day PC-BMT will show fewer treatment-related adverse effects and higher drug compliance, owing to its reduced treatment duration.

TRIAL REGISTRATION

Korean Clinical Research Information Service registry, KCT0007444. Registered on 28 June 2022, https://cris.nih.go.kr/cris/index/index.do .

Efficacy of genotypic susceptibility-guided tailored therapy for Helicobacter pylori infection: A systematic review and single arm meta-analysis

BACKGROUND AND AIM

The prevalence of antibiotic resistance for Helicobacter pylori (H. pylori) has been increasing over the year, making it more difficult for traditional empirical therapy to successfully eradicate H. pylori. Thus, tailored therapy (TT) guided by molecular-based antibiotic susceptibility testing (AST) has been frequently recommended. We conducted a single-arm meta-analysis to determine the efficacy of tailored therapy guided by molecular-based AST.

METHODS

A systematic literature review was performed on multiple databases, and studies on molecular-based TT were included. The eradication rates of TT by intention-to-treat (ITT) and per-protocol (PP) analyses were pooled respectively.

RESULTS

A total of 35 studies from 31 literature (4626 patients) were included in the single-arm meta-analysis. Overall, the pooled eradication rate of TT was 86.9% (95% CI:84.7%-89.1%) by the ITT analysis, and 91.5% (95% CI:89.8%-93.2%) by PP analysis. The pooled eradication rates of first-line TT and rescue TT were 86.6% and 85.1% by ITT analysis and 92.0% and 87.9% by PP analysis, respectively. When tailored rescue therapy was based on the genotypic resistance to at least four antibiotics, the pooled eradication rates reached 89.4% by ITT analysis and 92.1% by PP analysis. For genotype-susceptive strains, the pooled eradication rate of TT with targeted antibiotics was 93.1% (95% CI:91.3%-94.9%), among which the pooled eradication rate of tailored bismuth quadruple therapy was the highest (94.3%). Besides, the eradication rate of 7-day TT or tailored triple therapy without bismuth for genotype-susceptive strains could both reach more than 93.0%.

CONCLUSION

Tailored therapy guided by molecular-based AST can achieve somewhat ideal therapeutic outcomes. TT with a 7-day duration or without bismuth for genotype-susceptible strains can achieve good eradication efficacy. The effectiveness of TT can be improved to some extent by expanding the coverage of AST or by adding bismuth.

Helicobacter pylori infection: a dynamic process from diagnosis to treatment

Helicobacter pylori, a gram-negative microaerophilic pathogen, causes several upper gastrointestinal diseases, such as chronic gastritis, peptic ulcer disease, and gastric cancer. For the diseases listed above, H. pylori has different pathogenic mechanisms, including colonization and virulence factor expression. It is essential to make accurate diagnoses and provide patients with effective treatment to achieve positive clinical outcomes. Detection of H. pylori can be accomplished invasively and noninvasively, with both having advantages and limitations. To enhance therapeutic outcomes, novel therapeutic regimens, as well as adjunctive therapies with probiotics and traditional Chinese medicine, have been attempted along with traditional empiric treatments, such as triple and bismuth quadruple therapies. An H. pylori infection, however, is difficult to eradicate during treatment owing to bacterial resistance, and there is no commonly available preventive vaccine. The purpose of this review is to provide an overview of our understanding of H. pylori infections and to highlight current treatment and diagnostic options.

Biological Activities of Bismuth Compounds: An Overview of the New Findings and the Old Challenges Not Yet Overcome

Bismuth-based drugs have been used primarily to treat ulcers caused by Helicobacter pylori and other gastrointestinal ailments. Combined with antibiotics, these drugs also possess synergistic activity, making them ideal for multiple therapy regimens and overcoming bacterial resistance. Compounds based on bismuth have a low cost, are safe for human use, and some of them are also effective against tumoral cells, leishmaniasis, fungi, and viruses. However, these compounds have limited bioavailability in physiological environments. As a result, there is a growing interest in developing new bismuth compounds and approaches to overcome this challenge. Considering the beneficial properties of bismuth and the importance of discovering new drugs, this review focused on the last decade's updates involving bismuth compounds, especially those with potent activity and low toxicity, desirable characteristics for developing new drugs. In addition, bismuth-based compounds with dual activity were also highlighted, as well as their modes of action and structure-activity relationship, among other relevant discoveries. In this way, we hope this review provides a fertile ground for rationalizing new bismuth-based drugs.

Ilaprazole-amoxicillin dual therapy at high dose as a first-line treatment for helicobacter pylori infection in Hainan: a single-center, open-label, noninferiority, randomized controlled trial

OBJECTIVES

This study aimed to evaluate the efficacy, adverse events, patient compliance, and cost of dual therapy with Ilaprazole-amoxicillin (IA) at high dose versus Ilaprazole-amoxicillin-furazolidone-bismuth (IAFB) quadruple therapy for the Helicobacter pylori (H.pylori) infection among Chinese patients.

METHODS

200 patients who had tested positive for H. pylori and undergoing upper gastrointestinal endoscopy after being diagnosed with chronic gastritis participated in this open-label randomized controlled clinical trial. Patients were randomized to Group A and Group B: the 14-day IA dual treatment group (101) and IAFB quadruple treatment group (99). The 13 C urea breath test was conducted to determine whether H. pylori had been eliminated 4-6 weeks after the treatment. Eradication rates, drug-related adverse events, patient compliance, and drug costs were compared between the two treatment groups.

RESULTS

Eradication rates in group A were 92.1% and 94.9%, depending on the intention-to-treat (ITT), per-protocol (PP), respectively, which was similar to group B (91.9% and 93.6%). There was no significant difference observed in adverse events between the two groups (P = 0.518). Interestingly, compliance was significantly higher in group A compared to the group B (P = 0.031). In addition, drug costs were significantly lower for group A in comparison to the group B.

CONCLUSIONS

IA dual therapy was found to be equally effective, safer and less costly than IAFB quadruple therapy. Therefore, these therapies can be potentially considered as first-line regimens for empirical treatment.

Current trends in <i>Helicobacter pylori</i> eradication therapy

According to the Maastricht VI consensus, the triple therapy (PPI + clarithromycin + amoxicillin) and bismuth-based quadruple therapy (PPI + bismuth + tetracycline + metronidazole) are considered and may be proscribed empirically as first-line regimens in the regions with low clarithromycin resistance rates (<15%). In the regions with high clarithromycin resistance rates (> 15%), as well as in the regions with unknown resistance to this antibacterial agent, it is recommended to use classical quadruple therapy with bismuth drugs as the main choice and quadruple therapy without bismuth drugs (“simultaneous” or “concomitant”) as an alternative. The second-line regimens of empiric choice (when antimicrobial susceptibility testing is not available) include fluoroquinolone-based quadruple therapy (PPI + levofloxacin + amoxicillin + bismuth) or fluoroquinolone-based triple therapy (PPI + levofloxacin + amoxicillin) and bismuth-based quadruple therapy. The Maastricht VI consensus regulates the use of rifabutin-based triple therapy (PPI + amoxicillin + rifabutin) as a “rescue” therapy, if the above ET schemes are ineffective and there is no possibility to conduct an antimicrobial susceptibility test. In its latest clinical guidelines, the Russian Gastroenterological Association (RGA) recommends with a view to achieving maximum treatment efficiency during classic triple ET and levelling the risk of further progression of clarithromycin resistance in Russia to take additional measures to increase its effectiveness (detailed instruction of a patient and control over strict adherence to the prescribed regimen, prolonging the course up to 14 days; prescribing PPI at increased dose twice a day; the latest generation PPIs (rabeprazole and esomeprazole); adding bismuth tripotassium dicitrate (240 mg 2 times a day) to the standard triple therapy; adding cytoprotector rebamipide (100 mg 3 times a day) to the standard triple therapy; adding a probiotic with proven efficacy to the standard triple therapy within controlled studies).

Rescue therapy for refractory Helicobacter pylori infection: current status and future concepts

Helicobacter pylori infection is an important issue worldwide, and several guidelines have been published for clinicians to achieve successful eradication. However, there are still some patients who remain infected with H. pylori after treatment. Clinicians should identify the reasons that caused treatment failure and find strategies to manage them. We have searched and organized the literature and developed methods to overcome factors that contribute to prior treatment failure, such as poor compliance, inadequate intragastric acid suppression, and antibiotic resistance. To improve compliance, telemedicine or smartphone applications might play a role in the modern world by increasing doctor-patient relationships, while concomitant probiotics could be administered to reduce adverse effects and enhance adherence. For better acid suppression, high-potency and high-dose proton-pump inhibitors or potassium-competitive acid blockers have preferable efficacy. To overcome antibiotic resistance, susceptibility tests either by culture or by genotyping are the most commonly used methods and have been suggested for antibiotic selection before rescue therapy, but empirical therapy according to detailed medical history could be an alternative. Eradication with a longer treatment period (14 days) has a better outcome than shorter period (7 or 10 days). Ultimately, clinicians should select antibiotics based on the patient's history of drug allergy, previous antibiotic exposure, local antibiotic resistance, available medications, and cost. In addition, identifying patients with a high risk of cancer and shared decision-making are also essential for those who have experienced eradication failure.

Quantum Dynamics and Bi Metal Force Field Parameterization Yielding Significant Antileishmanial Targets

Amid emerging drug resistance to metal inhibitors, high toxicity, and onerous drug delivery procedures, the computational design of alternate formulations encompassing functional metal-containing compounds greatly relies on large-scale atomistic simulations. Simulations particularly with Au(I), Ag, Bi(V), and Sb(V) pose a major challenge to elucidate their molecular mechanism due to the absence of force field parameters. This study thus quantum mechanically derives force field parameters of Bi(V) as an extension of the previous experimental study conducted on heteroleptic triorganobismuth(V) biscarboxylates of type [BiR3(O2CR')2]. We have modeled two organo-bismuth(V) carboxylates, which are optimized and parameterized along with the famous pentavalent antimonial drug: meglumine antimoniate using quantum mechanics original Seminarian methods with the SBKJC effective core potential (ECP) basis set. Furthermore, molecular dynamics (MD) simulations of bismuth- and antimony-containing compounds in complex with two enzymes, trypanothione synthetase-amidase (TSA) and trypanothione reductase, are performed to target the (T(SH)2) pathway at multiple points. MD simulations provide novel insights into the binding mechanism of TSA and highlight the role of a single residue Arg569 in modulating the ligand dynamics. Moreover, the presence of an ortho group in a ligand is emphasized to facilitate interactions between Arg569 and the active site residue Arg313 for higher inhibitory activity of TSA. This preliminary generation of parameters specific to bismuth validated by simulations in replica will become a preamble of future computational and experimental research work to open avenues for newer and suitable drug targets.

Current Trends in the Management of Helicobacter pylori Infection in Serbia: Preliminary Results from the European Registry on H. pylori Management

BACKGROUND

Helicobacter pylori (H. pylori) is the most common chronic bacterial infection. Treatment effectiveness remains a subject of debate considering bacterial antimicrobial resistance. Our aim was to analyze the diagnostic methods and eradication treatments for H. pylori infection in Serbia.

METHODS

An observational multicenter prospective study was conducted in Serbia, as part of the European Registry on H. pylori Management (Hp-EuReg). Demographics, treatment indication, diagnostic methods, previous eradication attempts, and treatment were collected at AEG-REDCap e-CRF. Modified intention-to-treat (mITT) and per-protocol (PP) effectiveness analyses were performed. Safety, compliance, and bacterial antimicrobial resistance rates were reported. Data were quality checked.

RESULTS

Overall, 283 patients were included, with a mean age of 55 ± 15 years. Dyspepsia (n = 214, 77%) was the most frequent treatment indication, and histology (n = 144, 51%) was the most used diagnostic method. Overall eradication rate was 95% (PP) and 94% (mITT). Most prevalent first-line therapy was quadruple PPI + clarithromycin + amoxicillin + metronidazole, with a 96% effectiveness (p < 0.001). Second-line main treatment choice was triple amoxicillin + levofloxacin, with a 95% effectiveness (p < 0.05). Single-capsule Pylera® was the most prescribed third-line therapy, with 100% effectiveness (p < 0.05). Longer treatment duration was associated with a higher eradication rate in first-line therapy (p < 0.05). Clarithromycin and quinolone resistance rates in first-line were 24% and 8.3%, respectively. The overall adverse events' incidence rate was 13.4%, and therapy compliance was 97%.

CONCLUSIONS

Considering the high eradication rate, 14-day non-bismuth quadruple concomitant therapy is a reasonable first-line choice, while quinolone-based therapy and single-capsule Pylera® should be considered as rescue therapy options.

Recombinant Helicobacter pylori Vaccine Delivery Vehicle: A Promising Tool to Treat Infections and Combat Antimicrobial Resistance

Antimicrobial resistance (AMR) has become a global public health threat. Experts agree that unless proper actions are taken, the number of deaths due to AMR will increase. Many strategies are being pursued to tackle AMR, one of the most important being the development of efficient vaccines. Similar to other bacterial pathogens, AMR in Helicobacter pylori (Hp) is rising worldwide. Hp infects half of the human population and its prevalence ranges from <10% in developed countries to up to 90% in low-income countries. Currently, there is no vaccine available for Hp. This review provides a brief summary of the use of antibiotic-based treatment for Hp infection and its related AMR problems together with a brief description of the status of vaccine development for Hp. It is mainly dedicated to genetic tools and strategies that can be used to develop an oral recombinant Hp vaccine delivery platform that is (i) completely attenuated, (ii) can survive, synthesize in situ and deliver antigens, DNA vaccines, and adjuvants to antigen-presenting cells at the gastric mucosa, and (iii) possibly activate desired compartments of the gut-associated mucosal immune system. Recombinant Hp vaccine delivery vehicles can be used for therapeutic or prophylactic vaccination for Hp and other microbial pathogens.

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in various clinical fields.

Effectiveness of Rebamipide as a part of the <i>Helicobacter pylori</i> eradication therapy in Russia: a meta-analysis of controlled trials

Aim. To perform a meta-analysis of the data on Rebamipide efficacy and safety as a part of Helicobacter pylori eradication therapy in Russian patients. Materials and methods. A search for original studies was conducted in the electronic database of the Russian Science Citation Index (RSCI) on the Scientific Electronic Library (SEL Elibrary.ru). Google (Google.com) was used for the "grey" search. All Russian controlled studies comparing the efficacy and/or safety of Rebamipide as a part of the regimen of H. pylori eradication therapy were included in the final analysis. Results. In 6 included controlled trials with a cumulative population (considering double comparisons between multiple groups) of 531 patients (273 in Rebamipide groups and 258 in groups without Rebamipide), the pooled eradication effectiveness was 90.376% (95% confidence interval CI 86.31193.560) in patients receiving Rebamipide and 81.681% (95% CI 76.49986.141) in patients receiving eradication regimens without Rebamipide. The meta-analysis showed that the Rebamipide addition to eradication regimens significantly improved efficacy (odds ratio 2.162, 95% CI 1.2683.685; p=0.005). No significant heterogeneity was found between study results (p=0.863; I2=0.00%); therefore, a fixed effects model was used in the resulting analysis. In addition, the meta-analysis of included studies showed a reduction of adverse events (odds ratio 0.569, 95% CI 0.3330.970) in the groups receiving Rebamipide; p=0.038). This effect of Rebamipide deserves special attention and requires additional study, as the result was at the border of statistical significance in the subanalysis of three studies with a large margin of risk reduction in one of them (with the largest sample of patients). Conclusion. The present meta-analysis demonstrated that the Rebamipide addition to H. pylori eradication regimens significantly improves the treatment effectiveness in the Russian patient population.

Helicobacter Pylori-Induced Gastric Infections: From Pathogenesis to Novel Therapeutic Approaches Using Silver Nanoparticles

Helicobacter pylori is the first formally recognized bacterial carcinogen and the most important single digestive pathogen responsible for the induction of gastroduodenal diseases such as gastritis, peptic ulcer, and, finally, gastric neoplasia. The recently reported high rates of antimicrobial drug resistance hamper the current therapies of H. pylori, with therapeutic failure reaching up to 40% of patients. In this context, new treatment options and strategies are urgently needed, but the successful development of these new therapeutic tools is conditioned by the understanding of the high adaptability of H. pylori to the gastric acidic environment and the complex pathogenic mechanism. Due to several advantages, including good antibacterial efficiency, possible targeted delivery, and long tissular persistence, silver nanoparticles (AgNPs) offer the opportunity of exploring new strategies to improve the H. pylori therapy. A new paradigm in the therapy of H. pylori gastric infections using AgNPs has the potential to overcome the current medical limitations imposed by the H. pylori drug resistance, which is reported for most of the current organic antibiotics employed in the classical therapies. This manuscript provides an extensive overview of the pathology of H. pylori-induced gastritis, gastric cancer, and extradigestive diseases and highlights the possible benefits and limitations of employing AgNPs in the therapeutic strategies against H. pylori infections.

A Review on the Recent Advancements on Therapeutic Effects of Ions in the Physiological Environments

This review focuses on the therapeutic effects of ions when released in physiological environments. Recent studies have shown that metallic ions like Ag+, Sr2+, Mg2+, Mn2+, Cu2+, Ca2+, P+5, etc., have shown promising results in drug delivery systems and regenerative medicine. These metallic ions can be loaded in nanoparticles, mesoporous bioactive glass nanoparticles (MBGNs), hydroxyapatite (HA), calcium phosphates, polymeric coatings, and salt solutions. The metallic ions can exhibit different functions in the physiological environment such as antibacterial, antiviral, anticancer, bioactive, biocompatible, and angiogenic effects. Furthermore, the metals/metalloid ions can be loaded into scaffolds to improve osteoblast proliferation, differentiation, bone development, fibroblast growth, and improved wound healing efficacy. Moreover, different ions possess different therapeutic limits. Therefore, further mechanisms need to be developed for the highly controlled and sustained release of these ions. This review paper summarizes the recent progress in the use of metallic/metalloid ions in regenerative medicine and encourages further study of ions as a solution to cure diseases.

Zinc carnosine-based modified bismuth quadruple therapy vs standard triple therapy for Helicobacter pylori eradication: A randomized controlled study

BACKGROUND

Helicobacter pylori (H. pylori) infection is a worldwide problem with increasing burden on the health sector due to its increasing rate of resistance. The conventional triple therapy (TT) is becoming obsolete with a high failure rate of eradication, necessitating the need for better alternatives or regimens.

AIM

To investigate H. pylori eradication rate of TT vs modified bismuth quadruple therapy.

METHODS

Ninety-two patients with dyspepsia symptoms and positive ¹³C-urea breath test were randomly assigned to two groups. The first group (control group) was treated for 14 d using standard TT protocol: Esomeprazole (40 mg twice daily), amoxicillin (1 g twice daily) and clarithromycin (500 mg twice daily). On the other hand, the second group was prescribed a 10-d course of modified bismuth quadruple therapy fortified with zinc carnosine: TT in addition to bismuth subcitrate (240 mg twice daily) and zinc carnosine (75 mg twice daily). A repeated ¹³C-urea breath test was done 4 wk after the completion of the eradication therapy.

RESULTS

Among the 92 subjects, 67.4% were males and 32.6% were females. There were no differences in demographic characteristics (age, body mass index, smoking history, previous antibiotics use and ethnicity) between the modified bismuth quadruple therapy group and TT group. The eradication rate was higher [93.5% (43/46)] in the modified bismuth quadruple therapy group compared to 69.6% (32/46) in the standard TT group (P = 0.003). Of the tested predictor variables, only nationality, smoking and therapy type were statistically significant. Besides dizziness, which was recorded in modified bismuth quadruple therapy group, there were no significant differences in side effects between the two groups.

CONCLUSION

Ten days of modified bismuth quadruple therapy fortified with zinc carnosine is superior to 14 d of conventional TT in eradicating H. pylori infection, with no additional significant adverse events.

The efficacy and safety of different bismuth agents in Helicobacter pylori first-line eradication: A multicenter, randomized, controlled clinical trial

BACKGROUND

The aim of this study was to evaluate the efficacy and safety of bismuth pectin capsules and bismuth pectin granules in the first-line quadruple treatment of Helicobacter pylori (H. pylori).

METHODS

This study was a multicenter, randomized, open-labelled controlled clinical trial. Patients with a H. pylori infection were randomized into 4 groups (1:1:1:1) and treated with a 14-day bismuth-containing quadruple therapy. The 4 groups received either bismuth potassium citrate capsules (220 mg), colloidal bismuth pectin capsules (200 mg), bismuth pectin granules (150 mg), or bismuth pectin granules (300 mg). The primary outcome was the eradication rate of H. pylori. The secondary outcomes included symptom improvement, patient compliance, and incidence of adverse events. This study was registered at ClinicalTrials.gov (NCT04209933).

RESULTS

A total of 240 patients were included in this study, and 211 patients completed the follow-up. An intention-to-treat analysis showed that the H. pylori eradication rates of the 4 groups were 73.3%, 76.7%, 75.0%, and 71.7%, respectively. The per-protocol analysis showed that the H. pylori eradication rates of the 4 groups were 86.3%, 82.1%, 83.3%, and 86.0%. There was no significant difference among the 4 groups in the H. pylori eradication rate (P > .05). There were also no significant differences in the symptom improvement rate, overall adverse reaction rate, or patient compliance among the 4 groups.

CONCLUSIONS

Bismuth pectin capsules and bismuth pectin granules had similar efficacy and safety for H. pylori eradication compared to bismuth potassium citrate. These data suggest that bismuth pectin can be an alternative to bismuth potassium citrate to eradicate H. pylori when using bismuth-containing quadruple therapy.

Integrative proteomic and metabolomic analyses reveal the mechanism by which bismuth enables Helicobacter pylori eradication

BACKGROUND

Bismuth-based drugs are used to treat Helicobacter pylori infection; however, the antibacterial activity of bismuth, especially against H. pylori, has not been fully elucidated. In this study, the mechanisms by which bismuth exerts its detrimental effects on H. pylori were evaluated. Methods Six H. pylori strains isolated from different patients were cultured with or without bismuth; proteins and metabolites differentially expressed in these two sets of bacteria were detected via data independent acquisition proteomic and gas chromatography-mass spectrometry metabolic approaches, respectively. Gene ontology functional analysis and Kyoto Encyclopedia of Genes and Genomes database were used to identity pathway enrichment.

RESULTS

Bismuth inhibited H. pylori growth in vitro via the following mechanisms: downregulation of virulence proteins CagA and VacA; disruption of flagella assembly responsible for bacterial colonization; and inhibition of antioxidant enzymes, including catalase, catalase-related peroxidase, and superoxide dismutase. Diverse metabolic pathways related to growth and RNA translation in H. pylori were disrupted by bismuth. Bismuth treatment impaired many biological processes in H. pylori, including antioxidant response and purine, pyrimidine, amino acid, and carbon metabolism. Conclusions The findings of this study suggest that motility, virulence factors CagA and VacA, antioxidant defense system, and many important metabolic pathways associated with bacterial growth, including nucleotide and amino acid metabolism and translation in H. pylori, are inhibited by bismuth. This study provides novel insights into the mechanism by which bismuth eradicates H. pylori upon being incorporated into quadruple therapy.

Development of a bioactive and radiopaque bismuth doped baghdadite ceramic for bone tissue engineering

Baghdadite (Ca₃ZrSi₂O₉, BAG), is a Zr-doped calcium silicate that has outstanding bioactivity both in vitro and in vivo. Bioceramic scaffolds should be sufficiently radiopaque to be distinguishable in vivo from surrounding bone structures. To enhance the radiopacity of BAG, this study investigated the effect of incorporating bismuth ions into its crystalline structure (Bi_xCa_3-xZrSi₂O₉, x = 0, 0.1, 0.2, 0.5; BAG, Bi0.1-BAG, Bi0.2-BAG, Bi0.5-BAG, respectively). Monophasic baghdadite was retained after bismuth ion incorporation up to x = 0.2 at calcination temperatures of 1350 °C. When pressed and sintered, energy dispersive x-ray spectroscopy showed that BAG and Bi0.1-BAG retained crystalline homogeneity, but Bi0.2-BAG formed zirconium-rich crystalline regions. BAG, Bi0.1-BAG and Bi0.2-BAG exhibited non-degradation after 56 days of immersion in culture medium. Bi0.1-BAG exhibited the lowest change in culture medium pH (+0.0), compared to BAG (+0.7) and Bi0.2-BAG (+0.2) after 56 days of culture media immersion. Bi0.1-BAG exhibited similar strength and modulus to BAG (σ: 200-290 MPa; E: 4-5 GPa), and significantly higher compressive strength and modulus versus Bi0.2-BAG (σ: 150-200 MPa; E: 3.5-4 GPa) across 56 days of aqueous immersion. In vitro studies using primary human bone derived cells (HOBs) demonstrated a significant increase in HOBs proliferation when cultured on Bi0.1-BAG for seven days compared to BAG and Bi0.2-BAG. Importantly, Bi0.1-BAG showed increased radiopacity by ~33%, when compared to BAG, and by ~115% when compared to biphasic calcium phosphate. The properties of Bi0.1-BAG show promise for its use as a bioactive ceramic with sufficient radiopacity for treatment of bone defects.

Pretreatment with Ranitidine Bismuth Citrate May Improve Success Rates of Helicobacter pylori Eradication: A Prospective, Randomized, Controlled and Open-Label Study

Effective Helicobacter pylori (H. pylori) eradication is a major public health concern; however, eradication failure rates with the standard triple therapy remain high. We aimed to investigate the effectiveness and tolerability of ranitidine bismuth citrate (RBC) pretreatment before standard triple therapy for H. pylori eradication. A prospective, randomized, controlled, and open-label clinical trial was conducted from June to December 2019. H. pylori eradication rate, safety, and tolerability were compared between the standard treatment group (esomeprazole, amoxicillin, and clarithromycin for 7 days) and RBC pretreatment group (RBC for 2 weeks before standard triple therapy). This trial ended earlier than estimated owing to the N-nitrosodimethylamine concerns with ranitidine. Success rates of H. pylori eradication were 80.9% and 67.3% in the RBC pretreatment (n = 47) and standard treatment (n = 52) (p = 0.126) groups, respectively. Our trial was discontinued earlier than planned; however, a statistical significance would be achieved by expansion of our data (p = 0.031) if patient enrollment numbers reached those initially planned. Adverse event rates were comparable between groups (25.5% in the pretreatment group vs. 28.8% in the standard treatment group), without serious event. Tolerability was excellent in both groups, recorded as 97.9% and 100% in the pretreatment and standard treatment groups, respectively. Compared with the standard triple regimen, RBC pretreatment for 2 weeks may achieve higher H. pylori eradication rates, with excellent safety and tolerability. However, this study necessitates further validation as it was discontinued early owing to the N-nitrosodimethylamine issues of ranitidine.

Efficacy and safety of bismuth-based quadruple therapy for Helicobacter pylori eradication in children

OBJECTIVES

To evaluate the efficacy and safety of a 10-day quadruple therapy containing colloidal bismuth sub-citrate (CBS), esomeprazole (ESO), amoxicillin (AMO), and metronidazole (MET) for Helicobacter pylori (H. pylori) eradication in children.

METHODS

Monocentric, open-label, prospective, single-arm clinical trial in children aged 6-17 years with H. pylori infection. The study was carried out on consecutive patients with upper gastrointestinal symptoms and H. pylori infection confirmed by histology and culture of gastric biopsies. The outcome was evaluated using a ¹³ C-urea breath test 8-10 weeks post-therapy. Adverse events and compliance were evaluated by daily journal and pill counting.

RESULTS

A total of 36 children fulfilling the inclusion criteria were enrolled. Eight (22.2%) of them had a prior H. pylori eradication treatment. Thirteen (36.1%) patients were infected by a strain resistant to MET and 8 (22.2%) by a strain resistant to both MET and Clarithromycin (CLA). In the intention-to-treat population (ITT), eradication was achieved in 35/36 patients (95%CI: 85%-99%). Twenty-three children reported at least one adverse event (63.8%), mostly mild (nausea, vomiting, abdominal pain, diarrhea, dark stool, metallic taste, headache, and rash). The compliance rate was high, with 30 (83.3%) patients taking >90% of the treatment.

CONCLUSION

10-day quadruple therapy containing CBS, ESO, AMO, and MET for H. pylori eradication in children is a safe and very effective solution, especially for previously treated patients and those infected with double resistant strains.

Efficacy of bismuth added to standard triple therapy as the first-line eradication regimen for Helicobacter pylori infection

BACKGROUND

Addressing the increasing antibiotic resistance, including clarithromycin resistance, which affects Helicobacter pylori eradication therapy, is a challenge for clinicians. The objective of this study was to determine the efficacy of bismuth added to standard triple therapy as a first-line treatment regimen for Helicobacter pylori infection. The secondary outcome was the treatment efficacy for clarithromycin-resistant strains.

MATERIAL AND METHODS

A prospective study was undertaken from January to December 2019. A total of 107 patients with Helicobacter pylori infection were enrolled and received Helicobacter pylori eradication therapy with bismuth added to standard triple therapy for 14 days. We also evaluated the clarithromycin resistance rate by dual-priming oligonucleotide-based multiplex PCR and treatment efficacy.

RESULTS

A total of 104 patients completed standard triple therapy with bismuth added for Helicobacter pylori eradication. The eradication rates in the intention to treat and per-protocol analyses were 87.9% and 90.4%, respectively. The frequency of clarithromycin resistance was 33.6% (35/104), and the eradication rate was 77.1% in resistant strains (27/35).

CONCLUSION

Bismuth added to standard triple therapy could be acceptable as a first-line treatment regimen for Helicobacter pylori eradication in patients with clarithromycin-resistant strains. In particular, in areas with high clarithromycin tolerance, it is advisable to consider bismuth add-on therapy as the first-line treatment regimen.

Structurally restricted Bi(III) metallation of apo-βMT1a: metal-induced tangling

Non-toxic bismuth salts are used in anti-ulcer medications and to protect against nephrotoxicity from anticancer drugs. Bismuth salts also induce metallothionein (MT), a metal-binding protein that lacks a formal secondary structure. We report the impact on the metallation properties of Bi(III) to the 9-cysteine β fragment of MT as a function of cysteine accessibility using electrospray ionization mass spectrometry. At pH 7.4, Bi2βMT formed cooperatively. Cysteine modification shows that each Bi(III) was terminally bound to three cysteinyl thiolates. Non-cooperative Bi(III) binding was observed at pH 2.3, where cysteine accessibility is increased. However, competition from H4EDTA inhibited Bi(III) binding. When GdmCl, a well-known denaturing agent, was used to increase cysteine accessibility of the apoβMT at pH 7.4, a greater fraction of Bi3βMT formed using all nine cysteines. The change in binding profile and equilibrium of Bi2βMT was determined as a function of acidification, which changed as a result of competition with H4EDTA. There was no Bi(III) transfer between Bi2βMT, Cd3βMT, and Zn3βMT. This lack of metal exchange and the resistance towards binding the third Bi(III) suggest a rigidity in the Bi2βMT binding sites that inhibits Bi(III) mobility. These experiments emphasize the conformational control of metallation that results in substantially different metallated products: at pH 7.4 (many cysteines buried) Bi2βMT, whereas at pH 7.4 (all cysteines accessible) enhanced formation of Bi3βMT. These data suggest that the addition of the first two Bi(III) crosslinks the protein, blocking access to the remaining three cysteines for the third Bi(III), as a result of tangle formation.

Preparation of High-Drug-Loaded Clarithromycin Gastric-Floating Sustained-Release Tablets Using 3D Printing

The high-drug-loaded sustained-release gastric-floating clarithromycin (CAM) tablets were proposed and manufactured via semisolid extrusion (SSE)-based 3D printing. The physical and mechanical properties, such as dimensions, weight variation, friability, and hardness, were accessed according to the quality standards of Chinese Pharmacopoeia (Ch.P). The interactions among the drug-excipients were evaluated via differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques. Next, the rheological properties of the paste and the effect of the excipients and solvents were evaluated. Finally, a very high drug-loading of up to 81.7% (w/w) with the sustain release time of 8 h (125 mg) and 12 h (250 mg) was achieved. The results revealed the potential of SSE for achieving a high drug loading and identified the suitable properties of the paste for SSE-based 3D printing.

Comparative study of allicin-containing quadruple therapy vs. bismuth-containing quadruple therapy for the treatment of Helicobacter pylori infection: a prospective randomized study

BACKGROUND

Bismuth has antimicrobial activity and can improve the efficacy of triple Helicobacter pylori (H. pylori) therapy. Allicin added to conventional therapy for H. pylori infection also improves H. pylori eradication rates. Thus, this study aims to evaluate and compare the efficacy, safety and tolerability of allicin-containing quadruple therapy and bismuth-containing quadruple therapy and to investigate the factors that affect the eradication rates.

METHODS

Two hundred twenty H. pylori-infected patients were included and randomly (1:1) assigned to 14-day quadruple therapy: ilaprazole (5 mg bid), doxycycline (100 mg bid), and furazolidone (100 mg bid) with an allicin soft capsule (40 mg of DATS tid) (IDFA) or colloidal bismuth tartrate (220 mg of elemental bismuth bid) (IDFB). Eradication was confirmed by urea breath tests. Symptom improvement, adverse events, and adherence were assessed by a questionnaire.

RESULTS

In the intention-to-treat and per-protocol analysis, the eradication rates for IDFA and IDFB groups were 87.5% (70/80) vs. 86.3% (69/80, P = 0.815) and 91.9% (68/74) vs. 91.8% (67/73, P = 0.980) as first-line therapies; 83.3% (25/30) vs. 83.3% (25/30, P = 1) and 89.3% (25/28) vs. 88.9% (24/27, P = 1) as second-line therapies. Symptom improvement rates were 96.1% and 97.0% for IDFA and IDFB (P = 1). The adverse event rates were 10.9% in IDFA and 14.5% in IDFB groups (P = 0.418). Nausea occurred frequently in IDFB than IDFA (1.8% vs. 8.2%, P = 0.030). Smoking and sharing utensils significantly affected the efficacy.

CONCLUSION

Allicin-containing quadruple therapy might be regarded as a promising alternative to bismuth-containing quadruple therapy in H. pylori eradication.

Amoxicillin and Clarithromycin Mucoadhesive Delivery System for Helicobacter pylori Infection in a Mouse Model: Characterization, Pharmacokinetics, and Efficacy

Helicobacter pylori is the main pathogen responsible for gastric ulcers and a predisposing factor of stomach cancer. Although current treatment is usually successful, it requires high doses and frequent administration. An innovative mucoadhesive system (Mucolast^®) loaded with amoxicillin and clarithromycin is proposed to improve the efficacy of treatment against H. pylori. The drug product was optimized based on its viscoelastic properties to obtain long-term stability of the vehicle. The drug release mechanisms were different for both antibiotics based on their solubilization status. A systemic and stomach pharmacokinetic profile was obtained after three different doses were administered to mice, obtaining similar systemic exposure levels but an increase in drug concentration in the stomach. The efficacy results in mice infected with H. pylori also demonstrated the superiority of the antibiotics when administered in Mucolast^®, as shown by the bacterial count in stomach tissue and under histopathological and biochemical evaluation. The proposed treatment was efficacious and safe and is presented as a realistic alternative to current treatment options to improve patient compliance and to reduce bacterial resistance.

Amoxicillin or tetracycline in bismuth-containing quadruple therapy as first-line treatment for Helicobacter pylori infection

AIM

To compare the efficacy and safety between modified quadruple- and bismuth-containing quadruple therapy as first-line eradication regimen for Helicobacter pylori infection.

METHODS

This study was a multicenter, randomized-controlled, non-inferiority trial. Subjects endoscopically diagnosed with H. pylori infection were randomly allocated to receive modified quadruple- (rabeprazole 20 mg bid, amoxicillin 1 g bid, metronidazole 500 mg tid, bismuth subcitrate 300 mg qid [elemental bismuth 480 mg]; PAMB) or bismuth-containing quadruple therapy (rabeprazole 20 mg bid, bismuth subcitrate 300 mg qid, metronidazole 500 mg tid, tetracycline 500 mg qid; PBMT) for 14 days. Rates of eradication success and adverse events were investigated. Antibiotic resistance was determined using the agar dilution and DNA sequencing of the clarithromycin resistance point mutations in the 23 S rRNA gene of H. pylori.

RESULTS

In total, 233 participants were randomized, 27 were lost to follow-up, and four violated the protocol. Both regimens showed an acceptable eradication rate in the intention-to-treat (PAMB: 87.2% vs. PBMT: 82.8%, P = .37), modified intention-to-treat (96.2% vs. 96%, P > .99), and per-protocol (96.2% vs. 96.9%, P > .99) analyses. Non-inferiority in the eradication success between PAMB and PBMT was confirmed. The amoxicillin-, metronidazole-, tetracycline-, clarithromycin-, and levofloxacin-resistance rates were 8.3, 40, 9.4, 23.5, and 42.2%, respectively. Antimicrobial resistance did not significantly affect the efficacy of either therapy. Overall compliance was 98.1%. Adverse events were not significantly different between the two therapies.

CONCLUSION

Modified quadruple therapy comprising rabeprazole, amoxicillin, metronidazole, and bismuth is an effective first-line treatment for the H. pylori infection in regions with high clarithromycin and metronidazole resistance.

Rifamycin use for treatment of Helicobacter pylori infection: a review of recent data

Helicobacter pylori eradication has become increasingly challenging. We focused on recent data about rifamycin resistance and rifamycin-containing regimens. Rifampin (rifampicin) resistance rates were <1-18.8% (often ≤7%), while those to rifabutin were 0-<4%. To detect rifabutin resistance by rifampin, 4 mg/l breakpoint was suggested. Eradication success by rifaximin-based regimens was disappointing (<62%), while that of rifabutin-containing regimens was 54.5->96%, reaching >81% in four studies. Some newer rifamycin analogs like TNP-2092 need further investigation. Briefly, although rifabutin-based regimens carry a risk of adverse effects or increasing mycobacterial resistance, they may be a rational choice for some multidrug-resistant H. pylori strains and as a third-line eradication therapy. Bismuth addition to rifabutin-based therapy and combined rifabutin-containing capsules (Talicia) are promising treatment options.