Role of bismuth in improving Helicobacter pylori eradication with triple therapy

Relative potency of proton-pump inhibitors, Helicobacter pylori therapy cure rates, and meaning of double-dose PPI

BACKGROUND

Helicobacter pylori treatment recommendations often recommend use of double-dose PPI or greater. This is confusing because PPIs very markedly in relative potency such that a double dose of one may not even be equivalent to the single dose of another.

OBJECTIVE

To relate the concept of double-dose to specific amounts of the different PPIs METHODS: We used data standardizing PPI potency in terms of the duration of intragastric pH >4/24 hours (pH4-time) to rank PPIs. Relative potency varies from 4.5 mg omeprazole equivalents (20 mg pantoprazole) to 72 mg omeprazole equivalents (40 mg rabeprazole).

RESULTS

We defined PPI dosing for H. pylori therapy as low dose (eg, approximately 20 mg omeprazole equivalents, b.i.d.), high or double dose as approximately 40 mg omeprazole equivalents, b.i.d.) and high dose as approximately 60 mg omeprazole equivalents, b.i.d.). For example, standard double dose PPI would thus be 40 mg of omeprazole, 20 mg of esomeprazole or rabeprazole, 45 mg of lansoprazole, or 120 mg of pantoprazole each given b.i.d.

CONCLUSIONS

Simply doubling the dose of any PPI achieves markedly different effects on pH4-time. However, PPIs can be used interchangeably and cost effectively based on their omeprazole equivalency.

Systems Approaches for Unveiling the Mechanism of Action of Bismuth Drugs: New Medicinal Applications beyond Helicobacter Pylori Infection

Metallodrugs have been widely used as diagnostic and therapeutic agents. Understanding their mechanisms of action may lead to advances in rational drug design. However, to achieve this, diversified approaches are required because of the complexity of metal-biomolecule interactions. Bismuth drugs in combination with antibiotics as a quadruple therapy show excellent success rates in the eradication of Helicobacter pylori, even for antibiotic-resistant strains, and in fact, they have been used in the clinic for decades for the treatment of infection. Understanding the mechanism of action of bismuth drugs may extend their medicinal application beyond the treatment of H. pylori infection. This Account describes several general strategies for mechanistic studies of metallodrugs, including system pharmacology and metalloproteomics approaches. The application of these approaches is exemplified using bismuth drugs. Through a system pharmacology approach, we showed that glutathione- and multidrug-resistance-associated protein 1-mediated self-propelled disposal of bismuth in human cells might explain the selective toxicity of bismuth drugs to H. pylori but not the human host. The development of metalloproteomics has enabled extensive studies of the putative protein targets of metallodrugs with a dynamic range of affinity. Continuous-flow GE-ICP-MS allows simultaneous monitoring of metals and their associated proteins with relatively high affinity on a proteome-wide scale. The fluorescence approach relies on unique M ⁿ⁺-NTA-based fluorescence probes and is particularly applicable for mining those proteins that bind to metals/metallodrugs weakly or transiently. Integration of these methods with quantitative proteomics makes it possible to maximum coverage of bismuth-associated proteins, and the sustained efficacy of bismuth drugs lies in their ability to disrupt multiple biological pathways through binding and functional perturbation of key enzymes. The knowledge acquired by mechanistic studies of bismuth drugs led to the discovery of UreG as a new target for the development of urease inhibitors. The ability of Bi(III) to inhibit metallo-β-lactamase (MBL) activity through displacement of the Zn(II) cofactor renders bismuth drugs new potential as broad-spectrum inhibitors of MBLs. Therefore, bismuth drugs could be repurposed together with clinically used antibiotics as a cotherapy to cope with the current antimicrobial resistance crisis. We anticipate that the methodologies described in this Account are generally applicable for understanding the (patho)physiological roles of metals/metallodrugs. Our mechanism-guided discovery of new druggable targets as well as new medicinal applications of bismuth drugs will inspire researchers in relevant fields to engage in the rational design of drugs and reuse of existing drugs, eventually leading to the development of new effective therapeutics.

HONEY-DERIVED LACTOBACILLUS RHAMNOSUS ALLEVIATES HELICOBACTER PYLORI-INDUCED GASTRO-INTESTINAL INFECTION AND GASTRIC INFLAMMATION IN C57BL/6 MICE: AN IMMUNO-HISTOLOGIC STUDY

BACKGROUND

Helicobacter pylori (H. pylori) has been introduced by since 1983 by Marshal and Warren to play the main role in the pathophysiology of gastritis and gastric ulcers. Almost half of the world population1 is infected by H. pylori. Current therapeutic regimen against H. pylori includes the use of a proton pump inhibitor plus two or more antibiotics. However, the efficacy of this regimen is decreasing mainly due to antibiotic resistance and side effects of medications. This fact has resulted in public interest in other therapeutic options and the role of probiotics merits special attention in this regard.

OBJECTIVE

This study aims to evaluate the efficacy of honey-derived Lactobacillus rhamnosus on H. pylori-induced gastric inflammation and gastro-intestinal infection in C57BL/6 Mice.

METHODS

The 24 C57BL/6 Mice were randomly divided into three groups of eight mice each. All the mice were fed with 1cc suspension containing 5*1010 CFU/ mL of ATCC43504 strains of H. pylori for 3 consecutive days, twice daily via polyethylene gavage tubes. At the end of 4th week, infection with H. pylori was confirmed with stool Ag (ELISA) and following sacrifice of one mouse from each group, histopathologic study confirmed gastritis. The groups were subjected to different therapies as stated, 1: without Bismuth (Bi), Omeprazole (Om) and L. rhamnosus prescription, 2: Bi, Om and Clarithromycin (Cl) and 3: Bi, Om plus 1cc of suspension of 109 CFU/mL of L. rhamnosus. After 2 weeks, the stool was analyzed for Ag and the mice were sacrificed for evaluation of histopathologic changes.

RESULTS

Treatment with L. rhamnosus group provided Zero titer of stool Ag and was associated with improved gastric inflammation in all subjects, similar to the clarithromycin group.

CONCLUSION

Honey-derived L. rhamnosus probiotics provides similar results as clarithromycin in terms of improvement of H. pylori infection and gastritis in C57BL/6 Mice model, without its cons of antibiotic resistance.

Current and Future Treatment of Helicobacter pylori Infections

Helicobacter pylori is one of the most common human pathogens and it has been estimated that about 50% of the world's population is currently infected. The present consensus is that, unless there are compelling reasons, all H. pylori infections should be cured. Since the 1990s, different national and international guidelines for the management of H. pylori-related diseases have been published and periodically updated regarding indications for treatment, diagnostic procedures, and preferred treatment regimens. Most guidelines provide sophisticated meta-analyses examining the outcome of different regimens done in regions with variable, often high rates of resistance to antibiotics, for which the prevalence and effects of resistance was often ignored. Although successful antimicrobial therapy must be susceptibility-based, increasing antimicrobial resistance and general unavailability of susceptibility testing have required clinicians to generally rely on empiric regimens. Antibiotics resistance of H. pylori has reached alarming high levels worldwide, which has an effect to efficacy of treatment. The recommendations should provide regimes for multi-resistant infections or for those where susceptibility testing is unavailable or refused. The first rule is to use only proven locally effective therapies. Because of patient intolerances, drug allergies, and local experiences, the clinicians should have at least two options for first-line therapy. As with any antimicrobial therapy, a thorough review of prior antibiotic use is invaluable to identify the presence of probably resistance. The second key is patient education regarding potential and expected side-effects and the importance of completing the course of antibiotics. We also review here triple therapies, sequential-concomitant, hybrid therapies, bismuth therapies, dual therapy, vonoprazan, modern antibiotic treatments, probiotics and vaccination.

Gut microbiome can be restored without adverse events after Helicobacter pylori eradication therapy in teenagers

OBJECTIVES

The effect of Helicobacter pylori eradication on the gut microbiota of teenagers is unknown; hence, this study aimed to assess changes in the gut microbiome after H. pylori eradication therapy in teenagers.

MATERIALS AND METHODS

Changes in gut microbiota before and after H. pylori eradication were prospectively investigated in eight students without any underlying diseases, via next-generation sequencing of 16S rDNA. Twenty-four stool samples were collected, and operational taxonomic unit analysis was performed. As secondary analyses, alpha and beta diversity were evaluated. Furthermore, pre-treatment microbiome compositions were compared with those 1 week and 2 months after treatment.

RESULTS

Alpha diversity analysis revealed that both species richness and evenness were recovered to pre-treatment levels at 2 months after eradication therapy. Slight but non-significant differences were observed in bacterial species abundance between pre- and post-treatment samples, upon beta diversity analysis. Although the relative abundance of Bacteroidetes tended to increase and that of Actinobacteria significantly decreased immediately after eradication therapy, the taxonomic composition was similar to that before treatment and at 2 months post-eradication. However, two students showed significant changes in the gut microbiota in relative abundances at the level of the phylum, class, and order.

CONCLUSIONS

Although H. pylori eradication therapy caused short-term dysbiosis, microbial diversity was restored in healthy teenagers. However, as the relative abundance of gut microbiota in some cases remained altered, the effect of H. pylori eradication therapy on the gut microbiome should be continuously monitored.

Outcomes of furazolidone- and amoxicillin-based quadruple therapy for Helicobacter pylori infection and predictors of failed eradication

AIM

To evaluate the outcomes of furazolidone- and amoxicillin-based quadruple therapy for treatment of Helicobacter pylori (H. pylori) infection and identify predictors of failed eradication.

METHODS

Patients with H. pylori infection treated with furazolidone, amoxicillin, bismuth, and proton pump inhibitor therapy (January 2015 to December 2015) who received the ¹³C-urea breath test > 4 wk after treatment were evaluated. Demographic and clinical data including prior H. pylori treatment attempts, medication adherence, alcohol and cigarette consumption during therapy, and treatment-related adverse events were recorded by reviewing medical records and telephone surveys. H. pylori eradication rates for overall and subgroups were evaluated. Multivariate analysis was performed to identify independent predictors of failed H. pylori eradication.

RESULTS

Of the 992 patients treated and retested for H. pylori infection, the overall eradication rate was 94.5% [95% confidence interval (CI): 94.1%-95.9%]. H. pylori eradication rate of primary therapy was 95.0% (95%CI: 93.5%-96.5%), while that of rescue therapy was 91.3% (95%CI: 86.8%-95.8%). Among the 859 patients who completed the study protocol, 144 (17%) reported treatment-related adverse events including 24 (3%) leading to premature discontinuation. On multivariate analysis, poor medication adherence [adjusted odds ratio (AOR) = 6.7, 95%CI: 2.8-15.8], two or more previous H. pylori treatments (AOR = 7.4, 95%CI: 2.2-24.9), alcohol consumption during therapy (AOR = 4.4, 95%CI: 1.5-12.3), and possibly smoking during therapy (AOR = 1.9, 95%CI: 0.9-4.3) were associated with failed H. pylori eradication.

CONCLUSION

Furazolidone- and amoxicillin-based quadruple therapy for H. pylori infection in an area with a high prevalence of clarithromycin resistance demonstrated high eradication rates as primary and rescue therapies with a favorable safety profile. Patient education targeting abstinence from alcohol during therapy and strict medication adherence may further optimize H. pylori eradication.

Multi-omics and temporal dynamics profiling reveal disruption of central metabolism in Helicobacter pylori on bismuth treatment

Integration of multi-omics enables uncovering cellular responses to stimuli or the mechanism of action of a drug at a system level. Bismuth drugs have long been used for the treatment of Helicobacter pylori infection and their antimicrobial activity was attributed to dysfunction of multiple proteins based on previous proteome-wide studies. Herein, we investigated the response of H. pylori to a bismuth drug at transcriptome and metabolome levels. Our multi-omics data together with bioassays comprehensively reveal the impact of bismuth on a diverse array of intracellular pathways, in particular, disruption of central carbon metabolism is systematically evaluated as a primary bismuth-targeting system in H. pylori. Through temporal dynamics profiling, we demonstrate that bismuth initially perturbs the TCA cycle and then urease activity, followed by the induction of oxidative stress and inhibition of energy production, and in the meantime, induces extensive down-regulation in H. pylori metabolome. The present study thus expands our knowledge on the inhibitory actions of bismuth and provides a novel systematic perspective of H. pylori in response to a clinical drug that sheds light on enhanced therapeutic methodologies.

Furazolidone-containing triple and quadruple eradication therapy for initial treatment for Helicobacter pylori infection: A multicenter randomized controlled trial in China

BACKGROUND

The efficacy of Helicobacter pylori (H. pylori) eradication has steadily declined, primarily because of antibiotic resistance. This study aimed to evaluate the efficacy and safety of furazolidone eradication therapies as initial treatments for H. pylori infection.

METHODS

A national, multicenter, open-label, randomized controlled trial was performed at 16 sites across 13 provinces in China to evaluate the efficacy and safety of furazolidone-containing therapies for H. pylori infection. Treatment naïve patients were randomly assigned to: esomeprazole 20 mg, bismuth 220 mg, amoxicillin 1000 mg, and furazolidone 100 mg twice daily for 10 and 7 days (FAB 10 and FAB 7; the same therapy without bismuth (FA 10 and FA 7). The primary and secondary outcomes were the eradication rate and regimen safety, respectively. Treatment success was assessed by the ¹³ C urea breath test at least 4 weeks after treatment completion.

RESULTS

Overall, according to intention-to-treat (ITT) analysis, the eradication rates for FAB 10 and FAB 7 were 86.6% (95% confidence interval [CI], 79.9%-93.2%) and 83.6% (95% CI, 76.3%-90.9%) and for FA 10 and FA 7 were 82.4% (95% CI, 74.9%-89.8%) and 77.6% (95% CI, 69.4%-85.8%), respectively. According to per-protocol analysis, the overall eradication rates for FAB 10 and FAB 7 were 94.7% (95% CI, 90.3%-99.1%) and 90.8% (95% CI, 85.1%-96.5%) and for FA 10 and FA 7 were 90.6% (95% CI, 84.9%-96.3%) and 85.1% (95% CI, 78.2%-92.1%), respectively. The overall prevalence of side effects was 8.1%.

CONCLUSIONS

Furazolidone-containing therapies, particularly the tested 10-day quadruple therapy, exhibited satisfactory efficacy and safety. This 10-day quadruple therapy represents a promising initial treatment strategy for Chinese patients.

Understanding treatment guidelines with bismuth and non-bismuth quadruple Helicobacter pylori eradication therapies

INTRODUCTION

Recent Helicobacter pylori treatment guidelines recommend the 4-drug combinations bismuth quadruple therapy and concomitant therapy. Areas covered: We review antimicrobial therapy for H. pylori in the context of antimicrobial therapy in general and specifically in relation to good antimicrobial stewardship (defined as optimal selection, dose, and duration of an antimicrobial that results in the best clinical outcome for the treatment of infection, with minimal toxicity to the patient and minimal impact on subsequent resistance). Expert commentary: The lack of regional and local H. pylori susceptibility data prevents implementation of susceptibility-based antimicrobial therapy and forces compromises. Bismuth quadruple therapy employing at least 1,500 mg of metronidazole for 14 days is effective despite metronidazole resistance. The main drawback is side effects causing reduced adherence. Versions where amoxicillin replaces metronidazole or tetracycline also appear effective. It is likely that bismuth quadruple therapy can be simplified by giving bismuth and possibly tetracycline b.i.d., possibly with fewer side effects. Concomitant therapy (a proton pump inhibitor, metronidazole, clarithromycin, amoxicillin) is ineffective with dual clarithromycin-metronidazole resistance and all patients receive at least one unnecessary antibiotic thus promoting antimicrobial resistance worldwide. Concomitant therapy should be abandoned when susceptibility testing becomes widespread or an alternate becomes available.

Treating Helicobacter pylori effectively while minimizing misuse of antibiotics

Experts now recommend that all Helicobacter pylori infections be eradicated unless there are compelling reasons not to. As with other infectious diseases, effective therapy should be based on susceptibility.

The diagnosis and management of H. pylori infection in Singapore

Helicobacter pylori (H. pylori) is an infection that has a role in causing dyspepsia and complications such as peptic ulcer disease and gastric malignancies. In the primary care setting, one can adopt a stepwise approach with the 'test-and-treat' strategy to manage H. pylori-associated dyspepsia in young patients without alarm symptoms. Empiric first-line therapies should be for a two-week duration; options include clarithromycin-containing triple therapy alone or with the addition of bismuth, concomitant therapy and bismuth quadruple therapy. Post-treatment carbon urea breath test must be performed at least four weeks after the end of treatment to confirm the cure. Options for empiric second-line treatment include bismuth quadruple therapy and levofloxacin-containing triple therapy. Patients with persistent or alarm symptoms should be referred for further evaluation. Patients with persistent infection should be referred for gastroscopy so that gastric biopsies can be obtained for H. pylori culture and antibiotic susceptibility testing.

Efficacy and Tolerability of Two Quadruple Regimens: Bismuth, Omeprazole, Metronidazole with Amoxicillin or Tetracycline as First-Line Treatment for Eradication of Helicobacter Pylori in Patients with Duodenal Ulcer: A Randomized Clinical Trial

AIM

To evaluate the efficacy and tolerability of tetracycline vs. high-dose amoxicillin in bismuth-based quadruple therapy for Helicobacter pylori(H. pylori) eradication.

METHODS

This randomized, open-label clinical trial included 228 patients with H.pylori infection and duodenal ulcer without a history of H.pylori treatment. Patients were randomly divided into two groups. The amoxicillin group received metronidazole 500mg, bismuth subcitrate 240mg, and amoxicillin 1000mg, all three times a day, plus omeprazole 20 mg twice a day, for 14 days. The tetracycline group received metronidazole 500mg three times a day; bismuth subcitrate240mg and tetracycline HCl 500mg, both four times a day; and omeprazole 20 mg twice a day, for 14 days. Evaluation for compliance and drug-relatedadverse effects were evaluated at the end of two weeks. Eight weeks after the end of treatment, the rate of H.pylori eradication was assessed by the C13urease breath test.

RESULTS

There were no significant demographic differences between the two groups. Eradication rate was higher with the amoxicillin-containing regimen than the tetracycline-containing regimen: 105/110 (95.51%; 95% confidence interval, 91.5%-99.3%) vs. 88/105 (83.8%; 95%CI, 76.7%-90.8%) by per-protocol analysis (p = 0.005) and 92.9% (95%CI, 88.1%-97.6%) vs. 76.5% (95%CI, 68.7%-84.2%) by intention-to-treat analysis (ITT, p = 0.001). Adverse effects were significant higher in the tetracycline groupthan in the amoxicillin group (65.2% vs. 43.4%; p = 0.001).

CONCLUSION

Bismuth-based quadruple therapy including high-dose amoxicillin and metronidazole achieved an acceptable rate of H.pylori infection eradication with good tolerance in patients with duodenal ulcer. This regimen can overcome treatment resistance in areas with high prevalence of metronidazole and clarithromycin resistance.

TRIAL REGISTRATION

The Thai Clinical Trial Registry (TCTR) 20170623004.

Safety of first-line triple therapy with a potassium-competitive acid blocker for Helicobacter pylori eradication in children

BACKGROUND

Helicobacter pylori infection is a risk factor for gastric cancer, and it has been reported that eradication of H. pylori is effective for preventing such cancer. Recently, H. pylori eradication has been performed in children as first-line therapy against gastric cancer. Here, we report use of triple therapy with a potassium-competitive acid blocker (P-CAB) for H. pylori eradication in children.

METHODS

H. pylori infection testing and eradication therapy began in fiscal year 2015 in junior high school students located in Yurihonjo city and Nikaho city, Akita prefecture, Japan. Urine-based immunochromatography, stool antigen enzyme-linked immunosorbent assay tests, and serum antibody tests were performed as the initial screening examination. Those who tested positive on one of the three examinations then underwent a urea breath test (¹³C-UBT). Those who tested positive on ¹³C-UBT and expressed the desire to undergo H. pylori eradication then received eradication therapy comprising 20 mg P-CAB, 750 mg amoxicillin, and 200 mg clarithromycin twice a day for 7 days. At least 8 weeks after treatment, eradication success was evaluated using ¹³C-UBT.

RESULTS

A total of 118 students received eradication therapy. Eradication rates were 81.3% (95% confidence interval: 74.3-88.4, 96/118) in ITT analysis and 85.7% (95% confidence interval: 79.1-92.9 96/112) in PP analysis. Adverse effects associated with eradication therapy were observed in 25 of 118 subjects (21.1%), seven of whom required hospital treatment (rash in five, vomiting in two). All seven subjects either discontinued therapy or were administered anti-allergy drugs, which resulted in swift alleviation of symptoms.

CONCLUSIONS

First-line triple therapy with a P-CAB for H. pylori eradication in children was found to be safe.

Bismuth improves efficacy of proton-pump inhibitor clarithromycin, metronidazole triple Helicobacter pylori therapy despite a high prevalence of antimicrobial resistance

BACKGROUND

Helicobacter pylori (H. pylori) eradication has become increasingly difficult especially for penicillin allergy patients.

AIMS

To evaluate the efficacy of adding bismuth or high-dose metronidazole to an H. pylori eradication regimen containing a proton-pump inhibitor, clarithromycin, and metronidazole in patients allergic to penicillin.

METHODS

Pilot study in which penicillin-allergic, treatment-naive subjects were randomized (1:1) to 14-day esomeprazole (20 mg q12h), clarithromycin (500 mg q12h), and high dose of metronidazole (400 mg q6h) with (BECM group) or without (ECM group) bismuth (600 mg q12h). Eradication was confirmed by ¹³ C-urea breath test 6 weeks after therapy. Antimicrobial susceptibility was assessed by the agar dilution method. Adverse events were recorded.

RESULTS

Sixty-six subjects were randomized, four were lost to follow-up and eight violated the protocol. The eradication rates were 63.6% (95% CI: 47.2%-80.0%) for ECM vs 84.8% (95% CI 72.6%-97.1%) (p = .049) for BECM by intention-to-treat, 67.7% (95% CI 51.3%-84.2%) vs 90.3% (95% CI 79.9%-100%) (p = .029) by modified ITT, and 70% (95% CI 53.6%-86.4%) vs 96% (95% CI 88.3%-100%) (P = .033) by per-protocol. Metronidazole, clarithromycin, and dual-resistant rates were 74.2%, 24.2%, and 18.2%, respectively. The cure rates were significantly improved by the addition of bismuth for both clarithromycin-resistant isolates (100% vs 25%, P = .024) and metronidazole-resistant isolates (94.7% vs 63.6%, P = .043). Adverse events were reported by 45.5% of subjects in ECM group and 48.5% in the BECM group (P = .805).

CONCLUSIONS

This prospective trial demonstrated that while high-dose metronidazole could not completely overcome metronidazole resistance, bismuth was additive and improved the overall cure rates by 21%-26%.

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.

High-dose amoxicillin/esomeprazole dual therapy as a first-line therapy for Helicobacter pylori eradication

AIM

To evaluate the clinical efficacy and safety of high-dose amoxicillin/esomeprazole dual therapy as a first-line therapy for Helicobacter pylori (H. pylori) eradication.

METHODS

One hundred and forty-two subjects infected with H. pylori and naive to treatment were randomly assigned to receive either 14-d high-dose amoxicillin/esomeprazole dual therapy (esomeprazole 20 mg and amoxicillin 0.75 g, four times a day; EA group) or bismuth-based quadruple therapy [esomeprazole 20 mg, bismuth potassium citrate 220 mg (elemental bismuth), amoxicillin 1 g, and clarithromycin 0.5 g, twice a day; EBAC group]. Six weeks after treatment, H. pylori eradication was assessed by using the urea breath test (¹³C or ¹⁴C).

RESULTS

A total of 131 subjects completed this clinical trial. H. pylori eradication rates by intention-to-treat (ITT) and per-protocol (PP) analysis in the EA group were 82.9% and 89.2%, respectively, and those in the EBAC group were 86.1% and 93.9%, respectively. No significant difference was found in H. pylori eradication rates by both ITT and PP analysis (P > 0.05). The incidence of side effects by PP analysis in the EBAC group was significantly higher than that in the EA group (15.2% vs 3.1%, P < 0.05). All the side effects disappeared after discontinuing the drugs.

CONCLUSION

High-dose amoxicillin/esomeprazole dual therapy can be used as an effective and safety first-line therapy for H. pylori infection.

Dealing with uncertainty in the treatment of Helicobacter pylori

Helicobacter pylori treatment may be viewed as an uncertain situation, where current knowledge is insufficient to provide evidence-based recommendations for all possible scenarios. Evidence suggests that, under uncertainty conditions, a few simple rules of thumb tend to work better than complex algorithms. Overall, five evidence-based rules of thumb are suggested: (1) Use four drugs; (2) Use maximal acid inhibition; (3) Treat for 2 weeks; (4) Do not repeat antibiotics after treatment failure; and (5) If your treatment works locally, keep using it. These simple rules of thumb may help the reader to select the best alternative for a given patient, choosing between the heterogeneous recommendations provided by the many different consensus conferences on H. pylori treatment recently published.

Efficacy and safety of Bifidobacterium combined with ilaprazole-containning quadruple therapy in rescue eradication of Helicobacter pylori

AIM

To evaluate the efficacy and safety of Bifidobacterium combined with ilaprazole-containning quadruple therapy in rescue eradication of Helicobacter pylori (H. pylori).

METHODS

Two hundred and eighty H. pylori infected patients who failed initial treatment were randomly divided into four groups: A-D. Group A was treated with ilaprazole, amoxicillin, furazolidone, and colloidal bismuth pectin for 14 d. Group B was simultaneously given Bifidobacterium for 14 d on the basis of the therapy in group A. Groups C and D were, respectively, given Bifidobacterium for 28 d before the same therapy in groups A and B. H. pylori eradication was assessed by C¹³-urea breath test (C¹³-UBT), and the incidence of adverse reactions was compared in the four groups at 4 wk after treatment.

RESULTS

In total, 251 patients completed the treatment and follow-up according to the experimental design. Intention-to-treat (ITT) analysis showed that the H. pylori eradication rates in groups A, B, C, and D were 62.85, 71.43, 75.71, and 77.14, respectively, and per-protocol (PP) analysis showed that the eradication rates in groups A, B, C, and D were 72.13, 79.36, 84.13, and 84.38, respectively. The eradication rates in groups B, C, and D were significantly higher than that in group A (P < 0.05), and the eradication rates in groups C and D were significantly higher than that in group B (P < 0.05), while no statistically significant difference was found between groups C and D (P > 0.05). The completion rates in groups A, B, C, and D were 87.14 (61/70), 90.00 (63/70), 90.00 (63/70), and 91.43 (64/70), respectively. The completion rates in groups B, C, and D were significantly higher than that in group A (P < 0.05), while there was no significant difference in the completion rates among group B, C, and D (P > 0.05). The incidence of adverse reactions in groups A, B, C, and D was 14.92, 10.61, 7.46, and 6.06, respectively. The incidence of adverse reactions in groups B, C, and D was significantly lower than that in group A (P < 0.05), and the incidence of adverse reactions in groups C and D was significantly lower than that in group B (P < 0.05), while there was no significant difference in the incidence of adverse reactions between groups C and D (P > 0.05).

CONCLUSION

Bifidobacterium can effectively improve the rescue eradication rates of H. pylori, decrease the incidence of adverse reactions, and improve the compliance with treatment. The optimal strategy for rescue eradication is 28 d of Bifidobacterium before the ilaprazole-containning quadruple therapy.

Metallochaperone UreG serves as a new target for design of urease inhibitor: A novel strategy for development of antimicrobials

Urease as a potential target of antimicrobial drugs has received considerable attention given its versatile roles in microbial infection. Development of effective urease inhibitors, however, is a significant challenge due to the deeply buried active site and highly specific substrate of a bacterial urease. Conventionally, urease inhibitors are designed by either targeting the active site or mimicking substrate of urease, which is not efficient. Up to now, only one effective inhibitor—acetohydroxamic acid (AHA)—is clinically available, but it has adverse side effects. Herein, we demonstrate that a clinically used drug, colloidal bismuth subcitrate, utilizes an unusual way to inhibit urease activity, i.e., disruption of urease maturation process via functional perturbation of a metallochaperone, UreG. Similar phenomena were also observed in various pathogenic bacteria, suggesting that UreG may serve as a general target for design of new types of urease inhibitors. Using Helicobacter pylori UreG as a showcase, by virtual screening combined with experimental validation, we show that two compounds targeting UreG also efficiently inhibited urease activity with inhibitory concentration (IC)₅₀ values of micromolar level, resulting in attenuated virulence of the pathogen. We further demonstrate the efficacy of the compounds in a mammalian cell infection model. This study opens up a new opportunity for the design of more effective urease inhibitors and clearly indicates that metallochaperones involved in the maturation of important microbial metalloenzymes serve as new targets for devising a new type of antimicrobial drugs.

Urease, a metalloenzyme that catalyzes the hydrolysis of urea, plays important roles in the survival and virulence of many microbial pathogens, and has long been considered an important drug target for the development of novel antimicrobials. However, its deeply buried active site and highly specific substrate of bacterial urease make it very challenging to design effective urease inhibitors by conventional approaches. In this study, we reveal that a bismuth-based drug (colloidal bismuth subcitrate) inhibits urease activity in an unusual way. This drug binds the urease accessary protein UreG and inhibits its GTPase activity, thus perturbing nickel insertion into the apo-urease, a process called urease maturation. UreG is therefore proposed as an alternative target for the development of urease inhibitors. Using H. pylori UreG as an example, combined with virtual screening and experimental validation, we further show that several small molecules that bind and functionally disrupt UreG could indeed inhibit urease activity in bacteria and in a cell infection model and possess potent antimicrobial activity. In summary, we discovered metallochaperone UreG as a new target for the design of urease inhibitors. Such a strategy should have a broad application in the development of metalloenzyme inhibitors.

Evaluation of first-line bismuth-containing 7-day concomitant quintuple therapy for Helicobacter pylori eradication

OBJECTIVE

Helicobacter pylori (H. pylori) infection is difficult to cure, mainly due to antibiotic resistance. This study aimed to determine the efficacy and safety of 7-day bismuth-containing concomitant quintuple regimen for H. pylori eradication.

METHODS

Conducted from August 2015 to February 2016 at the First Affiliated Hospital of Nanchang University, this prospective trial enrolled 70 untreated patients who were positive for H. pylori. The patients received 7-day quintuple therapy consisting of bismuth subcitrate 220 mg, esomeprazole 20 mg, clarithromycin 500 mg, amoxicillin 1 g and metronidazole 400 mg, each was given twice daily. All patients underwent a ¹³ C-urea breath test at 4 weeks after treatment.

RESULTS

A total of 70 patients at a mean age of 43.5 years, including 36 men, were included in this trial. One person who violated the protocol was further excluded. The treatment compliance rate was 99.6%. The overall eradication rates of the 7-day bismuth-containing concomitant quintuple therapy were 75.4% (intention-to-treat analysis) and 86.7% (per-protocol analysis). The prevalence of side effects was 31.9%, including a bitter taste (23.2%), nausea (4.3%), dizziness (2.9%), diarrhea (2.9%), limb asthenia (2.9%), skin rash (1.4%), numbness of the tip of the tongue (1.4%) and insomnia (1.4%).

CONCLUSIONS

The 7-day bismuth-containing concomitant quintuple therapy may not be superior to traditionally widely accepted therapy due to its lack of acceptable efficacy and high rate of side effects.

It is time to rethink H. pylori therapy

.

First-Line Helicobacter pylori Eradication with Vonoprazan, Clarithromycin, and Metronidazole in Patients Allergic to Penicillin

AIM

To assess the efficacy of 7-day first-line Helicobacter pylori eradication with vonoprazan (VPZ), clarithromycin (CAM), and metronidazole (MNZ) in patients with penicillin allergy.

METHODS

Patients with penicillin allergy, diagnosed with Helicobacter pylori infection and did not have history of Helicobacter pylori eradication, were eligible for the study. Twenty patients were prospectively treated with 20 mg VPZ twice daily, 200 or 400 mg CAM twice daily, and 250 mg MNZ twice daily for 7 days. We also collected the data from 30 patients retrospectively treated with proton pump inhibitor (PPI), CAM, and MNZ. Safety was evaluated in patients completing an adverse effect questionnaire.

RESULTS

Both the intention-to-treat and per-protocol effectiveness of VPZ-based eradication were 100% (95% CI: 86.1-100%; n = 20). The eradication rates of PPI-based regimen were 83.3% (95% CI: 65.3-94.4%) in the ITT and 82.7% (95% CI: 64.2-94.2%) in the PP analyses. Abdominal fullness was more frequent in VCM compared to PCM. However, all patients with VCM regimen had taken 100% of their course of medication.

CONCLUSION

Triple therapy with VPZ, CAM, and MNZ is well tolerated and effective for eradicating Helicobacter pylori in patients allergic to penicillin. This study was registered in the UMIN Clinical Trials Registry as UMIN000016335.

Helicobacter pylori eradication in the Swedish population

OBJECTIVES

Helicobacter pylori is associated with peptic ulcers and gastric cancer and its eradication aims to prevent these conditions. The recommended eradication regimen is triple therapy, consisting of a proton-pump inhibitor in combination with clarithromycin and amoxicillin or metronidazole for 7 days. Yet, other antibiotic regimens are sometimes prescribed. We aimed to assess the use of eradication therapy for H. pylori in the Swedish population during the last decade.

MATERIALS AND METHODS

This population-based study used data from the Swedish Prescribed Drug Register. From July 2005 until December 2014, all regimens that can eradicate H. pylori were identified and evaluated according to patients' age and sex and calendar year of eradication.

RESULTS

We identified 157,915 eradication episodes in 140,391 individuals (53.8% women, 42.6% older than 60 years), who correspond to 1.5% of the Swedish population. The absolute number and incidence of eradications decreased over the study period. Overall, 91.0% had one eradication and 0.1% had more than three. Of all eradications, 95.4% followed the recommended regimen, while 4.7% did not. The latter group was overrepresented among individuals aged ≥80 years (7.8%). Amoxicillin and clarithromycin were most frequently prescribed, while metronidazole was rarely used (0.01%). Other prescribed antibiotics were ciprofloxacin (2.4%), doxycycline (1.4%), nitrofurantoin (0.7%), norfloxacin (0.5%) and erythromycin (0.3%).

CONCLUSIONS

During the last decade in Sweden H. pylori eradication has been frequently prescribed, but the incidence of eradication has slowly declined. Most eradications followed the recommended regimen, including those occurring after a previous eradication.

Fourteen-day high-dose esomeprazole, amoxicillin and metronidazole as third-line treatment for Helicobacter pylori infection

INTRODUCTION

The efficacy of currently recommended third-line therapies for Helicobacter pylori is suboptimal, even that of culture-guided treatments. Resistance to multiple antibiotics is the major factor related to treatment failure. The aim of this study was to evaluate the effectiveness and safety of a 14-day therapy using high-dose of amoxicillin, metronidazole and esomeprazole.

MATERIAL AND METHODS

Multicenter open-label study as a register in routine clinical practice in patients with two previous failures of eradication therapy. A triple therapy with esomeprazole 40 mg b.d., amoxicillin 1 g t.d.s and metronidazole 500 mg t.d.s for 2 weeks was administered as a third-line therapy after a first treatment including clarithromycin and a second treatment including a quinolone. Helicobacter pylori status was determined by either histology or ¹³ C-UBT both before and after treatment.

RESULTS

A total of 68 patients were included in this study. An interim analysis showed that only three out of eight patients who had received metronidazole in previous eradication regimens were cured (37%, 95% CI 8-75); as a result, after this interim analysis only metronidazole-naïve patients were included. The ITT eradication rate in metronidazole-naive patients was 64% (95% CI 51-76). Adverse events occurred in 58% of patients, all of them mild-to-moderate. Two patients (3%) did not complete >90% of the treatment because of side effects. No severe adverse events occurred.

CONCLUSION

Cure rates of this 14-day schedule using high-dose esomeprazole, amoxicillin and metronidazole as a third-line eradication regimen were suboptimal, especially in patients who had received metronidazole in previous failed eradication regimens.

Peptic ulcer disease

The rapidly declining prevalence of Helicobacter pylori infection and widespread use of potent anti-secretory drugs means peptic ulcer disease has become substantially less prevalent than it was two decades ago. Management has, however, become more challenging than ever because of the threat of increasing antimicrobial resistance worldwide and widespread use of complex anti-thrombotic therapy in the ageing population. Peptic ulcers not associated with H pylori infection or the use of non-steroidal anti-inflammatory drugs are now also imposing substantial diagnostic and therapeutic challenges. This Seminar aims to provide a balanced overview of the latest advances in the pathogenetic mechanisms of peptic ulcers, guidelines on therapies targeting H pylori infection, approaches to treatment of peptic ulcer complications associated with anti-inflammatory analgesics and anti-thrombotic agents, and the unmet needs in terms of our knowledge and management of this increasingly challenging condition.

Berberine containing quadruple therapy for initial Helicobacter pylori eradication: An open-label randomized phase IV trial

BACKGROUND

Due to increasing antimicrobial resistance, a bismuth-based quadruple regimen has been recommended as an alternative first-line therapy for Helicobacter pylori (H pylori) eradication. However, different results are varied greatly and the availability of bismuth was limited in some countries. We assessed the efficacy and safety of 14-day berberine-containing quadruple therapy as an alternative regimen for H pylori eradication.

METHODS

In a randomized, open-label, non-inferiority, phase IV trial between November 25, 2014, and October 15, 2015, 612 treatment-naive patients were randomly assigned to 14-day berberine-containing (n = 308) or 14-day bismuth-containing (n = 304) quadruple therapy. The primary outcomes were eradication rates determined by the C urea breath test (C-UBT) 28 days after the end of treatment. The secondary outcomes were adverse events and compliance.

RESULTS

The baseline demographic data including age, gender, body mass index (BMI), general condition and severity score were not statistically different in both groups. The eradication rates in bismuth and berberine groups were 86.4% (266/308) and 90.1% (274/304) in intention-to-treat (ITT) analysis (P = .149), and 89.6% (266/297) and 91.3% (273/299) in per-protocol (PP) analysis (P = .470), respectively. No statistically significant difference was found in the overall incidence of adverse events between both groups (35.7% vs 28.6%, P = .060).

CONCLUSIONS

Both regimens achieved the recommended efficacy for H pylori eradication. The berberine-containing quadruple regimen was not inferior to bismuth-containing quadruple regimen and can be recommended as an alternative regimen for H pylori eradication in the local region.

Furazolidone, an Underutilized Drug for H. pylori Eradication: Lessons from Iran

BACKGROUND

Treatment success of H. pylori eradication therapy has declined worldwide largely because of increased antimicrobial resistance. New therapeutic approaches are needed, especially for countries like Iran, where resistance to commonly used drugs is already widespread and traditional H. pylori therapies produce poor cure rates.

AIM

To review the results of quadruple therapy trials containing bismuth and furazolidone in Iran.

METHODS

We searched PubMed, Google scholar as well as the references of all published papers for studies conducted in Iran, utilizing furazolidone in the treatment of H. pylori infections. The target population was four drug studies that utilized a combination of bismuth, furazolidone, amoxicillin, or tetracycline plus a proton pump inhibitor.

RESULTS

Eighteen studies with 22 arms including 1713 subjects were found. The weighted mean cure rate for 14-day studies (six studies) using 200 mg b.i.d. furazolidone was 80% intention to treat (ITT) and 87% per protocol (PP). Studies using 100 mg b.i.d. (three studies) were less effective (weighted mean ITT cure rate = 67%). One small 14-day study with furazolidone 100 mg q.i.d. achieved cure rates of 94.5% ITT and PP.

CONCLUSIONS

Although furazolidone-bismuth quadruple therapy proved relatively effective in Iran, furazolidone-containing regimens remain to be optimized. Based on these data and results from China, it appears likely that 14-day therapy containing furazolidone 100 mg t.i.d. or q.i.d. is likely to provide the highest cure rates with lowest side effects; this remains to be experimentally tested. Detailed suggestions for further development of furazolidone-containing regimens are provided.

Randomized Clinical Trial: Esomeprazole, Bismuth, Levofloxacin, and Amoxicillin or Cefuroxime as First-Line Eradication Regimens for Helicobacter pylori Infection

BACKGROUND

The eradication of Helicobacter pylori infection remains a challenge, especially in the patients unsuitable to take penicillin. Cephalosporin has the potential to replace amoxicillin for H. pylori eradication.

AIMS

To compare the effectiveness, safety, and compliance of amoxicillin- and cefuroxime-containing quadruple regimens in treatment-naïve patients.

METHODS

In this open-label randomized control study, 400 patients with H. pylori infection were divided into amoxicillin-containing (esomeprazole 20 mg twice/day, amoxicillin 1000 mg twice/day, levofloxacin 500 mg once/day, and bismuth 220 mg twice/day for 14 days) or cefuroxime-containing (esomeprazole 20 mg twice/day, cefuroxime 500 mg twice/day, levofloxacin 500 mg once/day, and bismuth 220 mg twice/day for 14 days) quadruple therapy groups. The safety and compliance were assessed 1-3 days after eradication. Urea breath test was performed 8-12 weeks after eradication to determine treatment outcome.

RESULTS

The baseline data including antibiotic resistance were well matched between the two groups. The eradication rates between amoxicillin- and cefuroxime-containing quadruple therapy groups were not significantly different [intention-to-treat analysis: 83.5% (95% confidence interval 78.3-88.7%) vs. 81.0% (75.5-86.5%), P = 0.513; modified intention-to-treat analysis: 90.3% (86.0-94.6%) vs. 88.5% (83.9-93.2%), P = 0.586; per-protocol analysis: 91.6% (87.5-95.7%) vs. 89.8% (85.3-94.3%), P = 0.560]. The incidence of adverse effects (18.4 vs. 20.1%, P = 0.678) and compliance (94.7 vs. 94.2%, P = 0.813) were also similar. Variate analyses showed that antibiotic resistance and poor compliance were the independent risk factors for eradication failure.

CONCLUSIONS

Esomeprazole, bismuth, levofloxacin, and amoxicillin or cefuroxime achieved similar and relatively satisfactory cure rates, safety, and compliance in first-line H. pylori eradication. Cefuroxime may be a good alternative medicine for eradication instead of amoxicillin for the patients unsuitable to take penicillin.

Novel and Effective Therapeutic Regimens for Helicobacter pylori in an Era of Increasing Antibiotic Resistance

Helicobacter pylori (H. pylori) is a common gastrointestinal bacterial strain closely associated with the incidence of chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. A current research and clinical challenge is the increased rate of antibiotic resistance in H. pylori, which has led to a decreased H. pylori eradication rate. In this article, we review recent H. pylori infection and reinfection rates and H. pylori resistance to antibiotics, and we discuss the pertinent treatments. A PubMed literature search was performed using the following keywords: Helicobacter pylori, infection, reinfection, antibiotic resistance, bismuth, proton pump inhibitors, vonoprazan, susceptibility, quintuple therapy, dual therapy, and probiotic. The prevalence of H. pylori has remained high in some areas despite the decreasing trend of H. pylori prevalence observed over time. Additionally, the H. pylori reinfection rate has varied in different countries due to socioeconomic and hygienic conditions. Helicobacter pylori monoresistance to clarithromycin, metronidazole or levofloxacin was common in most countries. However, the prevalence of amoxicillin and tetracycline resistance has remained low. Because H. pylori infection and reinfection present serious challenges and because H. pylori resistance to clarithromycin, metronidazole or levofloxacin remains high in most countries, the selection of an efficient regimen to eradicate H. pylori is critical. Currently, bismuth-containing quadruple therapies still achieve high eradication rates. Moreover, susceptibility-based therapies are alternatives because they may avoid the use of unnecessary antibiotics. Novel regimens, e.g., vonoprazan-containing triple therapies, quintuple therapies, high-dose dual therapies, and standard triple therapies with probiotics, require further studies concerning their efficiency and safety for treating H. pylori.

Primary Antibiotic Resistance of Helicobacter pylori in China

BACKGROUND AND AIMS

Antibiotic resistance is the most important factor leading to the failure of eradication regimens; thus, it is important to obtain regional antibiotic resistance information. This review focuses on the prevalence of Helicobacter pylori primary resistance to clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and furazolidone in China.

METHODS

We searched the PubMed, EMBASE, the China National Knowledge Infrastructure, and Chinese Biomedical databases from the earliest date of each database to October 2016. The search terms included the following: H. pylori, antibiotic (including clarithromycin, metronidazole, amoxicillin, levofloxacin, tetracycline, and furazolidone) resistance with or without China or different regions of China. The data analysis was performed using MedCalc 15.2.2. Each article was weighted according to the number of isolated H. pylori strains. A pooled proportion analysis was performed.

RESULTS

Twenty-three studies (14 studies in English and 9 in Chinese) were included in this review. A total of 6274, 6418, 3921, 5468, 2802, and 275 H. pylori strains were included in this review to evaluate the prevalence of H. pylori primary resistance to clarithromycin, metronidazole, levofloxacin, amoxicillin, tetracycline, and furazolidone, respectively. Overall, the primary resistance rates of clarithromycin, metronidazole, levofloxacin, amoxicillin, tetracycline, and furazolidone were 28.9, 63.8, 28.0, 3.1, 3.9, and 1.7%, respectively.

CONCLUSIONS

In China, the prevalence of H. pylori primary resistance to clarithromycin, metronidazole, and levofloxacin was high and increased over time, whereas the resistance rates to amoxicillin, tetracycline, and furazolidone were low and stable over time.

Integrative approach for the analysis of the proteome-wide response to bismuth drugs in Helicobacter pylori

An integrative metalloproteomic approach to unveil the role of antimicrobial metals in general using bismuth as an example.

Bismuth drugs, despite being clinically used for decades, surprisingly remain in use and effective for the treatment of Helicobacter pylori infection, even for resistant strains when co-administrated with antibiotics. However, the molecular mechanisms underlying the clinically sustained susceptibility of H. pylori to bismuth drugs remain elusive. Herein, we report that integration of in-house metalloproteomics and quantitative proteomics allows comprehensive uncovering of the bismuth-associated proteomes, including 63 bismuth-binding and 119 bismuth-regulated proteins from Helicobacter pylori, with over 60% being annotated with catalytic functions. Through bioinformatics analysis in combination with bioassays, we demonstrated that bismuth drugs disrupted multiple essential pathways in the pathogen, including ROS defence and pH buffering, by binding and functional perturbation of a number of key enzymes. Moreover, we discovered that HpDnaK may serve as a new target of bismuth drugs to inhibit bacterium-host cell adhesion. The integrative approach we report, herein, provides a novel strategy to unveil the molecular mechanisms of antimicrobial metals against pathogens in general. This study sheds light on the design of new types of antimicrobial agents with multiple targets to tackle the current crisis of antimicrobial resistance.

Polaprezinc combined with clarithromycin-based triple therapy for Helicobacter pylori-associated gastritis: A prospective, multicenter, randomized clinical trial

The efficacy and safety of polaprezinc combined with triple therapy was compared with triple therapy alone in the eradication of Helicobacter pylori. A randomized, parallel-group, open-label, controlled, prospective multicenter study was conducted in 11 cities in China. Treatment-naive patients with H. pylori-associated gastritis were randomly assigned to one of three arms for a 14-day treatment: Arm A triple therapy (omeprazole 20 mg, amoxicillin 1 g, and clarithromycin 500 mg, each twice daily) plus polaprezinc 75 mg twice daily; Arm B triple therapy plus polaprezinc 150 mg twice daily, or Arm C triple therapy alone. The rate of H. pylori eradication was the primary endpoint. Secondary endpoints were symptom improvement and lower incidence of adverse events. 303 patients completed the study- 106, 96, and 101 patients in Arms A, B, and C, respectively. Intention-to-treat (ITT) analysis showed that the rate of H. pylori eradication was significantly higher for Arms A (77.0%) and B (75.9%) compared to Arm C (58.6%) (P < 0.01), whereas there was no difference between Arms A and B (P = 0.90). Per-protocol (PP) analysis showed that the rate of H. pylori eradication was significantly higher for Arms A (81.1%) and B (83.3%) compared to Arm C (61.4%) (P < 0.01), whereas there was no significant difference between Arms A and B (P = 0.62). All three groups reported significant symptom improvement at 7, 14, and 28 days after treatment, compared to baseline (P < 0.0001). The adverse event rate for Arm B (5.1%) was higher than for Arms A (2.8%) (P = 0.04) and C (1.9%) (P = 0.02). There were no serious adverse events in any group. It appears that standard dose polaprezinc combined with triple therapy can significantly improve the H. pylori eradication rate, without an increase in toxicity.

Functional disruption of peroxiredoxin by bismuth antiulcer drugs attenuates Helicobacter pylori survival

Bismuth drugs have been used clinically to treat infections from Helicobacter pylori, a pathogen that is strongly related to gastrointestinal diseases even stomach cancer. Despite extensive studies, the mechanisms of action of bismuth drugs are not fully understood. Alkyl hydroperoxide reductase subunit C (AhpC) is the most abundant 2-cysteine peroxiredoxin, crucial for H. pylori survival in the host by defense of oxidative stress. Herein we show that a Bi(III) antiulcer drug (CBS) binds to the highly conserved cysteine residues (Cys49 and Cys169) with a dissociation constant (K _d) of Bi(III) to AhpC of 3.0 (±1.0) × 10^-24 M. Significantly the interaction of CBS with AhpC disrupts the peroxiredoxin and chaperone activities of the enzyme both in vitro and in bacterial cells, leading to attenuated bacterial survival. Moreover, using a home-made fluorescent probe, we demonstrate that Bi(III) also perturbs AhpC relocation between the cytoplasm and membrane region in decomposing the exogenous ROS. Our study suggests that disruption of redox homeostasis by bismuth drugs via interaction with key enzymes such as AhpC contributes to their antimicrobial activity.

Helicobacter pylori treatment: New perspectives using current experience

Infection with Helicobacter pylori plays an essential role in the development of duodenal and gastric ulcers as well as in the pathobiology of gastric adenocarcinoma. Thus, successful elimination of the bacterium can reduce the risk of development of these diseases. Currently, most guidelines recommend standard triple therapy (amoxicillin+clarithromycin+proton pump inhibitor), although its efficacy is rapidly falling. Notably, traditional first-line therapy fails in almost 32% of H. pylori-carrying cases, suggesting the importance of choosing the best formulation for first-line therapy. Hence, due to the decreasing effectiveness of first-line treatment, we should be prepared to confront increasing H. pylori therapeutic defeat. Owing to increasing reports of antibiotic resistance worldwide, newer approaches and directions are necessary for managing this problematic infection. Developing and providing better anti-H. pylori strategies (probiotics, antibiotic therapy and non-traditional medicine) without using current clinical experience in treating the infection is impossible. Furthermore, development and examination of new preventive vaccines may also be a new therapeutic direction. Taken together, with regard to current experience, clinicians are highly recommended to consider all alternatives to eradicate H. pylori until a universal vaccine becomes practically available. This article aims to give an overview regarding the current status of H. pylori treatment, accordingly designing an actual overview to gain optimal strategies against this infection.

Four-times-daily Dosing of Rabeprazole with Sitafloxacin, High-Dose Amoxicillin, or Both for Metronidazole-Resistant Infection with Helicobacter pylori in Japan

BACKGROUND

The bacterial resistance of Helicobacter pylori to antimicrobial agents such as clarithromycin and metronidazole has been increasing worldwide, leading to the failure of eradication treatment. Here, we present an eradication regimen consisting of four-times-daily dosing (q.i.d.) of rabeprazole with potent acid inhibition.

AIM

To investigate the efficacy of eradication therapy with rabeprazole q.i.d. and amoxicillin or sitafloxacin in Japanese infected with a metronidazole-resistant strain.

METHODS

We retrospectively investigated the efficacy of eradication regimens with rabeprazole q.i.d. for 7 days in 111 Japanese pooled patients infected with a metronidazole-resistant strain of H. pylori at Hamamatsu University School of Medicine Hospital or the Shiga University of Medical Science Hospital: 1, with sitafloxacin 100 mg twice daily (b.i.d.) (n = 82); 2, with amoxicillin 500 mg q.i.d. (n = 15); and 3, with amoxicillin q.i.d. and sitafloxacin b.i.d.-combined regimen (n = 14). Eradication status was assessed at 8 weeks via a ¹³ C-urea breath test.

RESULTS

Eradication rate on intention-to-treat analysis was 93.7% (95% confidence interval: 87.4-97.4%, 104/111), irrespective of the high prevalence of strains resistant to clarithromycin (81.1%, 90/111) and levofloxacin (42.3%, 47/111). No significant differences in eradication rates were observed among the different treatment regimens (p = .408), eradication history (p = .096) and different CYP2C19 genotypes (p = .789). On multivariate analysis, no significant risk factor for eradication failure by therapy with potent acid inhibition was seen.

CONCLUSION

In Japanese patients infected with metronidazole-resistant strains of H. pylori, eradication rates exceeding 90% can be achieved using appropriate dosing of antibiotic agents with strain susceptibility (amoxicillin q.i.d. and/or sitafloxacin b.i.d.) together with acid inhibition for a full 24 h and rabeprazole 10 mg q.i.d. These findings may be further evidence for dual therapy with rabeprazole q.i.d. and an antibiotic agent (amoxicillin q.i.d. or sitafloxacin b.i.d.) in Japanese patients with metronidazole-resistant strains.

[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.

Characterization in Helicobacter pylori of a Nickel Transporter Essential for Colonization That Was Acquired during Evolution by Gastric Helicobacter Species

Metal acquisition is crucial for all cells and for the virulence of many bacterial pathogens. In particular, nickel is a virulence determinant for the human gastric pathogen Helicobacter pylori as it is the cofactor of two enzymes essential for in vivo colonization, urease and a [NiFe] hydrogenase. To import nickel despite its scarcity in the human body, H. pylori requires efficient uptake mechanisms that are only partially defined. Indeed, alternative ways of nickel entry were predicted to exist in addition to the well-described NixA permease. Using a genetic screen, we identified an ABC transporter, that we designated NiuBDE, as a novel H. pylori nickel transport system. Unmarked mutants carrying deletions of nixA, niuD and/or niuB, were constructed and used to measure (i) tolerance to toxic nickel exposure, (ii) intracellular nickel content by ICP-OES, (iii) transport of radioactive nickel and (iv) expression of a reporter gene controlled by nickel concentration. We demonstrated that NiuBDE and NixA function separately and are the sole nickel transporters in H. pylori. NiuBDE, but not NixA, also transports cobalt and bismuth, a metal currently used in H. pylori eradication therapy. Both NiuBDE and NixA participate in nickel-dependent urease activation at pH 5 and survival under acidic conditions mimicking those encountered in the stomach. However, only NiuBDE is able to carry out this activity at neutral pH and is essential for colonization of the mouse stomach. Phylogenomic analyses indicated that both nixA and niuBDE genes have been acquired via horizontal gene transfer by the last common ancestor of the gastric Helicobacter species. Our work highlights the importance of this evolutionary event for the emergence of Helicobacter gastric species that are adapted to the hostile environment of the stomach where the capacity of Helicobacter to import nickel and thereby activate urease needs to be optimized.

Rescue Therapy for Helicobacter pylori Eradication: A Randomized Non-Inferiority Trial of Amoxicillin or Tetracycline in Bismuth Quadruple Therapy

OBJECTIVES

To compare the efficacy and safety of bismuth-containing quadruple therapy with tetracycline or amoxicillin for rescue treatment of Helicobacter pylori.

METHODS

The study was a non-inferiority trial of H. pylori eradication with at least two previous treatment failures. Subjects were randomized to receive 14-day therapy with b.i.d. lansoprazole 30 mg and bismuth 220 mg, plus metronidazole 400 mg q.i.d and amoxicillin 1 g t.i.d (amoxicillin group) or tetracycline 500 mg q.i.d (tetracycline group). Antimicrobial susceptibility was assessed by the agar-dilution method. Primary outcome was H. pylori eradication at 6 weeks after treatment.

RESULTS

In all, 312 subjects were randomized, 13 were lost to follow-up; 29 violated the protocol. The intention-to-treat, per-protocol, and modified intention-to-treat eradication rates were (amoxicillin) 88.5% (138/156, 95% confidence interval (CI) 83.4-93.5%), 93.7% (133/142, 95% CI 89.7-97.7%), and 92.6% (138/149, 95% CI 88.4-96.8%). With tetracycline, they were 87.2% (136/156, 95% CI 81.9-92.4%), 95.3% (122/128, 95% CI 91.7-99.0%), and 90.7% (136/150, 95% CI 86.0-95.3%). Amoxicillin-, tetracycline-, and metronidazole-resistant rates were 8.3, 1.0, and 87.8%, respectively. Non-inferiority was confirmed (P<0.025). Metronidazole resistance did not affect the efficacy of either therapy. Compliance was greater and moderate and severe adverse events were less among those receiving amoxicillin than those receiving tetracycline.

CONCLUSIONS

The novel bismuth-containing quadruple therapy with metronidazole and amoxicillin is an alternative to classical bismuth quadruple therapy for H. pylori rescue treatment as it provides similar eradication with superior safety and compliance.

Treatment of Helicobacter pylori infection: Where are we now?

Gastric cancer and Helicobacter pylori infection remain a burden in many Asian countries. In the face of rising antibiotic resistance, the eradication rate of standard triple therapy is declining in many Asian countries. We reviewed the updated epidemiology of gastric cancer, prevalence of H. pylori infection, and antibiotic resistance in Asia. We also reviewed the strategies to improve the efficacy of H. pylori eradication therapies, including the use of high dose proton pump inhibitor, four drug therapies (including bismuth quadruple, concomitant, and sequential therapy), susceptibility guided therapy, extending the treatment duration to 14 days, and development of effective rescue therapy. Four drug therapies are usually more effective than triple therapy when given in the same duration, except in areas with concomitantly high metronidazole resistance and low clarithromycin resistance. The efficacies of different four drug regimens appeared to be similar. However, trials from different geographic areas showed contradictory results, indicating that the optimal therapy should be decided according to the local prevalence of antibiotic resistance. We proposed a prediction model to calculate the efficacy of different regimens according to the prevalence of antibiotic resistance. More large randomized trials which provide information on the antibiotic resistance are urgently needed to build a more accurate and reliable model. It is hoped that we will be able to decide the optimal regimens by routine surveillance of antibiotic resistance.