Rifabutin-Based Rescue Therapy for Helicobacter pylori Eradication: A Long-Term Prospective Study in a Large Cohort of Difficult-to-Treat Patients

Effectiveness of Rifabutin-Based Regimens in Treating Helicobacter pylori Infections

Helicobacter pylori has been reported as a health problem worldwide, affecting a sizable portion of people. Peptic ulcers, gastric cancer, and various extra gastric conditions are associated with this bacterium. The rampant overprescribing of antibiotics has led to the emergence of H. pylori strains resistant to multiple antibiotics, causing a decline in the effectiveness of current treatments. Recently, there has been growing interest in researching alternative treatment options for H. pylori infections that do not respond to initial therapy. Rifabutin, a rifamycin derivative initially designed for tuberculosis treatment and preventing Mycobacterium avium complex infection, has gained attention as a potential rescue medication. It has shown efficacy against H. pylori and the potential to eradicate the bacterium when combined with other antibiotics. This systematic review article focuses on using rifabutin-based regimens as a treatment option after initial treatments have failed. The authors screened literature published in the last five years, between 2017 and 2022, across various search engines and closely examined relevant studies following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The search covered a variety of electronic databases and focused on H. pylori gastritis, rifabutin-based treatment plans, and in vivo investigations in healthy individuals. The comprehensive review provides convincing evidence that rifabutin-based regimens are effective rescue treatments for H. pylori infections. Multiple studies in various areas consistently demonstrated high eradication rates, ranging from 70% to 90%, when rifabutin-containing regimens were used. The analysis found that only a tiny percentage of H. pylori strains (1%) were resistant to rifabutin therapy, further supporting the viability of Rifabutin as an alternative when other antibiotics failed to eradicate H. pylori. The cost of Rifabutin is a significant factor that may limit its accessibility, particularly in resource-constrained settings where H. pylori infection is common. Moreover, the potential side effects of Rifabutin, such as hematological problems, rashes, and digestive issues, need to be considered. However, these side effects are typically manageable and can be reduced by combining Rifabutin with other antibiotics. In conclusion, this systematic review provides evidence supporting the effectiveness of regimens derived from Rifabutin in eliminating H. pylori infections after initial therapy failure. Due to the observation that Rifabutin effectively eradicates resistant H. pylori infections, it can be considered a suitable choice for rescue therapy. Rifabutin-containing regimens should be reserved as fourth- or later-line therapy options, considering economic factors, the risk of microbial resistance, potential side effects, and the availability of alternative medications. Future research should focus on optimizing rifabutin-based regimens and investigating combination therapies that have better H. pylori eradication rates while also addressing the problem of resistant strains.

Molecular Mechanisms of Antibiotic Resistance and Novel Treatment Strategies for Helicobacter pylori Infections

Helicobacter pylori infects approximately 50% of the world's population and is considered the major etiological agent of severe gastric diseases, such as peptic ulcers and gastric carcinoma. Increasing resistance to standard antibiotics has now led to an ever-decreasing efficacy of eradication therapies and the development of novel and improved regimens for treatment is urgently required. Substantial progress has been made over the past few years in the identification of molecular mechanisms which are conducive to resistant phenotypes as well as for efficient strategies to counteract strain resistance and to avoid the use of ineffective antibiotics. These involve molecular testing methods, improved salvage therapies, and the discovery of novel and potent antimicrobial compounds. High rates of prevalence and gastric cancer are currently observed in Asian countries, including Japan, China, Korea, and Taiwan, where concomitantly intensive research efforts were initiated to explore advanced eradication regimens aimed at reducing the risk of gastric cancer. In this review, we present an overview of the known molecular mechanisms of antibiotic resistance and discuss recent intervention strategies for H. pylori diseases, with a view of the research progress in Asian countries.

Third-line and rescue therapy for refractory Helicobacter pylori infection: A systematic review

BACKGROUND

Due to increasing resistance rates of Helicobacter pylori (H. pylori) to different antibiotics, failures in eradication therapies are becoming more frequent. Even though eradication criteria and treatment algorithms for first-line and second-line therapy against H. pylori infection are well-established, there is no clear recommendation for third-line and rescue therapy in refractory H. pylori infection.

AIM

To perform a systematic review evaluating the efficacy and safety of rescue therapies against refractory H. pylori infection.

METHODS

A systematic search of available rescue treatments for refractory H. pylori infection was conducted on the National Library of Medicine’s PubMed search platform based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized or non-randomized clinical trials and observational studies evaluating the effectiveness of H. pylori infection rescue therapies were included.

RESULTS

Twenty-eight studies were included in the analysis of mean eradication rates as rescue therapy, and 21 of these were selected for analysis of mean eradication rate as third-line treatment. For rifabutin-, sitafloxacin-, levofloxacin-, or metronidazole-based triple-therapy as third-line treatment, mean eradication rates of 81.6% and 84.4%, 79.4% and 81.5%, 55.7% and 60.6%, and 62.0% and 63.0% were found in intention-to-treat (ITT) and per-protocol (PP) analysis, respectively. For third-line quadruple therapy, mean eradication rates of 69.2% and 72.1% were found for bismuth quadruple therapy (BQT), 88.9% and 90.9% for bismuth quadruple therapy, three-in-one, Pylera^® (BQT-Pylera), and 61.3% and 64.2% for non-BQT) in ITT and PP analysis, respectively. For rifabutin-, sitafloxacin-, levofloxacin-, or metronidazole-based triple therapy as rescue therapy, mean eradication rates of 75.4% and 78.8%, 79.4 and 81.5%, 55.7% and 60.6%, and 62.0% and 63.0% were found in ITT and PP analysis, respectively. For quadruple therapy as rescue treatment, mean eradication rates of 76.7% and 79.2% for BQT, 84.9% and 87.8% for BQT-Pylera, and 61.3% and 64.2% for non-BQT were found in ITT and PP analysis, respectively. For susceptibility-guided therapy, mean eradication rates as third-line and rescue treatment were 75.0% in ITT and 79.2% in PP analysis.

CONCLUSION

We recommend sitafloxacin-based triple therapy containing vonoprazan in regions with low macrolide resistance profile. In regions with known resistance to macrolides or unavailability of bismuth, rifabutin-based triple therapy is recommended.

The Inappropriateness of Using Rifampicin E-Test to Predict Rifabutin Resistance in Helicobacter pylori

BACKGROUND

The aim of this study was to evaluate the rifamycin cross-resistance in Helicobacter pylori, and whether the use of rifampicin E-test strips to screen H. pylori rifabutin resistance is appropriate.

METHODS

A total of 89 H. pylori isolates were included. Rifampicin minimum inhibitory concentrations (MICs) were obtained by E-test, while the MICs for rifapentine, rifaximin, and rifabutin were determined by agar dilution method. The rifamycin resistance rates based on different breakpoints were compared. Isolates with high-level rifampicin resistance were subjected to whole-genome sequencing.

RESULTS

A wide distribution of MICs (mostly in the range 0.125-8 mg/L) was observed for rifampicin, rifapentine, and rifaximin. Using MIC >1, ≥ 4, and > 4 mg/L as the breakpoints, resistance rates to rifampicin/rifapentine/rifaximin were 60.4%/48.3%/38.2%, 28.1%/25.8%/23.6%, and 15.7%/16.9%/7.9%, respectively. However, the rifabutin MICs of all the tested H. pylori isolates were extremely low (≤0.016 mg/L). Applying MIC ≥ 0.125 mg/L as the breakpoint, rifabutin resistance was nil. No mutation was found in the rpoB gene sequences of the 2 isolates with high-level rifampicin resistance.

CONCLUSIONS

There is a lack of cross-resistance between rifabutin and other rifamycins in H. pylori. The use of rifampicin E-test to predict H. pylori rifabutin resistance is inappropriate.

Treatment of refractory Helicobacter pylori infection: A new challenge for clinicians

Patients who have failed two or more attempts to eradicate Helicobacter pylori are commonly referred to as refractory. Although the incidence of refractory Helicobacter pylori infection is only 10–20%, with the increasing rate of antibiotic resistance in various regions, the treatment of refractory Helicobacter pylori infection has gradually become a difficult problem faced by clinicians. When choosing a rescue therapy, the physician must consider numerous factors. A longer treatment duration, higher doses of proton pump inhibitors (PPIs), or the use of potassium-competitive acid blocker (P-CAB) may increase the efficacy of triple therapy or bismuth quadruple therapy. Rescue treatment based on bismuth quadruple therapy usually achieves better results. At the same time, treatment based on drug susceptibility tests or genotypic resistance is recommended where available. Of course, appropriate empiric treatment can also be selected according to local drug resistance, a patient’s previous medication history and compliance. It is the best choice if it can improve the success rate of the first treatment and reduce the occurrence of refractory Helicobacter pylori infection. This review aims to summarize the articles related to refractory Helicobacter pylori in recent years and to explore a better remedial treatment plan for clinicians.

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.

Targeting IL-1β in patients with advanced Helicobacter pylori infection: a potential therapy for gastric cancer

Helicobacter pylori (H. pylori) infection is a causal factor of gastric cancer. Among the cytokines secreted during this infection, IL-1β is highly associated with promotion and progression of gastric cancer. On the therapeutic front, eradication of H. pylori was thought to be efficient to restore gastric homeostasis. However, successful H. pylori eradication in patients with advanced stages (intestinal metaplasia) failed to diminish inflammation that is due to heightened Th17 response and elevated IL-1β levels. In fact, association between these two components was established, suggesting that IL-1β is a critical target in these cases. In this review, we will discuss the functional relevance of IL-1β in advanced H. pylori infection and how its targeting may bring clinical benefit.

Helicobacter pylori eradication following first-line treatment failure in Europe: What, how and when chose among different standard regimens? A systematic review

Cure rate following standard first-line regimens for Helicobacter pylori eradication is decreasing so several patients require two or more treatments. Antibiotic susceptibility-based therapy, advised in current guidelines, is largely impracticable in clinical practice. Some 'standard' regimens (triple therapies based on either levofloxacin or rifabutin, bismuth-based quadruple therapies, sequential, concomitant and hybrid therapies) were empirically used as rescue therapies. We performed a systematic review on recent studies carried out in European countries dealing with these regimens. A total of 24 studies, with 3804 patients, were identified. As second-line therapy, Pylera (89.2%) and sequential therapy (92.5%) achieved significantly higher cure rates as compared to all the other regimens. As third-line therapy, levofloxacin-based therapy (84.1%) and Pylera (83.6%) achieved similarly high cure rates, whereas standard, bismuth-based quadruple therapy (64.1%) achieved the lowest. As a rescue therapy, the success rate was close to 75% following all therapies used, with data on rifabutin-based regimen consolidated in the larger sample size. Overall, levofloxacin-amoxicillin triple therapy achieved higher eradication rates when the 14- rather than 10-day regimen was used (87.1 vs. 72.2%; P = 0.003). Among bismuth-based therapies, Pylera achieved a significantly higher eradication rate than standard quadruple therapy (88 vs. 67%; P < 0.0001). These data suggest that a wise 'therapeutic package' following first-line therapy could be Pylera, levofloxacin- and rifabutin-based therapy, as long as Pylera therapy was not used as a first-line regimen and levofloxacin-based regimen was administered for 14 days.

Revisiting Therapeutic Strategies for H. pylori Treatment in the Context of Antibiotic Resistance: Focus on Alternative and Complementary Therapies

The prevalence of Helicobacter pylori infection remains significant worldwide and it depends on many factors: gender, age, socio-economic status, geographic area, diet, and lifestyle. All successful infectious diseases treatments use antibiotic-susceptibility testing, but this strategy is not currently practical for H. pylori and the usual cure rates of H. pylori are lower than other bacterial infections. Actually, there is no treatment that ensures complete eradication of this pathogen. In the context of an alarming increase in resistance to antibiotics (especially to clarithromycin and metronidazole), alternative and complementary options and strategies are taken into consideration. As the success of antibacterial therapy depends not only on the susceptibility to given drugs, but also on the specific doses, formulations, use of adjuvants, treatment duration, and reinfection rates, this review discusses the current therapies for H. pylori treatment along with their advantages and limitations. As an alternative option, this work offers an extensively referenced approach on natural medicines against H. pylori, including the significance of nanotechnology in developing new strategies for treatment of H. pylori infection.

Helicobacter pylori and Respiratory Diseases: 2021 Update

Helicobacter pylori (H. pylori) is a Gram-negative bacterium involved in the development of gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue. Unexplained iron deficiency anemia, idiopathic thrombocytopenic purpura and vitamin B12 deficiency have also been related to H. pylori infection, whereas for other extra-gastric diseases, the debate is still open. In this review, we evaluate and discuss the potential involvement of H. pylori infection in the pathogenesis of several respiratory diseases. A MEDLINE search of all studies published in English from 1965 to 2021 was carried out. Controversial findings have been reported in patients with bronchial asthma, chronic obstructive pulmonary disease, bronchiectasis, lung cancer, tuberculosis, cystic fibrosis, and sarcoidosis. Most of the available literature is concerned with case-control studies based on seroprevalence, with a small sample size and low consideration of confounders, which represents a potential issue. So far, there is no clear evidence of a causal association between H. pylori infection and respiratory diseases, and larger studies with appropriate epidemiological design are required.

Clinical Relevance of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) is a Gram-negative helical, microaerophilic bacterium which colonizes the antrum and body of the stomach, surviving in its harsh environment through mechanisms of acid resistance and colonization factors. It infects approximately 50% of the world population. Although the prevalence of this infection varies from country to country, as well as between different ethnic, social or age groups, it is estimated that about 50% of the human population only carries this microorganism. While H. pylori has been found to play a major etiological and pathogenic role in chronic gastritis, peptic ulcer disease and gastric cancer, its importance for many types of extra-gastric disease needs to be further investigated. The choice of tests to diagnose H. pylori infection, defined as invasive or non-invasive, depends on the clinical indication as to whether to perform upper gastrointestinal endoscopy. Focusing on bacterial eradication, the treatment should be decided locally based on the use of antibiotics and documented antibiotic resistance. The author provides an overview of the current state of knowledge about the clinical aspects of H. pylori infection, especially its diagnostic and therapeutic management.

Interplay of potassium channel, gastric parietal cell and proton pump in gastrointestinal physiology, pathology and pharmacology

Gastric acid secretion plays a pivotal role in the physiology of gastrointestinal tract. The functioning of the system encompasses a P2 ATPase pump (which shuttles electroneutral function at low pH) along with different voltage sensitive/neutral ion channels, cytosolic proteins, acid sensor receptors as well hormonal regulators. The increased acid secretion is a pathological marker of several diseases like peptic ulcer, gastroesophageal reflux disease (GERD), chronic gastritis, and the bug Helicobacter pylori (H. pylori) has also a critical role, which altogether affects the patient's quality of life. This review comprehensively describes about the nature of potassium ion channel and its mediators, the different clinical strategy to control acid rebound, and some basic experimental observations performed to study the interplay of ion channels, pumps, as well as mediators during acid secretion. Different aspects of regulation of gastric acid secretion have been focused either in terms of physiology of secretion or molecular interactions. The importance of H pylori infection and its treatment have also been discussed. Furthermore, the relevance of calcium signaling during acid secretion has been reviewed. The entire theme will make anyone to understand in details about the gastric secretion machinery in general.

Treatment Approach of Refractory Helicobacter pylori Infection: A Comprehensive Review

H. pylori is the most common infection in the world and is associated with gastrointestinal and extra-gastrointestinal manifestations, including peptic ulcer disease, gastrointestinal bleeding, and lymphoproliferative disorders. Despite being discovered less than half a century ago, antibiotic resistance, exacerbated by medication non-adherence and inefficacy of proton pump inhibitors, has grown substantially, explaining the rising incidence of refractory H. pylori infection. In this review, we discuss risk factors, treatment options, surveillance and follow-up, as well as emerging therapies for refractory H. pylori.

Rifabutin triple therapy for first-line and rescue treatment of Helicobacter pylori infection: A systematic review and meta-analysis

BACKGROUND AND AIM

Due to the increasing resistance of Helicobacter pylori, there is a need for novel antibiotic treatment protocols. We aimed to perform a systematic review and meta-analysis in order to determine the effectiveness and safety of rifabutin triple therapy for H. pylori infection.

METHODS

We performed a systematic review of prospective clinical trials with a treatment arm consisting of proton pump inhibitor, amoxicillin, and rifabutin and a meta-analysis of randomized controlled trials (RCTs).

RESULTS

Thirty-three prospective studies including 44 datasets were identified. Meta-analysis of four RCTs for rescue treatment found no difference between treatment groups (odds ratio [OR] 0.88, 95% confidence interval [CI] 0.437-1.791, I²  = 68.1%, P = 0.733). Only one RCT compared rifabutin therapy with control for first-line treatment of H. pylori infection (OR 3.78, 95% CI 2.44-5.87, P < 0.0001). Treatment was more likely to be successful in Asian versus non-Asian populations (81.0% vs 72.4%, P = 0.001) and when daily amoxicillin dose was ≥ 3000 mg or proton pump inhibitor dose was ≥ 80 mg or treatment duration was 14 days (80.6% vs 66.0%, P = 0.0001). The overall event rate for adverse effects was 24.8% (729/2937) (95% CI 0.23-0.26), and the pooled OR for adverse effects in the treatment versus control group was 0.93 (95% CI 0.50-1.75) (I²  = 79.76, P = 0.82).

CONCLUSION

Evidence for the effectiveness of rifabutin for the first-line treatment of H. pylori infection in adults is limited, and studies comparing rifabutin with conventional first-line treatments are lacking.

Rescue Therapies for H. pylori Infection in Italy

Background/Aims: Curing Helicobacter pylori infection remains challenging for clinicians, as no proposed first-line therapy achieves bacterial eradication in all treated patients so that several patients need two or more consecutive treatments. Bacterial culture with antibiotics susceptibility testing is largely unachievable in Italy, and empiric second-line and rescue therapies are generally used. This study aimed to identify what eradication regimens perform better in Italy, following first-line therapy failure. Methods: We performed a literature search on PubMed for studies on standard therapy regimens used as second-line or rescue treatments performed in adult patients. Studies including modified drug combinations were not considered. Both intention-to-treat and per- protocol analyses were computed for each therapy subgroup. Results: Data from 35 studies with a total of 4830 patients were eventually considered. As a second-line therapy, Pylera® (90.6%) and a sequential regimen (89.8%) achieved eradication rates significantly higher than other therapies. For third-line therapy, a levofloxacin-based regimen and Pylera® achieved comparable eradication rates (88.2% vs. 84.7%; p = 0.2). Among therapies used as fourth (or more) attempts, Pylera® and a rifabutin-based therapy achieved 77.4% and 66.4% cure rates, respectively (p = 0.013). A therapy sequence based on the type of first-line therapy used was proposed. Conclusions: Data obtained through our review indicate that standard therapies for H. pylori eradication can be used when following an appropriate sequence, allowing clinicians to improve the cure rate without resorting to bacterial culture.

[Helicobacter pylori: When to look for an infection and treat it in adults?]

Helicobacter pylori infection is acquired during childhood mainly within the family. It causes active chronic gastritis associated with the development of many digestive and extra digestive diseases. Its expression results from interactions between the bacteria, the host and environmental factors modulating the evolution of gastritis and acid secretion. The French recommendations for research and treatment for curative or preventive purposes were updated in 2017. These are indications with a high level of evidence for association and efficacy of the eradication treatment: peptic ulcer, taking non-steroidal anti-inflammatory drugs or aspirin with an ulcer history, gastric MALT lymphoma, and localized resection of gastric cancer. The recommendations relate to other diseases with a lower level of evidence: functional dyspepsia, risk factors for gastric adenocarcinoma (family history of gastric cancer, Lynch syndrome, pre-neoplastic lesions: atrophy, intestinal metaplasia, dysplasia), unexplained iron deficiency anemia and vitamin B12 deficiency, immunological thrombocytopenic purpura, bariatric surgery isolating part of the stomach. The diagnosis is made by examining gastric biopsies or by non-invasive test depending on the clinical situation. The 10-day triple therapies guided by the study of antibiotic sensitivity (proton pump inhibitors (PPI), amoxicillin, clarithromycin or levofloxacin) are recommended as first-line treatment because of the increase in resistance, allowing the reduction of the duration of treatment, the number of antibiotics and side effects. By default, probabilistic quadruple therapies of 14 days are possible and interchangeable (PPI with amoxicillin, clarithromycin, metronidazole, or a combination of bismuth salt, tetracycline and metronidazole). Eradication control is necessary.

Rifabutin for the Treatment of Helicobacter Pylori Infection: A Review

Nowadays, apart from having to know first-line Helicobacter pylori eradication regimens well, we must also be prepared to face treatment failures. The aim of this review is to summarize the role of rifabutin in the management of H. pylori infection. Bibliographical searches were performed in PubMed. Data on resistance and efficacy of rifabutin-containing regimens on H. pylori eradication were meta-analyzed. Mean H. pylori rifabutin resistance rate (39 studies, including 9721 patients) was 0.13%; when studies only including patients naïve to H. pylori eradication treatment were considered, this figure was even lower (0.07%). Mean H. pylori eradication rate (by intention-to-treat) with rifabutin-containing regimens (3052 patients) was 73%. Respective cure rates for second-, third-, fourth- and fifth-line therapies, were 79%, 69%, 69% and 72%. Most studies administered rifabutin 300 mg/day, which seemed to be more effective than 150 mg/day. The ideal length of treatment remains unclear, but 10–12-day regimens are generally recommended. Adverse events to rifabutin treatment in H. pylori studies were relatively infrequent (15%), and severe adverse events were exceptional (myelotoxicity was the most significant, although always reversible). In summary, rifabutin-containing therapy represents an encouraging strategy generally restricted, at present, to patients where previous (usually multiple) eradication regimens have failed.

An update on current and advancing pharmacotherapy options for the treatment of H. pylori infection

Introduction: Eradication of Helicobacter pylori (H. pylori) becomes more challenging due to increasing antimicrobial resistance. Consequently, the performance of clarithromycin-containing triple therapies is now declining to unacceptable levels and should be abandoned unless a prior susceptibility test precludes clarithromycin resistance.Areas covered: This review summarizes updated evidence concerning new and advancing pharmacotherapy options for H. pylori eradication.Expert opinion: Due to the declining efficacy of legacy triple therapies, most guidelines recommend bismuth quadruple therapy as the best initial empiric treatment. Concomitant, sequential and hybrid therapies are remarkable bismuth-free quadruple options, provided that dual clarithromycin-metronidazole resistance is low. Levofloxacin-, rifabutin-, furazolidone- and sitafloxacin-containing regimens remain useful, particularly as salvage options. To eradicate H. pylori in line with the rules of antibiotic stewardship, susceptibility-guided treatment appears as the ideal approach. However, the feasibility and cost-effectiveness of universal pre-treatment susceptibility testing warrants further evaluation. Molecular testing methods promise convenient characterization of H. pylori antibiotic susceptibility. High-dose dual therapy (proton-pump-inhibitor plus amoxicillin) and vonoprazan, a more potent acid inhibitor that likely enhances the activity of amoxicillin, are promising alternatives that could decrease misuse of antibiotics. Addition of certain probiotics could somewhat increase the performance of H. pylori eradication regimens, while improving tolerability.

Pharmacology, Dosing, and Side Effects of Rifabutin as a Possible Therapy for Antibiotic-Resistant Acinetobacter Infections

Acinetobacter baumannii has among the highest rates of antibiotic resistance encountered in hospitals. New therapies are critically needed. We found that rifabutin has previously unrecognized hyperactivity against most strains of A. baumannii. Here we review the pharmacology and adverse effects of rifabutin to inform potential oral dosing strategies in patients with A. baumannii infections. Rifabutin demonstrates dose-dependent increases in blood levels up to 900 mg per day, but plateaus thereafter. Furthermore, rifabutin induces its own metabolism after prolonged dosing, lowering its blood levels. Pending future development of an intravenous formulation, a rifabutin oral dose of 900-1200 mg per day for 1 week is a rational choice for adjunctive therapy of A. baumannii infections. This dosage maximizes AUC₂₄ to drive efficacy while simultaneously minimizing toxicity. Randomized controlled trials will be needed to definitively establish the safety and efficacy of rifabutin to treat A. baumannii infections.

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

Abstract

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

Key points

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

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

Efficacy and safety of a new rifabutin-based triple therapy with vonoprazan for refractory Helicobacter pylori infection: A prospective single-arm study

BACKGROUND

A small proportion of Helicobacter pylori-infected individuals in Japan suffer failure of eradication therapy with third-line regimens containing the potent acid suppressor, vonoprazan, and a quinolone.

OBJECTIVES

This prospective study evaluated the efficacy and safety of rifabutin-based triple therapy with vonoprazan for refractory H pylori infection.

METHODS

Patients who failed H pylori eradication by clarithromycin-based first-line, metronidazole-based second-line, and sitafloxacin-based third-line therapies were recruited. After obtaining informed consent, patients received eradication therapy with vonoprazan (20 mg), amoxicillin (750 mg), and rifabutin (150 mg) twice daily for 10 days. Eradication was confirmed by a negative H pylori stool antigen or urea breath test at least 8 weeks after the end of therapy.

RESULTS

Nineteen patients were included in the study. All of the patients completed the course of medication. Eradication of H pylori was confirmed in all of the patients (19/19; 100%, 95% confidence interval; 83-100%). The most common adverse event was soft stool/diarrhea (4/19, 21%). No severe adverse event was observed.

CONCLUSIONS

Ten-day rifabutin with amoxicillin and vonoprazan triple therapy appears to be effective and safe for refractory H pylori infections. However, considering the recent publications showing high eradication rates with vonoprazan amoxicillin dual therapy, confirmation will require future studies comparing our new therapy with vonoprazan-amoxicillin dual with similar doses and duration and with vonoprazan-rifabutin dual therapy.

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.

Best Helicobacter pylori Eradication Strategy in the Era of Antibiotic Resistance

Antibiotic resistance is the major reason for Helicobacter pylori treatment failure, and the increasing frequency of antibiotic resistance is a challenge for clinicians. Resistance to clarithromycin and metronidazole is a particular problem. The standard triple therapy (proton pump inhibitor, amoxicillin, and clarithromycin) is no longer appropriate as the first-line treatment in most areas. Recent guidelines for the treatment of H. pylori infection recommend a quadruple regimen (bismuth or non-bismuth) as the first-line therapy. This treatment strategy is effective for areas with high resistance to clarithromycin or metronidazole, but the resistance rate inevitably increases as a result of prolonged therapy with multiple antibiotics. Novel potassium-competitive acid blocker-based therapy may be effective, but the data are limited. Tailored therapy based on antimicrobial susceptibility test results is ideal. This review discussed the current important regimens for H. pylori treatment and the optimum H. pylori eradication strategy.

Rescue therapy with rifabutin regimen for refractory Helicobacter pylori infection with dual drug-resistant strains

Background

There is no current standard rescue treatment for dual drug-resistant strains of Helicobacter pylori (H. pylori). This aim of this study was to investigate the efficacy of rifabutin-based triple therapy for patients infected with dual drug-resistant strains to clarithromycin and levofloxacin.

Methods

After 2 or 3 H. pylori treatment failures, patients underwent upper endoscopy with tissue biopsies. Phenotypic and genotypic resistances were determined using agar dilution test and polymerase chain reaction with direct sequencing, respectively. Patients infected with dual drug-resistant (clarithromycin and levofloxacin) strains and receiving rifabutin-based triple therapy (rifabutin 150 mg bid, amoxicillin 1 g bid and esomeprazole 40 mg bid for 10 days) were enrolled. Eradication status was determined by 13C-urea breath test 4 weeks after treatment completion.

Results

A total of 39 patients infected with dual drug-resistant strains were enrolled in this study, with a mean age of 55.9 years. The eradication rate was 79.5% (31/39) (95% confidence intervals: 54.96% ~ 111.40%). Adverse event was reported in 23.1% (9/39) of patients but they were mild and tolerable. In univariate analysis, no factor was identified as an independent predictor of eradication failure.

Conclusions

Our current study demonstrated that rifabutin-based triple therapy was well tolerated and yielded an acceptable eradication rate for patients infected with dual drug-resistant strains of H. pylori.

The relationship between Helicobacter pylori and chronic kidney disease: update 2020

A number of studies has confirmed that the epidemiology of Helicobacter pylori is changing worldwide, with a decrease especially in developed countries. Nevertheless, since this gram-negative bacterium infects almost 50% of the world's population, it remains a global problem. Beyond its role in the pathogenesis of the main gastroduodenal diseases, including gastritis, peptic ulcer and gastric cancer, Helicobacter pylori has been suspected to be involved in several extra-gastroduodenal disorders. Patients with chronic kidney disease (CKD) present gastric mucosal injuries and dyspepsia more often than the general population. However, the reported relationship between CKD and Helicobacter pylori infection is conflicting. In fact, in this population these conditions have a multifactorial pathogenesis and Helicobacter pylori infection could play a limited role in their development. Nevertheless, while it seems that the prevalence of the bacterium is lower in patients with CKD than in controls, Helicobacter pylori has been shown to be associated to an increased occurrence of proteinuria in patients with type 2 diabetes mellitus. This narrative review analyzes the results of recent literature in this field with particular focus on data reported by meta-analyses.

Chemoprevention of gastric cancer development after Helicobacter pylori eradication therapy in an East Asian population: Meta-analysis

BACKGROUND

Helicobacter pylori (H. pylori) infection is a risk factor for gastric cancer (GC), especially in East Asian populations. Most East Asian populations infected with H. pylori are at higher risk for GC than H. pylori-positive European and United States populations. H. pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC, as well as in non-GC patients with atrophic gastritis.

AIM

To clarify the chemopreventive effects of H. pylori eradication therapy in an East Asian population with a high incidence of GC.

METHODS

PubMed and the Cochrane library were searched for randomized control trials (RCTs) and cohort studies published in English up to March 2019. Subgroup analyses were conducted with regard to study designs (i.e., RCTs or cohort studies), country where the study was conducted (i.e., Japan, China, and South Korea), and observation periods (i.e., ≤ 5 years and > 5 years). The heterogeneity and publication bias were also measured.

RESULTS

For non-GC patients with atrophic gastritis and patients after resection for GC, 4 and 4 RCTs and 12 and 18 cohort studies were included, respectively. In RCTs, the median incidence of GC for the untreated control groups and the treatment groups was 272.7 (180.4–322.4) and 162.3 (72.5–588.2) per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7 (406.5–2941.2) and 1126.2 (678.7–1223.1) per 100000 person-years in cases of after resection for GC. Compared with non-treated H. pylori-positive controls, the eradication groups had a significantly reduced risk of GC, with a relative risk of 0.67 [95% confidence interval (CI): 0.47–0.96] for non-GC patients with atrophic gastritis and 0.51 (0.36–0.73) for patients after resection for GC in the RCTs, and 0.39 (0.30–0.51) for patients with gastritis and 0.54 (0.44–0.67) for patients after resection in cohort studies.

CONCLUSION

In the East Asian population with a high risk of GC, H. pylori eradication effectively reduced the risk of GC, irrespective of past history of previous cancer.

Helicobacter pylori and diabetes mellitus: a controversial relationship

Research on Helicobacter pylori (H. pylori), a pathogenic bacterium that is widespread among humans, is investigating the medical implications of the infection in many fields beyond gastroenterology. Because of the ubiquitous presence of the infection, there is an increasing interest in finding a relationship between this bacterium and diabetes mellitus (DM). It is not clear whether a significant relation between H. pylori and DM exists, whether the infection influences diabetes or vice versa, and the mechanisms underlying such a relationship. This review provides an analysis of new insights from studies published in more recent years. New research on this topic concentrated on the common pathogenic aspects between the bacterium and insulin resistance or autoimmunity, on the role of the bacterial infection in cardiovascular risk and whether the infection worsen glycemic outcomes in patients with DM. Research in this field still has to conclusively assess and explain the existence of a possible relationship between H. pylori and DM. Some studies have reached antithetic conclusions. Unless more robust data from studies using consistent research methods become available in the near future, people with diabetes should be compared to the general population when it comes to investigating and treating the presence of H. pylori.

Resistance patterns of refractory H. pylori infection in a referral center in the Delaware Valley

Introduction

H. pylori (HP) resistance is increasing in the US. Guidelines suggest treatment based on local resistance patterns, yet are poorly studied. We describe resistance patterns of the Delaware Valley.

Methods

A retrospective study of patients referred to the Hospital of the University of Pennsylvania, between 2009-2019 who underwent endoscopy for culture. Chart review identified demographics, history, endoscopic and culture results, treatment, and follow up.

Results

Of 109 patients referred for refractory HP, 90 had identified HP. Median age was 53.2 years and the majority was female (74%), with median 2 previous antibiotic courses for HP. Gastric erythema was the most common endoscopic abnormality. 65 (72.2%) were culture positive, and 45 (69.2%) were resistant to levofloxacin, 27 (41.5%) to metronidazole, and 39 (43.3%) to clarithromycin.Being resistant to any one of the 3 antibiotics was associated with resistance to either of the other two. There was an association with number of previous antibiotics with resistance (OR 1.74, p<0.05).We prescribed therapy to 77 patients based on susceptibility profiles, and 34 (37.8%) were cured, 14 (15.6%) underwent endoscopic surveillance, 3 (3.3%) were followed by infectious disease, and 39 (43.3%) were lost to follow up.

Conclusions

Antibiotic resistance is associated with refractory HP, and continues to rise. Culturing is associated with cure, and its use in clinical practice regarding efficacy, cost-effectiveness, and ability to minimize antibiotic resistance should be further studied. Overall follow-up is limited by loss to follow up, emphasizing the need for appropriate treatment.

Two-week bismuth-containing quadruple therapy and concomitant therapy are effective first-line treatments for Helicobacter pylori eradication: A prospective open-label randomized trial

BACKGROUND

Increasing levels of antibiotic resistance have reduced the Helicobacter pylori (H. pylori) eradication rates afforded by the standard triple therapy. Thus, 2-wk first-line four-drug regimens must be considered.

AIM

To analyze the eradication rates of modified bismuth-containing quadruple therapy (mBCQT) and concomitant therapy (CT), the associated adverse events, and compliance.

METHODS

Patients infected with H. pylori were prospectively randomized to receive mBCQT or CT for 2 wk. mBCQT featured a proton pump inhibitor (PPI), bismuth, metronidazole, and tetracycline, taken twice daily. CT included a PPI, clarithromycin, metronidazole, and amoxicillin, taken twice daily. The ¹³C-urea breath test was performed no earlier than 4 wk after therapy concluded to confirm eradication. If either the histological or rapid urease test was positive, H. pylori infection was diagnosed.

RESULTS

The demographic characteristics of 68 patients who received mBCQT and 68 who received CT did not differ significantly. On intention-to-treat analysis, the eradication rate was 88.2% (60/68) in the mBCQT group and 79.4% (54/68) in the CT group (P = 0.162). By per-protocol analysis, the respective eradication rates were 98.4% (60/61) and 93.1% (54/58) (P = 0.199). More CT than mBCQT patients experienced adverse events [33.8% (23/68) mBCQT vs 51.5% (35/58) CT patients, respectively, P = 0.037]. All patients showed good compliance [85.3% (58/68) mBCQT vs 82.4% (56/68) CT patients, P = 0.641].

CONCLUSION

The H. pylori eradication rates of the 2-wk mBCQT and CT regimens are high. Most patients show good compliance, and more CT than mBCQT patients experience adverse events.

Review: Treatment of Helicobacter pylori Infection 2019

This review summarizes important studies regarding Helicobacter pylori therapy published from May 2018 to May 2019. The main themes that emerge involve studies assessing the efficacy of bismuth-based regimens. While in recent years the efficacy of bismuth-based quadruple therapy as a second-line therapy has been clearly established, there is now substantial evidence that it is the best performing first-line therapy. Antibiotic resistance was again intensely studied this year, and a clear and dramatic increase in resistance is noted for clarithromycin and levofloxacin; most notably, it may not be possible to support these therapies in most regions of the world much longer without testing. The utility of vonoprazan as an alternative to proton-pump inhibitor therapy, especially in resistant and difficult to treat groups, has also been considered in greater detail this year, as well as means of supporting and enhancing adherence to therapy. Several studies showed that the diversity of gut microbiota was significantly altered shortly after H pylori eradication. However, the diversity was restored to pre-treatment state after 2 months in patients treated with triple therapy. More studies are warranted to assess the long-term changes of gut microbiota after H pylori eradication.

Helicobacter pylori and cardiovascular disease: update 2019

Many studies have been performed concerning the potential role of Helicobacter pylori (H. pylori) in different extra-gastric diseases. Ischemic heart disease (IHD) remains the leading cause of mortality in developed countries. The traditional cardiovascular risk factors could not predict all cases of IHD. Hence, the scientists explore other potential etiologic factors, especially infections. H. pylori infection has been suspected to have a role in the pathogenesis of atherosclerosis. However, after 25 years from the first description, the role of the bacterium in the pathogenesis of IHD remains controversial and enigmatic. Since H. pylori infection is persistent and stimulates both a local and a systemic immune response that could cause significant changes in the markers of inflammation like cytokines, C-reactive protein, heat shock protein, fibrinogen, triglycerides, high density lipoprotein, it has been supposed that the outcomes of this process are atherosclerosis and a prothrombotic state which eventually leads to IHD. Alternative pathogenic mechanisms have been hypothesized, including the occurrence of molecular antigenicity. This hypothesis supposed that H. pylori could provoke autoimmunity as a result of molecular mimicry. The eradication of H. pylori infection as cardiovascular prevention strategy has been the object of some studies. However, the results are of difficult interpretation. Further studies, especially with a cohort and interventional design, have to be performed to reveal the potential relationship between H. pylori and IHD.