Rifabutin for the Treatment of Helicobacter Pylori Infection: A Review

Drug repurposing against antibiotic resistant bacterial pathogens

The growing prevalence of MDR and XDR bacterial pathogens is posing a critical threat to global health. Traditional antibiotic development paths have encountered significant challenges and are drying up thus necessitating innovative approaches. Drug repurposing, which involves identifying new therapeutic applications for existing drugs, offers a promising alternative to combat resistant pathogens. By leveraging pre-existing safety and efficacy data, drug repurposing accelerates the development of new antimicrobial therapy regimes. This review explores the potential of repurposing existing FDA approved drugs against the ESKAPE and other clinically relevant bacterial pathogens and delves into the identification of suitable drug candidates, their mechanisms of action, and the potential for combination therapies. It also describes clinical trials and patent protection of repurposed drugs, offering perspectives on this evolving realm of therapeutic interventions against drug resistance.

Antibiotic Susceptibility-Guided Concomitant Therapy Regimen with Vonoprazan, High-Dose Amoxicillin, Clarithromycin, and Metronidazole for Helicobacter pylori Eradication as Fourth-Line Regimen: An Interventional Study

This is the first registered intervention study for vonoprazan, high-dose amoxicillin, clarithromycin, and metronidazole 14-day concomitant therapy based on a susceptibility test of Helicobacter pylori. We conducted this study as a fourth-line rescue regimen in Japan.

METHODS

Twenty patients who underwent three rounds of eradication therapies (first- or second-line 7-day triple therapy consisting of amoxicillin and clarithromycin, or metronidazole- and sitafloxacin-based third-line therapy) and had failed eradication based on a urea breath test or fecal antigen test were recruited. All patients underwent endoscopic examination and culture tests before starting eradication therapy. The intervention was concomitant therapy consisting of vonoprazan 20 mg bid, amoxicillin 500 mg qid, clarithromycin 400 mg bid, and metronidazole 250 mg bid for 14 days, which were modified based on the susceptibility test, and the resistant drugs were removed from the regimen. Patients with negative culture results were treated with quadruple therapy. The primary outcome was the eradication rate (UMIN000025765, jRCTs 031180208).

RESULTS

The eradication rate of susceptibility-testing-based fourth-line eradication therapy was 63.2% (95%CI: 38.4-83.7%) in intent-to-treat analysis and 70.6% (95%CI: 44.0-89.7%) in per-protocol analysis. Thirteen patients received quadruple therapy, with eradication rates of 61.5% and 75.0%, respectively. No serious adverse events were reported.

CONCLUSIONS

This vonoprazan-based concomitant therapy modified by the susceptibility test is a potential option as fourth-line eradication after first-line clarithromycin-based 7-day triple, second-line metronidazole-based 7-day triple, and third-line sitafloxacin-based 7-day triple therapy failure.

Rifabutin: a repurposed antibiotic with high potential against planktonic and biofilm staphylococcal clinical isolates

Staphylococcus aureus poses a significant threat as an opportunistic pathogen in humans, and animal medicine, particularly in the context of hospital-acquired infections (HAIs). Effective treatment is a significant challenge, contributing substantially to the global health burden. While antibiotic therapy remains the primary approach for staphylococcal infections, its efficacy is often compromised by the emergence of resistant strains and biofilm formation. The anticipated solution is the discovery and development of new antibacterial agents. However, this is a time consuming and expensive process with limited success rates. One potential alternative for addressing this challenge is the repurposing of existing antibiotics. This study investigated the potential of rifabutin (RFB) as a repurposed antibiotic for treating S. aureus infections. The minimum inhibitory concentration (MIC) of rifabutin was assessed by the broth microdilution method, in parallel to vancomycin, against 114 clinical isolates in planktonic form. The minimum biofilm inhibitory concentration (MBIC50) was determined by an adaptation of the broth microdilution method, followed by MTT assay, against a subset of selected 40 clinical isolates organized in biofilms. The study demonstrated that RFB MIC ranged from 0.002 to 6.250 μg/mL with a MIC50 of 0.013 μg/mL. RFB also demonstrated high anti-biofilm activity in the subset of 40 clinical isolates, with confirmed biofilm formation, with no significant MBIC50 differences observed between the MSSA and MRSA strains, in contrast to that observed for the VAN. These results highlight the promising efficacy of RFB against staphylococcal clinical isolates with different resistance patterns, whether in planktonic and biofilm forms.

Microparticles and nanoparticles-based approaches to improve oral treatment of Helicobacter pylori infection

Helicobacter pylori is a gram-negative, spiral-shaped, flagellated bacterium that colonizes the stomach of half the world's population. Helicobacter pylori infection causes pathologies of varying severity. Standard oral therapy fails in 15-20% since the barriers of the oral route decrease the bioavailability of antibiotics and the intrinsic factors of bacteria increase the rates of resistance. Nanoparticles and microparticles are promising strategies for drug delivery into the gastric mucosa and targeting H. pylori. The variety of building blocks creates systems with distinct colloidal, surface, and biological properties. These features improve drug-pathogen interactions, eliminate drug depletion and overuse, and enable the association of multiple actives combating H. pylori on several fronts. Nanoparticles and microparticles are successfully used to overcome the barriers of the oral route, physicochemical inconveniences, and lack of selectivity of current therapy. They have proven efficient in employing promising anti-H. pylori compounds whose limitation is oral route instability, such as some antibiotics and natural products. However, the current challenge is the applicability of these strategies in clinical practice. For this reason, strategies employing a rational design are necessary, including in the development of nano- and microsystems for the oral route.

Single-Arm, Prospective, Interventional Study of Helicobacter pylori Eradication Rescue Therapy with Rifabutin, Metronidazole, and Vonoprazan

Background and Objective: Rescue Helicobacter pylori eradication can be challenging. Rifabutin (RBT) demonstrates high activity against Helicobacter pylori and is incorporated into various rescue eradication regimens. This exploratory study was performed to evaluate the efficacy and safety of a rescue regimen comprising RBT, metronidazole (MNZ), and vonoprazan (VPZ). Methods: This prospective, single-center, single-arm, interventional study was performed in Japan. Eligible patients were those who underwent failed primary eradication treatment (7-day treatment with three drugs: VPZ or a proton pump inhibitor [PPI], amoxicillin [AMPC], and clarithromycin) and secondary eradication treatment (7-day treatment with three drugs: VPZ or a PPI, AMPC, and MNZ) and those who were unable to receive first- and second-line therapy because of penicillin allergy. Twenty Helicobacter pylori-positive patients were treated with RBT (150 mg twice daily), MNZ (250 mg twice daily), and VPZ (20 mg twice daily) for 10 days (RBT-MNZ-VPZ therapy). Eradication success was evaluated using the urea breath test. Drug susceptibility test results were available in 16 patients. This study is registered in the Japan Registry of Clinical Trials (jRCT031220504). Results: The intention-to-treat (ITT) and per-protocol (PP) eradication rates of RBT-MNZ-VPZ therapy were 70% (90% confidence interval [CI]: 49.2%-86.0%) and 72.2% (95% CI: 50.2%-88.4%), respectively. In the MNZ-susceptible subgroup, the ITT (n = 8) and PP (n = 7) eradication rates were 100% (90% CI: 68.8%-100%) and 100% (90% CI: 65.2%-100%). In the MNZ-resistant subgroup, the ITT (n = 8) and PP (n = 7) eradication rates were both 62.5% (90% CI: 28.9%-88.9%). All infections were RBT-susceptible. Conclusions: These findings suggest that RBT-MNZ-VPZ therapy may be a promising rescue regimen, especially in MNZ- and RBT-susceptible infections or patients with penicillin allergy.

Current and Future Perspectives on the Management of Helicobacter pylori: A Narrative Review

The prevalence of Helicobacter pylori (H. pylori), a pathogen, has decreased globally in the last decade. To date, the management of H. pylori has focused on a reactive approach, whereby those diagnosed are treated with antimicrobials and acid suppression in combination. This review article provides an overview of the shift in the management of H. pylori from a reactive approach towards a proactive 'screen and treat' approach; the article reflects the current pharmacological landscape for H. pylori treatment by exploring similarities such as the first-line prescription of quadruple therapy in most countries and provides a summary table of the best practice guidance from Europe, Asia, and North America. It explores significant ongoing challenges in management, such as rising antimicrobial resistance rates, and explores a potential 'work smart' approach to antimicrobial susceptibility testing. We explore the role of registry databases in providing data on treatment efficacy and safety and how they can support a strategic approach to H. pylori treatment. We question if such a database's availability, update, and regular audit should serve as a key quality indicator in a population screening programme. Despite a call for vaccination against H. pylori and decades of research, not many have made it to a phase-three clinical trial. We explore the challenges that have complicated the development of such a vaccine, such as the genetic diversity of H. pylori, immunotolerance, and limitations of mouse models in research; we reflect on how these challenges are contributing to a low likelihood of having a vaccine in the short-medium term. Lastly, it explores the heterogeneity in research on probiotics and their role as an adjunct in the management of H. pylori.

Novel therapeutic regimens against Helicobacter pylori: an updated systematic review

Helicobacter pylori (H. pylori) is a strict microaerophilic bacterial species that exists in the stomach, and H. pylori infection is one of the most common chronic bacterial infections affecting humans. Eradicating H. pylori is the preferred method for the long-term prevention of complications such as chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. However, first-line treatment with triple therapy and quadruple therapy has been unable to cope with increasing antibacterial resistance. To provide an updated review of H. pylori infections and antibacterial resistance, as well as related treatment options, we searched PubMed for articles published until March 2024. The key search terms were "H. pylori", "H. pylori infection", "H. pylori diseases", "H. pylori eradication", and "H. pylori antibacterial resistance." Despite the use of antimicrobial agents, the annual decline in the eradication rate of H. pylori continues. Emerging eradication therapies, such as the development of the new strong acid blocker vonoprazan, probiotic adjuvant therapy, and H. pylori vaccine therapy, are exciting. However, the effectiveness of these treatments needs to be further evaluated. It is worth mentioning that the idea of altering the oxygen environment in gastric juice for H. pylori to not be able to survive is a hot topic that should be considered in new eradication plans. Various strategies for eradicating H. pylori, including antibacterials, vaccines, probiotics, and biomaterials, are continuously evolving. A novel approach involving the alteration of the oxygen concentration within the growth environment of H. pylori has emerged as a promising eradication strategy.

Safety, pharmacokinetics, and efficacy of rifasutenizol, a novel dual-targeted antibacterial agent in healthy participants and patients in China with Helicobacter pylori infection: four randomised clinical trials

BACKGROUND

Due to the rapid development of antimicrobial resistance, the efficacy of most Helicobacter pylori eradication therapies have progressively decreased to an unacceptable level. Rifasutenizol (TNP-2198) is a new molecular entity with a synergistic dual mechanism of action currently under clinical development for the treatment of microaerophilic and anaerobic bacterial infections. We aimed to evaluate the safety, pharmacokinetics, and efficacy of rifasutenizol in healthy Chinese participants and patients with H pylori.

METHODS

We conducted four clinical trials of rifasutenizol capsules in healthy participants (aged 18-55 years) and patients with asymptomatic H pylori infection (aged 18-65 years) in a clinical trial centre in Jilin province, China. Trial 1 was a phase 1, double-blind, randomised, placebo-controlled, single ascending dose study, in which participants were enrolled into one of seven rifasutenizol dose groups (50 mg, 100 mg, 200 mg, 400 mg, 600 mg, 800 mg, or 1000 mg) and were randomly assigned in a 4:1 ratio to study drug or placebo. Trial 2 was a phase 1, double-blind, randomised, placebo-controlled, multiple ascending dose study, in which patients were enrolled into one of three rifasutenizol dose groups (200 mg, 400 mg, or 600 mg) and were randomly assigned in a 3:1 ratio to study drug or placebo. Trial 3 was a phase 2a, open-label, randomised, multiple-dose, dose-finding study in which patients enrolled into one of four cohorts were randomly assigned in a 1:1:1:1 ratio to a rifasutenizol dual or triple regimen. Trial 4 was a phase 2b, open-label, randomised, multiple-dose, regimen exploration study, in which patients enrolled into one of five cohorts were randomly assigned in a 2:2:1:1:2 ratio to a rifasutenizol dual therapy, triple therapy, or a control cohort. Block randomisation (block size 4 or 8) was used in all four trials. The key primary endpoints for trials 1, 2, and 3 were the tolerability, safety, and pharmacokinetics of rifasutenizol. For trial 4, the primary endpoint was the eradication rate of H pylori. These four trials were registered at ClinicalTrials.gov (NCT06081699, NCT06081712, NCT06076681, and NCT06076694) and chinadrugtrials.org.cn (CTR20190734, CTR20192553, CTR20212050, and CTR20220625) and are completed.

FINDINGS

Between May 9, 2019, and Sept 14, 2022, 78 healthy participants (trial 1: n=10 per cohort in a 4:1 rifasutenizol:placebo ratio; and an additional eight for the food-effect cohort) and 168 patients with asymptomatic H pylori infection (trial 2: n=16 per cohort in a 3:1 rifasutenizol:placebo ratio; trial 3: n=10 per cohort; trial 4: n=10 or n=20 per cohort) were enrolled in the four clinical trials. Single doses of rifasutenizol (50-1000 mg) and multiple doses of rifasutenizol (200 mg to 600 mg, twice a day), either as monotherapy or co-administered with rabeprazole and amoxicillin, showed favourable safety and tolerability profiles. Most adverse events were mild, and no serious adverse events were reported. Rifasutenizol demonstrated a linear pharmacokinetic profile over the dose range of 50-800 mg, and there were no apparent pharmacokinetic interactions between rifasutenizol and the co-administrated drugs. Food intake slightly elevated the area under the plasma concentration-time curve (AUC) of rifasutenizol, and the geometric mean of AUC from time 0 to the last timepoint with a quantifiable concentration (AUC0-t) and AUC from time 0 to infinity (AUC0-∞) in the fed state were 1·334 and 1·396 times of those in the fasted state, respectively. There was mild accumulation after continuous administration of rifasutenizol, and the Rac(AUC) of rifasutenizol 400 mg in the dual and triple regiments in trial 3 were 1·37 and 1·49, respectively. In trial 3, the eradication rates of H pylori with 200 mg, 400 mg, or 600 mg of rifasutenizol in combination with rabeprazole, twice a day for 14 days, were 0% (95% CI 0-31), 30% (7-65), and 40% (12-74), respectively, identifying rifasutenizol 400 mg as the effective dose. In trial 4, H pylori eradication rates with the triple regimen in cohort A (400 mg rifasutenizol, 20 mg rabeprazole sodium, and 1 g amoxicillin) twice a day for 14 days was 95% (95% CI 74-100), and triple therapy (600 mg rifasutenizol, 20 mg rabeprazole sodium, and 1 g amoxicillin) three times a day for 7 days was 100% (69-100).

INTERPRETATION

Rifasutenizol monotherapy and combination therapy was generally safe and well tolerated in healthy participants and patients with H pylori infection. A triple regimen of 400 mg rifasutenizol capsules, 20 mg rabeprazole sodium enteric-coated tablets, and 1 g amoxicillin capsules twice a day for 14 days showed promising efficacy as a new treatment regimen for H pylori infection.

FUNDING

TenNor Therapeutics and National Natural Science Foundation of China.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Safety profile of Helicobacter pylori eradication treatments: literature review and updated data of the European Registry on Helicobacter pylori management (Hp-EuReg)

INTRODUCTION

Helicobacter pylori (H. pylori), the most prevalent chronic infection globally, is the major cause of relevant diseases such as gastric cancer, leading to high morbidity and mortality worldwide. Several studies have focused on optimize H. pylori eradication treatment through combination therapies and antibiotic resistance. However, the adverse events profile and its impact, as a primary outcome, remains underexplored.The aim of this review was to summarize the available data on the safety of the most common regimens for H. pylori eradication and its impact on the compliance.

AREAS COVERED

This review encompassed the published evidence from the years 2008 to 2023 regarding both the safety and compliance for most common H. pylori eradication regimens. The main sources for this review comprised MEDLINE, PubMed, and Cochrane electronic databases. Furthermore, it included a safety analysis of unpublished data from the European Registry on H. pylori management (Hp-EuReg).

EXPERT OPINION

Poor compliance is correlated with significantly lower cure rates, and this is a unique modifiable source of H. pylori treatment failure. Eradication treatments have become complex, involving multiple drugs and dosing intervals. Thus, patient education is crucial; doctors must explain to the patient about potential temporary and most often harmless side effects.

Change in Diagnosis of Helicobacter pylori Infection in the Treatment-Failure Era

Helicobacter pylori (H. pylori) infection is a prevalent global health issue, associated with several gastrointestinal disorders, including gastritis, peptic ulcers, and gastric cancer. The landscape of H. pylori treatment has evolved over the years, with increasing challenges due to antibiotic resistance and treatment failure. Traditional diagnostic methods, such as the urea breath test, stool antigen test, and endoscopy with biopsy, are commonly used in clinical practice. However, the emergence of antibiotic-resistant strains has led to a decline in treatment efficacy, necessitating a re-evaluation of common diagnostic tools. This narrative review aims to explore the possible changes in the diagnostic approach of H. pylori infection in the era of treatment failure. Molecular techniques, including polymerase chain reaction and whole genome sequencing, which have high sensitivity and specificity, allow the detection of genes associated with antibiotic resistance. On the other hand, culture isolation and a phenotypic antibiogram could be used in the diagnostic routine, although H. pylori is a fastidious bacterium. However, new molecular approaches are promising tools for detecting the pathogen and its resistance genes. In this regard, more real-life studies are needed to reveal new diagnostic tools suitable for identifying multidrug-resistant H. pylori strains and for outlining proper treatment.

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.

Current paradigms in the management of refractory Helicobacter pylori infection

Helicobacter pylori is the most prevalent chronic bacterial infection, with approximately half of the world's population estimated to be colonized. The World Health Organization (WHO) has classified Helicobacter pylori as a class-I carcinogen. All main society guidelines recommend its eradication in infected individuals. The global trend indicates that eradication rates are decreasing annually and the likelihood of eradication decreases with each unsuccessful therapeutic attempt. Resistance to antibiotics in H. pylori strains is the leading cause for eradication failure. Still, drug resistance and treatment failure may be complex, multi-dimensional and associated with several other factors. Knowledge of these factors can aid in optimizing eradication rates. This review will focus on the factors associated with refractory H. pylori, with a particular emphasis on antibiotic resistance mechanisms and their clinical implications. Also, the most recent literature and recommendations available for determining an appropriate regimen after the failure of the first attempt at eradication will be discussed.

Exploring Alternative Treatment Choices for Multidrug-Resistant Clinical Strains of Helicobacter pylori in Mongolia

Helicobacter pylori is a pathogen related to severe diseases such as gastric cancer; because of rising antimicrobial-resistant strains, failure to eradicate H. pylori with antibiotics has increased worldwide. Multidrug-resistant H. pylori and gastric cancer is common in Mongolia; therefore, we aimed to explore alternative antimicrobial treatments and the genomes of resistant strains in this country. A total of 361 H. pylori strains isolated from patients in Mongolia were considered. Minimal inhibitory concentrations for two fluoroquinolones (ciprofloxacin and moxifloxacin), rifabutin, and furazolidone were determined via two-fold agar dilution. Genomic mutations in antibiotic-resistant strains were identified by next-generation sequencing using the Illumina Miseq platform and compared with genes from a reference H. pylori strain (26695). The resistance rate of H. pylori strains to quinolones was high (44% to ciprofloxacin and 42% to moxifloxacin), and resistance to rifabutin was low (0.5%); none were resistant to furazolidone. Most quinolone-resistant strains possessed gyrA gene mutations causing amino acid changes (e.g., N87K, A88P, and D91G/Y/N). While one rifabutin-resistant strain had amino acid-substituting mutations in rpoB (D530N and R701C), the other had three novel rpoB mutations; both rifabutin-resistant strains were sensitive to furazolidone. Overall, our findings suggest that rifabutin and/or furazolidone may be an alternative, effective H. pylori treatment in patients who have failed to respond to other treatment regimens.

Refractory Helicobacter pylori infection in Australia: updated multicentre antimicrobial resistance

BACKGROUND AND AIM

Helicobacter pylori infection is responsible for considerable morbidity and mortality worldwide and eradication rates are falling globally because of increasing antimicrobial resistance. However, there is a paucity of local data to guide the choice of eradication therapy in Australia. This study aimed to evaluate current Australian rates of H. pylori antibiotic resistance in patients who had failed prior eradication therapy.

METHODS

A retrospective analysis of routine culture and antibiotic susceptibility data from two pathology laboratories servicing multiple tertiary referral hospitals in Western Australia (WA) and South Australia (SA), between 2018 and 2022, was performed. Rates of antimicrobial resistance and prevalence of multiresistant isolates in both SA and WA were calculated and comparison of temporal trends and differences between the two states was conducted.

RESULTS

A total of 796 H. pylori isolates revealed a clarithromycin resistance rate of 82%, metronidazole 68%, amoxicillin 4.4% and tetracycline 0.5%. Resistance to levofloxacin was observed in 22% and rifampicin 14%. Rates of resistance to clarithromycin were lower in SA compared with WA (incidence rate ratio [IRR]: 0.69, P = 0.0001). Multiresistant isolates were discovered in 63% of patients, with lower rates in SA compared with WA (IRR: 0.74, P = 0.002).

CONCLUSION

This first multicentre, multistate study of H. pylori resistance in Australian patients exposed to prior therapy demonstrated high rates of antimicrobial resistance, including levofloxacin (>20%). This raises concern about recommending levofloxacin in empirical second-line therapies. Increased monitoring and awareness of current H. pylori resistance rates in Australia are needed to guide local eradication practices.

Practice guidelines for the management of Helicobacter pylori infection: The Saudi H. pylori Working Group recommendations

The eradication rates for Helicobacter pylori globally are decreasing with a dramatic increase in the prevalence of antibiotic resistant bacteria all over the world, including Saudi Arabia. There is no current consensus on the management of H. pylori in Saudi Arabia. The Saudi Gastroenterology Association developed these practice guidelines after reviewing the local and regional studies on the management of H. pylori. The aim was to establish recommendations to guide healthcare providers in managing H. pylori in Saudi Arabia. Experts in the areas of H. pylori management and microbiology were invited to write these guidelines. A literature search was performed, and all authors participated in writing and reviewing the guidelines. In addition, international guidelines and consensus reports were reviewed to bridge the gap in knowledge when local and regional data were unavailable. There is limited local data on treatment of H. pylori. The rate of clarithromycin and metronidazole resistance is high; therefore, standard triple therapy for 10-14 days is no longer recommended in the treatment of H. pylori unless antimicrobial susceptibility testing was performed. Based on the available data, bismuth quadruple therapy for 10-14 days is considered the best first-line and second-line therapy. Culture and antimicrobial susceptibility testing should be considered following two treatment failures. These recommendations are intended to provide the most relevant evidence-based guidelines for the management of H. pylori infection in Saudi Arabia. The working group recommends further studies to explore more therapeutic options to eradicate H. pylori.

Diagnostic and therapeutic recommendations on Helicobacter pylori infection. Recommendations of the Working Group of the Polish Society of Gastroenterology

Helicobacter pylori remains a major health problem worldwide, causing considerable morbidity and mortality due to peptic ulcer disease and gastric cancer. These guidelines constitute an update of the previous "Recommendations on the diagnosis and management of Helicobacter pylori infection" issued in 2014. They have been developed by a Task Force organized by the Governing Board of the Polish Society of Gastroenterology. They discuss, with particular emphasis on new scientific data covering papers published since 2014: the epidemiology, clinical presentation, diagnostic principles and criteria for the diagnosis, and recommendations for the treatment of H. pylori infection. The guidelines in particular determine which patients need to be tested and treated for infection. The Task Force also discussed recommended treatment algorithms. Accordingly, a combination of available evidence and consensus-based expert opinion were used to develop these best practice advice statements. It is worth noting that guidelines are not mandatory to implement but they offer advice for pragmatic, relevant and achievable diagnostic and treatment pathways based on established key treatment principles and using local knowledge and available resources to guide regional practice.

Artesunate Dry Emulsion Formulation Combined with Antibiotics for Treatment of Helicobacter pylori Infections: In Vitro/In Vivo Evaluation

Helicobacter pylori is the primary pathogen responsible for causing gastroduodenal ulcers and stomach cancer. The standard treatment for H. pylori typically involves a combination of antibiotics and acid-reducing medications. However, the recurrence of ulcers is closely linked to the emergence of antibiotic resistance in H. pylori, necessitating the development of alternative drugs. This report focuses on the investigation of artesunate as a potential alternative to reduce antibiotic use and enhance effectiveness against H. pylori. Unfortunately, commercial artesunate is available in an acid form, which has poor solubility, especially in gastric acid fluid. The aim of this study is to utilize a water-soluble formulation of artesunate called dry emulsion formulation (ADEF) and combine it with amoxicillin to eradicate H. pylori. In vitro studies were conducted to evaluate the activity of ADEF against H. pylori and determine its inhibitory concentrations. In addition, pharmacokinetic parameters of orally administered ADEF and native artesunate were investigated in rats for in vivo studies. The results showed that when combined with amoxicillin and pantoprazole, ADEF exhibited effectiveness against H. pylori. It is worth noting that the solubility of ADEF in gastric acid appears to be a critical factor for achieving successful treatment. Consequently, ADEF could be considered a promising candidate for H. pylori therapy.

Physiologically-based pharmacokinetic modelling to predict intragastric rifabutin concentrations in the treatment of Helicobacter pylori infection

BACKGROUND

Sustained intragastric antibiotic exposure is important for Helicobacter pylori eradication, yet little is known about gastric pharmacology of commonly used H. pylori regimens. For rifabutin, differing intragastric concentrations based on dosing regimen may account for differences in reported eradication rates.

AIM

To compare intragastric rifabutin concentrations between low-dose rifabutin (50 mg three time daily; as in RHB-105) and generically dosed rifabutin 150 mg once daily, 150 mg twice daily, and 300 mg once daily using a validated Physiologically-based pharmacokinetic (PBPK) model.

METHODS

We obtained plasma pharmacokinetic data from the RHB-105 clinical development programs and used it to develop and validate a whole-body PBPK model using PK-SIM software. We modified the existing rifabutin model to include the impact of omeprazole on gastric pH and emptying time. Modelled intragastric rifabutin exposure was expressed as the time that each regimen maintained its concentration ≥MIC90 .

RESULTS

Rifabutin 50 mg three times daily achieved significantly longer times with intragastric concentration above MIC90 (22.3 ± 1.1 h) than 150 mg once daily (8.3 ± 1.7 h), 150 mg twice daily (16.3 ± 2.3 h), or 300 mg once daily (8.5 ± 1.9 h) while providing the lowest mean maximal plasma concentration and mean area under the plasma concentration-time curve of all regimens studied.

CONCLUSIONS

PBPK modelling showed rifabutin 50 mg three times daily had higher intragastric exposure times than 150 mg once daily or twice daily, or 300 mg once daily. This low-dose rifabutin regimen provides the highest potential for H. pylori eradication while minimising systemic rifabutin exposure.

Advances in the pharmacological and regulatory management of multidrug resistant Helicobacter pylori

INTRODUCTION

Antibiotic resistance of Helicobacter pylori (H. pylori) hampers the success of eradication and in recent years multidrug resistance (MDR) shows an increase worldwide.

AREAS COVERED

This review covers current aspects of pharmacological and regulatory management of MDR-resistant H. pylori infection.

EXPERT OPINION

MDR H. pylori is increasing worldwide and its prevalence varies both between continents and countries. High consumption and misuse of antibiotics, H. pylori treatment failures and bacterial factors such as mutations, efflux pumps and biofilms are among the factors associated with MDR. Important steps for confronting the rise of MDR H. pylori strains should follow the principles of antibiotic stewardship, i.e. eradication regimens should be optimized with regard to all aspects of therapy, including drugs, doses, formulation, frequency of administration, administration in relation to meals and duration of therapy that reliably achieve at least 90% (preferably >95%) cure rates in adherent patients with susceptible infections.

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

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

Helicobacter pylori infection

Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated. The infection affects around half of the population in the world but prevalence varies according to location and sanitation standards. H. pylori has unique properties to colonize gastric epithelium in an acidic environment. The pathophysiology of H. pylori infection is dependent on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors, resulting in distinct gastritis phenotypes that determine possible progression to different gastroduodenal pathologies. The causative role of H. pylori infection in gastric cancer development presents the opportunity for preventive screen-and-treat strategies. Invasive, endoscopy-based and non-invasive methods, including breath, stool and serological tests, are used in the diagnosis of H. pylori infection. Their use depends on the specific individual patient history and local availability. H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship.

DEVELOPMENT OF APIGENIN LOADED GASTRORETENTIVE MICROSPONGE FOR THE TARGETING OF HELICO BACTER PYLORI

The goal of the present work was to invent an apigenin-stacked gastroretentive microsponge to target H. pylori. The quasi-emulsion technique was used to prepare microsponges, which were then tested for various physicochemical properties, in-vivo gastric retention, and in-vitro anti-H. pylori study. The microsponge that demonstrated a comparatively good product yield (76.23 ± 0.84), excellent entrapment efficiency (97.84 ± 0.85), sustained in-vitro gastric retention period, and prolonged drug release were chosen for further investigations. The microsponge's SEM analysis showed that it had a spherical form, porous surface, and interconnected spaces. No drug-polymer interactions were detected in the FTIR investigation. Apigenin was found to be dispersed in the microsponge's polymeric matrix according to DSC & XRD investigations. Moreover, the microsponge in the rat's stomach floated for 4 h, according to the ultrasonography. The antibacterial activity of apigenin against H. pylori was nearly two folds more than the pure apigenin and had a more sustained release in the best microsponge, according to the in vitro MIC data, when compared to pure apigenin. To sum up, the developed gastroretentive microsponge with apigenin offers a viable alternative for the efficient targeting of H. pylori. But more preclinical & clinical studies of our best microsponge would yield considerably more fruitful results.

Effectiveness of first and second-line empirical treatment in Italy: Results of the European registry on Helicobacter pylori management

BACKGROUND AND AIMS

The optimal management of naïve and not naïve Helicobacter pylori patients remains unclear. Therefore, it is essential to evaluate whether the actual clinical practice mirrors the indications suggested by the guidelines. This study aimed to assess the effectiveness and the safety of the empirical first- and second-line treatments prescribed to patients enroled at Italian centres participating in the European Registry on H. pylori Management (Hp-EuReg).

METHODS

The Hp-EuReg is an international multicentre prospective non-interventional registry starting in 2013 aiming to evaluate the management of H. pylori infection by European gastroenterologists. Patients were registered in an e-CRF by AEG-REDCap. Variables assessed included demographics, previous eradication attempts, treatment regimen, effectiveness, and tolerance.

RESULTS

Overall, 3723 patients from 2013 to February 2021 were included: 2996 and 727 received an empirical first- and second-line treatment, respectively. According to the modified ITT analysis, among the first-line regimens, only the bismuth quadruple therapy with three-in-one-single capsule (BQT-TSC), the concomitant, and the sequential treatment - all lasting 10 days - achieved an eradication rate >90%. Among the second-line regimens, only the 10-day BQT-TSC reported an effectiveness >90%. High-dose PPI twice daily also significantly increased the effectiveness of some therapies. The BQT-TSC was the regimen with the highest incidence of adverse events.

CONCLUSIONS

Only quadruple therapies lasting at least 10 days achieved over 90% eradication rates among the empirical first- and second-line regimens. It remains unclear whether high-dose PPI twice daily can improve the efficacy of quadruple treatment.

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.

Empirical rescue treatment of Helicobacter pylori infection in third and subsequent lines: 8-year experience in 2144 patients from the European Registry on H. pylori management (Hp-EuReg)

OBJECTIVE

To evaluate the use, effectiveness and safety of Helicobacter pylori empirical rescue therapy in third and subsequent treatment lines in Europe.

DESIGN

International, prospective, non-interventional registry of the clinical practice of European gastroenterologists. Data were collected and quality reviewed until October 2021 at Asociación Española de Gastroenterología-Research Electronic Data Capture. All cases with three or more empirical eradication attempts were assessed for effectiveness by modified intention-to-treat and per-protocol analysis.

RESULTS

Overall, 2144 treatments were included: 1519, 439, 145 and 41 cases from third, fourth, fifth and sixth treatment lines, respectively. Sixty different therapies were used; the 15 most frequently prescribed encompassed >90% of cases. Overall effectiveness remained <90% in all therapies. Optimised treatments achieved a higher eradication rate than non-optimised (78% vs 67%, p<0.0001). From 2017 to 2021, only 44% of treatments other than 10-day single-capsule therapy used high proton-pump inhibitor doses and lasted ≥14 days. Quadruple therapy containing metronidazole, tetracycline and bismuth achieved optimal eradication rates only when prescribed as third-line treatment, either as 10-day single-capsule therapy (87%) or as 14-day traditional therapy with tetracycline hydrochloride (95%). Triple amoxicillin-levofloxacin therapy achieved 90% effectiveness in Eastern Europe only or when optimised. The overall incidence of adverse events was 31%.

CONCLUSION

Empirical rescue treatment in third and subsequent lines achieved suboptimal effectiveness in most European regions. Only quadruple bismuth-metronidazole-tetracycline (10-day single-capsule or 14-day traditional scheme) and triple amoxicillin-levofloxacin therapies reached acceptable outcomes in some settings. Compliance with empirical therapy optimisation principles is still poor 5 years after clinical practice guidelines update.

TRIAL REGISTRATION NUMBER

NCT02328131.

The key statements of the Maastricht VI consensus

An analysis of the most important changes and provisions of the Maastricht VI consensus published in August 2022 is presented. 41 experts from 29 countries took part in the creation of the consensus. Recommendations have been developed in five areas: (1) indications for treatment and clinical associations of Helicobacter pylori (H. pylori) infection, (2) diagnosis, (3) treatment, (4) prevention of gastric cancer, (5) H. pylori and gastric microbiota -intestinal tract (GIT), taking into account the level of evidence and the strength of recommendations. Emphasis is placed on molecular testing, which is becoming an increasingly accessible research method in the world to identify both H. pylori itself and its sensitivity to antibiotics. The growing resistance of H. pylori strains to previously effective antibacterial agents requires a treatment strategy that implies the ability to determine the sensitivity of H. pylori to antibacterial agents both in the population and in a particular individual. The use of modern diagnostic tests expands the possibilities of individualization of therapy, since it allows determining not only the presence of H. pylori in the gastric mucosa, but also the sensitivity of the infection to antibacterial drugs. Along with individual approaches to treatment, the most effective empirical therapy regimens are given in case of impossibility to determine individual resistance to antibiotics. New data on the effectiveness and results of the use of primary and secondary preventive strategies for gastric cancer are presented. Given the important role of the entire microbiome of the gastrointestinal tract in the functioning of the body, the question of the interaction of H. pylori with other microorganisms is discussed. The critical issues of the near future are related to the global prevention of gastric cancer; the need to control antibiotic resistance, and the development of new methods of therapy and prevention of Helicobacter pylori infection.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

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.

Efficacy and safety of low-dose rifabutin-based 7-day triple therapy as a third- or later-line Helicobacter pylori eradication regimen

BACKGROUND

Rifabutin-based regimens are used as rescue therapy for refractory Helicobacter pylori infection; however, the duration for which treatment is required and side effects are concerning. This study assessed the efficacy and safety of 7-day rifabutin, amoxicillin, and vonoprazan triple therapy as third- or later-line treatment for H. pylori infection.

MATERIALS AND METHODS

Patients who did not respond to second-line therapy were enrolled. After H. pylori infection was confirmed with the culture method, the patients received rifabutin-containing triple therapy (20 mg vonoprazan b.i.d., 500 mg amoxicillin q.i.d., and 150 mg rifabutin q.d.) for 7 days. Twelve weeks after the eradication therapy, successful eradication was confirmed using a ¹³ C urea breath test or the H. pylori stool antigen test. The results obtained from our previous study that reported a 10-day or 14-day esomeprazole based rifabutin-containing triple therapy as a third- or fourth-line rescue therapy treated patients were used as historical control. We determined the minimum inhibitory concentrations of amoxicillin and rifabutin. We also evaluated whether the patients were positive for the mutation of the rpoB gene.

RESULTS

Intention-to-treat and per-protocol analyses showed that our regimen resulted in a high eradication rate (91.2%, 95% CI: 84%-99% and 92.7%, 95% CI: 86%-100%, respectively). Adverse events occurred in 31.6% of the patients, and two patients discontinued the therapy.

CONCLUSIONS

This is the first study to evaluate the efficacy and safety of a 7-day low-dose rifabutin-based triple therapy with vonoprazan and amoxicillin. Our results suggest that our regimen was effective and safe as a third- or later-line H. pylori eradication regimen. To clarify what component in this regimen are critical, subsequent studies using a factorial design (comparing vonoprazan-amoxicillin dual therapy vs. vonoprazan-rifabutin triple therapy) will be needed.

Beyond the approved: target sites and inhibitors of bacterial RNA polymerase from bacteria and fungi

Covering: 2016 to 2022RNA polymerase (RNAP) is the central enzyme in bacterial gene expression representing an attractive and validated target for antibiotics. Two well-known and clinically approved classes of natural product RNAP inhibitors are the rifamycins and the fidaxomycins. Rifampicin (Rif), a semi-synthetic derivative of rifamycin, plays a crucial role as a first line antibiotic in the treatment of tuberculosis and a broad range of bacterial infections. However, more and more pathogens such as Mycobacterium tuberculosis develop resistance, not only against Rif and other RNAP inhibitors. To overcome this problem, novel RNAP inhibitors exhibiting different target sites are urgently needed. This review includes recent developments published between 2016 and today. Particular focus is placed on novel findings concerning already known bacterial RNAP inhibitors, the characterization and development of new compounds isolated from bacteria and fungi, and providing brief insights into promising new synthetic compounds.

V Spanish Consensus Conference on Helicobacter pylori infection treatment

Helicobacter pylori infection is very common in the Spanish population and represents the main cause of chronic gastritis, peptic ulcer, and gastric cancer. The last iteration of Spanish consensus guidelines on H. pylori infection was conducted in 2016. Recent changes in therapeutic schemes along with increasing supporting evidence were key for developing the V Spanish Consensus Conference (May 2021). Fourteen experts performed a systematic review of the scientific evidence and developed a series of recommendations that were subjected to an anonymous Delphi process of iterative voting. Scientific evidence and the strength of the recommendation were classified using GRADE guidelines. An eradication therapy, when prescribed empirically, is considered acceptable when it reliably achieves, or preferably surpass, 90% cure rates. Currently, only quadruple therapies (with or without bismuth) and generally lasting 14 days, accomplish this goal in first- and second-line therapies. A non-bismuth quadruple concomitant regimen (proton pump inhibitor, clarithromycin, amoxicillin, and metronidazole) or a quadruple bismuth-based combination (proton pump inhibitor, bismuth, tetracycline, and metronidazole), are recommended as first-line regimens. Rescue therapies after eradication failure and management of H. pylori infection in peptic ulcer disease were also reviewed.

Overcoming Mycobacterium tuberculosis through small molecule inhibitors to break down cell wall synthesis

Mycobacterium tuberculosis (MTB) utilizes multiple mechanisms to obtain antibiotic resistance during the treatment of infections. In addition, the biofilms, secreted by MTB, can further protect the latter from the contact with drug molecules and immune cells. These self-defending mechanisms lay a formidable challenge to develop effective therapeutic agents against chronic and recurring antibiotic-tolerant MTB infections. Although several inexpensive and effective drugs (isoniazid, rifampicin, pyrazinamide and ethambutol) have been discovered for the treatment regimen, MTB continues to cause considerable morbidity and mortality worldwide. Antibiotic resistance and tolerance remain major global issues, and innovative therapeutic strategies are urgently needed to address the challenges associated with pathogenic bacteria. Gratifyingly, the cell wall synthesis of tubercle bacilli requires the participation of many enzymes which exclusively exist in prokaryotic organisms. These enzymes, absent in human hepatocytes, are recognized as promising targets to develop anti-tuberculosis drug. In this paper, we discussed the critical roles of potential drug targets in regulating cell wall synthesis of MTB. And also, we systematically reviewed the advanced development of novel bioactive compounds or drug leads for inhibition of cell wall synthesis, including their discovery, chemical modification, in vitro and in vivo evaluation.

Exploration of the molecular mechanisms underlying the antibiotic resistance of Helicobacter pylori: A whole-genome sequencing-based study in Southern China

BACKGROUND

Although antimicrobial resistance (AMR) in Helicobacter pylori is a global threat to human health and the underlying molecular mechanisms have been explored previously, only a few of them are fully elucidated.

MATERIALS AND METHODS

In the present study, we isolated 54 Helicobacter pylori strains from Southern China and assessed their susceptibility to five antibiotics using the agar dilution assay. Whole-genome sequencing was performed to screen the AMR genotypes of the Helicobacter pylori isolates.

RESULTS

Our study revealed a high prevalence of resistance to clarithromycin (CLR), levofloxacin (LVX), and metronidazole (MTZ) in the Chinese isolates, 55.56% of which showed multidrug-resistant phenotypes. We screened for the 94 types of previously reported AMR mutations in 12 genes, but only a few of them were related to the AMR phenotype. Furthermore, we discovered four new mutations in the 23S rRNA gene and one mutation in infB related to CLR resistance. Another three mutations in gyrA and one in gyrB were closely correlated with the AMR pattern against LVX. We also demonstrated that the mutations R16C/H in rdxA, V56I in rpsU, and D54A in sodB might contribute to resistance to MTZ, which were previously reported in laboratory experiments but not found in clinical strains. We examined the concordance between the genotype and phenotype of AMR and identified several potential molecular biomarkers for predicting CLR and LVX resistance.

CONCLUSIONS

Our study explored the molecular mechanisms underlying the antibiotic resistance of Helicobacter pylori isolates from Southern China. We propose further epidemiologic investigations in China.

Experience with Rifabutin-Containing Therapy in 500 Patients from the European Registry on Helicobacter pylori Management (Hp-EuReg)

BACKGROUND

First-line Helicobacter pylori (H. pylori) treatments have been relatively well evaluated; however, it remains necessary to identify the most effective rescue treatments. Our aim was to assess the effectiveness and safety of H. pylori regimens containing rifabutin.

METHODS

International multicentre prospective non-interventional European Registry on H. pylori Management (Hp-EuReg). Patients treated with rifabutin were registered in AEG-REDCap e-CRF from 2013 to 2021. Modified intention-to-treat and per-protocol analyses were performed. Data were subject to quality control.

RESULTS

Overall, 500 patients included in the Hp-EuReg were treated with rifabutin (mean age 52 years, 72% female, 63% with dyspepsia, 4% with peptic ulcer). Culture was performed in 63% of cases: dual resistance (to both clarithromycin and metronidazole) was reported in 46% of the cases, and triple resistance (to clarithromycin, metronidazole, and levofloxacin) in 39%. In 87% of cases rifabutin was utilised as part of a triple therapy together with amoxicillin and a proton-pump-inhibitor, and in an additional 6% of the patients, bismuth was added to this triple regimen. Rifabutin was mainly used in second-line (32%), third-line (25%), and fourth-line (27%) regimens, achieving overall 78%, 80% and 66% effectiveness by modified intention-to-treat, respectively. Compliance with treatment was 89%. At least one adverse event was registered in 26% of the patients (most frequently nausea), and one serious adverse event (0.2%) was reported in one patient with leukopenia and thrombocytopenia with fever requiring hospitalisation.

CONCLUSION

Rifabutin-containing therapy represents an effective and safe strategy after one or even several failures of H. pylori eradication treatment.

Pitfalls of Physician-Directed Treatment of Helicobacter pylori: Results from Two Phase 3 Clinical Trials and Real-World Prescribing Data

BACKGROUND

Helicobacter pylori (H. pylori) infects ~ 35% of Americans and can lead to serious sequelae if left untreated. Growing evidence indicates that clarithromycin-based therapies (CBT) are becoming increasingly ineffective for treating H. pylori infection. RHB-105 was approved by the US Food and Drug Administration in 2019 for the treatment of H. pylori infection in adults.

AIMS

The primary aim of this study was to assess prescribing patterns and associated cure rates of physician-directed therapy for subjects with persistent H. pylori infection after participation in one of two Phase 3 clinical trials (ERADICATE Hp and ERADICATE Hp2).

METHODS

We reviewed study reports to identify specific physician-directed regimens selected for subjects whose H. pylori infection was not eradicated. We also conducted a CYP2C19 genotype analysis of subjects who were prescribed CBT. Finally, we analyzed real-world H. pylori retail prescription data and compared these with to the physician-directed therapies in the clinical trials studies.

RESULTS

Following ERADICATE Hp, CBT was prescribed for 27/31 (87%) subjects achieving a 59.3% cure rate. Following ERADICATE Hp2, CBT was prescribed for 48/94 (51%) subjects achieving a 60.4% cure rate. Rapid CYP2C19 metabolizers (2/11) had a cure rate of 18.2% with CBT. Real-world prescription data from IQVIA showed more than 80% of prescriptions for H. pylori infection were for CBT.

CONCLUSIONS

Rates of CBT use persist despite sub-optimal eradication rates. Since RHB-105 does not contain clarithromycin, it can be prescribed first-line without concerns about clarithromycin resistance or CYP2C19 status. NCT03198507 & NCT01980095.

Helicobacter pylori diagnosis and therapy in the era of antimicrobial stewardship

The diagnosis and therapy of Helicobacter pylori infection have undergone major changes based on the use the principles of antimicrobial stewardship and increased availability of susceptibility profiling. H. pylori gastritis now recognized as an infectious disease, as such there is no placebo response allowing outcome to be assessed in relation to the theoretically obtainable cure rate of 100%. The recent recognition of H. pylori as an infectious disease has changed the focus to therapies optimized to reliably achieve high cure rates. Increasing antimicrobial resistance has also led to restriction of clarithromycin, levofloxacin, or metronidazole to susceptibility-based therapies. Covid-19 resulted in the almost universal availability of polymerase chain reaction testing in hospitals which can be repurposed to utilize readily available kits to provide rapid and inexpensive detection of clarithromycin resistance. In the United States, major diagnostic laboratories now offer H. pylori culture and susceptibility testing and American Molecular Laboratories offers next-generation sequencing susceptibility profiling of gastric biopsies or stools for the six commonly used antibiotics without need for endoscopy. Current treatment recommendations include (a) only use therapies that are reliably highly effective locally, (b) always perform a test-of-cure, and (c) use that data to confirm local effectiveness and share the results to inform the community regarding which therapies are effective and which are not. Empiric therapy should be restricted to those proven highly effective locally. The most common choices are 14-day bismuth quadruple therapy and rifabutin triple therapy. Prior guidelines and treatment recommendations should only be used if proven locally highly effective.

Rescue Therapy with Furazolidone in Patients with at Least Five Eradication Treatment Failures and Multi-Resistant H. pylori infection

Helicobacter pylori infection may persist after multiple eradication treatments. The aim of this study was to evaluate the efficacy and safety of a furazolidone-based rescue regimen in hyper-refractory patients. A unicentre, prospective study was designed. Patients in whom five or more treatments had consecutively failed were included. All patients had previously received bismuth and key antibiotics, such as amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline, and rifabutin, and had positive H. pylori culture, demonstrating resistance to clarithromycin, metronidazole, and levofloxacin. A quadruple regimen with furazolidone (200 mg), amoxicillin (1 g), bismuth (240 mg), and esomeprazole (40 mg) was prescribed twice a day for 14 days. Eradication was confirmed by the stool antigen test. Compliance was determined through questioning, and adverse effects using a questionnaire. Eight patients (mean age 56 years, 63% men, 38% peptic ulcer disease, 12% gastric cancer precursor lesions, and 50% functional dyspepsia) were included. Per-protocol and intention-to-treat eradication rates were 63%. Compliance was 100%. Adverse effects were reported in two (25%) patients, and all were mild. Even after five or more previous H. pylori eradication failures, and a multi-resistant infection, rescue treatment with furazolidone may be effective in approximately two-thirds of the cases, constituting a valid strategy after multiple previous eradication failures with key antibiotics such as clarithromycin, metronidazole, tetracycline, levofloxacin, and rifabutin.

Next Generation Sequencing for the Prediction of the Antibiotic Resistance in Helicobacter pylori: A Literature Review

Background and aims: Only a few antimicrobials are effective against H. pylori, and antibiotic resistance is an increasing problem for eradication therapies. In 2017, the World Health Organization categorized clarithromycin resistant H. pylori as a "high-priority" bacterium. Standard antimicrobial susceptibility testing can be used to prescribe appropriate therapies but is currently recommended only after the second therapeutic failure. H. pylori is, in fact, a "fastidious" microorganism; culture methods are time-consuming and technically challenging. The advent of molecular biology techniques has enabled the identification of molecular mechanisms underlying the observed phenotypic resistance to antibiotics in H. pylori. The aim of this literature review is to summarize the results of original articles published in the last ten years, regarding the use of Next Generation Sequencing, in particular of the whole genome, to predict the antibiotic resistance in H. pylori.Methods: a literature research was made on PubMed. The research was focused on II and III generation sequencing of the whole H. pylori genome. Results: Next Generation Sequencing enabled the detection of novel, rare and complex resistance mechanisms. The prediction of resistance to clarithromycin, levofloxacin and amoxicillin is accurate; for other antimicrobials, such as metronidazole, rifabutin and tetracycline, potential genetic determinants of the resistant status need further investigation.