The challenge of Helicobacter pylori resistance to antibiotics: the comeback of bismuth-based quadruple therapy

Antimicrobial activity of Southern African medicinal plants on Helicobacter pylori and Lactobacillus species

ETHNOPHARMACOLOGICAL RELEVANCE

Numerous medicinal plants have been used traditionally in South Africa for gastric ulcer treatment. Helicobacter pylori is known for causing inflammation and the onset of gastric ulcers. While several studies explored medicinal plants against H. pylori, investigation of medicinal plants used for gastric ulcers has been neglected, as well as the effects these plants would have on bacteria occurring naturally in the gut microbiome.

AIM OF THE STUDY

This study aimed to investigate Southern African medicinal plants used traditionally for treating gastric ulcers against H. pylori , as well as the effects that these plants have when combined with Lactobacillus species and tested against H. pylori.

METHODOLOGY

Based on evidence from the ethnobotanical literature, 21 plants were collected. Their antimicrobial activity was assessed against five clinical H. pylori strains, and in combination with each of three Lactobacillus species, using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) broth microdilution assays. Toxicity was assessed using the brine shrimp lethality assay.

RESULTS

Noteworthy activity was observed against at least one H. pylori strain for 12 plant species. The lowest mean MICs were from organic extracts of Carissa edulis Vahl (0.18 mg/mL) and Chironia baccifera L. (0.20 mg/mL), and aqueous extracts of Sansevieria hyacinthoides (L.) Druce (0.26 mg/mL) and Dodonaea viscosa Jacq. (0.30 mg/mL). Aqueous extracts of the investigated plants were combined with Lactobacillus species, and the majority of combinations showed increased antimicrobial activity compared with the extracts alone. Combinations of Lactobacillus rhamnosus with 18 of the 21 aqueous plant extracts showed at least a two-fold decrease in the mean MBC against all H. pylori strains tested. Lactobacillus acidophilus combined with either Protea repens L., Carpobrotus edulis (L.) L. Bolus or Warburgia salutaris (Bertol.f.) Chiov. aqueous extracts had the best anti-H. pylori activity (mean MBCs of 0.10 mg/mL for each combination). Only four organic and one aqueous extract(s) were considered toxic.

CONCLUSION

These results highlight the potential of medicinal plants to inhibit H. pylori growth and their role in traditional treatments for the management of ulcers. The results also indicate that aqueous extracts of these plants do not hinder the growth of bacteria that occur naturally in the gut microbiome and play a role in maintaining gut health, as well as show the potential benefit of including Lactobacillus species as potentiators of H. pylori activity.

The multicenter real-world report of the efficacies of 14-day esomeprazole-based and rabeprazole-based high-dose dual therapy in first-line Helicobacter pylori eradication in Taiwan

BACKGROUND

High-dose dual therapy (HDDT) using proton-pump inhibitors (PPI) and amoxicillin attracted attention for its simplicity and lower adverse event profile. Besides, vonoprazan is not available worldwide. This real-world study aims to compare the efficacy of esomeprazole-based and rabeprazole-based HDDT regimens and to identify clinical factors influencing outcomes.

METHODS

A retrospective study enrolled 346 Helicobacter pylori-infected naïve patients from January 2016 to August 2023. Patients were assigned to either a 14-day esomeprazole-based HDDT (EA-14; esomeprazole 40 mg t.i.d. and amoxicillin 750 mg q.i.d. for 14 days, n = 173) or a 14-day rabeprazole-based HDDT (RA-14; rabeprazole 20 mg and amoxicillin 750 mg q.i.d. for 14 days, n = 173).

RESULTS

Five patients from the EA-14 group and 10 from the RA-14 group were lost to follow-up, resulting in 168 and 163 patients for the per-protocol (PP) analysis, respectively. Eradication rates for the EA-14 and RA-14 groups were 90.2% and 80.9% (P = 0.014) in intention-to-treat (ITT) analysis; and 92.9% and 85.9% (P = 0.039) in PP analysis. Adverse event rates were similar between the two groups (11.9% vs 11.7%, P = 0.944). In multiple logistic regression analysis, age≧60 was associated with eradication failure (P = 0.046) and a trend of significance for smoking (P = 0.060) in the EA-14 group but not in the RA-14 group. A trend of significance was also observed for eradication regimens (EA-14 vs RA-14) (P = 0.071). The antibiotic resistance rates were amoxicillin (2.3%), clarithromycin (14.7%), metronidazole (40.3%), and dual resistance to clarithromycin and metronidazole (7.0%).

CONCLUSIONS

Esomeprazole-based HDDT achieved over 90% eradication rates but rabeprazole-based HDDT, which failed.

The mechanisms of metronidazole resistance of Helicobacter pylori: A transcriptomic and biochemical study

Helicobacter pylori (H. pylori) is a bacterial pathogen in the stomach, causing gastritis, gastric ulcer, duodenal ulcer and even gastric cancer. The triple therapy containing one bismuth-containing compound or a proton-pump inhibitor with two antibiotics was the cornerstone of the treatment of H. pylori infections. However the drug resistance of Helicobacter pylori is more and more common, which leads to the continued decline in the radical cure rate. The purpose of this study was to investigate the mechanism of metronidazole resistance of H. pylori through transcriptomics and biochemical characterizations. In this study, a 128-time-higher metronidazole-resistant H. pylori strain compared to the sensitive strain was domesticated, and 374 significantly differential genes were identified by transcriptomic sequencing as compared to the metronidazole-sensitive strain. Through GO and KEGG enrichment analysis, antibiotic-resistance pathways were found to be mainly involved in redox, biofilm formation and ABC transportation, and the results were verified by qRT-PCR. The subsequent biochemical analysis found that the urease activity of the drug-resistant strain decreased, and whereas the capabilities of bacterial energy production, membrane production and diffusion ability increased. The work here will drop hints for the mechanisms of antibiotic-resistance of H. pylori and provide promising biomarkers for the further development of new-kind drugs to treat metronidazole-resistant H. pylori.

Helicobacter Pylori: A Review of Current Treatment Options in Clinical Practice

BACKGROUND

When prescribing antibiotics, infection eradication rates, local resistance rates, and cost should be among the most essential considerations. Helicobacter pylori is among the most common infections worldwide, and it can lead to burdensome sequela for the patient and the healthcare system, without appropriate treatment. Due to constantly fluctuating resistance rates, regimens must be constantly assessed to ensure effectiveness.

METHODS

This was a narrative review. The sources for this review are as follows: searching on PubMed, Google Scholar, Medline, and ScienceDirect; using keywords: Helicobacter pylori, Treatment Options, Clinical Practice.

RESULTS

Multiple antibiotics are prescribed as part of the regimen to thwart high resistance rates. This can lead to unwanted adverse reactions and adherence issues, due to the amount and timing of medication administration, which also may contribute to resistance. Single-capsule combination capsules have reached the market to ease this concern, but brand-only may be problematic for patient affordability. Due to the previously mentioned factors, effectiveness and affordability must be equally considered.

CONCLUSIONS

This review will utilize guidelines to discuss current treatment options and give cost considerations to elicit the most effective regimen for the patient.

Empirical Second-Line Therapy in 5000 Patients of the European Registry on Helicobacter pylori Management (Hp-EuReg)

BACKGROUND & AIMS

After a first Helicobacter pylori eradication attempt, approximately 20% of patients will remain infected. The aim of the current study was to assess the effectiveness and safety of second-line empiric treatment in Europe.

METHODS

This international, multicenter, prospective, non-interventional registry aimed to evaluate the decisions and outcomes of H pylori management by European gastroenterologists. All infected adult cases with a previous eradication treatment attempt were registered with the Spanish Association of Gastroenterology-Research Electronic Data Capture until February 2021. Patients allergic to penicillin and those who received susceptibility-guided therapy were excluded. Data monitoring was performed to ensure data quality.

RESULTS

Overall, 5055 patients received empiric second-line treatment. Triple therapy with amoxicillin and levofloxacin was prescribed most commonly (33%). The overall effectiveness was 82% by modified intention-to-treat analysis and 83% in the per-protocol population. After failure of first-line clarithromycin-containing treatment, optimal eradication (>90%) was obtained with moxifloxacin-containing triple therapy or levofloxacin-containing quadruple therapy (with bismuth). In patients receiving triple therapy containing levofloxacin or moxifloxacin, and levofloxacin-bismuth quadruple treatment, cure rates were optimized with 14-day regimens using high doses of proton pump inhibitors. However, 3-in-1 single capsule or levofloxacin-bismuth quadruple therapy produced reliable eradication rates regardless of proton pump inhibitor dose, duration of therapy, or previous first-line treatment. The overall incidence of adverse events was 28%, and most (85%) were mild. Three patients developed serious adverse events (0.3%) requiring hospitalization.

CONCLUSIONS

Empiric second-line regimens including 14-day quinolone triple therapies, 14-day levofloxacin-bismuth quadruple therapy, 14-day tetracycline-bismuth classic quadruple therapy, and 10-day bismuth quadruple therapy (as a single capsule) provided optimal effectiveness. However, many other second-line treatments evaluated reported low eradication rates. ClincialTrials.gov number: NCT02328131.

Review on Plant-Based Management in Combating Antimicrobial Resistance - Mechanistic Perspective

Antimicrobial resistance (AMR) occurs when microbes no longer respond to any pharmacological agents, rendering the conventional antimicrobial agents ineffective. AMR has been classified as one of the top 10 life-threatening global health problems needed multilevel attention and global cooperation to attain the Sustainable Development Goals (SDGs) according to the World Health Organization (WHO), making the discovery of a new and effective antimicrobial agent a priority. The recommended treatments for drug-resistant microbes are available but limited. Furthermore, the transformation of microbes over time increases the risk of developing drug resistance. Hence, plant metabolites such as terpenes, phenolic compounds and alkaloids are widely studied due to their antibacterial, antiviral, antifungal and antiparasitic effects. Plant-derived antimicrobials are preferred due to their desirable efficacy and safety profile. Plant metabolites work by targeting microbial cell membranes, interfering with the synthesis of microbial DNA/RNA/enzymes and disrupting quorum sensing and efflux pump expression. They also work synergistically with conventional antibiotics to enhance antimicrobial effects. Accordingly, this review aims to identify currently available pharmacological therapies against microbes and AMR, as well as to discuss the importance of plant and secondary metabolites as a possible solution for AMR together with their mechanisms of action. All the information was obtained from government databases, WHO websites, PubMed, Springer, Google Scholar and Science Direct. Based on the information obtained, AMR is regarded as a significant warning to global healthcare. Plant derivatives such as secondary metabolites may be considered as potential therapeutic targets to mitigate the non-ending AMR.

Ni+2 permease system of Helicobacter pylori contains highly conserved G-quadruplex motifs

The genome of a micro-organism contains all the information required for its survival inside its host cells. The guanine rich regions of the genome can form stable G-quadruplex structures that act as the regulators of gene expression. Herein, the completely sequenced genomes of Helicobacter pylori were explored for the identification and characterization of the conserved G-quadruplex motifs in this gastrointestinal pathogen. Initial in silico analysis revealed the presence of ~8241 GQ motifs in the H. pylori genome. Metal binding proteins of H. pylori are significantly enriched in the GQ motifs. Our study emphasizes the identification and characterization of four highly conserved G-quadruplex forming motifs (HPGQs) in the nickel transporter genes (nixA, niuB1, niuB2, and niuD) of the H. pylori. Nickel is a virulence determinant in H. pylori and is required as a co-factor for the urease and [NiFe] hydrogenase enzymes that are crucial for its survival in the stomach lining of humans. The presence of GQ motifs in these nickel transporter genes can affect their expression and may alter the functioning of Urease and [NiFe] hydrogenase. Similar to human and virus G-quadruplexes, targeting these conserved PGQs with bioactive molecules may represent a novel therapeutic avenue for combating infection of H. pylori. The identified HPGQs were characterized in-vitro by using CD spectroscopy, electrophoresis technique, and NMR spectroscopy at both acidic (4.5) and neutral pH (7.0). ITC revealed the specific interaction of these HPGQs with high affinity to the known G-quadruplex binding ligand, TMPyP4. The mTFP based reporter assay showed decrease in the gene expression of mTFP in the TMPyP4 treated cells as compared to the untreated and further affirmed the formation of stable G-quadruplex structures in the HPGQ motifs in vivo. This is the first report for characterizing G-quadruplex motifs in nickel transport-associated genes in the H. pylori bacterium.

Genotypic detection of metronidazole and clarithromycin resistance in dyspeptic patients with helicobacter pylori

In Egypt, antibiotic sensitivity analysis for Helicobacter pylori is not routinely performed. We aimed to identify the clarithromycin and metronidazole resistance directly from gastric biopsies for better guide treatment regimens. This cross-sectional descriptive study included 75 adult dyspeptic patients referred to the upper endoscopy unit in Suez Canal University Hospital, Ismailia, Egypt. Gastric biopsies were taken for rapid urease test (RUT) and cultured on brucella agar with antibiotic supplements. Genomic DNA was extracted directly from the specimen, and PCR was performed for direct detection of H. pylori. Also, to explore clarithromycin and metronidazole resistance, mutations in the 23S rRNA gene and the rdxA gene were investigated. We found that 60 samples were positive to RUT (80%), and only 4 samples were positive by culture. UreC gene was detected in 45 specimens. Meanwhile, 26 isolates were contained mutations at positions 2142 and 2143. Amplification of the metronidazole rdx gene was performed by conventional PCR. Out of 45 isolates, DNA sequence analysis of PCR product showed the wild type (ACA) in 9 isolates, while the mutant type (ATA) was detected in 28 isolates. We found a significant proportion of clarithromycin and metronidazole resistance among H. pylori infected patients in our region.

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.

Nickel, an essential virulence determinant of Helicobacter pylori: Transport and trafficking pathways and their targeting by bismuth

Metal acquisition and intracellular trafficking are crucial for all cells and metal ions have been recognized as virulence determinants in bacterial pathogens. Nickel is required for the pathogenicity of H. pylori. This bacterial pathogen colonizes the stomach of about half of the human population worldwide and is associated with gastric cancer that is responsible for 800,000 deaths per year. H. pylori possesses two nickel-enzymes that are essential for in vivo colonization, a [NiFe] hydrogenase and an abundant urease responsible for resistance to gastric acidity. Because of these two enzymes, survival of H. pylori relies on an important supply of nickel, implying tight control strategies to avoid its toxic accumulation or deprivation. H. pylori possesses original mechanisms for nickel uptake, distribution, storage and trafficking that will be discussed in this review. During evolution, acquisition of nickel transporters and specific nickel-binding proteins has been a decisive event to allow Helicobacter species to become able to colonize the stomach. Accordingly, many of the factors involved in these mechanisms are required for mouse colonization by H. pylori. These mechanisms are controlled at different levels including protein interaction networks, transcriptional, post-transcriptional and post-translational regulation. Bismuth is another metal used in combination with antibiotics to efficiently treat H. pylori infections. Although the precise mode of action of bismuth is unknown, many targets have been identified in H. pylori and there is growing evidence that bismuth interferes with the essential nickel pathways. Understanding the metal pathways will help improve treatments against H. pylori and other pathogens.

Levofloxacin-based therapy as an efficient alternative for eradicating Helicobacter pylori infection in Iran: a systematic review and meta-analysis

OBJECTIVES

Despite excessive resistance of Helicobacter pylori to clarithromycin among Iranian population, unfortunately, clarithromycin-based therapy is still prescribed in Iran. Recent studies have shown high rates of H. pylori eradication in patients treated with levofloxacin. The main purpose of this study was to compare the effect of levofloxacin with clarithromycin on the eradication of H. pylori infection in Iranian population.

METHODS

A comprehensive meta-analysis was done for the relevant cohort studies and clinical trials to compare the therapeutic effects of levofloxacin with clarithromycin in Iranian population. We pooled the data using odds ratio corresponding to 95% confidence intervals to find the clinical efficacy of levofloxacin versus clarithromycin to treat H. pylori infection. The heterogeneity and publication bias were also measured for the included studies.

RESULTS

A total of 13 studies were included in the quantitative synthesis. Eradication rate in patients receiving levofloxacin and clarithromycin were 75% and 66.3%, respectively (OR: 1.76; 95% CI: 1.40-2.20). In addition, in the subgroup analysis, it was confirmed that cure rate is relatively higher in levofloxacin-treated cases. However, there is significant heterogeneity as well as publication bias, thus, the results need to be interpreted with caution.

CONCLUSIONS

We found that the success of levofloxacin treatment was significantly higher than that of clarithromycin. Therefore, it is suggested that clarithromycin-based triple therapy be replaced by levofloxacin-based triple therapy in countries with high resistance rate to clarithromycin such as Iran. Nevertheless, findings of the present study need to be approved with larger investigation on Iranian population.

Medicinal chemistry and biomedical applications of bismuth-based compounds and nanoparticles

Bismuth as a relatively non-toxic and inexpensive metal with exceptional properties has numerous biomedical applications. Bismuth-based compounds are used extensively as medicines for the treatment of gastrointestinal disorders including dyspepsia, gastric ulcers and H. pylori infections. Recently, its medicinal application was further extended to potential treatments of viral infection, multidrug resistant microbial infections, cancer and also imaging, drug delivery and biosensing. In this review we have highlighted the unique chemistry and biological chemistry of bismuth-209 as a prelude to sections covering the unique antibacterial activity of bismuth including a description of research undertaken to date to elucidate key molecular mechanisms of action against H. pylori, the development of novel compounds to treat infection from microbes beyond H. pylori and the significant role bismuth compounds can play as resistance breakers. Furthermore we have provided an account of the potential therapeutic application of bismuth-213 in targeted alpha therapy as well as a summary of the biomedical applications of bismuth-based nanoparticles and composites. Ultimately this review aims to provide the state of the art, highlight the untapped biomedical potential of bismuth and encourage original contributions to this exciting and important field.

Eradication of Porphyromonas gingivalis Persisters Through Colloidal Bismuth Subcitrate Synergistically Combined With Metronidazole

Microbial persisters enable the development of certain intrinsic strategies for survival with extreme tolerance to multiple antimicrobials. Porphyromonas gingivalis is considered to be the "keystone" periodontopathogen. Indeed, periodontitis, as a highly common inflammatory disease, is the major cause of severe tooth loss and edentulism in adults globally, and yet it is crucially involved in various systemic comorbidities like diabetes. We have recently revealed P. gingivalis persisters-induced perturbation of immuno-inflammatory responses and effective suppression of this key pathogen by bismuth drugs. This study further explored novel approaches to eradicating P. gingivalis persisters through synergistic combination of colloidal bismuth subcitrate (CBS) with traditional antibiotics. P. gingivalis (ATCC 33277) cells in planktonic and biofilm states were cultured to stationary phase, and then treated with metronidazole (100 mg/L), amoxicillin (100 mg/L), CBS, (100 μM) and combinations of these medications, respectively. Persister survival rate was calculated by colony-forming unit. Cell viability and cytotoxicity of CBS were assessed in human gingival epithelial cells (HGECs). Notably, CBS combined with metronidazole enabled the effective eradication of P. gingivalis persisters in planktonic mode, and nearly eliminated their existence in biofilm mode. Importantly, CBS exhibited no effects on the viability of HGECs, along with minimal cytotoxicity (<5%) even at a high concentration (400 μM). This pioneering study shows that P. gingivalis persisters could be well eliminated via the synergistic combination of CBS with metronidazole. Our findings may contribute to developing novel approaches to tackling periodontitis and inflammatory systemic comorbidities.

Identification of antibiotic resistance patterns in Helicobacter pylori strains isolated from gastric biopsies using real-time PCR and genotypic analysis

BACKGROUND

Helicobacter pylori (H. pylori) is associated with dyspepsia, mucus-associated lymphoid tissue lymphoma, gastritis, and peptic ulcer disease. Treatment in Malta consists of triple therapy, which consists of a proton pump inhibitor and 2 of the antibiotics amoxicillin, clarithromycin, metronidazole and fluoroquinolones. We aimed to determine the resistance rates for clarithromycin and fluoroquinolones in patients with H. pylori, and its incidence, in patients undergoing an esophagogastroduodenoscopy (EGD) using real-time polymerase chain reaction (RT-PCR).

METHODS

Patients undergoing an EGD were recruited. A rapid urease test (RUT) was performed, and 4 gastric biopsies were also taken (2 from antrum, 2 from corpus) and analyzed using RT-PCR. Positive samples were tested for antibiotic resistance using amplification and reverse hybridization techniques.

RESULTS

Two hundred patients (mean age 53.6 [range 20-92] years; 53.1% female) were recruited; the majority were (78%) non-smokers. H. pylori was identified in 21.0% of the patients. Fluoroquinolone resistance was detected in 21.4% of the patients. Clarithromycin resistance was observed in 26.2%, with dual resistance identified in 4.8% of the patients. A high concordance was present with patients testing negative for H. pylori with both RUT and RT-PCR (94.3%). Only 57.6% of patients tested positive with both tests. However, 92.9% of RT-PCR positive patients had a positive genotype HelicoDR test.

CONCLUSIONS

This data demonstrates a high rate of H. pylori resistance to both clarithromycin and fluoroquinolones. These should be avoided when treating H. pylori by utilizing different treatment regimes. Furthermore, we derived important data on the role of RT-PCR, which may be implemented in routine clinical practice.

Helicobacter pylori-targeting multiligand photosensitizer for effective antibacterial endoscopic photodynamic therapy

Helicobacter pylori (H. pylori) infection is closely associated with the development of gastric inflammatory diseases and cancer. However, the continued abuse and misuse of antibiotics has accelerated the spread of antibiotic-resistant strains, which poses a tremendous challenge for antibiotic-based H. pylori treatment. In this study, a H. pylori-targeting photodynamic therapy (PDT) system is proposed that multiple 3'-sialyllactose (3SL)-conjugated, poly-_l-lysine-based photosensitizer (p3SLP). p3SLP facilitates H. pylori-targeting PDT via the specific interaction between 3SL and sialic acid-binding adhesin (SabA) in the H. pylori membrane. p3SLP can be orally administered to H. pylori infected mice and irradiated using an endoscopic laser system. The gastrointestinal pathological analysis of the H. pylori-infected mice demonstrated significant H. pylori specific antibacterial effects of PDT without side effects to normal tissue. In addition, an anti-inflammatory response was observed at the site of infection after p3SLP treatment. Consequently, this study demonstrates the superior efficacy of anti-H. pylori PDT with p3SLP in H. pylori-infected mice, and this approach shows great potential for replacing antibiotic-based therapy.

Modified bismuth quadruple therapy with low-dose metronidazole as first-line therapy for Helicobacter pylori infection

BACKGROUND

Bismuth-containing quadruple therapy is an effective alternative first-line therapy for Helicobacter pylori infection. We evaluated the efficacy and safety of a modified twice-a-day bismuth quadruple regimen (BQT-2) with low-dose (1000 mg total) metronidazole as first-line therapy for the eradication of H pylori.

MATERIALS AND METHODS

In this prospective pilot study, patients diagnosed with H pylori infection and naïve to eradication therapy were included. The modified BQT-2 therapy consisted of rabeprazole 20 mg, amoxicillin 1 g, metronidazole 500 mg, and tripotassium dicitrato bismuthate 600 mg (elemental bismuth 240 mg) twice daily, given 30 minutes before morning and evening meals for 14 days. H pylori eradication was assessed by ¹³ C-urea breath test conducted at least 4 weeks after therapy completion.

RESULTS

In 66 patients who received the modified BQT-2 regimen, the compliance rate was 100% and the H pylori eradication rate was 77.3%. H pylori was successfully cultured in 50 (75.8%) patients. The resistance rates to metronidazole and clarithromycin were 30.0% and 22.0%, respectively. Eradication rates were not significantly different according to the resistance to metronidazole (metronidazole-susceptible: 74.3% [26/35], metronidazole-resistant: 73.3% [11/15]; P > .99). Most of the adverse events were mild, with 20 (30%) patients developing nausea, epigastric soreness, loose stool, asthenia, skin rash, dizziness, taste perversion, headache, or dyspepsia.

CONCLUSIONS

Twice-a-day modified BQT-2 regimen with low-dose metronidazole was suboptimal as an alternative first-line therapy for eradicating H pylori, despite high patient compliance.

Periodontal Treatment Is Associated With Improvement in Gastric Helicobacter pylori Eradication: An Updated Meta-analysis of Clinical Trials

Objectives

The efficacy of conventional systemic antibiotic therapy for eradication of Helicobacter pylori has been seriously challenged by antibiotic resistance. Identification of alternative therapeutic strategies might help to overcome this limitation. The aim of this study was to update previous meta-analyses that investigated the effect of periodontal treatment on gastric H. pylori eradication.

Methods

A systematic electronic search of the literature was conducted to identify all published clinical trials that compared the effect of adjunct periodontal treatment on conventional systemic H. pylori eradication therapy.

Results

The updated analysis (consisting of 541 participants representing six studies) demonstrated that, compared with conventional systemic eradication therapy alone, the addition of periodontal treatment resulted in improvements in gastric H. pylori eradication rates with OR 4.11 (P = 0.01). Moreover, not to lose any data, the previously presented Chinese results that could not be assessed by any available mechanism deduced from previously published meta-analysis and with other records were re-analysed. Similarly, the second meta-analysis adding up to a final cluster of 10 studies (909 participants) gives further credence to periodontal treatment as a useful concomitant therapy in the H. pylori eradication therapy (odds ratio [OR] = 2.65; P = 0.0002). Finally, the meta-analysis of four trials consisting of 177 cases and 161 controls showed that periodontal treatment also improved non-recurrence rates of gastric H. pylori infection, with an OR of 5.36 (P-value = 0.0002).

Conclusion

Although the inclusion of five additional clinical trials in this updated meta-analysis has not changed the result of the previous review, the current meta-analysis is superior for having removed one study involving the use of chlorhexidine, which did not meet appropriate criteria for inclusion. Our results strengthen the value of periodontal treatment as an adjunctive remedy. Consistency of these results suggests that the incorporation of professional periodontal treatment with systemic eradication therapy may be a wise strategy, enhancing the efficacy of H. pylori eradication therapy. Systematic review registration: in PROSPERO ID number: CRD42019119347.

European Registry on Helicobacter pylori management (Hp-EuReg): patterns and trends in first-line empirical eradication prescription and outcomes of 5 years and 21 533 patients

OBJECTIVE

The best approach for Helicobacter pylori management remains unclear. An audit process is essential to ensure clinical practice is aligned with best standards of care.

DESIGN

International multicentre prospective non-interventional registry starting in 2013 aimed to evaluate the decisions and outcomes in H. pylori management by European gastroenterologists. Patients were registered in an e-CRF by AEG-REDCap. Variables included demographics, previous eradication attempts, prescribed treatment, adverse events and outcomes. Data monitoring was performed to ensure data quality. Time-trend and geographical analyses were performed.

RESULTS

30 394 patients from 27 European countries were evaluated and 21 533 (78%) first-line empirical H. pylori treatments were included for analysis. Pretreatment resistance rates were 23% to clarithromycin, 32% to metronidazole and 13% to both. Triple therapy with amoxicillin and clarithromycin was most commonly prescribed (39%), achieving 81.5% modified intention-to-treat eradication rate. Over 90% eradication was obtained only with 10-day bismuth quadruple or 14-day concomitant treatments. Longer treatment duration, higher acid inhibition and compliance were associated with higher eradication rates. Time-trend analysis showed a region-dependent shift in prescriptions including abandoning triple therapies, using higher acid-inhibition and longer treatments, which was associated with an overall effectiveness increase (84%-90%).

CONCLUSION

Management of H. pylori infection by European gastroenterologists is heterogeneous, suboptimal and discrepant with current recommendations. Only quadruple therapies lasting at least 10 days are able to achieve over 90% eradication rates. European recommendations are being slowly and heterogeneously incorporated into routine clinical practice, which was associated with a corresponding increase in effectiveness.

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.

Comparison of the Diagnostic Performance of qPCR, Sanger Sequencing, and Whole-Genome Sequencing in Determining Clarithromycin and Levofloxacin Resistance in Helicobacter pylori

Helicobacter pylori antibiotic resistance is increasing worldwide, emphasizing the urgent need for more rapid resistance detection prior to the administration of H. pylori eradication regimens. Macrolides and fluoroquinolones are widely used to treat H. pylori. In this study, we aimed to compare the diagnostic performance of A) 23SrDNA qPCR (with melting curve analysis) and an in-house developed gyrA qPCR followed by Sanger sequencing with a commercial IVD-marked hybridization probe assay (for 23SrDNA and gyrA) using 142 gastric biopsies (skipping culturing) and B) the same two qPCR for 23SrDNA and gyrA (including Sanger sequencing) with whole-genome sequencing (WGS) and phenotypic characterization of clarithromycin and levofloxacin resistance using 76 cultured isolates. The sensitivity of both qPCRs was 100% compared to that of the commercial IVD-marked hybridization probe assay for the detection of H. pylori in gastric biopsies (without resistance testing). The specificity of the qPCR gyrA followed by Sanger sequencing was 100%, indicating that the best sequence identity was always H. pylori. The results show good agreement between molecular tests, especially between qPCR (inclusive Sanger sequencing) and WGS. Discrepancies (concerning mutated or wild type of positive H. pylori gastric biopsies) were observed between Sanger sequencing of the gyrA gene and the corresponding commercial hybridization probe assay, mostly because the high sequence diversity of the gyrA gene even at positions adjacent to the relevant codons of 87 and 91 interfered with obtaining correct results from the hybridization probe assay. Interestingly, we found several mixed sequences, indicating mixed populations in the gastric biopsies (direct detection without culturing). There was a high percentage of both levofloxacin and clarithromycin resistance in gastric biopsies (both between 22% and 29%, direct detection in gastric biopsies). Therefore, we recommend analyzing both targets in parallel. We confirmed that phenotypic resistance is highly correlated with the associated mutations. We concluded that the two qPCR followed by Sanger sequencing of the gyrA gene is a fast, cost-effective and comprehensive method for resistance testing of H. pylori directly in gastric biopsies.

Synthesis and Biological Evaluation of Carvacrol-Based Derivatives as Dual Inhibitors of H. pylori Strains and AGS Cell Proliferation

This study reports on the synthesis, structural assessment, microbiological screening against several strains of H. pylori and antiproliferative activity against human gastric adenocarcinoma (AGS) cells of a large series of carvacrol-based compounds. Structural analyses consisted of elemental analysis, 1H/13C/19F NMR spectra and crystallographic studies. The structure-activity relationships evidenced that among ether derivatives the substitution with specific electron-withdrawing groups (CF3 and NO2) especially in the para position of the benzyl ring led to an improvement of the antimicrobial activity, whereas electron-donating groups on the benzyl ring and ethereal alkyl chains were not tolerated with respect to the parent compound (MIC/MBC = 64/64 µg/mL). Ester derivatives (coumarin-carvacrol hybrids) displayed a slight enhancement of the inhibitory activity up to MIC values of 8-16 µg/mL. The most interesting compounds exhibiting the lowest MIC/MBC activity against H. pylori (among others, compounds 16 and 39 endowed with MIC/MBC values ranging between 2/2 to 32/32 µg/mL against all the evaluated strains) were also assayed for their ability to reduce AGS cell growth with respect to 5-Fluorouracil. Some derivatives can be regarded as new lead compounds able to reduce H. pylori growth and to counteract the proliferation of AGS cells, both contributing to the occurrence of gastric cancer.

Optimization Strategies Aimed to Increase the Efficacy of Helicobacter pylori Eradication Therapies with Quinolones

H. pylori infection is the main cause of gastritis, gastroduodenal ulcer disease, and gastric cancer. Fluoroquinolones such as levofloxacin, or more recently moxifloxacin or sitafloxacin, are efficacious alternatives to standard antibiotics for H. pylori eradication. The aim of the present review is to summarize the role of quinolone-based eradication therapies, mainly focusing on the optimization strategies aimed to increase their efficacy. Several meta-analyses have shown that, after failure of a first-line eradication treatment, a levofloxacin-containing rescue regimen is at least equally effective, and better tolerated, than the generally recommended bismuth quadruple regimen. Compliance with the levofloxacin regimens is excellent, and the safety profile is favourable. Higher cure rates have been reported with longer treatments (>10-14 days), and 500 mg levofloxacin daily is the recommended dose. Adding bismuth to the standard triple regimen (PPI-amoxicillin-levofloxacin) has been associated with encouraging results. Unfortunately, resistance to quinolones is easily acquired and is increasing in most countries, being associated with a decrease in the eradication rate of H. pylori. In summary, a quinolone (mainly levofloxacin)-containing regimen is an encouraging second-line (or even third-line) strategy, and a safe and simple alternative to bismuth quadruple therapy in patients whose previous H. pylori eradication therapy has failed.

Bacteriophages and the One Health Approach to Combat Multidrug Resistance: Is This the Way?

Antimicrobial resistance necessitates action to reduce and eliminate infectious disease, ensure animal and human health, and combat emerging diseases. Species such as Acinetobacter baumanniii, vancomycin resistant Enterococcus, methicillin resistance Staphylococcus aureus, and Pseudomonas aeruginosa, as well as other WHO priority pathogens, are becoming extremely difficult to treat. In 2017, the EU adopted the “One Health” approach to combat antibiotic resistance in animal and human medicine and to prevent the transmission of zoonotic disease. As the current therapeutic agents become increasingly inadequate, there is a dire need to establish novel methods of treatment under this One Health Framework. Bacteriophages (phages), viruses infecting bacterial species, demonstrate clear antimicrobial activity against an array of resistant species, with high levels of specificity and potency. Bacteriophages play key roles in bacterial evolution and are essential components of all ecosystems, including the human microbiome. Factors such are their specificity, potency, biocompatibility, and bactericidal activity make them desirable options as therapeutics. Issues remain, however, relating to their large-scale production, formulation, stability, and bacterial resistance, limiting their implementation globally. Phages used in therapy must be virulent, purified, and well characterized before administration. Clinical studies are warranted to assess the in vivo pharmacokinetics and pharmacodynamic characteristics of phages to fully establish their therapeutic potential.

Sugar Codes Conjugated Alginate: An Innovative Platform to Make a Strategic Breakthrough in Simultaneous Prophylaxis of GERD and Helicobacter pylori Infection

INTRODUCTION

Currently, gastroesophageal reflux disease (GERD) is one of the most ubiquitous problems in clinical practice. An antacid-alginate combination (under the trade name Gaviscon) is a natural-based product that effectively suppresses GERD. This product acts via the formation of viscous gel that floats on the top of the gastric content. On the other hand, efficient management of Helicobacter pylori infection with minimal side effects is an important goal for gastroenterologists. Furthermore, some H. pylori-positive patients suffer from GERD.

METHODS

Here, we present the results of investigations on alginate conjugated to sugar codes in order to find initial clues regarding the potential ability of this conjugate in the simultaneous prophylaxis of GERD and H. pylori infection in an in vitro assay.

RESULTS

It is noteworthy that our results reveal that sugar codes conjugated alginate considerably decrease (approximately 74%) the adhesion of H. pylori to gastric epithelial cells in vitro. Moreover, surprisingly after conjugation of sugar codes, alginate can maintain its ability to create gel. Our results demonstrate that alginate conjugated to sugar codes is not cytotoxic.

CONCLUSION

The preparation of these conjugates can be regarded as the first step to establish a new roadmap for the simultaneous prevention of GERD and H. pylori infection in future studies on in vivo models.

Annual eradication rate of bismuth-containing quadruple therapy as second-line treatment for Helicobacter pylori infection: A 15-year prospective study at a tertiary hospital in Korea

BACKGROUND

Bismuth-containing quadruple therapy is widely used as second-line treatment for Helicobacter pylori infection. This prospective study investigated the changes in the annual H. pylori eradication rates of quadruple therapy.

METHODS

This study included an intention-to-treat (ITT) population of 452 subjects who failed first-line eradication therapy for H. pylori between 2003 and 2018. All subjects received a 14-day course of bismuth-containing quadruple therapy consisting of esomeprazole (40 mg twice daily), metronidazole (500 mg thrice daily), bismuth subcitrate (120 mg four times daily), and tetracycline (500 mg four times daily). Per-protocol (PP) analysis of data was performed in subjects who followed up with strict treatment adherence. Eradication was confirmed based on the results of the ¹³ C-urea breath test, rapid urease test (CLOtest^® ), and histopathologic evaluation. Compliance and adverse effects were also investigated. A minimal inhibitory concentration test was performed on tissue samples obtained from 103 subjects.

RESULTS

The overall eradication rates following ITT and PP analyses were 78.8% (356/452) and 89.5% (314/351), respectively. The annual eradication success rate did not show significant changes (P = .062 [ITT], P = .857 [PP]) over the 15-year study period. Adverse events were reported in 57.3% of the ITT population. The rates of resistance to metronidazole and tetracycline were 44.7% and 18.4%, respectively.

CONCLUSIONS

Despite high antibiotic resistance rates, no significant reduction in annual eradication rates was observed during the study period.

Pregnancy outcomes among women with peptic ulcer disease

Background Little is known about the impact of peptic ulcer disease (PUD) on pregnancy. Our objective was to evaluate the effect of PUD on pregnancy and newborn outcomes. Methods A retrospective cohort study was carried out using the Healthcare Cost and Utilization Project (HCUP)-National Inpatient Sample (NIS) from the United States. The cohort consisted of all births that took place from 1999 to 2015. PUD was classified on the basis of the International Classification of Diseases-Ninth Revision (ICD-9) coding. Multivariate logistic regression was used to evaluate the adjusted effect of PUD on maternal and neonatal outcomes. Results Of the 13,792,544 births in this cohort, 1005 were to women with PUD (7/100,000 births). Between 1999 and 2015, prevalence of PUD in pregnancy increased from 4/100,000 to 11/100,000, respectively. Women with PUD were more commonly older and more likely to have comorbid illnesses. Women with PUD were at greater risk of preeclampsia [odds ratio (OR) 2.11, 95% confidence interval (CI) 1.67-2.66], preterm premature rupture of membranes (PPROM; OR 2.16, 95% CI 1.30-3.59), cesarean delivery (OR 1.60, 95% CI 1.40-1.82), venous thromboembolism (OR 3.77, 95% CI 2.08-6.85) and maternal death (OR 24.50, 95% CI 10.12-59.32). Births to women with PUD were at increased risk of intrauterine growth restriction (IUGR; OR 1.54, 95% CI 1.11-2.14), preterm birth (OR 1.84, 95% CI 1.54-2.21), intrauterine fetal death (OR 2.18, 95% CI 1.35-3.52) and congenital anomalies (OR 2.69, 95% CI 1.59-4.56). Conclusion The prevalence of PUD in pregnancy has risen over the last several years. PUD in pregnancy should be considered a high-risk condition associated with important adverse maternal and neonatal outcomes.

High Prevalence of Antibiotic Resistance in Iranian Helicobacter pylori Isolates: Importance of Functional and Mutational Analysis of Resistance Genes and Virulence Genotyping

The high prevalence of antibiotic resistance in Helicobacter pylori has become a great challenge in Iran. The genetic mutations that contribute to the resistance have yet to be precisely identified. This study aimed to investigate the prevalence of antibiotic resistance and virulence markers in Iranian H. pylori isolates and to analyze if there is any association between resistance and genotype. Antibiotic susceptibility patterns of 68 H. pylori isolates were investigated against metronidazole, clarithromycin, amoxicillin, rifampicin, ciprofloxacin, levofloxacin, and tetracycline by the agar dilution method. The frxA, rdxA, gyrA, gyrB, and 23S rRNA genes of the isolates were sequenced. The virulence genotypes were also determined using PCR. Metronidazole resistance was present in 82.4% of the isolates, followed by clarithromycin (33.8%), ciprofloxacin (33.8%), rifampicin (32.4%), amoxicillin (30.9%), levofloxacin (27.9%), and tetracycline (4.4%). Overall, 75% of the isolates were resistant to at least two antibiotics tested and considered as a multidrug resistance (MDR) phenotype. Most of the metronidazole-resistant isolates carried frameshift mutations in both frxA and rdxA genes, and premature termination occurred in positions Q5Stop and Q50Stop, respectively. Amino acid substitutions M191I, G208E, and V199A were predominantly found in gyrA gene of fluoroquinolone-resistant isolates. A2143G and C2195T mutations of 23S rRNA were found in four clarithromycin-resistant isolates. Interestingly, significant associations were found between resistance to metronidazole (MNZ) and cagA-, sabA-, and dupA-positive genotypes, with p = 0.0002, p = 0.0001, and p = 0.0001, respectively. Furthermore, a significant association was found between oipA “on” status and resistance to amoxicillin (AMX) (p = 0.02). The prevalence of H. pylori antibiotic resistance is high in our region, particularly that of metronidazole, clarithromycin, ciprofloxacin, and MDR. Simultaneous screening of virulence and resistance genotypes can help clinicians to choose the appropriate therapeutic regime against H. pylori infection.

Helicobacter pylori senses bleach (HOCl) as a chemoattractant using a cytosolic chemoreceptor

The gastric pathogen Helicobacter pylori requires a noncanonical cytosolic chemoreceptor transducer-like protein D (TlpD) for efficient colonization of the mammalian stomach. Here, we reconstituted a complete chemotransduction signaling complex in vitro with TlpD and the chemotaxis (Che) proteins CheW and CheA, enabling quantitative assays for potential chemotaxis ligands. We found that TlpD is selectively sensitive at micromolar concentrations to bleach (hypochlorous acid, HOCl), a potent antimicrobial produced by neutrophil myeloperoxidase during inflammation. HOCl acts as a chemoattractant by reversibly oxidizing a conserved cysteine within a 3His/1Cys Zn-binding motif in TlpD that inactivates the chemotransduction signaling complex. We found that H. pylori is resistant to killing by millimolar concentrations of HOCl and responds to HOCl in the micromolar range by increasing its smooth-swimming behavior, leading to chemoattraction to HOCl sources. We show related protein domains from Salmonella enterica and Escherichia coli possess similar reactivity toward HOCl. We propose that this family of proteins enables host-associated bacteria to sense sites of tissue inflammation, a strategy that H. pylori uses to aid in colonizing and persisting in inflamed gastric tissue.

Synthesis and In Vitro Enzymatic Studies of New 3-Aryldiazenyl Indoles as Promising Helicobacter pylori IMPDH Inhibitors

BACKGROUND & OBJECTIVE

Helicobacter pylori infection is one of the primary causes of peptic ulcer followed by gastric cancer in the world population. Due to increased occurrences of multi-drug resistance to the currently available antibiotics, there is an urgent need for a new class of drugs against H. pylori. Inosine 5'-monophosphate dehydrogenase (IMPDH), a metabolic enzyme plays a significant role in cell proliferation and cell growth. It catalyses guanine nucleotide synthesis. IMPDH enzyme has been exploited as a target for antiviral, anticancer and immunosuppressive drugs. Recently, bacterial IMPDH has been studied as a potential target for treating bacterial infections. Differences in the structural and kinetic parameters of the eukaryotic and prokaryotic IMPDH make it possible to target bacterial enzyme selectively.

METHODS

In the current work, we have synthesised and studied the effect of substituted 3-aryldiazenyl indoles on Helicobacter pylori IMPDH (HpIMPDH) activity. The synthesised molecules were examined for their inhibitory potential against recombinant HpIMPDH.

RESULTS

In this study, compounds 1 and 2 were found to be the most potent inhibitors amongst the database with IC50 of 0.8 ± 0.02µM and 1 ± 0.03 µM, respectively.

CONCLUSION

When compared to the most potent known HpIMPDH inhibitor molecule C91, 1 was only four-fold less potent and can be a good lead for further development of selective and potent inhibitors of HpIMPDH.

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

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

Molecular docking, pharmacophore based virtual screening and molecular dynamics studies towards the identification of potential leads for the management of H. pylori

The enzyme pantothenate synthetase panC is one of the potential new antimicrobial drug targets, but it is poorly characterized in H. pylori. H. pylori infection can cause gastric cancer and the management of H. pylori infection is crucial in various gastric ulcers and gastric cancer. The current study describes the use of innovative drug discovery and design approaches like comparative metabolic pathway analysis (Metacyc), exploration of database of essential genes (DEG), homology modelling, pharmacophore based virtual screening, ADMET studies and molecular dynamics simulations in identifying potential lead compounds for the H. pylori specific panC. The top ranked virtual hits STOCK1N-60270, STOCK1N-63040, STOCK1N-44424 and STOCK1N-63231 can act as templates for synthesis of new H. pylori inhibitors and they hold a promise in the management of gastric cancers caused by H. pylori.

Computational approaches such as pharmacophore modeling, virtual screening and MD simulations were explored to find the potential hits as H. pylori specific panC inhibitors for the management of gastric ulcers and gastric cancers.

Antimicrobial resistance among Helicobacter pylori isolates in Alaska, 2000-2016

OBJECTIVES

Alaska Natives experience a high burden of Helicobacter pylori infection and concomitant high rates of gastric cancer. Additionally, the prevalence of antimicrobial-resistant H. pylori has been shown to be high in Alaska. In this study, antimicrobial resistance over time among sentinel surveillance isolates was evaluated and risk factors for carrying antimicrobial-resistant H. pylori were assessed.

METHODS

Through Alaska's H. pylori sentinel surveillance system, antral and fundal biopsies from Alaska Native patients undergoing esophagogastroduodenoscopy for clinical indications during 2000-2016 were collected and cultured. For positive cultures, minimum inhibitory concentrations (MICs) of metronidazole, amoxicillin, clarithromycin, tetracycline and levofloxacin were determined.

RESULTS

A total of 800 H. pylori isolates obtained from 763 patients were tested. Resistance to metronidazole was most common (342/800; 42.8%), followed clarithromycin (238/800; 29.8%), both clarithromycin and metronidazole (128/800; 16.0%) and levofloxacin (113/800; 14.1%). Low proportions of isolates were resistant to amoxicillin and tetracycline. Levofloxacin resistance increased between 2000 and 2016 (P<0.001), but resistance to other antimicrobials did not change over time. Metronidazole and clarithromycin resistance were more common among women (P<0.001 for both), whilst levofloxacin resistance was more common among those with an urban residence (P=0.003). Metronidazole and levofloxacin resistance were more common among older patients (P<0.05).

CONCLUSION

Between 2000 and 2016, a large percentage of H. pylori isolates received by the Alaska Sentinel Surveillance System demonstrated resistance to common antimicrobials. The surveillance system provides valuable information for clinicians to make informed treatment choices for patient with H. pylori.

F. A review on the development of urease inhibitors as antimicrobial agents against pathogenic bacteria

Ureases are enzymes that hydrolyze urea into ammonium and carbon dioxide. They have received considerable attention due to their impacts on living organism health, since the urease activity in microorganisms, particularly in bacteria, are potential causes and/or factors contributing to the persistence of some pathogen infections. This review compiles examples of the most potent antiurease organic substances. Emphasis was given to systematic screening studies on the inhibitory activity of rationally designed series of compounds with the corresponding SAR considerations. Ureases of Canavalia ensiformis, the usual model in antiureolytic studies, are emphasized. Although the active site of this class of hydrolases is conserved among bacteria and vegetal ureases, the same is not observerd for allosteric site. Therefore, inhibitors acting by participating in interactions with the allosteric site are more susceptible to a potential lack of association among their inhibitory profile for different ureases. The information about the inhibitory activity of different classes of compounds can be usefull to guide the development of new urease inhibitors that may be used in future in small molecular therapy against pathogenic bacteria.

Helicobacter pylori Biofilm Formation and Its Potential Role in Pathogenesis

Despite decades of effort, Helicobacter pylori infections remain difficult to treat. Over half of the world's population is infected by H. pylori, which is a major cause of duodenal and gastric ulcers as well as gastric cancer. During chronic infection, H. pylori localizes within the gastric mucosal layer, including deep within invaginations called glands; thanks to its impressive ability to survive despite the harsh acidic environment, it can persist for the host's lifetime. This ability to survive and persist in the stomach is associated with urease production, chemotactic motility, and the ability to adapt to the fluctuating environment. Additionally, biofilm formation has recently been suggested to play a role in colonization. Biofilms are surface-associated communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances. Biofilms pose a substantial health risk and are key contributors to many chronic and recurrent infections. This link between biofilm-associated bacteria and chronic infections likely results from an increased tolerance to conventional antibiotic treatments as well as immune system action. The role of this biofilm mode in antimicrobial treatment failure and H. pylori survival has yet to be determined. Furthermore, relatively little is known about the H. pylori biofilm structure or the genes associated with this mode of growth. In this review, therefore, we aim to highlight recent findings concerning H. pylori biofilms and the molecular mechanism of their formation. Additionally, we discuss the potential roles of biofilms in the failure of antibiotic treatment and in infection recurrence.

IVTH BRAZILIAN CONSENSUS CONFERENCE ON HELICOBACTER PYLORI INFECTION

ABSTRACT Significant progress has been obtained since the III Brazilian Consensus Conference on H. pylori infection held in 2012, in Bento Gonçalves, Brazil, and justify a fourth meeting to establish updated guidelines on the current management of H. pylori infection. Therefore, the Núcleo Brasileiro para Estudo do Helicobacter pylori e Microbiota (NBEHPM), association linked to Brazilian Federation of Gastroenterology (FBG) held its fourth meeting again in Bento Gonçalves, RS, Brazil, on August 25-27, 2017. Twenty-six delegates, including gastroenterologists, endoscopists, and pathologists from the five regions of Brazil as well as one international guest from the United States, participated in the meeting. The participants were invited based on their knowledge and contribution to the study of H. pylori infection. The meeting sought to review different aspects of treatment for infection; establish a correlation between infection, dyspepsia, intestinal microbiota changes, and other disorders with a special emphasis on gastric cancer; and reassess the epidemiological and diagnostic aspects of H. pylori infection. Participants were allocated into four groups as follows: 1) Epidemiology and Diagnosis, 2) Dyspepsia, intestinal microbiota and other afections, 3) Gastric Cancer, and, 4) Treatment. Before the consensus meeting, participants received a topic to be discussed and prepared a document containing a recent literature review and statements that should be discussed and eventually modified during the face-to-face meeting. All statements were evaluated in two rounds of voting. Initially, each participant discussed the document and statements with his group for possible modifications and voting. Subsequently, during a second voting in a plenary session in the presence of all participants, the statements were voted upon and eventually modified. The participants could vote using five alternatives: 1) strongly agree; 2) partially agree; 3) undecided; 4) disagree; and 5) strongly disagree. The adopted consensus index was that 80% of the participants responded that they strongly or partially agreed with each statement. The recommendations reported are intended to provide the most current and relevant evidences to management of H. pylori infection in adult population in Brazil.

A colorimetric broth microdilution method for assessment of Helicobacter pylori sensitivity to antimicrobial agents

Helicobacter pylori is a major infective etiological agent of the upper gastrointestinal tract diseases. The bacterium exhibits resistance to various conventional antibiotics, being usually challenging for eradication. Since there is an urge to consider alternative therapeutic strategies, the aim of the study was to examine selected essential oils of plants belonging to families Cupressaceae (Juniperus communis) and Lamiaceae (Hyssopus officinalis, Salvia officinalis, Melissa officinalis, Lavandula angustifolia, Ocimum basilicum and Thymus serpyllum) against H. pylori, using an improved microdilution broth method. The oils were examined in concentration range from 0.03 to 4 μL/mL. The method comprises Brain-heart infusion broth supplemented with yeast extract, horse serum and IsoVitaleX. After 3 day incubation, an equal volume of double strengthen Christensen's urea was added into each well and incubated for additional 4 h. In wells with present H. pylori, the medium changed color from yellow to purple, allowing MIC determination even without a microtitre plate reader. The microtitre format method is convenient as it is less expensive, easier to perform and requires less amount of an anti-H. pylori agent. The improved method enhances specificity to H. pylori, as fast urease activity is almost an exclusive property of this bacterium. The application of the second step incubation with Christensen's urea decreases the possibility of false positive/negative results due to contaminant growth or commonly poor H. pylori growth. Among the examined oils, J. communis, H. officinalis and O. basilicum were not active with the highest applied concentrations, while the most active was T. serpyllum, with MIC 2.0-4.0 μL/mL. This is the first report on essential oils activity of T. serpyllum and H. officinalis against H. pylori.

Treatment of Helicobacter pylori infection: A clinical practice update

BACKGROUND

Helicobacter pylori infection is still frequent in the community and all infected subjects should be offered an eradication therapy. Nowadays physicians have to face the challenge of antibiotic resistance in treating Helicobacter pylori-infected individuals.

AIM

This review provides an overview of current international guidelines and reports recent evidence from systematic reviews and clinical trials on the treatment of Helicobacter pylori infection and should help physicians to better treat their patients.

RESULTS

General rules to optimize the management of Helicobacter pylori infection include: (i) considering previous patient's exposure to antibiotics; (ii) using high dose of proton-pump inhibitors; and (iii) avoiding repeating the same regimen, if it has already failure. Bismuth quadruple therapy and concomitant therapy are the best first-line empirical treatments in areas with high clarithromycin resistance and in individuals with previous use of macrolides; otherwise, the 14-day clarithromycin-containing triple therapy is a valid regimen. The sequential therapy is no longer a suggested treatment by international guidelines.

CONCLUSIONS

Current international guidelines are consistent in defining treatment strategies for Helicobacter pylori infection. The use of national registries to monitor the efficacy and tolerability of different regimens in the real world of clinical practice is now needed.

Rescue therapy with bismuth quadruple regimen in patients with Helicobacter pylori -resistant strains

BACKGROUND

Bismuth quadruple therapy (BQT) is the recommended rescue therapy for Helicobacter pylori (H. pylori) infection. This study aimed to assess the efficacy and safety of a 10-day BQT regimen in patients who failed previous therapies and were infected with multiresistant H. pylori strains MATERIALS AND METHODS: Helicobacter pylori-infected patients underwent endoscopy, culture, and susceptibility test for clarithromycin, metronidazole, and levofloxacin. Treatment with three-in-one capsule (Pylera®) four times daily and esomeprazole 20 mg twice daily for 10 days was administered. Treatment-emergent adverse events (TEAEs) were registered.

RESULTS

A total of 116 patients with persistent H. pylori infection following at least one eradication therapy attempt were treated. Overall, resistance toward clarithromycin was detected in 80% of strains, toward metronidazole in 70%, and levofloxacin in 47.5%, with dual or triple resistance in 72.5% of cases. An eradication rate of 81.0% (95% CI: 73.0-87.1) and 87.0% (95% CI: 79.4-92.1) at ITT and PP analyses, respectively, was achieved. The cure rate remained high until it was used as fourth-line regimen, while it dropped to low values (<67%) in those patients with more than 4 therapy failures. A total of 65.7% (95% CI: 56.4-74.0) patients complained of TEAEs.

CONCLUSIONS

Our data found that bismuth-based quadruple regimen is effective as rescue therapy for curing patients infected with multiresistant H. pylori strains.