Treatment for H. pylori infection: new challenges with antimicrobial resistance

pH-Responsive Polymeric Micelle Dynamic Complexes for Selective Killing of Helicobacter pylori

Helicobacter pylori, the world's most common chronic infection-causing pathogen, is responsible for causing gastric ulcers, the fourth-leading cause of cancer-related death globally in 2020. In recent years, the effectiveness of the current treatment regimen (two antibiotics and one proton pump inhibitor) has often been plagued with problems such as resistance and the undesired elimination of commensal bacteria. Herein, we report the synthesis of block and random copolycarbonates, functionalized with cationic guanidinium and anionic acetate functional groups, aimed at selectively killing H. pylori in the acidic environment of the stomach, while remaining nontoxic to the commensal bacteria in the gut. The compositions of the polymers were fine-tuned so that the polymers were readily dispersed in water without any difficulty at both pH 3.0 and 7.4. The self-assembly behavior of the polymers at different pH values by dynamic light scattering showed that the random and block copolymers formed stable micelles in a simulated gastric environment (pH 3.0) while aggregated at pH 7.4. Both polymers demonstrated stronger antibacterial activity against H. pylori than the guanidinium-functionalized homopolymer without any acetate functional group at pH 3.0. The block copolymer was significantly more bactericidal at pH 3.0 across the concentrations tested, as compared to the random copolymer, while it did not show significant toxicity toward rat red blood cells (rRBCs) and HK-2 cells or bactericidal effect toward E. coli (a common gut bacterium) and nor caused aggregation of rRBCs at its effective concentration and at physiological pH of 7.4. Additionally, both the block and random copolymers were much more stable against hydrolysis at pH 3.0 than at pH 7.4. This study provides insight into the influence of both polymer architecture and dynamic assembly on the bioactivities of antimicrobial polymers, where the disassembly of coacervates into narrowly dispersed micelles at pH 3 make them potent antimicrobials aided by the protonated carboxylic acid block.

The biophysics of bacterial infections: Adhesion events in the light of force spectroscopy

Bacterial infections are the most eminent public health challenge of the 21st century. The primary step leading to infection is bacterial adhesion to the surface of host cells or medical devices, which is mediated by a multitude of molecular interactions. At the interface of life sciences and physics, last years advances in atomic force microscopy (AFM)-based force spectroscopy techniques have made possible to measure the forces driving bacteria-cell and bacteria-materials interactions on a single molecule/cell basis (single molecule/cell force spectroscopy). Among the bacteria-(bio)materials surface interactions, the life-threatening infections associated to medical devices involving Staphylococcus aureus and Escherichia coli are the most eminent. On the other hand, Pseudomonas aeruginosa binding to the pulmonary and urinary tract or the Helicobacter pylori binding to the gastric mucosa, are classical examples of bacteria-host cell interactions that end in serious infections. As we approach the end of the antibiotic era, acquisition of a deeper knowledge of the fundamental forces involved in bacteria - host cells/(bio)materials surface adhesion is crucial for the identification of new ligand-binding events and its assessment as novel targets for alternative anti-infective therapies. This article aims to highlight the potential of AFM-based force spectroscopy for new targeted therapies development against bacterial infections in which adhesion plays a pivotal role and does not aim to be an extensive overview on the AFM technical capabilities and theory of single molecule force spectroscopy.

High-dose dual therapy is effective as first-line treatment for Helicobacter pylori infection

BACKGROUND/AIMS

Although many regimens, including quadruple, sequential, and concomitant treatment, are used and recommended as first-line or rescue therapies for Helicobacter pylori infection, eradication rates are still below 90% in intention-to-treat analyses. Treatment protocols with substantially high eradication rates and low antibiotic resistance are needed. In this study, we investigated the efficacy of high-dose dual therapy as first-line treatment in a Turkish population.

MATERIALS AND METHODS

All patients underwent upper gastrointestinal endoscopy for the initial H. pylori status because of dyspeptic symptoms. All patients received a 14-day, high-dose dual therapy comprising rabeprazole (20 mg t.i.d.) and amoxicillin (1 g t.i.d.) for H. pylori eradication. H. pylori stool antigen tests of eradication were administered to all participants at least 4 weeks after the completion of the treatment.

RESULTS

The high-dose dual therapy demonstrated a 91.3% rate of successful eradication of H. pylori infection. Per-protocol success was 94.4% among female patients (n=51) and 89.6% among male patients (n=86); in terms of gender, the differences were not significant (p=0.310). No side effects were observed during the study in any patient. Six other patients did not take adequate doses of the treatment protocol.

CONCLUSION

High-dose dual therapy with rabeprazole and amoxicillin was highly effective and well tolerated as a first-line therapy for H. pylori eradication.

The Application of High-Dose Proton Pump Inhibitor Induction Treatment before Dual Therapy for Helicobacter pylori Eradication: An Open-Label Random Trial

This was a prospective, randomized, open-label trial. Patients without previous Helicobacter pylori eradication therapy were randomly assigned to either a high-dose dual therapy (HDDT) group or a traditional clarithromycin/amoxicillin triple therapy (CATT) group. In the HDDT group, patients took rabeprazole, 20 mg, four times per day for three days and then dual therapy with rabeprazole, 20 mg, and amoxicillin, 500 mg, four times per day during the patient’s breakfast, lunch, dinner, and bedtime for 14 days. In the CATT group, patients received conventional triple therapy for 14 days (rabeprazole 20 mg, amoxicillin 1 g, and clarithromycin 500 mg twice per day). In the HDDT group, the success rates of H. pylori eradication were 91.7% (95% confidence interval (CI): 0.78–0.97) by intention-to-treat (ITT) and 94.3% (95% CI: 0.79–0.99) by per-protocol (PP) analysis. In the CATT group, the eradication rates were 77.1% (95% CI: 0.61–0.87) by ITT and 84.3% (95% CI: 0.66–0.94) by PP analysis. The study completion rates were 97.2% (35/36) in the HDDT group. Three-day high-dose rabeprazole induction treatment before dual therapy and a schedule of taking the drug at meal and bed times could achieve an acceptable H. pylori eradication rate (>90%) and good drug compliance.

High-dose dual therapy versus bismuth-containing quadruple therapy for the treatment of Helicobacter pylori infection – A review of the strengths, weaknesses, and proposed solutions

Helicobacter pylori is the principal cause of peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. The first treatment to H. pylori infection is dual therapy (a bismuth compound plus metronidazole). On the launch of omeprazole in 1988, dual therapy became omeprazole and amoxicillin (low dose). The poor H. pylori eradication rates by either bismuth-based or low-dose dual therapy drove more combinations of antibiotics were needed. Antibiotic resistance, especially clarithromycin and metronidazole, has made bismuth-containing quadruple therapy (BCQT) a savior for first-line and second-line treatments. However, its complicated dosing regimen commonly causes more adverse events and poor drug compliance. Thus, high-dose dual therapy (HDDT) has been re-arising. This article reviews the strengths and weaknesses of HDDT versus BCQT with proposed solutions.

3-Pentylcatechol, a Non-Allergenic Urushiol Derivative, Displays Anti-Helicobacter pylori Activity In Vivo

We previously reported that 3-pentylcatechol (PC), a synthetic non-allergenic urushiol derivative, inhibited the growth of Helicobacter pylori in an in vitro assay using nutrient agar and broth. In this study, we aimed to investigate the in vivo antimicrobial activity of PC against H. pylori growing in the stomach mucous membrane. Four-week-old male C57BL/6 mice (n = 4) were orally inoculated with H. pylori Sydney Strain-1 (SS-1) for 8 weeks. Thereafter, the mice received PC (1, 5, and 15 mg/kg) and triple therapy (omeprazole, 0.7 mg/kg; metronidazole, 16.7 mg/kg; clarithromycin, 16.7 mg/kg, reference groups) once daily for 10 days. Infiltration of inflammatory cells in gastric tissue was greater in the H. pylori-infected group compared with the control group and lower in both the triple therapy- and PC-treated groups. In addition, upregulation of cytokine mRNA was reversed after infection, upon administration of triple therapy and PC. Interestingly, PC was more effective than triple therapy at all doses, even at 1/15th the dose of triple therapy. In addition, PC demonstrated synergism with triple therapy, even at low concentrations. The results suggest that PC may be more effective against H. pylori than established antibiotics.

Helicobacter pylori Biofilm Confers Antibiotic Tolerance in Part via A Protein-Dependent Mechanism

Helicobacter pylori, a WHO class I carcinogen, is one of the most successful human pathogens colonizing the stomach of over 4.4 billion of the world’s population. Antibiotic therapy represents the best solution but poor response rates have hampered the elimination of H. pylori. A growing body of evidence suggests that H. pylori forms biofilms, but the role of this growth mode in infection remains elusive. Here, we demonstrate that H. pylori cells within a biofilm are tolerant to multiple antibiotics in a manner that depends partially on extracellular proteins. Biofilm-forming cells were tolerant to multiple antibiotics that target distinct pathways, including amoxicillin, clarithromycin, and tetracycline. Furthermore, this tolerance was significantly dampened following proteinase K treatment. These data suggest that H. pylori adapts its phenotype during biofilm growth resulting in decreased antibiotic susceptibility but this tolerance can be partially ameliorated by extracellular protease treatment.

Surface Grafted MSI-78A Antimicrobial Peptide has High Potential for Gastric Infection Management

As we approach the end of the antibiotic era, newer therapeutic options, such as antimicrobial peptides (AMPs), are in urgent demand. AMP surface grafting onto biomaterials has been described as a good strategy to overcome problems associated with their in vivo stability. Helicobacter pylori is among the bacteria that pose greatest threat to human health, being MSI-78A one of the few bactericidal AMPs against this bacterium. Here, we report that MSI-78A grafted onto model surfaces (Self-Assembled Monolayers –SAMs), in a concentration of 30.3 ± 1.2 ng/cm² determined by quartz crystal microbalance with dissipation (QCM-D), was able to kill, by contact, 98% of planktonic H. pylori in only 2 h. This fact was not verified against the control bacteria (Staphylococcus epidermidis), although the minimal inhibitory concentration (MIC) of MSI-78A in solution is much lower for S. epidermidis (2 μg/mL) than for H. pylori (64 μg/mL). Our results also demonstrated that, in opposite to other bacteria, H. pylori cells were attracted to ethylene glycol terminated (antiadhesive) surfaces, which can explain the high bactericidal potential of grafted MSI-78A. This proof of concept study establishes the foundations for development of MSI-78A grafted nanoparticles for gastric infection management within a targeted nanomedicine concept.

Helicobacter pylori infections in Ethiopia; prevalence and associated factors: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori (H.pylori) infections are prevalent and recognized as major cause of gastrointestinal diseases in Ethiopia. However, Studies conducted on the prevalence, risk factors and other clinical forms of H.pylori on different population and geographical areas are reporting conflicting results. Therefore, this review was conducted to estimate the pooled prevalence of H.pylori infections and associated factors in Ethiopia.

METHODS

PubMed, Embase, Google scholar, and Ethiopian Universities' repositories were searched following the Preferred Items for Systematic review and Meta-analysis (PRISMA) guideline. The quality of included studies was assessed using the Newcastle-Ottawa Scale in meta-analysis. Heterogeneity between studies was assessed using Cochrane Q test and I2 test statistics based on the random effects model. Comprehensive meta-analysis (CMA 2.0) and Review Manager (RevMan 5.3) were employed to compute the pooled prevalence and summary odds ratios of factors associated with of H.pylori infection.

RESULTS

Thirty seven studies with a total of 18,890 participants were eligible and included in the analysis. The overall pooled prevalence of H.pylori infection was 52.2% (95% CI: 45.8-58.6). In the subgroup analysis by region, the highest prevalence was found in Somalia (71%; 95% CI: 32.5-92.6) and the lowest prevalence was reported in Oromia (39.9%; 95% CI: 17.3-67.7). Absence of hand washing after toilet (OR = 1.8, 95% CI; 1.19-2.72), alcohol consumption (OR = 1.34, 95% CI; 1.03-1.74) and gastrointestinal (GI) symptoms (OR = 2.23, 95% CI; 1.59-3.14) were associated with H.pylori infection. The trend of H.pylori infection showed a decreasing pattern overtime from 1990 to 2017 in the meta-regression analysis.

CONCLUSION

The prevalence of H.pylori infection remains high; more than half of Ethiopians were infected. Although the trend of infection showed a decreasing pattern; appropriate use of eradication therapy, health education primarily to improve knowledge and awareness on the transmission dynamics of the bacteria, behavioral changes, adequate sanitation, population screening and diagnosis using multiple tests are required to reduce H.pylori infections. Recognizing the bacteria as a priority issue and designing gastric cancer screening policies are also recommended.

Design, synthesis, and biological evaluation of Helicobacter pylori inosine 5'-monophosphate dehydrogenase (HpIMPDH) inhibitors

Inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes a crucial step in the biosynthesis of guanine nucleotides. Being a validated target for immunosuppressive, antiviral, and anticancer drug development, lately it has been exploited as a promising target for antimicrobial therapy. Extending our previous work on Mycobacterium tuberculosis IMPDH, GuaB2, inhibitor development, we screened a set of 23 new chemical entities (NCEs) with substituted flavone (Series 1) and 1,2,3-triazole (Series 2) core structures for their in vitro Helicobacter pylori IMPDH (HpIMPDH) and human IMPDH2 (hIMPDH2) inhibitory activities. All the NCEs possessed acceptable molecular, physicochemical, and toxicity property profiles. The ranges for HpIMPDH and hIMPDH2 inhibition were 9-99.9% and 16-57%, respectively, at 10 μM concentration. The most potent HpIMPDH inhibitor, 25c, exhibited IC₅₀ value of 1.27 μM with no hIMPDH2 inhibitory activity. The moderately potent, structurally novel hit molecule, 25c, may serve as a lead for further design and development of highly potent HpIMPDH inhibitors.

Helicobacter pylori Biofilm Involves a Multigene Stress-Biased Response, Including a Structural Role for Flagella

Biofilms, communities of bacteria that are embedded in a hydrated matrix of extracellular polymeric substances, pose a substantial health risk and are key contributors to many chronic and recurrent infections. Chronicity and recalcitrant infections are also common features associated with the ulcer-causing human pathogen H. pylori. However, relatively little is known about the role of biofilms in H. pylori pathogenesis, as well as the biofilm structure itself and the genes associated with this mode of growth. In the present study, we found that H. pylori biofilm cells highly expressed genes related to cell envelope and stress response, as well as those encoding the flagellar apparatus. Flagellar filaments were seen in high abundance in the biofilm. Flagella are known to play a role in initial biofilm formation, but typically are downregulated after that state. H. pylori instead appears to have coopted these structures for nonmotility roles, including a role building a robust biofilm.

Helicobacter pylori has an impressive ability to persist chronically in the human stomach. Similar characteristics are associated with biofilm formation in other bacteria. The H. pylori biofilm process, however, is poorly understood. To gain insight into this mode of growth, we carried out comparative transcriptomic analysis between H. pylori biofilm and planktonic cells, using the mouse-colonizing strain SS1. Optimal biofilm formation was obtained with a low concentration of serum and 3 days of growth, conditions that caused both biofilm and planktonic cells to be ∼80% coccoid. Transcriptome sequencing (RNA-seq) analysis found that 8.18% of genes were differentially expressed between biofilm and planktonic cell transcriptomes. Biofilm-downregulated genes included those involved in metabolism and translation, suggesting these cells have low metabolic activity. Biofilm-upregulated genes included those whose products were predicted to be at the cell envelope, involved in regulating a stress response, and surprisingly, genes related to formation of the flagellar apparatus. Scanning electron microscopy visualized flagella that appeared to be a component of the biofilm matrix, supported by the observation that an aflagellated mutant displayed a less robust biofilm with no apparent filaments. We observed flagella in the biofilm matrix of additional H. pylori strains, supporting that flagellar use is widespread. Our data thus support a model in which H. pylori biofilm involves a multigene stress-biased response and that flagella play an important role in H. pylori biofilm formation.

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.

Helicobacter pylori Infection: An Update for the Internist in the Age of Increasing Global Antibiotic Resistance

Helicobacter pylori infects approximately half the world's population and is especially prevalent in the developing world. H. pylori is an important cause of global ill health due to its known etiological role in peptic ulcer disease, dyspepsia, gastric cancer, lymphoma, and more recently, recognized in iron deficiency anemia and idiopathic thrombocytopenic purpura. Increased antibiotic usage worldwide has led to antibiotic resistance among many bacteria, including H. pylori, resulting in falling success rates of first-line anti-H. pylori therapies. Eradication failures are principally due to resistance to clarithromycin, levofloxacin, and metronidazole. Several new treatment options or modifications of established regimens are now recommended by updated practice guidelines for primary or secondary therapy. Because these updated recommendations were published in the gastroenterological literature, internists and primary care physicians, who commonly manage H. pylori, may be unaware of these advances. In this review, we outline the changing epidemiology of H. pylori, advise on diagnostic test selection for patients not undergoing endoscopy, and highlight current management options in this era of growing antibacterial resistance.

Monotherapy with a novel intervenolin derivative, AS-1934, is an effective treatment for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) infection causes various gastrointestinal diseases including gastric cancer. Hence, eradication of this infection could prevent these diseases. The most popular first-line treatment protocol to eradicate H. pylori is termed "triple therapy" and consists of a proton pump inhibitor (PPI), clarithromycin, and amoxicillin or metronidazole. However, the antibiotics used to treat H. pylori infection are hindered by the antibiotics-resistant bacteria and by their antimicrobial activity against intestinal bacteria, leading to side effects. Therefore, an alternative treatment with fewer adverse side effects is urgently required to improve the overall eradication rate of H. pylori.

OBJECTIVE

The aim of this study was to assess the effectiveness and mechanism of action of an antitumor agent, intervenolin, and its derivatives as an agent for the treatment of H. pylori infection.

RESULTS

We demonstrate that intervenolin, and its derivatives showed selective anti-H. pylori activity, including antibiotic-resistant strains, without any effect on intestinal bacteria. We showed that dihydroorotate dehydrogenase, a key enzyme for de novo pyrimidine biosynthesis, is a target and treatment with intervenolin or its derivatives decreased the protein and mRNA levels of H. pylori urease, which protects H. pylori against acidic conditions in the stomach. Using a mouse model of H. pylori infection, oral monotherapy with the intervenolin derivative AS-1934 had a stronger anti-H. pylori effect than the triple therapy commonly used worldwide to eradicate H. pylori.

CONCLUSION

AS-1934 has potential advantages over current treatment options for H. pylori infection.

Seven-day genotypic resistance-guided triple Helicobacter pylori eradication therapy can be highly effective

BACKGROUND

The efficacy and applicability of molecular testing to guide the selection of antibiotics in triple Helicobacter pylori (H. pylori) eradication regimens have not been reported. We tested a 7-day, genotypic resistance-guided triple H. pylori eradication therapy in a high-resistance setting.

METHODS

Consecutive dyspeptic patients with H. pylori infection were prospectively enrolled. Genotypic resistances to clarithromycin (23SrRNA mutations) and fluoroquinolones (gyrA mutations) were determined from gastric biopsy specimens using a commercially available molecular assay (GenoTypeâ HelicoDR). A tailored genotypic resistance-guided 7-day triple therapy comprised esomeprazole, amoxicillin, and either clarithromycin (wild-type 23SrRNA), levofloxacin (23SrRNA mutated/wild-type gyrA) or rifabutin (both 23SrRNA/gyrA mutated). H. pylori eradication was confirmed by 13C-urea breath test.

RESULTS

Of 148 subjects screened, 51 patients were enrolled (male/female: 27/24, mean age: 50.7±11.4 years, treatment-naïve/-experienced: 32/19). The molecular kit was easily implemented, allowing for rapid (within 24 h) and relatively inexpensive determination of H. pylori resistance (clarithromycin: 47.1%, fluoroquinolones: 15.7%, dual clarithromycin/fluoroquinolones: 7.8%). For patients who received clarithromycin-, levofloxacin- and rifabutin-containing triple therapy, the respective eradication rates were 24/27, 20/20, and 2/4 by intention-to-treat (ITT); and 24/24, 19/19 and 2/3 by per-protocol (PP) analysis. Overall eradication rates were 90.2% (95% confidence interval [CI] 77.8-96.3%) by ITT and 97.8% (95%CI 87-99.8%) by PP analysis, showing no significant difference between treatment-naïve and -experienced patients (ITT: 87.5% vs. 94.7%, P=0.64; PP: 96.4% vs. 100%, respectively, P=1.00).

CONCLUSIONS

Regardless of prior treatment history, a genotypic resistance-guided 7-day triple therapy, based on a simple molecular assay, achieved a high H. pylori eradication rate.

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.

[The Efficacy of Moxifloxacin-containing Triple Therapy after Hybrid Therapy Failure in Helicobacter pylori Eradication]

Background/Aims

Hybrid therapy was successful in eradicating Helicobacter pylori (H. pylori) according to previous reports. However, to the best of our knowledge, there have only been a few studies evaluating the optimal choice after hybrid failure. Hence, we aimed to evaluate the efficacy of moxifloxacin-containing triple therapy after hybrid therapy failure in H. pylori eradication.

Methods

Between January 2013 and March 2016, we retrospectively reviewed patients who underwent failed hybrid therapy, as first line treatment, in eradicating H. pylori (rabeprazole and amoxicillin b.i.d for 14 days, in addition to clarithromycin and metronidazole b.i.d for final 7 days). Then, we investigated the eradication rates of moxifloxacin-containing triple therapy (rabeprazole, amoxicillin b.i.d and moxifloxacin qd) as the second line of treatment. Intention-to-treat (ITT) and per-protocol (PP) analyses were used to determine the eradication rate. We evaluated the status of H. pylori by using ¹³C-urea breath test 6 weeks after the final treatment. Moreover, compliance and adverse effects of each patient were analyzed.

Results

Among those who failed the initial hybrid therapy, 11 patients received moxifloxacin-containing triple therapy. The overall eradication rates, as determined by ITT and PP, were 72.7% (n=8/11) and 80% (n=8/10), respectively. The compliance rate was 100%, and there were no serious adverse effects.

Conclusions

Moxifloxacin-containing triple therapy can be used as a second line therapy in case of hybrid therapy failure. A large scale study is necessary to confirm the findings of this study and establish clinical evidence.

Host Determinants of Expression of the Helicobacter pylori BabA Adhesin

Expression of the Helicobacter pylori blood group antigen binding adhesin A (BabA) is more common in strains isolated from patients with peptic ulcer disease or gastric cancer, rather than asymptomatic colonization. Here we used mouse models to examine host determinants that affect H. pylori BabA expression. BabA expression was lost by phase variation as frequently in WT mice as in RAG2−/− mice that do not have functional B or T cells, and in MyD88−/−, TLR2−/− and TLR4−/− mice that are defective in toll like receptor signaling. The presence of other bacteria had no effect on BabA expression as shown by infection of germ free mice. Moreover, loss of BabA expression was not dependent on Le^b expression or the capacity of BabA to bind Le^b. Surprisingly, gender was the host determinant most associated with loss of BabA expression, which was maintained to a greater extent in male mice and was associated with greater bacterial load. These results suggest the possibility that loss of BabA expression is not driven by adaptive immunity or toll-like receptor signaling, and that BabA may have other, unrecognized functions in addition to serving as an adhesin that binds Le^b.

Comparison of sequential therapy and amoxicillin/tetracycline containing bismuth quadruple therapy for the first-line eradication of Helicobacter pylori: a prospective, multi-center, randomized clinical trial

BACKGROUND

The <80 % Helicobacter pylori eradication rate with sequential therapy is unsatisfactory. Modified bismuth quadruple therapy, replacing metronidazole with amoxicillin, could be promising because H. pylori resistance to tetracycline or to amoxicillin is relatively low. A 14-day modified bismuth quadruple protocol as first-line H. pylori treatment was compared with 10-day sequential therapy.

METHODS

In total, 390 H. pylori-infected subjects participated in the randomized clinical trial: 10-day sequential therapy (40 mg pantoprazole plus 1 g amoxicillin twice a day for 5 days, then 40 mg pantoprazole and 500 mg clarithromycin twice a day and 500 mg metronidazole three times a day for 5 days) or 14-day modified bismuth quadruple therapy (40 mg pantoprazole, 600 mg bismuth subcitrate, 1 g tetracycline, and 1 g amoxicillin, twice a day). (13)C-urea breath test, rapid urease testing, or histology was performed to check for eradication.

RESULTS

Intention-to-treat (ITT) eradication rates of 10-day sequential and 14-day quadruple therapy were 74.6 % and 68.7 %, respectively, and the per-protocol (PP) rates were 84.2 and 76.5 %, respectively. The eradication rate was higher in the sequential therapy group, but neither the ITT nor the PP analyses had a significant difference (P = 0.240 and P = 0.099, respectively). However, the adverse events were significantly lower in the modified bismuth quadruple therapy group than the sequential therapy group (36.9 vs. 47.7 %, P = 0.040).

CONCLUSIONS

Ten-day sequential therapy appears to be more effective despite frequent adverse events. However, both 10-day SQT and 14-day PBAT did not reach the excellent eradication rates that exceed 90 %. Additional trials are needed to identify a more satisfactory first-line eradication therapy.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT02159976 ); Registration date: 2014-06-03, CRIS ( KCT0001176 ); Registration date: 2014-07-23.

Quinolone-based first, second and third-line therapies for Helicobacter pylori

Helicobacter pylori (H. pylori) is a very common bacterium that infects about 50% of the world population in urban areas and over 90% of people living in rural and developing countries. Fluoroquinolones, a class of antimicrobials, have been extensively used in eradication regimens for H. pylori. Levofloxacin is the most commonly used, and in second-line regimens, is one of the most effective options. However, an increasing resistance rate of H. pylori to fluoroquinolones is being observed, that will likely affect their effectiveness in the near future. Other novel fluoroquinolone molecules, such as moxifloxacin, sitafloxacin, gatifloxacin and gemifloxacin, have been proposed and showed encouraging results in vitro, although data on their clinical use are still limited. Further studies in large sample trials are needed to confirm their safety and efficacy profile in clinical practice.

Antimicrobial susceptibility of Canadian isolates of Helicobacter pylori in Northeastern Ontario

BACKGROUND

Helicobacter pylori plays a significant role in gastritis and ulcers. It is a carcinogen as defined by the WHO, and infection can result in adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. In Canada, rates of antimicrobial resistance are relatively unknown, with very few studies conducted in the past 15 years.

OBJECTIVE

To examine rates of resistance in Sudbury, Ontario, compare antimicrobial susceptibility methods and attempt to determine the molecular basis of antibiotic resistance.

METHODS

Patients attending scheduled visits at Health Sciences North (Sudbury, Ontario) provided gastric biopsy samples on a volunteer basis. In total, 20 H pylori isolates were collected, and antimicrobial susceptibility testing (on amoxicillin, tetracycline, metronidazole, ciprofloxacin, levofloxacin and clarithromycin) was conducted using disk diffusion and E-test methods. Subsequently, genomic DNA from these isolates was sequenced to detect mutations associated with antimicrobial resistance.

RESULTS

Sixty-five percent of the isolates were found to be resistant to at least one of the listed antibiotics according to E-test. Three isolates were found to be resistant to ≥3 of the above-mentioned antibiotics. Notably, 25% of the isolates were found to be resistant to both metronidazole and clarithromycin, two antibiotics that are normally prescribed as part of first-line regimens in the treatment of H pylori infections in Canada and most of the world. Among the resistant strains, the sequences of 23S ribosomal RNA and gyrA, which are linked to clarithromycin and ciprofloxacin/levofloxacin resistance, respectively, revealed the presence of known point mutations associated with antimicrobial resistance.

CONCLUSIONS

In general, resistance to metronidazole, ciprofloxacin/levofloxacin and clarithromycin has increased since the studies in the early 2000s. These results suggest that surveillance programs of H pylori antibiotic resistance may need to be revisited or improved to prevent antimicrobial therapy failure.

Helicobacter pylori Eradication in Patients with Immune Thrombocytopenic Purpura: A Review and the Role of Biogeography

Idiopathic thrombocytopenic purpura (ITP) is typically a diagnosis of exclusion, assigned by clinicians after ruling out other identifiable etiologies. Since a report by Gasbarrini et al. in 1998, an accumulating body of evidence has proposed a pathophysiological link between ITP and chronic Helicobacter pylori (H. pylori) infection. Clinical reports have described a spontaneous resolution of ITP symptoms in about 50% of chronic ITP patients following empirical treatment of H. pylori infection, but response appears to be geography dependent. Studies have also documented that ITP patients in East Asian countries are more likely to express positive antibody titers against H. pylori-specific cytotoxic-associated gene A (CagA), a virulence factor that is associated with an increased risk for gastric diseases including carcinoma. While a definitive mechanism by which H. pylori may induce thrombocytopenia remains elusive, proposed pathways include molecular mimicry of CagA by host autoantibodies against platelet surface glycoproteins, as well as perturbations in the phagocytic activity of monocytes. Traditional treatments of ITP have been largely empirical, involving the use of immunosuppressive agents and immunoglobulin therapy. However, based on the findings of clinical reports emerging over the past 20 years, health organizations around the world increasingly suggest the detection and eradication of H. pylori as a treatment for ITP. Elucidating the exact molecular mechanisms of platelet activation in H. pylori-positive ITP patients, while considering biogeographical differences in response rates, could offer insight into how best to use clinical H. pylori eradication to treat ITP, but will require well-designed studies to confirm the suggested causative relationship between bacterial infection and an autoimmune disease state.

Gastroretentive montmorillonite-tetracycline nanoclay for the treatment of Helicobacter pylori infection

The paper aims to explore the potential benefits provided by an organically modified montmorillonite (nanoclay) in the problematic management of the Helicobacter pylori gastric infection that is one of the most prevalent infectious diseases worldwide. Two nanoclay samples were produced by the intercalation of tetracycline (TC) into the interlayer of montmorillonite (MM) under two different pH reaction conditions (pH 3.0 and 8.7). MM/TC nanoclays were characterized by EDX, XRD, FTIR, DSC, drug adsorption extent, in vitro mucoadhesiveness and desorption in simulated gastric media. The reaction between MM and TC led to a complete MM cation (Na(+) and Ca(2+)) exchange process, an increase of MM characteristic interlayer spacing as well as an involvement of NHR3(+) group of TC, regardless of the reaction pH value. However, MM/TC nanoclay obtained under alkaline conditions provided a lower TC adsorption as well as a drug fraction weakly linked to MM in comparison with the nanoclay obtained in acidic conditions. Both the nanoclays exhibited good mucoadhesion properties to porcine mucin and TC desorption occurring mainly via a cation exchange process by H(+) ions. Based on the results obtained, TC intercalation into MM nanoplatelets could represent a potential advantageous approach allowing the antibiotic to distribute homogeneously on the gastric mucosa, diffuse through the gastric mucus layer and achieve the microorganism localization.

Current Helicobacter pylori treatment in 2014

Helicobacter pylori is one of the most commonly seen bacterium worldwide. It’s in the etiology of multiple gastrointestinal diseases, ranging from gastritis to gastric carcinoma. The antimicrobial therapies, which are frequently prescribed empirically, are losing their effectivity as a result of the increasing antimicrobial resistance. As the standard triple therapy is now left especially in areas with high-clarithromycin resistance due to decreased eradication rates, quadruple therapies are recommended in most regions of the world. Alternatively, concomitant, sequential and hybrid therapies are used. There is still a debate going on about the use of levofloxacin-based therapy in order to prevent the increase in quinolone resistance. If no regimen can achieve the desired eradication rate, culture-guided individualized therapies are highly recommended. Probiotics, statins and n-acetylcysteine are helpful as adjuvant therapies in order to increase the effectiveness of the eradication therapy. Herein, we focused on different eradication regimens in order to highlight the current Helicobacter pylori treatment.

Primary Antimicrobial Susceptibility Changes in Children with Helicobacter pylori Infection over 13 Years in Northern Italy

The eradication therapy of Helicobacter pylori (H. pylori) infection is still a challenge for gastroenterologists. One of the main causes of failure in H. pylori eradication is the antibiotic resistance mainly to clarithromycin. Culture from biopsies is maybe the most used method among the antimicrobial susceptibility techniques. In this study, we compared the antimicrobial susceptibility changes in children with H. pylori infection over 13 years and we confirmed that clarithromycin resistance has been increased (16% versus 26%) though with no statistically signficant value. Therefore, clarithromycin should not be used in empiric treatment of H. pylori eradication therapy in children, but its use should be limited only to children with known antimicrobial susceptibility. On the other hand, metronidazole resistance has decreased over this time period in statistically significant manner (56% versus 33%, p = 0.014). Furthermore, ampicillin resistance has been confirmed to be very rare (3% versus 0%) in children with H. pylori infection. In conclusion, in H. pylori infection, if we do not know the antibiotic susceptibility of patients, we should recommend an eradication therapy based on the local distribution of antibiotic resistance rates trying to limit the therapeutic failures.

High-dose dual therapy is superior to standard first-line or rescue therapy for Helicobacter pylori infection

BACKGROUND & AIMS

The efficacy of treatment of Helicobacter pylori infection has decreased steadily because of increasing resistance to clarithromycin, metronidazole, and levofloxacin. Resistance to amoxicillin is generally low, and high intragastric pH increases the efficacy of amoxicillin, so we investigated whether a combination of a high-dose proton pump inhibitor and amoxicillin (dual therapy) was more effective than standard first-line or rescue therapies in eradicating H pylori.

METHODS

We performed a large-scale multihospital trial to compare the efficacy of a high-dose dual therapy (HDDT) with that of standard therapies in treatment-naive (n = 450) or treatment-experienced (n = 168) patients with H pylori infection. Treatment-naive patients were randomly assigned to groups given HDDT (rabeprazole 20 mg and amoxicillin 750 mg, 4 times/day for 14 days, group A1), sequential therapy for 10 days (group B1), or clarithromycin-containing triple therapy for 7 days (group C1). Treatment-experienced patients were randomly assigned to groups given HDDT for 14 days (group A2), sequential therapy for 10 days (B2), or levofloxacin-containing triple therapy for 7 days (C2). H pylori infection was detected by using the (13)C-urea breath test. We evaluated factors associated with treatment outcomes.

RESULTS

In the intention-to-treat analysis, H pylori was eradicated in 95.3% of patients in group A1 (95% confidence interval [CI], 91.9%-98.8%), 85.3% in B1 (95% CI, 79.6%-91.1%), and 80.7% in group C1 (95% CI, 74.3%-87.1%). Infection was eradicated in 89.3% of patients in group A2 (95% CI, 80.9%-97.6%), 51.8% in group B2 (95% CI, 38.3%-65.3%), and 78.6% (95% CI, 67.5%-89.7%) in group C2. The efficacy of HDDT was significantly higher than that of currently recommended regimens, irrespective of CYP2C19 genotype. Bacterial resistance to drugs was associated with treatment failure. There were no significant differences between groups in adverse events or patient adherence.

CONCLUSIONS

HDDT is superior to standard regimens as empirical first-line or rescue therapy for H pylori infection, with similar safety profiles and tolerability. ClinicalTrials.gov number: NCT01163435.

Optimal initiation of Helicobacter pylori eradication in patients with peptic ulcer bleeding

AIM: To evaluate when Helicobacter pylori (H. pylori) eradication therapy (ET) should be started in patients with peptic ulcer bleeding (PUB).

METHODS: Clinical data concerning adults hospitalized with PUB were retrospectively collected and analyzed. Age, sex, type and stage of peptic ulcer, whether endoscopic therapy was performed or not, methods of H. pylori detection, duration of hospitalization, and specialty of the attending physician were investigated. Factors influencing the confirmation of H. pylori infection prior to discharge were determined using multiple logistic regression analysis. The H. pylori eradication rates of patients who received ET during hospitalization and those who commenced ET as outpatients were compared.

RESULTS: A total of 232 patients with PUB were evaluated for H. pylori infection by histology and/or rapid urease testing. Of these patients, 53.7% (127/232) had confirmed results of H. pylori infection prior to discharge. In multivariate analysis, duration of hospitalization and ulcer stage were factors independently influencing whether H. pylori infection was confirmed before or after discharge. Among the patients discharged before confirmation of H. pylori infection, 13.3% (14/105) were lost to follow-up. Among the patients found to be H. pylori-positive after discharge, 41.4% (12/29) did not receive ET. There was no significant difference in the H. pylori eradication rate between patients who received ET during hospitalization and those who commenced ET as outpatients [intention-to-treat: 68.8% (53/77) vs 60% (12/20), P = 0.594; per-protocol: 82.8% (53/64) vs 80% (12/15), P = 0.723].

CONCLUSION: Because many patients with PUB who were discharged before H. pylori infection status was confirmed lost an opportunity to receive ET, we should confirm H. pylori infection and start ET prior to discharge.

Treatment of Helicobacter pylori infection: Past, present and future

Helicobacter pylori (H. pylori) is a major human pathogen associated with significant morbidity and mortality. However, after decades of efforts, treatment of H. pylori remains a challenge for physicians, as there is no universally effective regimen. Due to the rising prevalence of antimicrobial resistance, mainly to clarithromycin, efficacy of standard triple therapies has declined to unacceptably low levels in most parts of the world. Novel regimens, specifically experimented to improve the therapeutic outcome against antibiotic-resistant H. pylori strains, are now recommended as first-line empirical treatment options providing high efficacy (reportedly > 90% in intention to treat analysis) even in high clarithromycin resistance settings. These include the bismuth quadruple, concomitant, sequential and hybrid therapies. Due to the rapid development of quinolone resistance, levofloxacin-based regimens should be reserved as second-line/rescue options. Adjunct use of probiotics has been proposed in order to boost eradication rates and decrease occurrence of treatment-related side effects. Molecular testing methods are currently available for the characterization of H. pylori therapeutic susceptibility, including genotypic detection of macrolide resistance and evaluation of the cytochrome P450 2C19 status known to affect the metabolism of proton pump inhibitors. In the future, use of these techniques may allow for culture-free, non-invasive tailoring of therapy for H. pylori infection.

Standard triple therapy for Helicobacter pylori infection in China: a meta-analysis

AIM

To assess the efficacy and safety of standard triple therapy compared with other pre-existing and new therapies in China.

METHODS

Literature searches were conducted in the following databases: PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, the VIP database, the China National Knowledge Infrastructure database, and the Chinese Biomedical Database. A meta-analysis of all randomized controlled trials (RCTs) comparing standard triple therapy for the eradication of Helicobacter pylori with pre-existing and new therapies in China was performed using Comprehensive Meta-Analysis 2.0. There were 49 studies that met our criteria and the qualities of these studies were assessed using the Jadad scale. The Mantel-Haenszel method was used for pooling dichotomous data. We also conducted subgroup analyses according to age, duration of treatment and drug type. Sensitivity analyses and a cumulative meta-analysis were also performed with CMA 2.0. Publication bias was evaluated using Egger's test, Begg's test or a funnel plot.

RESULTS

A total of 49 RCTs including 8332 patients were assessed. This meta-analysis showed that standard triple therapy with proton pump inhibitors (PPIs), amoxicillin (AMO) and clarithromycin (CLA) was inferior to sequential therapy [relative risk (RR) = 0.863; 95% confidence interval (CI): 0.824-0.904], but was not superior to quadruple therapy (RR = 1.073; 95%CI: 0.849-1.357) or other triple therapies (RR = 1.01; 95%CI: 0.936-1.089). The meta-analysis also suggested that standard triple therapy is slightly more effective than dual therapy (RR = 1.14; 95%CI: 0.99-1.31). However, the differences were not statistically significant. We removed the only trial with a regimen lasting 14 d by sensitivity analysis and found that 7-d standard triple therapy was superior to 7-d dual therapy (RR = 1.222; 95%CI: 1.021-1.461). Moreover, a sub-analysis based on the duration of quadruple therapy indicated that the 7-d and 10-d standard triple therapies were inferior to sequential therapy (RR = 0.790; 95%CI: 0.718-0.868; RR = 0.917; 95%CI: 0.839-1.002, respectively). Additionally, there were no significant differences in cure rate or adverse events among standard triple therapy, quadruple therapy, and other triple therapies (RR = 0.940; 95%CI: 0.825-1.072; RR = 1.081; 95%CI: 0.848-1.378, respectively). Standard triple therapy had a higher occurrence of side effects than sequential therapy (RR = 1.283; 95%CI: 1.066-1.544).

CONCLUSION

The eradication rates with a standard triple therapy consisting of PPI, AMO, and CLA are suboptimal in China, and new treatment agents need to be developed.

[Future trends of Helicobacter pylori eradication therapy in Korea]

The prevalence of Helicobacter pylori infection in Korea shows a decreasing trend and has changed to that of developed country, especially for those below 30 years old. However, the primary antibiotic resistance rates are higher than those of developed countries. The reason for the decrease in the efficacy of standard triple therapy is mainly due to the increase in the resistance against clarithromycin. Sequential therapy seems to be more effective than the standard triple therapy, but the intention-to-treat eradication rate of sequential therapy in Korea, which is mostly under 80.0%, is still not satisfactory. Therefore, a promising regimen is needed. Recently, the Japanese health insurance system admitted 'H. pylori-infected gastritis'as an indication of eradication. Furthermore, the Kyoto Consensus Meeting on H. pylori Gastritis held from January 30th to February 1st, 2014, proposed that 'all H. pylori positive patients should be offered to receive H. pylori eradication'. This suggests that the concept of eradication has been changed from 'treatment' to 'prevention'. Various individualized tailored therapy based on the polymorphism, age and other demographic factors and antibiotic resistance has been attempted to maximize H. pylori eradication therapy. The aim of this article is to review the current epidemiology, H. pylori resistance state, treatment guideline, and to assess the possible future strategy and treatment for H. pylori infection in Korea.

Treatment of Helicobacter pylori infection: meeting the challenge of antimicrobial resistance

Treatment of Helicobacter pylori (H. pylori) infection is paramount for the management of prevalent gastrointestinal disorders including peptic ulcer disease and gastric cancer. Due to the wide increase in prevalence of H. pylori resistance to antibiotics, clarithromycin-based triple therapies are not any more suitable for unconditional empiric use, and should not be recommended, unless local resistance to this antibiotic is low (< 20%). Alternative strategies have been proposed to overcome the issue of increasing clarithromycin resistance, and some of them are already implemented in clinical practice. These comprise: (1) adoption of novel, more effective, empirical treatments: bismuth quadruple, sequential, non-bismuth quadruple (concomitant), dual-concomitant (hybrid), and levofloxacin-based regimens, the latter mainly designated as second-line/rescue options; (2) perspectives for a susceptibility-guided (tailored) therapeutic approach based on culture-free molecular testing methods; and (3) adjunct use of probiotics to improve eradication rates. The present article is aimed to provide a comprehensive overview of current and emerging strategies in the treatment of H. pylori infection, focusing on the challenge of antimicrobial resistance.

Helicobacter pylori: Future perspectives in therapy reflecting three decades of experience

The rising prevalence of antibiotic resistance has created a need to reassess the established Helicobacter pylori (H. pylori) eradication protocols, and to develop new ones. Various bacterial and host factors are evaluated, and their contribution to eradication failure is estimated. For a long time being considered the cornerstone eradication scheme, the standard triple therapy has been replaced with novel, more efficient regimens, namely sequential and concomitant, along with the emergence of a new design of bismuth quadruple therapy. A rescue levofloxacin based regimen has overcome the fear of therapy failure due to higher prevalence of dual resistant (clarithromycin and metronidazole) H. pylori. Culture-free and efficient susceptibility test are reestablishing the concept of tailored therapy, making eradication success close to originally desirable rates. Alleviating therapy side effects and improving patient compliance are as important as choosing appropriate eradication schemes, so various probiotic compound supplements are taken into consideration. Finally, we summarize the emerging efforts and obstacles in creating efficient H. pylori vaccine.