Treatment of Helicobacter pylori infection: Current and future insights

Implications of lncRNAs in Helicobacter pylori-associated gastrointestinal cancers: underlying mechanisms and future perspectives

Helicobacter pylori (H. pylori) is a harmful bacterium that is difficult to conveniently diagnose and effectively eradicate. Chronic H. pylori infection increases the risk of gastrointestinal diseases, even cancers. Despite the known findings, more underlying mechanisms are to be deeply explored to facilitate the development of novel prevention and treatment strategies of H. pylori infection. Long noncoding RNAs (lncRNAs) are RNAs with more than 200 nucleotides. They may be implicated in cell proliferation, inflammation and many other signaling pathways of gastrointestinal cancer progression. The dynamic expression of lncRNAs indicates their potential to be diagnostic or prognostic biomarkers. In this paper, we comprehensively summarize the processes of H. pylori infection and the treatment methods, review the known findings of lncRNA classification and functional mechanisms, elucidate the roles of lncRNAs in H. pylori-related gastrointestinal cancer, and discuss the clinical perspectives of lncRNAs.

Eradication of Helicobacter pylori: a prospective comparative randomized trial of standard versus optimized quadruple therapy

The treatment of Helicobacter pylori infection remains a challenge. None of the proposed treatment regimens has resulted in a 100% eradication rate. The aim of our study was to compare the rate of H. pylori eradication after standard or dose-optimized amoxicillin quadruple therapy. We conducted a prospective comparative study collating patients naive to any anti-H. pylori treatment and with chronic H. pylori infection documented by histological examination. Patients were randomly assigned to either standard quadruple therapy or optimized quadruple therapy. Eradication control was performed by urea breath test. Eighty-eight eligible patients were included with 44 in each group.There was no significant difference between the eradication rates of Qo-14 and Qs-14 neither in ITT (84 vs 70.4%; p = 0.127) nor in PP (82.1 vs 77.7%; p = 0.473). Compliance and tolerance appeared similar in each group.

Chemical constituents of the aerial parts of Mitracarpus hirtus (L.) DC (Rubiaceae)

A phytochemical investigation of the aerial parts of Mitracarpus hirtus afforded thirteen compounds, including a new naphthoquinone di-glycoside (1), three isopentenyl isoflavones (2-4), four flavonoids (5-8), three iridoid glycosides (9 - 11) and two coumarins (12 and 13). Their structures were elucidated based on extensive spectroscopic analyses, chemical methods, and the comparison with the literature. Among them, compound 1 possesses a 2-(3-methylnaphthalen-2-yl)acetic acid core with two glucosyl groups, compounds 2-4 are the first three representatives from the Rubiaceae family, and compounds 9-11 and 13 were isolated from Mitracarpus genus for the first time. Additionally, compounds 2-4 displayed potent antibacterial activities against Helicobacter pylori G27/HP159/JRES00015 (MIC = 4-16 μg/mL) , comparable to metronidazole. To date, wighteone (2) is the most active isoflavone with favourable predicted ADMET properties reported against H. pylori.

Role of proton pump inhibitors dosage and duration in Helicobacter pylori eradication treatment: Results from the European Registry on H. pylori management

BACKGROUND

Management of Helicobacter pylori (H. pylori) infection requires co-treatment with proton pump inhibitors (PPIs) and the use of antibiotics to achieve successful eradication.

AIM

To evaluate the role of dosage of PPIs and the duration of therapy in the effectiveness of H. pylori eradication treatments based on the 'European Registry on Helicobacter pylori management' (Hp-EuReg).

METHODS

Hp-EuReg is a multicentre, prospective, non-interventionist, international registry on the routine clinical practice of H. pylori management by European gastroenterologists. All infected adult patients were systematically registered from 2013 to 2022.

RESULTS

Overall, 36,579 patients from five countries with more than 1000 patients were analysed. Optimal (≥90%) first-line-modified intention-to-treat effectiveness was achieved with the following treatments: (1) 14-day therapies with clarithromycin-amoxicillin-bismuth and metronidazole-tetracycline-bismuth, both independently of the PPI dose prescribed; (2) All 10-day (except 10-day standard triple therapy) and 14-day therapies with high-dose PPIs; and (3) 10-day quadruple therapies with clarithromycin-amoxicillin-bismuth, metronidazole-tetracycline-bismuth, and clarithromycin-amoxicillin-metronidazole (sequential), all with standard-dose PPIs. In first-line treatment, optimal effectiveness was obtained with high-dose PPIs in all 14-day treatments, in 10- and 14-day bismuth quadruple therapies and in 10-day sequential with standard-dose PPIs. Optimal second-line effectiveness was achieved with (1) metronidazole-tetracycline-bismuth quadruple therapy for 14- and 10 days with standard and high-dose PPIs, respectively; and (2) levofloxacin-amoxicillin triple therapy for 14 days with high-dose PPIs. None of the 7-day therapies in both treatment lines achieved optimal effectiveness.

CONCLUSIONS

We recommend, in first-line treatment, the use of high-dose PPIs in 14-day triple therapy and in 10-or 14-day quadruple concomitant therapy in first-line treatment, while standard-dose PPIs would be sufficient in 10-day bismuth quadruple therapies. On the other hand, in second-line treatment, high-dose PPIs would be more beneficial in 14-day triple therapy with levofloxacin and amoxicillin or in 10-day bismuth quadruple therapy either as a three-in-one single capsule or in the traditional scheme.

Helicobacter pylori: A Contemporary Perspective on Pathogenesis, Diagnosis and Treatment Strategies

Helicobacter pylori (H. pylori) is a Gram-negative bacterium that colonizes the gastric mucosa and is associated with various gastrointestinal disorders. H. pylori is a pervasive pathogen, infecting nearly 50% of the world's population, and presents a substantial concern due to its link with gastric cancer, ranking as the third most common cause of global cancer-related mortality. This review article provides an updated and comprehensive overview of the current understanding of H. pylori infection, focusing on its pathogenesis, diagnosis, and treatment strategies. The intricate mechanisms underlying its pathogenesis, including the virulence factors and host interactions, are discussed in detail. The diagnostic methods, ranging from the traditional techniques to the advanced molecular approaches, are explored, highlighting their strengths and limitations. The evolving landscape of treatment strategies, including antibiotic regimens and emerging therapeutic approaches, is thoroughly examined. Through a critical synthesis of the recent research findings, this article offers valuable insights into the contemporary knowledge of Helicobacter pylori infection, guiding both clinicians and researchers toward effective management and future directions in combating this global health challenge.

Efficacy and Safety of Potassium-Competitive Acid Blockers Versus Proton Pump Inhibitors as Helicobacter pylori Eradication Therapy: A Meta-Analysis of Randomized Clinical Trials

Helicobacter pylori is a gram-negative bacterium that chronically infects the gastric epithelium. Potassium-competitive acid blockers (P-CABs) are a promising alternative, being more potent than standard proton pump inhibitors (PPIs). The meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria were randomized controlled trials (RCTs) comparing P-CAB and PPI-based therapy, confirmed H. pylori infection, and measured eradication rates after at least four weeks. Subgroup analyses were conducted based on therapy type and trial location. Quality assessment used the Cochrane risk-of-bias tool, RoB 2.0, and statistical analysis was performed using ReviewManager (RevMan) 5.4 (2020; The Cochrane Collaboration, London, United Kingdom). A p-value of <0.05 is considered statistically significant. In the intention-to-treat (ITT) analysis, P-CABs demonstrated superior overall efficacy, consistently observed in the first-line treatment subgroup. However, no significant difference was found in the subgroup receiving salvage therapy. Another ITT subgroup analyzed the impact of geographical location, favoring P-CABs in the overall study population and the Japanese subgroup. However, no statistically significant differences were found in the subgroups of other countries. In the PPA, P-CABs showed superior efficacy overall, consistently seen in the first-line treatment subgroup. However, no significant difference was found in the subgroup receiving salvage eradication therapy. Another PPA subgroup analysis considered the geographical impact on eradication rates, revealing P-CABs as superior to PPIs in the overall study population and the Japanese subgroup, but not in other countries. No significant adverse event outcomes were observed. P-CAB-based triple therapy is more effective than PPI-based triple therapy as the primary treatment for H. pylori eradication, particularly in Japanese patients. Nevertheless, regarding salvage therapy, both treatments show comparable efficacy. Additionally, the tolerability of P-CAB-based and PPI-based triple therapy is similar, with a similar occurrence of adverse events.

Treatment of Helicobacter pylori infection 14-day concomitant quadruple therapy versus triple therapy: A parallel double-blind randomized controlled trial

Background and Aims

Successful Helicobacter pylori (Hp) eradication with the traditional 7-day course of proton pump inhibitor triple therapy is declining. Prolonging therapy to 14 days is associated with better eradication rates. Most learned societies recommend concomitant quadruple therapy (QC) as a first-line alternative therapy for this bacterial infection. The aim of this study is to compare the efficacy and safety of triple therapy (TT) and QC for the eradication of Hp infection.

Methods

A parallel double-blind randomized controlled trial was conducted. The diagnosis of Hp infection was made by pathological examination of gastric biopsies. Patients were randomly assigned to two treatment groups: either QC (esomeprazole 80 mg, amoxicillin 2000 mg, clarithromycin 1000 mg, and metronidazole 1000 mg daily) or triple therapy (esomeprazole 80 mg, amoxicillin 2000 mg, and clarithromycin 1000 mg daily in divided doses) for 14 days. The efficacy of the treatment is defined by Hp eradication attested by a negative breath test performed 6 weeks after the completion of treatment. Treatment outcomes were compared using the chi-square test, while binary logistic regression identified predictors of treatment failure.

Results

Ninety-two patients were included. Forty-two patients belonged to the QC group and 50 to the TT group. No significant difference was noted between the two groups concerning the rate of Hp eradication either by intention to treat (81% vs. 72% respectively, p = 0.31) or per protocol (81.6% vs. 76.1% respectively, p = 0.54). Likewise, there was no difference between the two groups in terms of tolerance to treatment (59.5% for QC vs. 58% for TT, p = 0.88). No factor has been associated with treatment failure.

Conclusion

There was no significant difference in the rate of HP eradication between the QC and the 14-day triple therapy. Neither regimen should be used topically because of their low eradication rates.

Targeted delivery of a short antimicrobial peptide (CM11) against Helicobacter pylori gastric infection using concanavalin A-coated chitosan nanoparticles

Helicobacter pylori is the cause of most cases of stomach ulcers and also causes some digestive cancers. The emergence and spread of antibiotic-resistant strains of H. pylori is one of the most important challenges in the treatment of its infections. The present study aims to develop a concanavalin A (ConA) coated chitosan (CS) nanocarrier-based drug delivery for the targeted release of peptides to the site of H. pylori infection. Accordingly, chitosan was used as an encapsulating agent for CM11 peptide delivery by applying ionotropic gelation method. Con-A was used for coating CS nanoparticles to target H. pylori. The CS NPs and ConA-CS NPs were characterized by FTIR, dynamic light scattering (DLS), and scanning electron microscopy (SEM). The MIC of CM11-loaded ConA-CS NPs against H. pylori SS1 strain was analyzed in vitro. In order to evaluate the treatment efficiency in vivo, a gastric infection model of H. pylori SS1 strain was established in mice and histopathological studies and IL-1β cytokine assay were performed. Based on the results, the size frequency for CS NPs and ConA-CS NPs was about 200 and 350 nm, respectively. The prepared CM11-loaded ConA-CS NPs exhibited antibacterial activity against H. pylori SS1 strain with a concentration of 32 µg/ml. The highest healing process was observed in synthesized CM11-loaded ConA-CS NPs treatments and a significant decrease in IL-1β was observed. Our findings highlight the potential of chitosan nanoparticles as a drug delivery vehicle in the treatment of gastric infection model of H. pylori SS1 strain.

Unusually high clarithromycin resistance in Mycobacterium abscessus subsp. abscessus isolated from human gastric epithelium

Mycobacterium abscessus subsp. abscessus is a rapidly growing facultative intracellular pathogen that usually infects human lung and skin epithelium. Recently, we and another group have shown that it also has the potential to colonize human gastric epithelium, but its significance with respect to gastric diseases remains unclear. Although Helicobacter pylori still remains the only definite gastric pathogen, recent studies have shown that M. abscessus subsp. abscessus also has the potential to colonize human gastric epithelium. M. abscessus subsp. abscessus is known to exhibit multidrug resistance and clarithromycin has been used as the drug of choice. We aimed to determine the clarithromycin resistance profile of 117 (74 rough and 43 smooth) gastric M. abscessus subsp. abscessus strains and to detect the point mutations in rrl and erm (41) genes conferring the resistance. Our data showed 79.48% (19 smooth and 74 rough) of M. abscessus subsp. abscessus strains were resistant to clarithromycin (MIC90 ≤ 512 μg/mL), while 20.51% (24 smooth) were susceptible (MIC90 ≤ 8 μg/mL). Nucleotide sequence analysis of the rrl gene with reference strains of M. abscessus subsp. abscessus did not show any mutation that is relevant to the clarithromycin resistance. However, analysis of erm (41) gene showed that M. abscessus subsp. abscessus strains, which were susceptible to clarithromycin had C, C, G, and C at their nucleotide positions 28, 159, 238, and 330, respectively, while the resistant strains showed T, T, A, and A at the same positions. Based on antibiogram and sequence analysis data we recommend further studies involving genomic analysis to identify the other genes involved in high clarithromycin resistance in gastric M. abscessus subsp. abscessus along with the mechanisms involved.

Single-capsule bismuth-based quadruple therapy as a rescue therapy for Helicobacter pylori eradication

INTRODUCTION

Helicobacter pylori (H. pylori) infection is highly prevalent in Portugal and its eradication is formally recommended. However, the indiscriminate use of antimicrobials has led to a drastic rise in antibiotic resistance, with the failure of traditional eradication schemes. A single-capsule bismuth-based quadruple therapy became recently available in Portugal. This study aims to evaluate the efficacy and safety of a bismuth-based quadruple therapy as a second-line or rescue therapy.

PATIENTS AND METHODS

This was a multicentric study. All consecutive patients that were treated with bismuth-based quadruple therapy, as second-line or salvage treatment between July 2017 and April 2019 were enrolled. Their medical records were reviewed and clinical and laboratorial parameters, as well as data on treatment efficacy and adverse events were retrieved. Patients were also contacted by phone after treatment to confirm compliance, adverse events, and global satisfaction with this specific therapy.

RESULTS

A total of 151 subjects were included (female-68.9%; mean age-56 ± 13.5 years). Patients were previously submitted to 212 eradication schemes (Median-1; 1-5; IQR:4): 33.5% triple clarithromycin-based, 25% sequential, 7.5% concomitant, 5.2% others, and in 28.8% it was not possible to know the previous eradication scheme(s) followed by the patient. The PPI of choice was esomeprazole (39.7%), followed by omeprazole (27.8%). Compliance was achieved in 93.4% and the overall eradication rate was 90.1% (95% CI: 84.6-94.2). Treatment-related adverse effects were experienced by 63 patients (41.7%; 95% CI: 34-49.7), being mild in 29, moderate in 19, and severe in 15. The main drawbacks of the treatment, from the patient's perspective, were the high price (47%) and the adverse effects (16.6%). Failure to eradicate H. pylori was correlated with the following: previous rifabutin-based scheme (0 vs. 100%; p = 0.010) and a higher number of previous treatment schemes (1.5 ± 0.7 vs. 2.3 ± 1.2; p < 0.001).

CONCLUSION

In this South-European country a single-capsule bismuth-based quadruple therapy is an excellent option as a second-line or rescue therapy, with acceptable compliance and side effects.

The Importance of Accurate Early Diagnosis and Eradication in Helicobacter pylori Infection: Pictorial Summary Review in Children and Adults

Among the most widespread childhood infections, Helicobacter pylori (H. pylori) develops potentially life-threatening conditions in adults if not appropriately treated. Helicobacter pylori is a common human pathogen that was first described in the stomach many years ago. The discovery of H. pylori was crucial in gastroenterology; this bacterium is associated with chronic gastritis, peptic ulcers, gastric cancer, and lymphoid tissue lymphoma related to the gastric mucosa. Studies published so far estimate that approximately 10% of subjects infected with H. pylori develop a peptic ulcer, and 1-3% of subjects develop gastric cancer. The clinical manifestations are variable and characteristically depend on the individual factors of the host. Various methods of detection and diagnosis of H. pylori infection have been developed, each with advantages, disadvantages, and/or limitations. Available diagnostic tests are usually performed using invasive (endoscopy, biopsy, rapid urease test, cultures, and molecular tests) and noninvasive methods (urea breath test, stool antigen examination, and serological and molecular tests). Although there is extensive accessibility for diagnosing and treating H. pylori infection, the prevalence of antibiotic resistance is not negligible. Thus, numerous studies and meta-analyses are focused on a new orientation of gastroenterologists in diagnosing and treating H. pylori infections. A fascinating perspective hypothesis is the administration of probiotics to reduce H. pylori adhesion to gastric epithelial cells, preventing H. pylori colonization, especially in children, or reinfection with H. pylori in high-risk adult patients.

Helicobacter pylori Antibiotic Resistance in Egypt: A Single-Center Study

Purpose

Helicobacter pylori (H. pylori) is the most common human bacterial infection worldwide, infecting approximately half of the world’s population. Although antibiotic use is indicated for H. pylori eradication, the recommended type of antibiotic varies from country to country according to the H. pylori resistance pattern; developing countries, such as Egypt, may have different patterns than developed countries. We evaluated the antibiotic resistance of H. pylori in Egypt.

Methods

This cross-sectional study included 134 adult patients with upper gastrointestinal (GI) complaints. Patients with a history of PPI during the last 2 weeks or antibiotics during the last 4 weeks before endoscopy were excluded. Upper GI endoscopies were performed and biopsies were collected for histopathology and H. pylori culture. Demographic, clinical, and endoscopic data were also collected. Antimicrobial susceptibility testing for H. pylori was performed for nine therapeutically relevant antibiotics using the Kirby–Bauer disc diffusion method.

Results

The H. pylori antibiotic resistance rates were as follows: moxifloxacin, 10%; doxycycline, 15%; levofloxacin, 20%; clarithromycin, 40%; azithromycin, 40%; erythromycin, 65%; rifampicin, 90%; amoxicillin, 95%; and metronidazole, 100%. Dual resistance rates were 40% for amoxicillin/clarithromycin, 40% for metronidazole/clarithromycin, and 95% for amoxicillin/metronidazole.

Conclusion

In Egyptian patients, H. pylori had >90% resistance to metronidazole and amoxicillin; modest resistance to erythromycin, azithromycin, and clarithromycin; and low resistance to moxifloxacin, and levofloxacin (≤20%). Dual resistance was high for amoxicillin/clarithromycin and amoxicillin/metronidazole, which prefers using quinolones rather than clarithromycin or metronidazole for first-line treatment of H. pylori in Egypt.

Antibiotic resistance status of helicobacter pylori strains isolated from initial eradication patients in Ningbo, China, from 2017 to 2021

BACKGROUND

Resistance of Helicobacter pylori (H. pylori) to antibiotics is an evolving and dynamic process. Presence of antibiotic resistance impacts the success rate of initial eradication strategies in the clinic.

AIM

To improve the success rate of initial eradication therapy and explore new antibiotic regimens, a large sample-based study utilizing antimicrobial susceptibility testing was performed. A total of 2508 H. pylori strains from patients subjected to initial eradication therapy were isolated, cultured, and tested for drug susceptibility from 2017 to 2021. The minimal inhibitory concentration (MIC) was recorded. H. pylori susceptibility profiles and its change trends from initial eradication patients were analyzed. The relationships between drug resistance, year of sample collection, age, and sex of patients were analyzed.

RESULTS

The overall resistance rates were as follows: amoxicillin (9.25%), clarithromycin (38.48%), levofloxacin (42.86%), furazolidone (11.28%), doxycycline (8.56%), rifampicin (10.81%), tinidazole (74.32%), gatifloxacin (61.71%), tetracycline (0%), metronidazole (78.71%), ornidazole (97.87%), and fosfomycin (31.67%). Only 38.04% of the strains were pansusceptible to amoxicillin, clarithromycin, levofloxacin, and furazolidone, followed by those of mono resistance (29.90%), double resistance (24.96%), triple resistance (6.34%), and quadruple resistance (0.76%). Significant differences in the resistance rate and MIC were also observed in different age and sex groups. Time of collection and patient age and sex were associated with the distribution of antibiotic resistance.

CONCLUSION

With the increasing resistance rate and multiple resistance of H. pylori to commonly used antibiotics, drug susceptibility testing is imperative to permit individualized therapy, and a regimen containing the combination of amoxicillin, furazolidone, tetracycline, doxycycline, or rifampicin is reasonable for initial empirical eradication therapy.

Correlation between the intensity of Helicobacter pylori colonization and severity of gastritis: Results of a prospective study

Helicobacter pylori infection is strongly associated with chronic gastritis and is probably the main course of chronic inflammation in the gastric mucosa. Gradually, H. pylori gastritis will result in gastric atrophy and intestinal metaplasia. Identifying the relationship between intensity of colonization and activity of gastritis helps the clinician in more effective treatment and post-treatment follow-ups. The aim of our work was to analyze the relationship between the density of H. pylori colonization of the gastric mucosa and the severity of histological parameters of gastritis (inflammation activity, gastric atrophy, and intestinal metaplasia). This was a prospective monocentric study conducted from January 2020 to December 2020, collecting patients naive to any anti-H. pylori treatment and having a chronic H. pylori infection documented by histological examination. Epidemiological, endoscopic, and anathomopathological data were collected. Ninety-seven patients with a mean age of 42.6 years [18-65 years] and a sex ratio of M/F = 0.64 were included. The density of H. pylori colonization was mild (+) in 43.3% of patients, moderate (++) in 47.4% of patients, and significant (+++) in 9.3% of patients. Nearly, ten per cent of patients had no gastritis, 33% had mild gastritis, 50.5% had moderate gastritis, and 6.2% had severe gastritis. Gastric atrophy and intestinal metaplasia were found in 44.3% and 10.3% of our population, respectively. Patients with mild H. pylori colonization rates had the highest level of mild activity (59.5%). There was a statistically significant association between the severity of H. pylori infection and gastritis activity (p < .001). Gastric atrophy was significantly associated with the intensity of H. pylori colonization (p = .049). No significant relationship was found between the intensity of colonization and metaplasia (p = .08). Our study shows that there is a statistically significant association between the density of H. pylori and histopathological findings including gastritis activity and intestinal atrophy.

Synergistic Effect between Amoxicillin and Zinc Oxide Nanoparticles Reduced by Oak Gall Extract against Helicobacter pylori

Helicobacter pylori (H. pylori) is a global health threat, and the World Health Organization has included H. pylori among 12 bacterial species that require high priority future strategies for the development of new antibiotics due mainly to its high rates of resistance. Metallic nanoparticles are known for their antimicrobial properties. The FDA (Food and Drug Administration) has approved zinc oxide nanoparticles (ZnONPs) as biocompatible antimicrobials. Green synthesis of ZnONPs was performed based on Oak galls extract (OGE) and was characterized by UV, IR, DLS, TEM, and SEM measurements. In addition, LC-MS/MS was used for the identification of OGE constituents. A checkerboard assay was used to evaluate the activity of synthesized Qi-ZnONPs and OGE against H. pylori, and their synergistic effects with amoxicillin were evaluated. LC-MS/MS analyses identified 20 compounds as major gallic acid conjugates. The ZnONPs had average particle sizes of 5.5 nm (DLS) and 7.99 nm (TEM). Both OGE and Qi-ZnONPs exhibited moderate activity against H. pylori. Amoxicillin and Qi-ZnONPs combinations (1:2 and 1:4 amoxicillin:/Qi-ZnONPs) significantly decreased the MIC₉₀ by two-fold and four-fold, respectively, and FIC values for the combinations were more significant than with OGE alone. OGE is rich in phenolics. The synergism between Qi-ZnONPs and amoxicillin can provide an alternative safe agent of low cost to combat H. Pylori infections.

Randomized Clinical Trial on the Efficacy of Triple Therapy Versus Sequential Therapy in Helicobacter pylori Eradication

Introduction: Helicobacter pylori (H. pylori) colonization is prevalent all over the world, and it is associated with low socioeconomic status, poor hygiene, and overcrowding. Its eradication is important since it is an etiologic agent for gastritis, peptic ulcer, gastric carcinoma, and mucosa-associated lymphoid tissue lymphoma. Different regimens are available for the eradication of H. pylori and include triple therapy and sequential therapy. Our study aims to compare the efficacy of triple therapy versus sequential therapy in the eradication of H. pylori.

Material and methods: This randomized clinical trial was conducted at the Pakistan Institute of Medical Sciences Hospital, Islamabad, from September 2016 to September 2017 after the approval of the institutional review board. A total of 160 patients were enrolled and equally divided into two, group A and group B. A twice-daily dose of amoxicillin 1,000 mg, rabeprazole 20 mg, and clarithromycin 500 mg was given to group A for 10 days, while group B was initially given rabeprazole 20 mg and amoxicillin 1,000 mg two times daily for the first five days (i.e., induction phase), followed by triple therapy that included rabeprazole 20 mg, clarithromycin 500 mg, and metronidazole/tinidazole 500 mg twice daily for the next five days. A negative stool antigen test performed four weeks after the completion of therapy was considered an effective eradication. A proforma was used to collect data that included age, gender, city or province of residence, family income, group (group A or group B), and eradication efficacy. Analysis of the data was performed using the Statistical Package for the Social Sciences version 17 (SPSS Inc., Chicago, USA).

Results: A total of 160 patients were included, with mean age and standard deviation of 40.02±24.4 years. The male/female ratio was 1.8:1. Successful eradication of H. pylori achieved in group A was 67.5% (N=54) in comparison to group B, which was 95% (N=76) (p=0.001).

Conclusion: Sequential therapy was superior to triple therapy in H. pylori eradication.

Rational Development of Bacterial Ureases Inhibitors

Urease, an enzyme that catalyzes the hydrolysis of urea, is a virulence factor of various pathogenic bacteria. In particular, Helicobacter pylori, that colonizes the digestive tract and Proteus spp., that can infect the urinary tract, are related to urease activity. Therefore, urease inhibitors are considered as potential therapeutics against these infections. This review describes current knowledge of the structures, activity, and biological importance of bacterial ureases. Moreover, the structure-based design of several classes of bacterial urease inhibitors is presented and discussed. Phosphinic and phosphonic acids were applied as transition-state analogues, while Michael acceptors and ebselen derivatives were applied as covalent binders of cysteine residue. This review incorporates bacterial urease inhibitors from literature published between 2008 and 2021.

Synergistic activity and molecular modelling of fosfomycin combinations with some antibiotics against multidrug resistant Helicobacter pylori

Antibiotic resistance represents the main challenge of Helicobacter pylori infection worldwide. This study investigates the potential bactericidal effects of fosfomycin combinations with clarithromycin, metronidazole, ciprofloxacin, amoxicillin, rifampicin, and doxycycline against thirty-six H. pylori strains using the checkerboard and time-kill assay methods. The results showed that ≥ 50% of the strains were resistant to the six antibiotics. Remarkably, only six strains exerted resistance to these antibiotics, with the minimum inhibitory concentrations (MICs) ranges of (3.2–12.8 mg/l), (32–256 mg/l), (3.2–51.2 mg/l), (3.2–25.6 mg/l), (1.6–3.2 mg/l), and (25.6 > 51.2 mg/l), respectively. The seven antibiotics were evaluated through in silico studies for their permeability and ability to bind UDP-N-acetylglucosamine1-carboxyvinyltransferase (MurA) of H. pylori. The results indicated that fosfomycin exhibited the highest predicted membrane permeability (membrane ∆G insert = − 37.54 kcal/mol) and binding affinity (docking score = − 5.310 kcal/mol) for H. pylori MurA, compared to other tested antibiotics. The combinations of fosfomycin with these antibiotics exerted synergistic interactions (Fractional inhibitory concentration, FIC index < 1) against the six strains. Importantly, the combinations of fosfomycin with clarithromycin, doxycycline and rifampicin achieved bactericidal effects (reduction ≥ 3.0 Log₁₀ cfu/ml) against the most resistant H. pylori strain. Notably, these effects increased with presence of metronidazole, which enhanced the activity of the fosfomycin combination with amoxicillin from a weak inhibition to bactericidal effect. This study provides evidence that the combination of fosfomycin with either clarithromycin, amoxicillin, doxycycline, or rifampicin (especially with the presence of metronidazole) could be a promising option for treating MDR H. pylori infection.

Quinone Derivatives as Promising Anti-Helicobacter pylori Agents from Aerial Parts of Mitracarpus hirtus

Seven new naphthoquinone diglycosides (1-7), three new anthraquinones (8-10), and eight known analogues were obtained from the aerial parts of Mitracarpus hirtus collected from West Africa in a bioassay-guided phytochemical investigation. All isolated compounds were elucidated by comparison with the literature and interpretation of spectroscopic data, and the absolute configurations of the new naphthoquinone diglycosides (1-10) were confirmed by chemical methods and ECD calculations. Notably, compound 1 was found to be the first naphthoquinone diglycoside containing carboxylic acid and isopentenyl side chains isolated from a species in the genus Mitracarpus. Compounds 6-18 showed antibacterial activity against multiple Helicobacter pylori strains with MIC values ranging from 0.0625 to 64 μg/mL. Particularly, 1-hydroxybenzoisochromanquinone (17) and benzo[g]isoquinoline-5,10-dione (18), with MIC values of 0.0625 and 0.125 μg/mL, displayed 32-512-fold higher potencies than a positive control, metronidazole. Compound 18 also demonstrated high antibiofilm activity and killed biofilm-encased Helicobacter pylori cells more effectively than metronidazole.

Mutants of Helicobacter pylori IMPDH: Kinetics and in silico Studies to Determine the Structural and Functional Role of Key Amino Acids

The emergence of antibiotic-resistant strains of Helicobacter pylori necessitates the development of novel therapeutic strategies to fight against its infection. Recently, the enzyme inosine-5'-monophosphate dehydrogenase (IMPDH) has emerged as a promising target to treat bacterial infections due to its crucial role in the de novo purine biosynthesis pathway. The differences between the prokaryotic and eukaryotic IMPDHs, in the NAD + binding domain and flap region, allow the identification of pathogen-specific inhibitors. In the present study, seven point mutants of wild type Helicobacter pylori IMPDH are constructed by site-directed mutagenesis, and characterized using in silico and kinetic studies. Point mutations in the NAD + binding domain and the flap region are shown to impart significant changes in the enzyme's structure and function. In addition, the product inhibition characteristics of the Arg396-Tyr397 dyad (RY dyad) show that both the residues are important for water activation in the reaction. The results obtained are beneficial for the design and development of small molecule inhibitors, capable of species-specific inhibition.

Effect of a Probiotic Mixture in Captive Cheetahs (Acinonyx Jubatus) with Gastrointestinal Symptoms—A Pilot Study

Simple Summary

In recent years, many studies have demonstrated the effectiveness of probiotics in acute and chronic gastrointestinal disorders in both humans and animals. The objective of this study is to evaluate the effect of a specific probiotic mixture in cheetahs. In the wild, cheetah populations have drastically reduced due to habitat destruction, human–wildlife conflict and illegal wildlife trade. In captivity, chronic gastrointestinal diseases have a high prevalence. Based on our results, it can be concluded that probiotics may be helpful as a dietary supplement in cheetahs suffering from gastrointestinal disease.

Abstract

Cheetahs (Acinonyx jubatus) are classified as “vulnerable” species due to the low numbers persisting in the wild. Gastrointestinal diseases are very common in this species when they are kept in captivity, in particular gastritis. Clinical signs are predominantly characterized by vomiting, diarrhea, weight loss and anorexia. In this study, we evaluated the efficacy of a multi-strain probiotic in two groups of cheetahs: Group A (n = 4)—rescued cheetahs housed at the Cheetah Conservation Fund (Otjiwarongo, Namibia); Group B (n = 9)—captive cheetahs housed in Italian zoos. Animals showed gastrointestinal signs of different severity, and were positive for Helicobacter spp., detected by PCR in stool samples. Two sachets of probiotic formulation were administered to all cheetahs once a day for 21 consecutive days. Clinical conditions (appetite loss, vomiting, stool consistency and Body Condition Score) before (T0) and after 21 days of probiotic administration (T1) were then compared using a simplified Feline Chronic Enteropathy Activity Index (FCEAI) score. A slight but not significant improvement in the scores was observed in Group A, which had mild intestinal symptoms, while a significant decrease in vomiting and stool consistency (**p < 0.01) scores was observed in Group B, which had more pronounced symptoms. Results suggest that high concentrations of live probiotics can be of help in managing gastrointestinal signs in cheetahs.

Improving Antibacterial Activity of a HtrA Protease Inhibitor JO146 against Helicobacter pylori: A Novel Approach Using Microfluidics-Engineered PLGA Nanoparticles

Nanoparticle drug delivery systems have emerged as a promising strategy for overcoming limitations of antimicrobial drugs such as stability, bioavailability, and insufficient exposure to the hard-to-reach bacterial drug targets. Although size is a vital colloidal feature of nanoparticles that governs biological interactions, the absence of well-defined size control technology has hampered the investigation of optimal nanoparticle size for targeting bacterial cells. Previously, we identified a lead antichlamydial compound JO146 against the high temperature requirement A (HtrA) protease, a promising antibacterial target involved in protein quality control and virulence. Here, we reveal that JO146 was active against Helicobacter pylori with a minimum bactericidal concentration of 18.8–75.2 µg/mL. Microfluidic technology using a design of experiments approach was utilized to formulate JO146-loaded poly(lactic-co-glycolic) acid nanoparticles and explore the effect of the nanoparticle size on drug delivery. JO146-loaded nanoparticles of three different sizes (90, 150, and 220 nm) were formulated with uniform particle size distribution and drug encapsulation efficiency of up to 25%. In in vitro microdilution inhibition assays, 90 nm nanoparticles improved the minimum bactericidal concentration of JO146 two-fold against H. pylori compared to the free drug alone, highlighting that controlled engineering of nanoparticle size is important in drug delivery optimization.

In silico design and in vitro assessment of anti-Helicobacter pylori compounds as potential small-molecule arginase inhibitors

Related to a variety of gastrointestinal disorders ranging from gastric ulcer to gastric adenocarcinoma, the infection caused by the gram-negative bacteria Helicobacter pylori (H. pylori) poses as a great threat to human health; hence, the search for new treatments is a global priority. The H. pylori arginase (HPA) protein has been widely studied as one of the main virulence factors of this bacterium, being involved in the prevention of nitric oxide-mediated bacterial cell death, which is a central component of innate immunity. Given the growing need for the development of new drugs capable of combating the infection by H. pylori, the present work describes the search for new HPA inhibitors, using virtual screening techniques based on molecular docking followed by the evaluation of the proposed modes of interaction at the HPA active site. In vitro studies of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), followed by cytotoxicity activity in gastric adenocarcinoma and non-cancer cells, were performed. The results highlighted compounds 6, 11, and 13 as potential inhibitors of HPA; within these compounds, the results indicated 13 presented an improved activity toward H. pylori killing, with MIC and MBC both at 64 µg/mL. Moreover, compound 13 also presented a selectivity index of 8.3, thus being more selective for gastric adenocarcinoma cells compared to the commercial drug cisplatin. Overall, the present work demonstrates the search strategy based on in silico and in vitro techniques is able to support the rational design of new anti-H. pylori drugs.

Grafting MSI-78A onto chitosan microspheres enhances its antimicrobial activity

MSI-78A (Pexiganan A) is one of the few antimicrobial peptides (AMPs) able to kill Helicobacter pylori, a pathogenic bacterium that colonizes the gastric mucosa of half of the world's population. Antibiotics fail in 20-40% of H. pylori-infected patients, reinforcing the need for alternative treatments. Herein, a bioengineered approach was developed. MSI-78A with a C-terminal cysteine was grafted onto chitosan microspheres (AMP-ChMic) by thiol-maleimide (Michael-addition) chemistry using a long heterobifunctional spacer (NHS-PEG₁₁₃-MAL). Microspheres with ∼4 µm diameter (near H. pylori length) and stable at low pH were produced by spray drying using a chitosan solution with an incomplete genipin crosslinking. A 3 × 10^-5 µg AMP/microsphere grafting was estimated/confirmed by UV/Vis and FTIR spectroscopies. AMP-ChMic were bactericidal against H. pylori J99 (highly pathogenic human strain) at lower concentrations than the free peptide (∼277 µg grafted MSI-78A-SH/mL vs 512 µg free MSI-78A-SH/mL), even after pre-incubation in simulated gastric conditions with pepsin. AMP-ChMic killed H. pylori by membrane destabilization and cytoplasm release in a ratio of ∼10 bacteria/microsphere. This can be attributed to H. pylori attraction to chitosan, facilitating the interaction of grafted AMP with bacterium membrane. Overall, it was demonstrated that the peptide-microsphere conjugation chemistry did not compromise the MSI-78A antimicrobial activity, instead it boosted its bactericidal performance against H. pylori. STATEMENT OF SIGNIFICANCE: Half of the world's population is infected with Helicobacter pylori, a gastric bacterium that is responsible for 90% of non-cardia gastric cancers. Therefore, H. pylori eradication is now advocated in all infected individuals. However, available antibiotic therapies fail in up to 40% patients. Antimicrobial peptides (AMPs) are appealing alternatives to antibiotics, but their high susceptibility in vivo limits their clinical translation. AMP immobilization onto biomaterials surface will overcome this problem. Herein, we demonstrate that immobilization of MSI-78A (one of the few AMPs with activity against H. pylori) onto chitosan microspheres (AMP-ChMic) enhances its anti-H. pylori activity even at acidic pH (gastric settings). These results highlight the strong potential of AMP-ChMic as an antibiotic alternative for H. pylori eradication.

Establishment of a TaqMan-MGB probe multiplex real-time PCR system for one-step levofloxacin and clarithromycin resistant Helicobacter pylori detection

Due to the abuse of antibiotics, the prevalence of antibiotic resistant Helicobacter pylori strains continues to increase. Therefore, antibiotic resistance assessment is now essential in addition to general H. pylori diagnosis in medical institutions to fulfill clinicians administering effective antibiotic regimens. However, the conventional antibiotic resistance assessment methods, such as in vitro antibiotic susceptibility test and E-test, are skilled-staff dependent and time-consuming. The aim of this study was to establish an easy-operating TaqMan-MGB probe multiplex real-time PCR system for one-step detection of levofloxacin and clarithromycin resistance mutations with concurrent H. pylori infection diagnosis. Through the optimization of primers, probes and reaction buffers, this proposed system could accurately distinguish the recombinant plasmids with different mutation markers. More importantly, the diagnosis results of this detection system exhibited excellent consistence with the gold standard of gastric biopsy and Sanger sequencing on the detection of H. pylori infection and relevant antibiotic resistant strains, the Kappa values of which all exceeded 0.90. In addition, the results of this detection system could also be applied for the prevalence statistics of antibiotic resistance patterns for patients by age, gender and geographical location. This simple and rapid system should be beneficial for clinicians issuing personalized treatments according to the patient's H. pylori strains and avoid the abuse of antibiotics.

The influence of pretreatment with PPI on Helicobacter pylori eradication: A systematic review and meta-analysis

BACKGROUND

In this meta-analysis, we aimed to comprehensively investigate the impact of pretreatment with proton pump inhibitor (PPI) on Helicobacter pylori (H. pylori) eradication and provide novel inspiration to clinical practice.

METHODS

Relevant studies were selected through PubMed, Embase, and Cochrane Library from inception to March 2021. Two reviewers performed the selection independently. The primary outcome of the meta-analysis was the eradication rate. A modified Jadad scale was used to evaluate literature quality quantitatively.

RESULTS

Ten studies were included in this research. The results showed no significant difference between PPI pretreatment and standard treatment on eradication of H. pylori [relative risk (RR): 1.17, 95% confidence interval (95% CI): 0.0.73-1.88]. There was no significant difference between the PPI pretreatment group and the standard therapy group for conventional triple therapy, PPI and amoxicillin and clarithromycin (RR: 1.29, 95% CI: 0.60-2.77). Similar results were obtained in the therapy strategy of PPI and amoxicillin and metronidazole (RR: 3.01, 95% CI: 0.62-14.74). Interestingly, for the therapy regimen of PPI and clarithromycin and metronidazole, PPI pretreatment indicated superiority on H. pylori eradication rate (RR: 0.48, 95% CI: 0.23-0.97, P < .05).

CONCLUSION

PPI pretreatment did not affect the H. pylori eradication rates, regardless of the various types of bacteriostatic antibiotic, except the therapy regimen of PPI and clarithromycin and metronidazole.

Selective inhibition of Helicobacter pylori methionine aminopeptidase by azaindole hydroxamic acid derivatives: Design, synthesis, in vitro biochemical and structural studies

Methionine aminopeptidases (MetAPs) are an important class of enzymes that work co-translationally for the removal of initiator methionine. Chemical inhibition or gene knockdown is lethal to the microbes suggesting that they can be used as antibiotic targets. However, sequence and structural similarity between the microbial and host MetAPs has been a challenge in the identification of selective inhibitors. In this study, we have analyzed several thousands of MetAP sequences and established a pattern of variation in the S1 pocket of the enzyme. Based on this knowledge, we have designed a library of 17 azaindole based hydroxamic acid derivatives which selectively inhibited the MetAP from H. pylori compared to the human counterpart. Structural studies provided the molecular basis for the selectivity.

Exploiting drug delivery systems for oral route in the peptic ulcer disease treatment

Peptic ulcer disease (PUD) is a common condition that is induced by acid and pepsin causing lesions in the mucosa of the duodenum and stomach. The pathogenesis of PUD is a many-sided scenario, which involves an imbalance between protective factors, such as prostaglandins, blood flow, and cell renewal, and aggressive ones, like alcohol abuse, smoking, Helicobacter pylori colonisation, and the use of non-steroidal anti-inflammatory drugs. The standard oral treatment is well established; however, several problems can decrease the success of this therapy, such as drug degradation in the gastric environment, low oral bioavailability, and lack of vectorisation to the target site. In this way, the use of strategies to improve the effectiveness of these conventional drugs becomes interesting. Currently, the use of drug delivery systems is being explored as an option to improve the drug therapy limitations, such as antimicrobial resistance, low bioavailability, molecule degradation in an acid environment, and low concentration of the drug at the site of action. This article provides a review of oral drug delivery systems looking for improving the treatment of PUD.

Cholesterol glucosylation-based survival strategy in Helicobacter pylori

Helicobacter pylori is a major chronic health problem, infecting more than half of the population worldwide. H. pylori infection is linked with various clinical complications ranging from gastritis to gastric cancer. The resolution of gastritis and peptic ulcer appears to be linked with the eradication of H. pylori. However, resistance to antibiotics and eradication failure rates are reaching alarmingly high levels. This calls for urgent action in finding alternate methods for H. pylori eradication. Here, we discuss the recently identified mechanism of H. pylori known as cholesterol glucosylation, mediated by the enzyme cholesterol-α-glucosyltransferase, encoded by the gene cgt. Cholesterol glucosylation serves several functions that include promoting immune evasion, enhancing antibiotic resistance, maintaining the native helical morphology, and supporting functions of prominent virulence factors such as CagA and VacA. Consequently, strategies aiming at inhibition of the cholesterol glucosylation process have the potential to attenuate the potency of H. pylori infection and abrogate H. pylori immune evasion capabilities. Knockout of H. pylori cgt results in unsuccessful colonization and elimination by the host immune responses. Moreover, blocking cholesterol glucosylation can reverse antibiotic susceptibility in H. pylori. In this work, we review the main roles of cholesterol glucosylation in H. pylori and evaluate whether this mechanism can be targeted for the development of alternate methods for eradication of H. pylori infection.

Efficacy of butyric acid inclusion in eradication regimens for <i>Helicobacter pylori </i>infection: a meta-analysis of controlled trials

Aim. Systematization of data on the efficacy and safety of butyric acid inclusion in eradication therapy (ET) regimens for Helicobacter pylori infection. Methods. Research searches were carried out in the electronic databases MEDLINE/PubMed, EMBASE, Cochrane, Google Scholar, the Russian Science Citation Index (RSCI) until November 2020. All controlled studies comparing the efficacy and/or safety of including butyric acid in ET regimens for H. pylori infection were included in the final analysis. Results. The meta-analysis included 6 controlled studies (1 Italy, 5 Russia) involving 736 patients (381 in the ET groups with butyric acid; 355 in the comparison groups). The pooled eradication efficiency in the butyric acid groups was 90.23% (95% confidence interval CI 86.73493.069), while in the comparison groups it was 65.69% (95% CI 60.44170.669). Meta-analysis showed that the addition of butyric acid to ET regimens significantly increased the eradication efficiency (odds ratio OR 5.355, 95% CI 3.5048.184; p0.001). There was no significant heterogeneity between results (p=0.1408; I2=42.1%). The addition of butyric acid to ET regimens significantly reduces the risk of diarrhea (OR 0.225, 95% CI 0.09230.549; p=0.001; I2=34.21%) and abdominal distention (OR 0.357, 95% CI 0.1550.818; p=0.015; I2=80.13%) by the end of the 1st week of treatment. Conclusion. The present meta-analysis demonstrated that the inclusion of butyric acid in ET regimens for H. pylori infection significantly increases the effectiveness of treatment and reduce the incidence of side effects. Apparently, the increase in the effectiveness of eradication is due to an increase in patient compliance with treatment due to an improvement in the safety profile of therapy.

Antibiotic Resistance Results of Helicobacter pylori in a University Hospital: Comparison of the Hybridization Test and Real-Time Polymerase Chain Reaction

Aim

H. pylori is a bacterial pathogen in the human stomach which infects about 50% of the world population. Untreated infection can lead to various diseases leading to cancer. Some of the H. pylori strains are asymptomatic, but some of them cause more severe diseases. Standard treatment protocol used for the treatment of H. pylori infection is triple therapy, which includes omeprazole as a proton pump inhibitor (PPI) and two antibiotics usually consist of amoxicillin and clarithromycin or metronidazole. In the recent years, because of the increase in the rate of antibiotic resistance, the eradication rate has decreased.

Materials and Methods

We evaluated 140 patients who applied to a university hospital gastroenterology department and underwent biopsy during endoscopy. In these patients, we analysed floroquinolone and clarithromycin resistance using the GenoType® HelicoDR (Hain Life Science, Germany). We also used the real-time method for clarithromycin resistance.

Results

We found the number and rate of floroquinolone resistance as 20 (25.6%) and clarithromycine resistance as 31 (39.7%). With the real-time PCR method, we detected clarithromycine resistance in 26 (33.3%) patients. These results were not statistically significant. Discussion and Conclusion. Our results show similarity to the other studies held in our country. There should be more studies for the policy of eradication through our country.

Pimarane-derived diterpenoids with anti-Helicobacter pylori activity from the tuber of Icacina trichantha

Two novel diterpenoids and ten known analogs were obtained from the tuber of Icacina trichantha. All compounds exhibited antibacterial activity against Helicobacter pylori strains with MIC values ranging from 8 to 64 μg mL⁻¹.

Live Attenuated Measles Virus Vaccine Expressing Helicobacter pylori Heat Shock Protein A

Measles virus (MV) Edmonston derivative strains are attractive vector platforms in vaccine development and oncolytic virotherapy. Helicobacter pylori heat shock protein A (HspA) is a bacterial heat shock chaperone with essential function as a Ni-ion scavenging protein. We generated and characterized the immunogenicity of an attenuated MV strain encoding the HspA transgene (MV-HspA). MV-HspA showed faster replication within 48 h of infection with >10-fold higher titers and faster accumulation of the MV proteins. It also demonstrated a superior tumor-killing effect in vitro against a variety of human solid tumor cell lines, including sarcoma, ovarian and breast cancer. Two intraperitoneal (i.p.) doses of 10⁶ 50% tissue culture infectious dose (TCID₅₀) MV-HspA significantly improved survival in an ovarian cancer xenograft model: 63.5 days versus 27 days for the control group. The HspA transgene induced a humoral immune response in measles-permissive Ifnarko-CD46Ge transgenic mice. Eight of nine animals developed a long-term anti-HspA antibody response with titers of 1:400 to 1:12,800 without any negative impact on development of protective anti-MV immune memory. MV-HspA triggered an immunogenic cytopathic effect as measured by an HMGB1 assay. The absence of significant elevation of PD-L1 expression indicated that vector-encoded HspA could act as an immunomodulator on the immune check point axis. These data demonstrate that MV-HspA is a potent oncolytic agent and vaccine candidate for clinical translation in cancer treatment and immunoprophylaxis against H. pylori.

Antibacterial action of acriflavine hydrochloride for eradication of the gastric pathogen Helicobacter pylori

Helicobacter pylori, a type 1 carcinogen, accounts for numerous gastric cancer-related deaths worldwide. Repurposing existing drugs or developing new ones for a combinatorial approach against increasing antimicrobial resistance is the need of the hour. This study highlights the efficacy of acriflavine hydrochloride (ACF-HCl) in inhibiting the growth of H. pylori reference strain and antibiotic-resistant clinical isolates at low concentrations. ACF-HCl inhibits H. pylori growth at MIC value 10 times less than that in Escherichia coli, another Gram-negative bacteria. Furthermore, ACF-HCl demonstrates synergistic effect with clarithromycin, a commonly used antibiotic against H. pylori. ACF-HCl treatment also eradicates H. pylori infection in the mice model efficiently. Our in vitro data indicate that bacterial membrane is the prime target. The novel action of ACF-HCl against antibiotic-resistant clinical isolates, synergistic effect with the conventional antibiotic clarithromycin and eradication of H. pylori from infected mice highlight the potential of ACF-HCl as a promising therapeutic agent against H. pylori by itself as well as for combinatorial therapy.

A comparative study of the effect of 10-day esomeprazole containing levofloxacin versus clarithromycin sequential regimens on the treatment of Iranian patients with Helicobacter pylori infection

OBJECTIVE:

Helicobacter Pylori (H. pylori) treatment may be different depending on the host and microbial factors in each region. The study was planned to estimate the effect of two 10-day esomeprazole containing clarithromycin and levofloxacin sequential therapies on H. pylori treatment.

MATERIALS AND METHODS:

Totally, 186 H. pylori-infected patients with gastro-duodenal ulcer who had not yet received treatment for infection, were enrolled. We randomly designated patients to group A (N = 94) who treated with esomeprazole 40 mg and amoxicillin 1 g bid during the early half of treatment, and continued the same dose of esomeprazole with levofloxacin 500 mg and tinidazole 500 mg bid during the second half of treatment and Group B (N = 92) who treated with the identical treatment excepting clarithromycin 500 mg bid as a substitute of levofloxacin. To assess eradication, C14-urea breath test was implemented 8 weeks afterward treatment.

RESULTS:

Finally, 172 patients completed the trial. We calculated 85.1% (95% confidence interval [CI] = 77.9–92.3) and 83.7% (95% CI = 76.2–91.2) eradication intention-to-treat analysis (P = 0.302) and so, 93.0% (95% CI = 87.6–98.4) and 90.0% (95% CI = 83.6–96.3) eradication by per-protocol analysis (P = 0.420) for Group A and B, respectively. No significant difference was seen among regimens. Drug adverse reactions were not significantly different between regimens. Group A had a 97.8% adherence rate to treatment and Group B had 98.9%.

CONCLUSIONS:

Both esomeprazole containing sequential regimens including levofloxacin and clarithromycin showed good eradication rates in spite of significant differences in antimicrobial resistance patterns in vitro. The efficacy of esomeprazole in lowering gastric acidity beside its antimicrobial effect should be considered in H. pylori regimens.

Synthesis of Fucose Derivatives with Thiol Motifs towards Suicide Inhibition of Helicobacter pylori

The syntheses of six thiol-exhibiting monosaccharides towards suicide inhibition of Helicobacter pylori are reported. Blood group Antigen Binding Adhesin (BabA), a bacterial membrane-bound lectin, binds to human ABO and Lewis b blood group structures displayed on the surface of host epithelial cells. Crystal structures of the carbohydrate-recognition domain revealed a conserved disulfide bonded loop that anchors a critical fucose residue in these blood group structures. Disruption of this loop by N-acetylcysteine results in reduced BabA-mediated adherence to human gastric tissue sections and attenuated virulence in Lewis b-expressing transgenic mice. With a view of creating specific inhibitors of the lectin, we designed and successfully synthesised six fucose-derived compounds with thiol motifs to engage in a thiol-disulfide exchange with this disulfide bond of BabA and form a glycan-lectin disulfide linkage. Branching and extending the fucose backbone with 2- and 3-carbon thiol motifs delivered a range of candidates to be tested for biological activity against BabA.

Orally administrated chitosan microspheres bind Helicobacter pylori and decrease gastric infection in mice

Persistent Helicobacter pylori (H. pylori) infection is related to 90% of gastric cancers. With bacterial resistance rising and treatment inefficiency affecting 15% of the patients, alternative treatments urge. Chitosan microspheres (ChMics) have been proposed as an H. pylori-binding system. This work evaluates ChMics biocompatibility, mucopenetration and capacity to treat H. pylori infection in mice after oral administration. ChMics of different size (XL, ∼120 µm and XS, ∼40 µm) and degree of acetylation (6% and 16%) were developed and revealed to be able to adhere both human and mouse-adapted H. pylori strains without cytotoxicity towards human gastric cells. Ex vivo studies showed that smaller (XS) microspheres penetrate further within the gastric foveolae, suggesting their ability to reach deeply adherent bacteria. In vivo assays showed 88% reduction of infection when H. pylori-infected mice (C57BL/6) were treated with more mucoadhesive XL6 and XS6 ChMics. Overall, ChMics clearly demonstrate ability to reduce H. pylori gastric infection in mice, with chitosan degree of acetylation being a dominant factor over microspheres' size on H. pylori removal efficiency. These results evidence the strong potential of this strategy as an antibiotic-free approach to fight H. pylori infection, where microspheres are orally administered, bind H. pylori in the stomach, and remove them through the gastrointestinal tract. STATEMENT OF SIGNIFICANCE: Approximately 90% of gastric cancers are caused by the carcinogenic agent Helicobacter pylori, which infects >50% of the world population. Bacterial resistance, reduced antibiotic bioavailability, and the intricate distribution of bacteria in mucus and within gastric foveolae hamper the success of most strategies to fight H. pylori. We demonstrate that an antibiotic-free therapy based on bare chitosan microspheres that bind and remove H. pylori from stomach can achieve 88% reduction of infection from H. pylori-infected mice. Changing size and mucoadhesive properties, microspheres can reach different areas of gastric mucosa: smaller and less mucoadhesive can penetrate deeper into the foveolae. This promising, simple and inexpensive strategy paves the way for a faster bench-to-bedside transition, therefore holding great potential for clinical application.

Insights into the Design of Inhibitors of the Urease Enzyme - A Major Target for the Treatment of Helicobacter pylori Infections

Expressed by a variety of plants, fungi and bacteria, the urease enzyme is directly associated with the virulence factor of many bacteria, including Helicobacter pylori, a gram-negative bacterium related to several gastrointestinal diseases and responsible for one of the most frequent bacterial infections throughout the world. The Helicobacter pylori Urease (HPU) is a nickel-dependent metalloenzyme expressed in response to the environmental stress caused by the acidic pH of the stomach. The enzyme promotes the increase of gastric pH through acid neutralization by the products of urea hydrolysis, then critically contributing to the colonization and pathogenesis of the microorganism. At the same time, standard treatments for Helicobacter pylori infections have limitations such as the increasing bacterial resistance to the antibiotics used in the clinical practice. As a strategy for the development of novel treatments, urease inhibitors have proved to be promising, with a wide range of chemical compounds, including natural, synthetic and semisynthetic products to be researched and potentially developed as new drugs. In this context, this review highlights the advances in the field of HPU inhibition, presenting and discussing the basis for the research of new molecules aiming at the identification of more efficient therapeutic entities.

Manilkara hexandra (Roxb.) Dubard Ameliorates Acetic Acid-induced Rat Gastric Ulcer

Manilkara hexandra (Roxb; Family:sapotaceae) is reported to exert preventive effect in several experimental ulcer models. However, there is no report of M. hexandra on gastric ulcer healing property. Thus, the present study was designed to evaluate the gastric ulcer healing activity of methanolic stem bark extract of M. hexandra (MH) and to derive a plausible molecular level of mechanism of action. MH was subjected to several phytochemical screening tests and standardized to quercetin by HPTLC. In the first pharmacological experiment, the standardized MH (50, 100 and 200 mg/kg) was carried out for ulcer healing activity against acetic acid (AA)-induced gastric ulcer in male rats. MH (100 and 200 mg/kg) ameliorated AA-induced rat gastric lesions. Further, MH (100 and 200 mg/kg) attenuated AA-induced changes in the levels of lipid peroxidation (LPO), reduced glutathione (GSH), oxidized glutathione (GSSG) and ratio of GSH/GSSG and activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) enzymes, and level of hame oxygenase-1 (HO-1) in stomach tissue. In the subsequent set of experiment, trigonelline (30 mg/kg; p.o.), a potent Nrf2 antagonist, significantly abrogated the gastric ulcer healing activity of MH (100 mg/kg) in AA challenged animals. Further, trigonelline attenuated the effects of MH (100 mg/kg) on the levels of LPO, GSH, GSSG and ratio of GSH/GSSG and activity of SOD, CAT, GPx and GR enzymes, and level of HO-1 in AA challenged rodents. These observations implicate the fact that MH could be a better therapeutic alternative in the management of gastric ulcer.

Helicobacter pylori Infection, Virulence Genes' Distribution and Accompanying Clinical Outcomes: The West Africa Situation

Data on Helicobacter pylori (H. pylori) infection and virulence factors in countries across West Africa are scattered. This systematic review seeks to present an update on the status of H. pylori infection focusing on prevalence rate, distribution of virulent genes, and their link to clinical outcomes across countries in the western part of Africa. This information is expected to broaden the knowledge base of clinicians and researchers regarding H. pylori infection and associated virulence factors in West African countries. Search Method. A comprehensive search of the scientific literature in PubMed and ScienceDirect was conducted using the search terms including “Helicobacter pylori infection in West Africa”. Databases were sourced from January 1988 to December 2018. Results. Data on the incidence of H. pylori infection and related pathological factors were found for some countries, whereas others had no information on it. Smoking, alcohol, exposure to high levels of carcinogens and diet were reported to be involved in the pathogenesis of gastroduodenal diseases and gastric cancer. Besides the environmental factors and genetic characteristics, there are important characteristics of H. pylori such as the ability to infect, replicate, and persist in a host that have been associated with the pathogenesis of various gastroduodenal diseases. Concluding Remarks. This systematic search has provided information so far available on H. pylori virulence factors and clinical outcomes in West Africa. Accordingly, this piece has identified gaps in the body of knowledge highlighting the need for more studies to clarify the role of H. pylori virulence factors and associated clinical outcomes in the burden of this bacterial infection in West Africa, as data from these countries do not give the needed direct relation.

Pathogenesis and clinical management of Helicobacter pylori gastric infection

Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. However, its prevalence varies among different geographic areas, and is influenced by several factors. The infection can be acquired by means of oral-oral or fecal-oral transmission, and the pathogen possesses various mechanisms that improve its capacity of mobility, adherence and manipulation of the gastric microenvironment, making possible the colonization of an organ with a highly acidic lumen. In addition, H. pylori presents a large variety of virulence factors that improve its pathogenicity, of which we highlight cytotoxin associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and gamma-glutamyl transpeptidase. The host immune system, mainly by means of a Th1-polarized response, also plays a crucial role in the infection course. Although most H. pylori-positive individuals remain asymptomatic, the infection predisposes the development of various clinical conditions as peptic ulcers, gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. Invasive and non-invasive diagnostic methods, each of them with their related advantages and limitations, have been applied in H. pylori detection. Moreover, bacterial resistance to antimicrobial therapy is a major challenge in the treatment of this infection, and new therapy alternatives are being tested to improve H. pylori eradication. Last but not least, the development of effective vaccines against H. pylori infection have been the aim of several research studies.

Efficiency of the Inclusion of Rebamipide in the Eradication Therapy for Helicobacter pylori Infection: Meta-Analysis of Randomized Controlled Studies

Background: There has been a negative trend in the effectiveness of classic eradication therapy regimens for Helicobacter pylori (H. pylori), which has largely been determined from the emergence and spread of antibiotic resistance. Several studies have shown that adding rebamipide to eradication regimens leads to an increase in the effectiveness of treatment. Aim: To evaluate the efficacy and safety of including rebamipide in the eradication regimens for H. pylori infection. Methods: The literature search was conducted in the MEDLINE/PubMed, EMBASE, Cochrane Central Register, Korean Medical Citation Index, and Russian Science Citation Index databases. All identified randomized controlled trials comparing rebamipide supplementation with non-rebamipide-containing eradication regimens for the treatment of H. pylori infection were included in the final analysis. Results: We identified 11 randomized controlled trials (RCTs) involving 1227 patients (631 in groups with rebamipide and 596 in groups without rebamipide). The meta-analysis showed that the addition of rebamipide to eradication regimens significantly increased the effectiveness of treatment (odds ratio (OR) 1.753, 95% confidence interval (CI) 1.312–2.333, p < 0.001). The subgroup analysis demonstrated that rebamipide significantly increased the effectiveness of eradication when added to a dual therapy regimen (OR 1.766, 95% CI: 1.167–2.495, p = 0.006); however, no significant improvement in effectiveness was observed when it was added to the triple therapy regimen (OR 1.638, 95% CI 0.833–3.219, p = 0.152). Conclusion: This meta-analysis demonstrated that the addition of rebamipide to H. pylori eradication regimens significantly increases the effectiveness of treatment.

Identifying potential novel drugs against Helicobacter pylori by targeting the essential response regulator HsrA

The increasing antibiotic resistance evolved by Helicobacter pylori has alarmingly reduced the eradication rates of first-line therapies. To overcome the current circulating resistome, we selected a novel potential therapeutic target in order to identify new candidate drugs for treating H. pylori infection. We screened 1120 FDA-approved drugs for molecules that bind to the essential response regulator HsrA and potentially inhibit its biological function. Seven natural flavonoids were identified as HsrA binders. All of these compounds noticeably inhibited the in vitro DNA binding activity of HsrA, but only four of them, apigenin, chrysin, kaempferol and hesperetin, exhibited high bactericidal activities against H. pylori. Chrysin showed the most potent bactericidal activity and the most synergistic effect in combination with clarithromycin or metronidazole. Flavonoid binding to HsrA occurs preferably at its C-terminal effector domain, interacting with amino acid residues specifically involved in forming the helix-turn-helix DNA binding motif. Our results validate the use of HsrA as a novel and effective therapeutic target in H. pylori infection and provide molecular evidence of a novel antibacterial mechanism of some natural flavonoids against H. pylori. The results further support the valuable potential of natural flavonoids as candidate drugs for novel antibacterial strategies.

The Maturation Pathway of Nickel Urease

Maturation of urease involves post-translational insertion of nickel ions to form an active site with a carbamylated lysine ligand and is assisted by urease accessory proteins UreD, UreE, UreF and UreG. Here, we review our current understandings on how these urease accessory proteins facilitate the urease maturation. The urease maturation pathway involves the transfer of Ni2+ from UreE → UreG → UreF/UreD → urease. To avoid the release of the toxic metal to the cytoplasm, Ni2+ is transferred from one urease accessory protein to another through specific protein–protein interactions. One central theme depicts the role of guanosine triphosphate (GTP) binding/hydrolysis in regulating the binding/release of nickel ions and the formation of the protein complexes. The urease and [NiFe]-hydrogenase maturation pathways cross-talk with each other as UreE receives Ni2+ from hydrogenase maturation factor HypA. Finally, the druggability of the urease maturation pathway is reviewed.

Inflammatory responses induced by Helicobacter pylori on the carcinogenesis of gastric epithelial GES‑1 cells

Helicobacter pylori (HP) is a pathogenic bacterium associated with chronic gastritis, gastric ulcer and gastric cancer. In the present study, the primary carcinogenesis process of normal gastric epithelial cells (GES‑1) infected with HP was investigated. It was determined that infected gastric mucosal epithelial GES‑1 cells secreted increased interleukin‑8 (IL‑8) and IL‑23, and exhibited enhanced expression of inducible nitric oxide synthase and cyclooxygenase‑2, inducing inflammatory reactions and resulting in apoptosis. The bacterial infection significantly increased the expression of carcinogenesis‑associated genes, including p16, c‑Myc, p53 and p21, as well as the expression of cell surface signaling molecules cluster of differentiation 44 (CD44) and CD54 in GES‑1 cells or tissues of patients with gastritis and gastric cancer in vitro or in vivo. Simultaneously, the migration and invasion abilities of normal gastric epithelial GES‑1 cells were increased following HP infection. These observations demonstrated that the inflammatory response of HP infection could cause normal gastric epithelial cells to undergo significant cancerous reactions, indicating that HP is a risk factor for gastric cancer.