Targeting Helicobacter pylori for antibacterial drug discovery with novel therapeutics

Current Trends in Antibiotic Therapy and Resistance: A Comparative Study of Various Spectrums

Background The global public health concern posed by antibiotic resistance is threatening the usefulness of existing therapies. This calls for an urgent reconsideration of the contemporary trends in antibiotic usage. This study compares narrow-, broad-, and extended-spectrum antibiotics to elucidate resistance patterns, evaluate the therapeutic outcomes, and suggest new ways for combating resistance. Methods The research was analyzed based on 1,050 observations of demographic, clinical, diagnostic, laboratory, and therapeutic parameters. The analysis of effectiveness, safety, and resistance rates was statistically evaluated across different antibiotic spectra and healthcare settings. Results According to reviews of recorded patient entries encompassing 1,050 files, broad-spectrum antibiotics distributed by pharmacies, particularly ceftriaxone (27.9%), were mostly medically prescribed. A history of previous infections was reported in 67.5% of the patients. The antibiotics ceftriaxone and penicillin were the most widely used. The patient care was equally divided into standalone, community based, and hospital based. High-dose drugs were administered to 36.5% of patients; on average, treatment effectiveness is 77.43% with safety rates of 84.77%. The average diagnosis delay was four days. Most of the identified agents were Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. The overall resistance rate was 27.95%. The highest resistance was noted against S. aureus and K. pneumoniae. Resistance varied widely across classes of antibiotics, with penicillins and cephalosporins showing the highest rates. The burden of comorbidities in terms of diabetes, heart diseases, and chronic obstructive pulmonary diseases has been of particular concern, as seen in patients. Conclusions The results stress the urgent need to promote antibiotic stewardship programs and establish precise methods in medicine. This comparison of antibiotic spectra offers actionable insights to inform treatment and policy considerations, especially in areas where resistance rates are considerably high.

Real Way to Target Gram-Negative Pathogens: Discovery of a Novel Helicobacter pylori Antibiotic Class

In an era of escalating antibiotic resistance, there is a pressing need for innovative strategies to develop novel antibiotics. Gram-negative bacteria, characterized by their robust dual-membrane, are intrinsically resistant to a wide range of antibiotics and can readily develop new resistances. Members of this bacterial class comprise numerous pathogenic organisms, including the primary cause of gastric cancer, Helicobacter pylori. In this study, we used the Giga-sized collection of theoretical molecules inside Enamine's REAL Space to identify inhibitors for H. pylori glutamate racemase. These compounds displayed a diverse range of activity in preventing H. pylori growth, with our most potent hits capable of selective full growth inhibition for metronidazole and clarithromycin resistant H. pylori strains. Alongside the introduction of a novel antibiotic class for this carcinogenic pathogen, our unique implementation of REAL Space holds great promise for Gram-negative antibiotic development as a whole.

Efficacy and safety of vonoprazan-amoxicillin dual therapy versus bismuth-containing quadruple therapy for patients with Helicobacter pylori infection: a meta-analysis

Introduction

This meta-analysis aims to compare the efficacy and safety of vonoprazan-amoxicillin (VA) dual therapy in comparison to bismuth-containing quadruple therapy (BQT) for patients with Helicobacter pylori (H. pylori) infection.

Materials and methods

Four databases (PubMed, Embase, Web of Science, and Cochrane Library) were searched published from establishment of database to June 1, 2024, for articles studying VA dual therapy compared to BQT for patients with H. pylori infection. Meta-analyses of eradication rates, adverse events, compliance and cost were preformed.

Results

A total of 17 studies were included for meta-analysis. Compared with BQT, VA increased the incidence of H. pylori eradication rate, with significant difference under the ITT analysis (86.9% vs. 80.4%, RR = 1.07, 95% CI: 1.01-1.12, p = 0.01) but there no significant difference under the PP analysis (90.7% vs. 86.5%, RR = 1.03, 95% CI: 0.99-1.08, p = 0.13). Besides, VA significantly increased compliance (RR = 1.03, 95% CI: 1.01-1.05, p < 0.01) and decreased the occurrence of total adverse events (27.0% vs. 11.5%, RR = 0.43, 95% CI: 0.37-0.51, p < 0.01). Furthermore, VA has lower cost compared to BQT.

Conclusion

Our findings indicated that VA dual therapy provided a higher eradication rate, enhanced compliance, decreased adverse events, and lowered cost relative to BQT for patients with H. pylori infection.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024576738, identifier CRD42024576738 (PROSPERO).

Helicobacter pylori Efflux Pumps: A Double-Edged Sword in Antibiotic Resistance and Biofilm Formation

Helicobacter pylori is a major pathogen associated with various gastric diseases. Despite decades of research, the treatment of H. pylori remains challenging. One of the primary mechanisms contributing to failures of therapies targeting this bacterium is genetic mutations in drug target sites, although the growing body of scientific data highlights that efflux pumps may also take part in this process. Efflux pumps are proteinaceous transporters actively expelling antimicrobial agents from the interior of the targeted cells and reducing the intracellular concentration of these compounds. Considering that efflux pumps contribute to both antimicrobial resistance and biofilm formation, an in-depth understanding of their properties may constitute a cornerstone in the development of novel therapeutics against H. pylori. In line with this, the aim of the current review is to describe the multitude of efflux pumps produced by H. pylori and present the data describing the involvement of these proteins in tolerance and/or resistance to various classes of antimicrobial substances.

Discovery and evolution of berberine analogues as anti-Helicobacter pylori agents with multi-target mechanisms

Thirty protoberberine derivatives, of which twenty five were new, were synthesized and evaluated for their anti-Helicobacter pylori (HP) activities, taking 2,3,10-trimethoxy-9-p-methylbenzylaminoprotopalmatine chloride 1 as the lead. Among them, berberine (BBR) derivative 7c displayed the highest potency against six tested metronidazole (MTZ)-resistant strains and two tested MTZ-susceptible strains with the MIC values of 0.4-1.6 μg/mL with favorable druglike profiles including low toxicity and high stabilities in plasma and artificial gastric fluid. Mechanistic study revealed that 7c might target HP urease with IC50 value of 0.27 μg/mL against Jack bean urease. Furthermore, 7c might change the permeability of the bacterial membrane and direct interact with HP DNA, which also contribute to its bactericidal activity. Therefore, BBR derivatives constituted a new family of anti-HP candidates, with the advantage of good safety profile and multi-target mechanisms, and are worthy for further investigation.

Opportunities for Helicobacter pylori Eradication beyond Conventional Antibiotics

Helicobacter pylori (H. pylori) is a bacterium known to be associated with a significant risk of gastric cancer in addition to chronic gastritis, peptic ulcer, and MALT lymphoma. Although only a small percentage of patients infected with H. pylori develop gastric cancer, Gastric cancer causes more than 750,000 deaths worldwide, with 90% of cases being caused by H. pylori. The eradication of this bacterium rests on multiple drug regimens as guided by various consensus. However, the efficacy of empirical therapy is decreasing due to antimicrobial resistance. In addition, biofilm formation complicates eradication. As the search for new antibiotics lags behind the bacterium's ability to mutate, studies have been directed toward finding new anti-H. pylori agents while also optimizing current drug functions. Targeting biofilm, repurposing outer membrane vesicles that were initially a virulence factor of the bacteria, phage therapy, probiotics, and the construction of nanoparticles might be able to complement or even be alternatives for H. pylori treatment. This review aims to present reports on various compounds, either new or combined with current antibiotics, and their pathways to counteract H. pylori resistance.

Helicobacter pylori CAs inhibition

Infections from Helicobacter pylori (Hp) are endangering Public Health safety worldwide, due to the associated high risk of developing severe diseases, such as peptic ulcer, gastric cancer, diabetes, and cardiovascular diseases. Current therapies are becoming less effective due to the rise of (multi)drug-resistant phenotypes and an urgent need for new antibacterial agents with innovative mechanisms of action is pressing. Among the most promising pharmacological targets, Carbonic Anhydrases (EC: 4.2.1.1) from Hp, namely HpαCA and HpβCA, emerged for their high druggability and crucial role in the survival of the pathogen in the host. Thereby, in the last decades, the two isoenzymes were isolated and characterized offering the opportunity to profile their kinetics and test different series of inhibitors.

Novel carbonic anhydrase inhibitors for the treatment of Helicobacter pylori infection

INTRODUCTION

Helicobacter pylori, the causative agent of peptic ulcer, gastritis, and gastric cancer encodes two carbonic anhydrases (CA, EC 4.2.1.1) belonging to the α- and β-class (HpCAα/β), which have been validated as antibacterial drug targets. Acetazolamide and ethoxzolamide were also clinically used for the management of peptic ulcer.

AREAS COVERED

Sulfonamides were the most investigated HpCAα/β compounds, with several low nanomolar inhibitors identified, some of which also crystallized as adducts with HpCAα, allowing for the rationalization of the structure-activity relationship. Few data are available for other classes of inhibitors, such as phenols, sulfamides, sulfamates, dithiocarbamates, arylboronic acids, some of which showed effective in vitro inhibition and for phenols, also inhibition of planktonic growth, biofilm formation, and outer membrane vesicles spawning.

EXPERT OPINION

Several recent drug design studies reported selenazoles incorporating seleno/telluro-ethers attached to benzenesulfonamides, hybrids incorporating the EGFR inhibitor erlotinib and benzenesulfonamides, showing KIs < 100 nM against HpCAα and MICs in the range of 8-16 µg/mL for the most active derivatives. Few drug design studies for non-sulfonamide inhibitors were performed to date, although inhibition of these enzymes may help the fight of multidrug resistance to classical antibiotics which emerged in the last decades also for this bacterium.

Antimicrobial combinations against Helicobacter pylori including benzoxadiazol-based flavodoxin inhibitors: in vitro characterization

IMPORTANCE

The antimicrobial resistance of Helicobacter pylori (Hp) currently poses a threat to available treatment regimens. Developing antimicrobial drugs targeting new bacterial targets is crucial, and one such class of drugs includes Hp-flavodoxin (Hp-fld) inhibitors that target an essential metabolic pathway in Hp. Our study demonstrated that combining these new drugs with conventional antibiotics used for Hp infection treatment prevented the regrowth observed with drugs used alone. Hp-fld inhibitors show promise as new drugs to be incorporated into the treatment of Hp infection, potentially reducing the development of resistance and shortening the treatment duration.

Clodronic Acid has Strong Inhibitory Interactions with the Urease Enzyme of Helicobacter pylori: Computer-aided Design and in vitro Confirmation

BACKGROUND

Helicobacter pylori (HP) infection could lead to various gastrointestinal diseases. Urease is the most important virulence factor of HP. It protects the bacterium against gastric acid.

OBJECTIVE

Therefore, we aimed to design urease inhibitors as drugs against HP infection.

METHODS

The DrugBank-approved library was assigned with 3D conformations and the structure of the urease was prepared. Using a re-docking strategy, the proper settings were determined for docking by PyRx and GOLD software. Virtual screening was performed to select the best inhibitory drugs based on binding affinity, FitnessScore, and binding orientation to critical amino acids of the active site. The best inhibitory drug was then evaluated by IC50 and the diameter of the zone of inhibition for bacterial growth.

RESULTS

The structures of prepared drugs were screened against urease structure using the determined settings. Clodronic acid was determined to be the best-identified drug, due to higher PyRx binding energy, better GOLD FitnessScore, and interaction with critical amino acids of urease. In vitro results were also in line with the computational data. IC50 values of Clodronic acid and Acetohydroxamic Acid (AHA) were 29.78 ± 1.13 and 47.29 ± 2.06 μg/ml, respectively. Diameters of the zones of inhibition were 18 and 15 mm for Clodronic acid and AHA, respectively.

CONCLUSION

Clodronic acid has better HP urease inhibition potential than AHA. Given its approved status, the development of a repurposed drug based on Clodronic acid would require less time and cost. Further, in vivo studies would unveil the efficacy of Clodronic acid as a urease inhibitor.

Involvement of Nitric Oxide in Protecting against Radical Species and Autoregulation of M1-Polarized Macrophages through Metabolic Remodeling

When the expression of NOS2 in M1-polarized macrophages is induced, huge amounts of nitric oxide (•NO) are produced from arginine and molecular oxygen as the substrates. While anti-microbial action is the primary function of M1 macrophages, excessive activation may result in inflammation being aggravated. The reaction of •NO with superoxide produces peroxynitrite, which is highly toxic to cells. Alternatively, however, this reaction eliminates radial electrons and may occasionally alleviate subsequent radical-mediated damage. Reactions of •NO with lipid radicals terminates the radical chain reaction in lipid peroxidation, which leads to the suppression of ferroptosis. •NO is involved in the metabolic remodeling of M1 macrophages. Enzymes in the tricarboxylic acid (TCA) cycle, notably aconitase 2, as well as respiratory chain enzymes, are preferential targets of •NO derivatives. Ornithine, an alternate compound produced from arginine instead of citrulline and •NO, is recruited to synthesize polyamines. Itaconate, which is produced from the remodeled TCA cycle, and polyamines function as defense systems against overresponses of M1 macrophages in a feedback manner. Herein, we overview the protective aspects of •NO against radical species and the autoregulatory systems that are enabled by metabolic remodeling in M9-polarized macrophages.