Relationship between ureB Sequence Diversity, Urease Activity and Genotypic Variations of Different Helicobacter pylori Strains in Patients with Gastric Disorders

Helicobacter pylori in the post-antibiotics era: from virulence factors to new drug targets and therapeutic agents

Helicobacter pylori is considered one of the most prevalent human pathogenic microbes globally. It is the main cause of a number of gastrointestinal ailments, including peptic and duodenal ulcers, and gastric tumors with high mortality rates. Thus, eradication of H. pylori is necessary to prevent gastric cancer. Still, the rise in antibiotic resistance is the most important challenge for eradication strategies. Better consideration of H. pylori virulence factors, pathogenesis, and resistance is required for better eradication rates and, thus, prevention of gastrointestinal malignancy. This article is aimed to show the role of virulence factors of H. pylori. Some are involved in its survival in the harsh environment of the human gastric lumen, and others are related to pathogenesis and the infection process. Furthermore, this work has highlighted the recent advancement in H. pylori treatment, as well as antibiotic resistance as a main challenge in H. pylori eradication. Also, we tried to provide an updated summary of the evolving H. pylori control strategies and the potential alternative drugs to fight this lethal resistant pathogen. Recent studies have focused on evaluating the efficacy of alternative regimens (such as sequential, hybrid, concomitant treatment, vonoprazan (VPZ)-based triple therapy, high-dose PPI-amoxicillin dual therapy, probiotics augmented triple therapy, or in combination with BQT) in the effective eradication of H. pylori. Thus, innovating new anti-H. pylori drugs and establishing H. pylori databanks are upcoming necessities in the near future.

Helicobacter pylori Virulence Factors-Mechanisms of Bacterial Pathogenicity in the Gastric Microenvironment

Gastric cancer constitutes one of the most prevalent malignancies in both sexes; it is currently the fourth major cause of cancer-related deaths worldwide. The pathogenesis of gastric cancer is associated with the interaction between genetic and environmental factors, among which infection by Helicobacter pylori (H. pylori) is of major importance. The invasion, survival, colonization, and stimulation of further inflammation within the gastric mucosa are possible due to several evasive mechanisms induced by the virulence factors that are expressed by the bacterium. The knowledge concerning the mechanisms of H. pylori pathogenicity is crucial to ameliorate eradication strategies preventing the possible induction of carcinogenesis. This review highlights the current state of knowledge and the most recent findings regarding H. pylori virulence factors and their relationship with gastric premalignant lesions and further carcinogenesis.

Antibacterial self-assembled nanodrugs composed of berberine derivatives and rhamnolipids against Helicobacter pylori

The prevalence of infections with Helicobacter pylori (H. pylori) has progressively increased worldwide, which demonstrated to be closely correlated to its biofilm formation. H. pylori biofilms protect the bacteria by significantly decreasing their sensitivity to antibiotics. Moreover, H. pylori colonizes on the gastrointestinal tract epithelium which is covered by mucus layer, acting as another barrier to prevent antibacterial agents from reaching the colonization sites. Herein, we prepared four types of versatile self-assembled nanodrugs (BD/RHL NDs) containing lipophilic alkyl berberine derivatives (BDs) and rhamnolipids (RHL) to overcome the dual obstructions of both mucus layer and biofilms. Molecular dynamics simulations estimated that the driving forces for self-assembly of BD/RHL NDs were electrostatic and hydrophobic interactions. BD/RHL NDs, characterized by appropriate size, negative charge and enhanced hydrophilicity, successfully penetrated through mucus layer without interacting with mucins. In in vitro experiments, BD/RHL NDs exhibited substantial ability to eradicate H. pylori biofilms by destroying their extracellular polymeric substances (EPS) and killing planktonic H. pylori. Furthermore, BD/RHL NDs inhibited the adherence of H. pylori on both biotic and abiotic surfaces, therefore cut off the critical step of the biofilm re-formation which was associated with the recrudescence of infections. In an H. pylori-infected mice model, C10-BD/RHL NDs group showed 40 folds less remnant H. pylori and greater mucosal protection compared with the conventional clinical triple therapy. In conclusion, BD/RHL NDs could penetrate through mucus layer and effectively eradicate H. pylori biofilms in vitro and in vivo, providing a novel strategy for clinical treatment of biofilm-related infections.

Prevalence of non Helicobacter pylori gastric Helicobacters in Iranian dyspeptic patients

BACKGROUND

Non Helicobacter pylori gastric Helicobacters (NHPGHs) are associated with a range of upper gastrointestinal symptoms, histologic and endoscopic findings. For the first time in Iran, we performed a cross-sectional study in order to determine the prevalence of five species of NHPGHs in patients presenting with dyspepsia.

METHODS

The participants were divided into H. pylori-infected and NHPGH-infected groups, based on the rapid urease test, histological analysis of biopsies, and PCR assay of ureA, ureB, and ureAB genes. The study included 428 gastric biopsies form dyspeptic patients, who did not receive any treatment for H. pylori. The samples were collected and sent to the laboratory within two years. H. pylori was identified in 368 samples, which were excluded from the study. Finally, a total of 60 non-H. pylori samples were studied for NHPGH species.

RESULTS

The overall frequency of NHPGH species was 10 for H. suis (three duodenal ulcer, three gastritis, and four gastric ulcer samples), 10 for H. felis (one gastritis, three duodenal ulcer, and six gastric ulcer samples), 20 for H. salomonis (four duodenal ulcer, five gastritis, and 11 gastric ulcer samples), 13 for H. heilmannii (three gastritis, five duodenal ulcer, and five gastric ulcer samples), and 7 for H. bizzozeronii (zero gastric ulcer, two duodenal ulcer, and five gastritis samples).

CONCLUSIONS

Given our evidence about the possibility of involvement of NHPGHs in patients suffering from gastritis and nonexistence of mixed H. pylori infection, bacteriological testing of subjects negative for H. pylori becomes clinically relevant and important. Our findings suggest H. salomonis has the highest rate among the NHPGH species in Iranian dyspeptic patients.

Effect of trimethylamine N-oxide on inflammation and the gut microbiota in Helicobacter pylori-infected mice

Diet is one of the factors contributing to symptom of Helicobacter pylori (H. pylori) infection. Trimethylamine N-oxide (TMAO), a diet-related microbial metabolite, is associated with inflammatory and metabolic diseases. The aim of this study is to investigate the effects of TMAO intake on inflammation and gut microbiota composition in H. pylori-infected mice via 16S rRNA sequencing and biochemical analyses. The in vitro experiments showed that TMAO not only increased the expression of growth- and metabolism-associated genes and the urease activity of H. pylori, but increased the production of virulence factors. Moreover, TMAO intake increased the production of inflammatory markers and reduced the richness and diversity of the gut microbiota in H. pylori-infected mice. Further analysis showed that TMAO increased the relative abundance of Escherichia_Shigella in H. pylori-infected mice, which had positive correlation with the levels of LPS, CRP, and CXCL1. Collectively, our results suggest that TMAO may aggravate H. pylori-induced inflammation by increasing the viability and virulence of H. pylori and may aggravate inflammation in association with the gut microbiota in H. pylori-infected mice. This study may provide a novel insight into the mechanism for the effect of diet-derived metabolites such as TMAO on H. pylori-induced disease development.