BACKGROUND:Previous studies have suggested a possible association between Helicobacter pylori (H. pylori) infection and an increased risk of colorectal cancer (CRC). OBJECTIVE:We examined the associations of H. pylori infection and H. pylori treatment with incident CRC risk and evaluated whether these associations were modified by genetic susceptibility. DESIGN:This study was based on two randomised trial cohorts: the Shandong Intervention Trial (SIT; n=3365; 1995-2024) and the Mass Intervention Trial in Linqu, Shandong Province (MITS; n=180 284; 2011-2024). Within MITS, we further conducted a case-cohort study to assess CRC risk according to seropositivity for H. pylori virulence factors and host genetic predisposition. RESULTS:Compared with H. pylori-negative individuals, H. pylori-positive individuals who did not receive antibiotic treatment had a significantly higher risk of CRC (SIT: HR=2.96, 95% CI 1.30 to 6.71; MITS: HR=1.27, 95% CI 1.04 to 1.55). The increased risk was particularly evident among individuals seropositive for four H. pylori-specific antigens (CagA, HpaA, Omp and HP0305) and those at high genetic risk (top decile of the Polygenic Risk Score). In SIT, H. pylori treatment was associated with a significantly reduced CRC risk over 29.4 years of follow-up (HR=0.47, 95% CI 0.22 to 0.99), with a greater reduction observed among participants with successful eradication (HR=0.38, 95% CI 0.15 to 0.94). In MITS, no overall benefit was observed 13.8 years after treatment (HR=1.17, 95% CI 0.95 to 1.43). However, a protective effect was apparent among individuals at high genetic risk and among those seropositive for key H. pylori-specific antigens. CONCLUSION:In post hoc observational analyses of two established trial cohorts, H. pylori infection was associated with an increased risk of CRC. H. pylori treatment reduced CRC risk in SIT, whereas in MITS, the benefit appeared to be limited to individuals at high genetic risk or those infected with specific virulence factor subtypes.

Metronidazole is a front-line drug for the treatment of Helicobacter pylori infections. However, its mode of action and cellular targets are poorly defined, and higher dosing and combination therapies are required to overcome resistance. Here we performed activity-based protein profiling with tailored metronidazole probes and identified chaperonin HpGroEL and thiol peroxidase HpTpx as prominent targets, the latter being essential for H. pylori survival under oxidative stress. Alkynylated ether probes exhibited enhanced antibacterial potency compared with the parent drug in vitro, including activity against resistant strains. Biological assays, chemical proteomics and co-crystallization studies confirmed target engagement, with enhanced binding of ether derivatives to HpTpx. Refined ether analogues exhibited favourable pharmacological profiles without cytotoxicity. The in vivo activity of ether analogues using an H. pylori mouse model demonstrated full bacterial eradication at low dosing of 0.3 mg kg-1 day-1. Our findings reveal that stress induction and simultaneous inhibition of the stress response represent a mechanism of this compound class.

INTRODUCTION:Immunomodulating effects of Helicobacter pylori (H. pylori) have been shown to inhibit antitumor immunity. Resistance to immune checkpoint inhibitor (ICI)-based therapies is common among patients with hepatocellular carcinoma (HCC). This study aimed to assess the effect of H. pylori on the outcomes of ICI in patients with HCC. METHODS:We conducted a multicenter study in patients with HCC across a broad range of treatments. Patients received either ICI-based combination regimens or sorafenib-based therapy. H. pylori serostatus and virulence factors were determined and correlated with overall survival (OS), progression-free survival (PFS), and safety across the treatment modalities. RESULTS:180 patients with HCC were included; among these, 64 were treated with ICI-based regimen and 116 with sorafenib-based regimen. In patients treated with ICI, median OS was shorter in H. pylori-positive patients (10.9 months in H. pylori-positive vs. 18.3 months; p = 0.0384). H. pylori positivity was associated with a shorter PFS in ICI recipients (3.9 months vs. 6.8 months, p = 0.0499). In patients treated with sorafenib, median OS was not shorter among H. pylori-positive patients (13.4 months in H. pylori-positive vs. 10.6 months; p = 0.3353). Immune-related adverse events and rates of gastrointestinal bleeding were comparable between H. pylori-positive and -negative patients. CONCLUSION:H. pylori seropositivity was linked to poorer outcomes in patients with HCC treated with ICI. This association was not observed among patients receiving sorafenib-based therapies.

Helicobacter pylori γ-glutamyltransferase (gGT) is a virulence factor that promotes bacterial colonization and immune tolerance. Although some studies addressed potential functional mechanisms, the supportive role of gGT for in vivo colonization remains unclear. Additionally, it is unknown how different gGT expression levels may lead to compensatory mechanisms ensuring infection and persistence. Hence, it is crucial to unravel the in vivo function of gGT. We assessed acid survival under conditions mimicking the human gastric fluid and elevated the pH in the murine stomach prior to H. pylori infection to link gGT-mediated acid resistance to colonization. By comparing proteomes of gGT-proficient and -deficient isolates before and after infecting mice, we investigated proteomic adaptations of gGT-deficient bacteria during infection. Our data indicate that gGT is crucial to sustain urease activity in acidic environments, thereby supporting survival and successful colonization. Absence of gGT triggers expression of proteins involved in the nitrogen and iron metabolism and boosts the expression of adhesins and flagellar proteins during infection, resulting in increased motility and adhesion capacity. In summary, gGT-dependent mechanisms confer a growth advantage to the bacterium in the gastric environment, which renders gGT a valuable target for the development of new treatments against H. pylori infection.

BACKGROUND:Helicobacter pylori resistance to antibiotics commonly used in eradication regimens is increasing dramatically in many locations; new strategies are needed to manage this infectious disease. OBJECTIVE:This study's aim was to collect and update information on antibiotic resistance (AR) rates in H. pylori as well as current strategies for H. pylori management, including public health issues, from a global perspective. DESIGN:An international survey was conducted in 31 countries on 6 continents to address key issues concerning the management of H. pylori-related AR. Individual aspects included the prevalence of AR for specific antibiotics, antibiotic susceptibility testing (AST) in different healthcare systems, availability of drugs, reimbursement issues and strategies for H. pylori AR surveillance. RESULTS:Resistance to the most effective antibiotics used in H. pylori eradication regimens is increasing globally, with clarithromycin and levofloxacin resistance exceeding 15% in 24/31 and 18/31 countries, respectively. Amoxicillin remains an exception, with resistance rates under 2% in 14/31 countries; though African countries have reported amoxicillin resistance rates of over 90%. Bismuth-based treatment regimens are the most effective and are recommended as first-line treatment in several countries. However, more than 1 billion inhabitants worldwide have no access to bismuth-based regimens. PCR-based tests for AR are used in 16/26 countries but are reimbursed in only 4, while next generation sequencing-based tests are available, but not reimbursed, in 3 countries. In 22/26 countries only culture-based methods are available (reimbursed in 9/26 countries). AR surveillance programmes have only been established in 4/26 countries. Therefore, in most countries, empirical therapy with the most effective local regimen available locally is practiced. CONCLUSION:The dramatic global rise in H. pylori antibiotic resistance requires an urgent revision of current management strategies. Possible solutions include AST-based selection of effective treatment regimens, identification of novel combinations of existing drugs and exploration of novel drugs.

Kidney transplantation (KT) is the best treatment for end-stage kidney disease, with graft survival critically affected by the recipient's immune response. The role of the gut microbiome in modulating this immune response remains underexplored. Our study investigates how microbiome alterations might be associated with allograft rejection by analyzing the gut microbiome using 16S rRNA gene amplicon sequencing of a multicenter prospective study involving 562 samples from 245 individuals of whom 217 received KT. Overall, gut microbiome composition showed gradual recovery post-KT, mirroring chronic kidney disease (CKD)-to-health transition as indicated by an increase in Shannon diversity. Prior to graft rejection, we observed a decrease in microbial diversity and short-chain fatty acid-producing taxa. Functional analysis highlighted a decreased potential for short-chain fatty acid production in patients preceding the rejection event, validated by quantitative PCR for the production potential of propionate and butyrate. Postrejection analysis revealed normalization of these microbiome features. Comparison to published microbiome signatures from CKD patients demonstrated a partial overlap of the microbiome alterations preceding graft rejection with the alterations typically found in CKD. Our findings suggest that alterations in gut microbiome composition and function may precede and influence KT rejection, suggesting potential implications as biomarkers or for early therapeutic microbiome-targeting interventions.

BACKGROUND:Helicobacter pylori infection is the most prevalent bacterial infection worldwide. Attempts to develop a vaccine have not been successful, partly due to the absence of well-defined immune correlates of protection. The inflammatory response to H. pylori infection is characterised by the recruitment of T cells expressing markers of tissue-resident memory T (TRM) cells to the gastric mucosa. However, the function of TRM cells in gastric tissue during H. pylori reinfection remained poorly understood. OBJECTIVE:We aimed to investigate the induction, development and function of gastric TRM cells during primary and secondary H. pylori infection. DESIGN:We characterised gastric H. pylori-specific TRM cells in mice and humans by flow cytometry, immunohistochemistry, immunofluorescence, ChipCytometry staining and single-cell RNA sequencing. The function of gastric TRM cells was established in H. pylori eradication and reinfection experiments as well as by targeted depletion of Hobit+ TRM cells and neutrophils in mice. RESULTS:Expression of the transcription factor Hobit governs the induction and development of gastric TRM cells, which largely depend on the presence of the H. pylori virulence factor Cytotoxin-associated gene A. H. pylori-specific CD4+ and CD8+ TRM cells resided long-term in the stomach and conferred complete protection from reinfection with the help of neutrophils. Gastric CD8+ TRM cells exhibited varying Hobit expression levels and clustered into distinct subgroups based on distinct transcriptomic and cytokine profiles, suggesting functional specialisation. CONCLUSION:These findings establish gastric TRM cells as bona fide correlates of protection against H. pylori, highlighting their potential for future prophylactic and therapeutic strategies.

Background Helicobacter pylori is a significant risk factor for gastric cancer, peptic ulcers, and MALT lymphoma. Rising antibiotic resistance rates complicate treatment strategies. While nucleotide sequence based assays are reliable in predicting clarithromycin and levofloxacin resistance, predicting metronidazole resistance is more challenging due to diverse metabolic pathways contributing to resistance, and high genomic variability. Methods We assembled a cohort of 483 H. pylori clinical isolates, combining whole-genome sequencing with phenotypic susceptibility testing. Machine learning models (SVM, XGBoost, FNN) were trained on genomic variants to predict resistance phenotypes. A sliding-window approach and SHAP-based importance scoring were used for feature selection to identify biologically relevant mutations, improving prediction accuracy, particularly for metronidazole resistance. Results The best-performing FNN model improved metronidazole resistance prediction by 16% compared to conventional (non-ML, single polymorphisms) sequence-based detection methods applied to the same strain collection. Feature selection identified 32 feature sets, with 11 sets significantly improving F1-scores over the baseline. Combining 2–4 feature sets revealed 53 synergistic combinations across all models. Validation showed that 87% of these combinations significantly outperformed non-ML molecular testing, with 16 combinations achieving F1-scores above 0.65. Conclusion Machine-learning can significantly improve the performance of sequence-based susceptibility testing for metronidazole in H. pylori . Novel candidate predictive markers identified from whole-genome data offer testable hypotheses about yet unexplored mechanisms of metronidazole resistance. These findings support the potential for ML-based approaches to enable more accurate susceptibility-guided therapies. ### Competing Interest Statement The authors have declared no competing interest. Bavarian State Ministry for Science and Art, https://ror.org/01a44gd51, bayresq.net/Helicopredict