Background: The issue of Helicobacter pylori (H. pylori) resistance to clarithromycin (CLR) has consistently posed challenges for clinical treatment. Hence, a rapid susceptibility testing (AST) method urgently needs to be developed. Methods: In the present study, 35 isolates of H. pylori were isolated from 203 gastritis patients of the Guangzhou cohort, and the antimicrobial resistance phenotypes were associated with their genomes to analyze the relevant mutations. Based on these mutations, a rapid detection system utilizing high-resolution melting (HRM) curve analysis was designed and verified by the Shenzhen cohort, which consisted of 38 H. pylori strains. Results: Genomic analysis identified the mutation of the 2143 allele from A to G (A2143G) of 23S rRNA as the most relevant mutation with CLR resistance (p < 0.01). In the HRM system, the wild-type H. pylori showed a melting temperature (Tm) of 79.28 ± 0.01 °C, while the mutant type exhibited a Tm of 79.96 ± 0.01 °C. These differences enabled a rapid distinction between two types of H. pylori (p < 0.01). Verification examinations showed that this system could detect target DNA as low as 0.005 ng/μL in samples without being affected by other gastric microorganisms. The method also showed a good performance in the Shenzhen validation cohort, with 81.58% accuracy, and 100% specificity. Conclusions: We have developed an HRM system that can accurately and quickly detect CLR resistance in H. pylori. This method can be directly used for the detection of gastric microbiota samples and provides a new benchmark for the simple detection of H. pylori resistance.

Small non-coding RNAs (sRNAs) in bacteria are important regulatory molecules for controlling virulence. In Vibrio spp., Qrr sRNAs are critical for quorum-sensing pathways and regulating the release of some virulence factors. However, the detailed role of Qrr sRNAs in the virulence of Vibrio parahaemolyticus remains poorly understood. In this study, we identified a Vibrio sRNA Qrr5 that positively regulates cytotoxicity and adherence in Caco-2 cells by primarily regulating the T3SS1 gene cluster. A number of 185, 586, 355, and 74 differentially expressed genes (DEGs) detected at 0, 2, 4, and 6 h post-infection, respectively, were mainly associated with ABC transporters and two-component system pathways. The DEGs exhibited a dynamic change in expression at various time points post-infection owing to the deletion of Qrr5. Accordingly, 17 related genes were identified in the co-expression network, and their interaction with Qrr5 was determined based on weighted co-expression network analysis during infection. Taken together, our results provide a comprehensive transcriptome profile of V. parahaemolyticus during infection in Caco-2 cells.

Background . Helicobacter pylori infection is a major risk factor for gastric cancer (GC), especially in East Asia. However, the mechanisms through which bacterial strain heterogeneity contributes to GC risk remain poorly understood. This study aims to elucidate the roles of specific virulence factors, antibiotic resistance profiles and genetic variations in H. pylori in GC development. Methods. We integrated host clinical data with phenotypic and genomic analyses of 31 clinical H. pylori isolates. Genomic analysis was performed to determine phylogenetic lineage and virulence markers. Antibiotic susceptibility and biofilm-forming ability of the clinical isolates were also assessed, and a genome-wide association study (GWAS) was employed to identify genetic polymorphisms linked to GC risk. Results. Among the isolates, 93.5 % of isolates belonged to the East Asian lineage and carried high-risk virulence markers ( cagA EPIYA-ABD, vacA s1m1). However, multidrug resistance was observed in 64.5 % of isolates, with high resistance rates to metronidazole (71.0%) and levofloxacin (48.4%) exceeding global averages. Strong biofilm-forming strains were significantly associated with tetracycline resistance compared to weak biofilm-forming strains. Additionally, GWAS identified five SNPs significantly associated with GC risk, with variants in hemC , babB and C694_RS04850 being enriched in high-risk strains. Conclusions. This study demonstrates the critical impact of H. pylori strain diversity in GC development, emphasizing the necessity for region-specific surveillance and innovative therapeutic strategies.