Helicobacter pylori (H. pylori) adhesion to human gastric epithelial cells is closely linked with fucosylated glycans. Therefore, investigation of fucosylation in the interaction of gastric epithelial cells with H. pylori is critical. In this study we used lectin microarrays to detect the expression of fucosylated glycans in gastric epithelial cells (GES-1) infected with H. pylori strains isolated from patients with different diseases including chronic gastritis, duodenal ulcers, and gastric cancer (each containing two strains) at 4 h. In addition, we investigated the time-course expression of fucosyltransferase (FUT) 1–6 genes in GES-1 cells stimulated with H. pylori strains at 0.5–8 h. At 4 h post-infection, Lotus, AAA, BC2LCN, PA-IIL, CNL and ACG lectins had increased signals in H. pylori-infected GES-1 cells compared to uninfected cells. Higher expression of FUT1 and FUT2 was detected in all H. pylori-infected GES-1 cells within 2 h, regardless of the H. pylori strain. In particular, the expression of FUT2 was higher in H. pylori-infected GES-1 cells with a higher fold change in levels of BC2LCN lectin specific to α1-2 linked fucose (Fuc) at 4 h. The results suggest that the high levels of α1, 2-linked Fuc synthesized by FUT1/2, might play a role in the preliminary stage of H. pylori infection. This provides us with pivotal information to understand the adhesion of H. pylori to human gastric epithelial cells.

Accurate diagnostic techniques and effective therapeutic methods are required to treat H. pylori. The application of chicken single-chain variable fragment (scFv) antibodies may diagnose and treat H. pylori. This study used the phage display technique to construct a chicken-derived immune scFv antibody library against H. pylori. Total RNA was extracted from the spleens of five immunized chickens and reverse transcribed into cDNA. A fragment of scFv was produced by overlap extension PCR and cloned into a pHEN2 phagemid vector. After the package with the M13KO7 helper phage, the recombinant HpaA protein was used as a target antigen to validate the screening ability of our antibody library by bio-panning. The dilution counting results showed that the size of the primary antibody library was estimated to be 1 × 10⁹ cfu/mL. PCR analysis of 47 clones from the library revealed that about 100% of the clones were positive with scFv fragments, and there were no identical sequences, indicating the good diversity of the antibody library. After three rounds of bio-panning, high-affinity antibodies against recombinant HpaA protein were successfully obtained. The selected antibody specifically recognized HpaA protein in nine different H. pylori strains, confirming the screening ability of our library. The chicken immune scFv antibody library against H. pylori was successfully constructed, and the antibody library’s screening ability was validated by selecting specific scFv antibodies against recombinant HpaA and clinical strains. It provided a simple and rapid method to obtain antibodies against H. pylori for diagnosis or treatment.

Introduction: Metronidazole (MNZ) is widely used to treat Helicobacter pylori infection worldwide. However, due to excessive and repeated use, resistance rates have exceeded 90% in some regions. The mechanisms of MNZ resistance have been extensively studied, and RdxA has been identified as the primary enzyme responsible for MNZ activation. Mutations in RdxA, particularly termination mutations, can lead to high-level MNZ resistance.Methods: We identified a strain, ICDC15003s, which harbored RdxA termination mutation but remained highly susceptible to MNZ. To explore this phenomenon, we conducted comparative genomic and transcriptomic analyses to define RdxA-independent mechanisms of MNZ metabolism.Results and discussion: We found missense mutations in genes such as yfkO, acxB, alr1, glk, and cobB. Additionally, the expression of multiple genes, including TonB-dependent receptor and mod, significantly changed in resistant strains. Notably, the sequences and expression levels of known nitroreductases like FrxA and FdxB remained unchanged after induction of MNZ resistance, suggesting they were not responsible for MNZ sensitivity in ICDC15003s. Instead, transcriptional alterations were observed in genes encoding NADH-quinone oxidoreductase subunit (M, J, H and K), suggesting a potential compensatory mechanism for the loss of RdxA activity. We proposed that NADH-quinone oxidoreductase might serve as an RdxA-independent mechanism for MNZ metabolism and resistance through regulation of its expression levels. This discovery could provide new strategies to address MNZ resistance and aid in developing nitroimidazole antibiotics.