Candida serves as a reservoir associating with facilitating the survival and pathogenesis of Helicobacter pylori

Helicobacter pylori (H. pylori) is a key pathogen in gastritis and gastric ulcers, noted for its high recurrence rates. <i>H. pylori</i> internalization into <i>Candida</i> vacuoles may enhance its survival and pathogenicity. In this study, we investigated the intrinsic association between <i>H. pylori</i> and <i>Candida</i> by performing <i>H. pylori</i>-related assays on <i>Candida</i> isolates obtained from clinical fecal samples, gastric mucosal tissues, and vaginal secretions. About 399 isolates of <i>Candida</i> were isolated from fecal samples of patients with digestive diseases. <i>H. pylori</i> antigens in feces and 16S rDNA within <i>Candida</i> isolates were detected, showing a significant correlation. After co-culturing <i>H. pylori</i> and <i>Candida in vitro</i>, <i>H. pylori</i> 16S rDNA-positive <i>Candida</i> (CacoHp) were obtained. <i>In vitro</i>, the CacoHp strain showed enhanced inhibitory and adhesive effects on GES-1 cells than standard <i>Candida</i> strain. <i>H. pylori</i> 16S rDNA was detected in CacoHp and <i>Candida</i> isolates obtained from gastric mucosal tissue and vaginal secretions. CacoHp and <i>H. pylori</i> 16S rDNA-positive clinical isolates exhibited urease activity, as evidenced by the color change of urea containing Sabouraud glucose agar medium from yellow to red. Gene expression analysis indicated that the <i>H. pylori ureA</i> gene was expressed at low levels in the CacoHp and <i>H. pylori</i> 16S rDNA-positive clinical isolates under the experimental conditions. Using direct immunofluorescence and fluorescence <i>in situ</i> hybridization, <i>H. pylori</i> antigens and genes were detected in <i>Candida</i>. Fluorescent staining indicated the potential presence of viable bacteria within <i>Candida</i>, suggesting that viable <i>H. pylori</i> might be present intracellularly within these <i>Candida</i> cells. These findings suggest that <i>H. pylori</i> may persist within <i>Candida</i>, with potential implications for human health.