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

## TL;DR

This study shows that Candida can host Helicobacter pylori, helping it survive and cause disease, which could explain its high recurrence rates.

## Contribution

The study reveals a novel intracellular association between H. pylori and Candida, suggesting Candida as a survival reservoir for H. pylori.

## Key findings

- H. pylori antigens and 16S rDNA were detected within Candida isolates from multiple clinical sources.
- CacoHp strains showed enhanced inhibitory and adhesive effects on GES-1 cells compared to standard Candida.
- Fluorescent staining suggests viable H. pylori may reside intracellularly within Candida cells.

## Abstract

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