Work

Exopolysaccharides of Streptococcus mutans Enhance Oral Colonisation and Drug Tolerance in Helicobacter pylori

Year: 2026

Type: article

Abstract: INTRODUCTION AND AIMS: The oral cavity is an extragastric reservoir for Helicobacter pylori (H. pylori), preventing its gastric eradication and causing recurrence. However, the oral environment is not ideal for H. pylori, and the factors facilitating oral H. pylori survival and colonisation are unclear. We explored how exopolysaccharides (EPSs), the fundamental building blocks of Streptococcus mutans (S. mutans) biofilms, affect H. pylori colonisation and drug tolerance in the oral cavity. METHODS: The EPS contents of 3 S. mutans biofilms (UA159, UA159ΔgtfB, and UA159ΔgtfBC) were determined via confocal laser scanning microscopy (CLSM). A coculture system of the H. pylori Sydney strain (SS1) and the 3 biofilms was established. The bacterial morphology and adhesive forces of the coculture systems were detected by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. CLSM observations confirmed the ability of glucosyltransferases (Gtfs) from S. mutans to form EPSs around SS1. The tolerance of SS1 to 2 representative antibiotics in the presence of EPSs was confirmed via colony-forming unit (CFU) counting and in vivo experiments. RESULTS: As the EPS content of the S. mutans biofilms increased, both the adhesive forces between SS1 and the S. mutans biofilms and the number of colonised SS1 cells increased. We extracted active Gtfs from UA159 and confirmed that Gtfs synthesised EPSs around SS1. The EPSs gradually accumulated over time, eventually encapsulating SS1. Both in vitro and in vivo experiments confirmed that S. mutans EPSs help protect SS1 against amoxicillin or clarithromycin, potentially confounding gastric lesion outcomes. CONCLUSIONS: S. mutans biofilms mediate the adhesion, colonisation, and antibiotic tolerance of oral H. pylori via Gtf-driven EPS biosynthesis.

Source: International Dental Journal

DOI: 10.1016/j.identj.2026.109405

Authors: Yujia Hao, Yuqiu Huang, Ruonan Chen, Yuqing Li, Xiaojing Huang

Institutions: Fujian Medical University, Sichuan University, State Key Laboratory of Oral Diseases

Language: English

Topic: Oral microbiology and periodontitis research

Subfield: Periodontics

Field: Dentistry

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,550