Limosilactobacillus reuteri DSM 17648 as an adjuvant in the fight against Helicobacter pylori infection: Mechanisms of action, clinical efficacy, and prospects

Helicobacter pylori infection remains a key risk factor for chronic gastritis, peptic ulcer disease, and gastric adenocarcinoma. However, the efficacy of standard eradication regimens is substantially declining due to rising antibiotic resistance and frequent therapy-related adverse effects. In this context, interest in adjuvant strategies is growing, including the use of probiotics and postbiotics / metabiotics capable of increasing eradication rates and improving treatment tolerability through strain-specific mechanisms of action and modulation of the gastrointestinal microbiota. This review focuses on the postbiotic / metabiotic Limosilactobacillus reuteri DSM 17648, which has demonstrated anti-H. pylori activity that persists after inactivation and is independent of H. pylori antibiotic resistance. The article discusses the main mechanisms of action of L. reuteri DSM 17648, including strain-specific coaggregation with H. pylori, competitive blocking of pathogen adhesion to gastric epithelium, inhibition of H. pylori virulence factors, masking of its adhesins, as well as the production of antimicrobial and anti-inflammatory metabolites (organic acids, reuterin, exopolysaccharides, etc.) that contribute to reduced expression of urease, vacA, and cagA genes and attenuation of the inflammatory response in the gastric mucosa. A review of major clinical studies in adults and children is provided, including randomized placebo-controlled trials in Europe and Asia, which have shown that adding L. reuteri DSM 17648 to standard triple therapy increases H. pylori eradication rates by an average of 10–20%, reduces bacterial load (as assessed by urea breath test), alleviates dyspeptic symptoms, and decreases the frequency of gastrointestinal adverse effects by 20–40% compared to eradication therapy alone. Data from pediatric studies are separately examined, confirming the efficacy and favorable safety profile of the metabiotic during courses of up to 56 days, as well as the absence of serious adverse events in patients across different age groups. Based on cumulative experimental and clinical evidence, practical aspects of L. reuteri DSM 17648 use are discussed, including its incorporation into standard H. pylori eradication regimens and as monotherapy (in infected individuals without immediate eradication indications, between antibiotic courses, and in special patient populations), its place in current guidelines (Maastricht VI, Russian clinical guidelines), and future perspectives for use in combined and alternative therapeutic regimens, including the potential to reduce gastric cancer risk in infected individuals through its multifaceted impact on bacterial load, H. pylori virulence factors, inflammation, and gastric mucosal barrier function.