New concepts of chitosan-based mucosal formulations for supporting control of the gastric pathogen Helicobacter pylori.

Helicobacter pylori (H. pylori) is a human gastric pathogen that colonizes the stomach by adapting to acidic pH, penetrating the gastric mucus layer, adhering to epithelial and mucosal receptors, and delivering virulence factors that promote inflammation and immune evasion. Antibiotic-based regimens have markedly reduced the burden of H. pylori-associated disease; however, increasing antimicrobial resistance, treatment failure, recurrence, and disruption of the gut microbiota remain important clinical challenges. Future therapeutic strategies should therefore combine bacterial control with modulation of the gastric environment that sustains chronic infection and impaired host responses. Chitosan-based micro- and nanoparticles are promising delivery systems for drugs and biologically active compounds because of their biodegradability, cationic surface charge, and mucoadhesive properties. This Mini Review summarizes chitosan-based formulations proposed for the delivery of antibiotics, plant-derived antimicrobial compounds, and antimicrobial peptides, as well as systems targeting H. pylori adhesins, bacterial biofilm, or urease activity. We also discuss an experimental concept in which the immunomodulatory vaccine strain Mycobacterium bovis Bacillus Calmette-Guerin (BCG) is encapsulated in chitosan micro- or nanoparticles for gastric and/or intestinal delivery. Available in vitro and in vivo evidence suggests that chitosan-based systems may increase local exposure to active components, support mucosal immune responses, and potentially facilitate epithelial repair. Nevertheless, most data remain preclinical, and clinical efficacy in humans has not been demonstrated. The review highlights the need for broader independent validation, careful biosafety assessment, and standardized formulation parameters before these approaches can be considered for translation.