Unraveling the complexity of Helicobacter pylori: Virulence factors, biofilm formation, and antibiotic resistance.

Abstract

Helicobacter pylori infection remains one of the most common chronic bacterial infections worldwide and represents a major etiological factor in diseases of the upper gastrointestinal tract, including chronic gastritis, peptic ulcer disease, and gastric cancer. Despite continuous refinement of eradication regimens based on antibiotics and proton pump inhibitors, treatment efficacy has progressively declined, primarily due to increasing antimicrobial resistance and the ability of H. pylori to form biofilm structures. Accumulating evidence indicates that biofilm formation, bacterial virulence, and modulation of host immune responses constitute an interconnected network of mechanisms that collectively promote bacterial persistence and therapeutic failure. This review outlines an integrated pathogenic framework for H. pylori, focusing on the functional interplay between key virulence determinants - including CagA, VacA, neutrophil-activating protein (NAP), high-temperature requirement A (HtrA), IceA, DupA, urease, catalase, and adhesins - and their contribution to biofilm development, epithelial barrier disruption, and sustained gastric inflammation. Biofilm formation is highlighted as a central adaptive strategy that not only limits antibiotic penetration but also induces metabolic dormancy, enhances efflux pump activity, and increases tolerance to oxidative stress and immune-mediated clearance, thereby significantly reducing the effectiveness of standard eradication therapies. In addition, the review incorporates novel insights derived from recent high-throughput omics approaches, including genomics, transcriptomics, proteomics, and metabolomics, which have advanced the understanding of H. pylori pathogenicity, adaptive responses, and resistance mechanisms at a systems level. A major emphasis is placed on recent advances in therapeutic strategies that extend beyond conventional antibiotic-based regimens. The review summarizes current pharmacological approaches, including the use of more potent acid-suppressive agents such as vonoprazan, susceptibility-guided and personalized eradication therapies, and emerging anti-biofilm interventions, including antimicrobial peptides, phytochemicals, small-molecule inhibitors, and enzymatic degradation of the extracellular polymeric matrix. In addition, nanotechnology-based drug delivery systems are discussed as promising tools to improve antibiotic stability, bioavailability, and targeted release within the hostile gastric environment. In conclusion, effective management of H. pylori infection requires a mechanistically informed and multidisciplinary approach that integrates bacterial virulence, biofilm biology, host immune modulation, and regional antimicrobial resistance profiles. The combination of established pharmacological therapies with innovative anti-biofilm and nanomedicine-based strategies represents a promising direction for improving eradication outcomes and limiting the further development of antimicrobial resistance.