Association Between Biofilm Formation and Structure and Antibiotic Resistance in H. pylori

Background: Persistent infections caused by Helicobacter pylori ( H. pylori ), which are resistant to antibiotic treatment, pose a growing global public health concern. Biofilm formation is known to be associated with persistent infections due to its role in enhancing antimicrobial resistance and the tolerance of many pathogenic bacteria. Objective: This study aims to evaluate the biofilm formation of clinical isolates of H. pylori and its impact on antibiotic eradication. Methods: The thickness, morphology, and structure of biofilms derived from nine H. pylori strains were examined using confocal laser scanning microscopy, scanning electron microscopy, and transmission electron microscopy. Subsequently, the susceptibility of both planktonic and biofilm bacteria was assessed through the determination of minimum inhibitory concentration and minimum biofilm eradication concentration for amoxicillin, clarithromycin, levofloxacin, and tetracycline. Results: The results revealed varying biofilm thicknesses and densities among the strains, characterised by the presence of numerous filaments intertwining and connecting bacterial cells. Additionally, several cases exhibited susceptibility based on MIC measurements but resistance according to MBEC measurements, with MBEC indicating a higher resistance rate. Pearson Correlation analysis demonstrated a positive correlation between biofilm thickness and MBEC results (0 < r < 1), notably significant for amoxicillin ( r = 0.801, P = 0.009) and tetracycline ( r = 0.696, P = 0.037). Conclusion: Different strains of H. pylori exhibit variations in their capacity to release outer membrane vesicles (OMVs) and form biofilms. Biofilm formation can influence the effectiveness of amoxicillin and tetracycline in eradicating susceptible bacterial strains. Keywords: Helicobacter pylori , antibiotic resistance, biofilm formation, biofilm-specific resistance