Overcoming antimicrobial resistance in Helicobacter pylori: the roles of collateral sensitivity and biofilm dynamics.

Objectives: The increasing prevalence of antimicrobial resistance (AMR) in Helicobacter pylori (H. pylori) poses a significant challenge to eradication strategies. This study investigates the role of biofilm formation in AMR and explores the potential of collateral sensitivity (CS) as a therapeutic approach to optimize treatment regimens.

Methods: Two H. pylori clinical isolates (HJ1 and HJ9) were assessed for antibiotic susceptibility using broth microdilution assays. Biofilm formation was characterized through crystal violet staining, scanning electron microscopy and Raman microspectroscopy. CS profiling was conducted by generating adaptive-resistant strains through serial exposure to sub-inhibitory antibiotic concentrations, and susceptibility testing using disk diffusion assays.

Results: • The antibiotic-resistant strain HJ1 exhibited enhanced biofilm formation over time compared to HJ9, with Raman microspectroscopy revealing significant biochemical alterations in its extracellular polymeric substance (EPS).• CS profiling demonstrated reciprocal susceptibility changes; resistance to tetracycline increased levofloxacin susceptibility in HJ1, while resistance to rifampicin increased amoxicillin susceptibility in HJ9.• The findings suggest that strategic antibiotic cycling, leveraging CS relationships, may enhance treatment efficacy and limit resistance development.

Conclusions: Biofilm formation plays a critical role in H. pylori AMR, reinforcing the challenge of eradication. CS profiling indicates that resistance acquisition can be exploited therapeutically to enhance antibiotic efficacy. Integrating CS-based treatment strategies with biofilm-disrupting interventions may provide a novel approach of overcoming multi-drug resistance in H. pylori. Further research is required to elucidate the molecular mechanisms underpinning CS and biofilm-mediated resistance to refine treatment strategies.