The airway environment in individuals with muco-obstructive airway diseases (MADs) is characterized by dehydrated mucus due to hyperabsorption of airway surface liquid and impaired mucociliary clearance. As MADs progress, pathological mucus becomes increasingly viscous due to mucin overproduction and host-derived extracellular DNA (eDNA) accumulation. Pseudomonas aeruginosa, a major pathogen in MADs, colonizes this mucus niche persistently. Despite inhaled antibiotic therapies and the absence of antibiotic resistance, antipseudomonal treatment failure remains a clinical challenge.

We used JMP's data visualization and statistical modeling to investigate how mucin and eDNA concentrations – dominant polymers in respiratory mucus – affect P. aeruginosa’s antibiotic tolerance to understand antibiotic recalcitrance. Our findings reveal that polymer concentration and molecular weight impact P. aeruginosa survival after antibiotic exposure. Surprisingly, polymer-driven tolerance is not solely linked to reduced antibiotic diffusion. Additionally, we established an in vitro model that mirrors ex vivo antibiotic tolerance observed in expectorated sputum across different MAD etiologies, ages, and disease severities, highlighting the intrinsic variability in host-evolved P. aeruginosa populations.