A physical linkage between cystic fibrosis airway surface dehydration and Pseudomonas aeruginosa biofilms

H Matsui, VE Wagner, DB Hill… - Proceedings of the …, 2006 - National Acad Sciences
H Matsui, VE Wagner, DB Hill, UE Schwab, TD Rogers, B Button, RM Taylor, R Superfine
Proceedings of the National Academy of Sciences, 2006National Acad Sciences
A vexing problem in cystic fibrosis (CF) pathogenesis has been to explain the high
prevalence of Pseudomonas aeruginosa biofilms in CF airways. We speculated that airway
surface liquid (ASL) hyperabsorption generates a concentrated airway mucus that interacts
with P. aeruginosa to promote biofilms. To model CF vs. normal airway infections, normal
(2.5% solids) and CF-like concentrated (8% solids) mucus were prepared, placed in flat
chambers, and infected with an≈ 5× 103 strain PAO1 P. aeruginosa. Although bacteria …
A vexing problem in cystic fibrosis (CF) pathogenesis has been to explain the high prevalence of Pseudomonas aeruginosa biofilms in CF airways. We speculated that airway surface liquid (ASL) hyperabsorption generates a concentrated airway mucus that interacts with P. aeruginosa to promote biofilms. To model CF vs. normal airway infections, normal (2.5% solids) and CF-like concentrated (8% solids) mucus were prepared, placed in flat chambers, and infected with an ≈5 × 103 strain PAO1 P. aeruginosa. Although bacteria grew to 1010 cfu/ml in both mucus concentrations, macrocolony formation was detected only in the CF-like (8% solids) mucus. Biophysical and functional measurements revealed that concentrated mucus exhibited properties that restrict bacterial motility and small molecule diffusion, resulting in high local bacterial densities with high autoinducer concentrations. These properties also rendered secondary forms of antimicrobial defense, e.g., lactoferrin, ineffective in preventing biofilm formation in a CF-like mucus environment. These data link airway surface liquid hyperabsorption to the high incidence of P. aeruginosa biofilms in CF via changes in the hydration-dependent physical–chemical properties of mucus and suggest that the thickened mucus gel model will be useful to develop therapies of P. aeruginosa biofilms in CF airways.
National Acad Sciences