Mucus hypoxia promotes infection in cystic fibrosis

Cystic fibrosis (CF) is an inherited condition characterized by abnormal, highly adherent viscous mucus. The mucus favors intractable infections in the lungs, typically with Pseudomonas aeruginosa but the precise mechanism of bacterial invasion and colonization remains unclear. In February 1 Journal of Clinical Investigation, Dieter Worlitzsch and colleagues from University of Tübingen, Germany show that airway mucus hypoxia contributes to the early pathogenesis of P. aeruginosa infection in CF patients.

Worlitzsch et al. examined freshly excised CF airways after lung transplantation, and found that P. aeruginosa are localized within the intraluminal mucus and do not adhere directly to the epithelial layer. Further in vivo and in vitro studies showed that CF-specific increases in epithelial O₂ consumption caused hypoxic gradients within poorly cleared intraluminal mucus. In hypoxic mucus, inhaled P. aeruginosa bacteria switch to alginate production, helping the bacteria to evade host defenses and survive exposure to...