Abstract

Lung transplantation (LT) is the ultimate treatment option for patients suffering from end stage cystic fibrosis (CF). Most LT-patients, colonized pre-LT by Pseudomonas aeruginosa witness colonization of their non-CF allograft within a few days or weeks post-LT, thereby compromising graft and life expectancy. How P. aeruginosa isolates adapted for years to the specific CF lung environment efficiently colonize and survive in the non-CF allograft environment remains unclear. To address this question, we collected sequential isolates from CF LT-recipients and non-CF LT-recipients and performed phenotypic and genetic analyses of pairs of early and late isolates from LT-patients. We found evidence for mutations compatible with a switch from biofilm to planktonic lifestyle as well as loss of mucoid phenotypes. Hypermutators, characteristic of chronic CF-adapted isolates, were also found in four LT-patients. Their persistence in the non-CF allograft environment suggests a continuous seeding from the sinuses. Our results suggest that in CF LT-recipients efficient colonisation by P. aeruginosa of the allograft implies both adaptation and continuous seeding from the sinuses to the lower respiratory tract.