Combined bacteriophage and antibiotc treatment prevents Pseudomonas aeruginosa infection of wild type and cftr- epithelial cells

Here we studied in an ex vivo human airway epithelial cell line model the efficacy of phage and ciprofloxacin alone and in combination to treat infection by Pseudomonas aeruginosa. The Calu-3 cell line and the isogenic CFTR knock down cell line (cftr-) infected apically with P. aeruginosa strain PAO1 showed a progressive reduction in transepithelial resistance during 24h. Administration at 6h p.i. of single phage, phage cocktails or ciprofloxacin alone prevented epithelial layer destruction at 24h p.i. Bacterial regrowth, due to phage resistant mutants harboring mutations in LPS synthesis genes, occurred thereafter both in vitro and ex vivo