Cystic Fibrosis-Modulated Phenotypic Changes of Pseudomonas aeruginosa May Be a Critical Determinant for Respiratory Infections and Unresponsiveness to Antimicrobial Agents

Objective: Cystic fibrosis (CF) patients are exposed to respiratory system pathogens mostly forming biofilms, and therefore therapeutic interventions frequently fail. In this study, we aimed to investigate the resulting phenotypic changes in Pseudomonas aeruginosa due to interaction between bacteria and respiratory epithelium of CF patients. Methods: In vitro investigation of some phenotypic characteristics of P. aeruginosa such as biofilm formation, adhesion, and its growth rate was made in normal and CF bronchial (BEAS-2B and IB3-1) and tracheal (1HAEoand CFTE29o-) epithelium. P. aeruginosa PAO1, a green fluorescent protein expressing strain, was used in the experiments. Results: Adhesion of P. aeruginosa to CF bronchial epithelium had decreased and biofilm formation had increased in CF bronchial epithelium compared to normal bronchial epithelium. Moreover, P. aeruginosa was found to be the cause of morphological changes in the CF bronchial epithelium. Conclusions: Our findings support that the changes in respiratory epithelium with CF directly affect bacterial phenotypic characteristics in infected CF patients, and these phenotypic changes may be the major determinant of unresponsiveness to antimicrobial agents during treatment of infections. Klimik Dergisi 2019; 32(1): 22-8.