WS2.2 Identification of two novel immunogenic Burkholderia cepacia complex proteins involved in lung cell attachment

Objective: Cystic fibrosis (CF) lungs infected with antibiotic resistant bacteria is very difficult to treat. Our aim is to improve the effectiveness of existing antipseudomonal drugs through the use of liposomal antibiotic formulations. Methods: The effect of sub-inhibitory concentrations of liposomal clarithromycin on P. aeruginosa (PA) adherence to human lung epithelial cell (A549) in culture and the mechanisms of anti-adherence property of the formulation were investigated by comparing outer membrane protein profiles of antibiotic treated cultures to that of controls using 2D gel electrophoresis. The release kinetics in CF sputum, the antibacterial activity against biofilm forms of PA and the mucus penetrating ability of liposomal clarithromycin in cystic fibrosis sputum were assessed by HPLC, fluorescence and microbiological assay. The nebulized liposomal clarithromycin was prepared using a (PARI) nebulizer and the physicochemical properties of nebulized were analyzed using scanning electron microscopy. Results: The sub-inhibitory concentrations of liposomal clarithromycin were found to diminish the ability of PA to bind to human lung epithelial cell (A549). The liposomal formulation penetrated into deep mucus layers and kept it up longer. The antibacterial activity liposomal clarithromycin against biofilm forms of PA was increased by several folds compared to clarithromycin alone. Conclusion: These liposomal formulation played an important role in preventing the attachment of PA to cell surfaces and their administration by Inhalation is achievable. This strategy could prevent PA from causing infections and damaging the lung in CF patients.