Evaluation of liposomal bismuth-ethanedithiol-tobramycin for treatment of cystic fibrosis pulmonary pseudomonas aeruginosa infection

Abstract

The effectiveness of liposomes incorporating bismuth-ethanedithiol and loaded with tobramycin (LipoBiEDT-TOB) at sub-inhibitory concentrations to inhibit the production of quorum sensing signaling molecules and virulence factors induced by P. aeruginosa was evaluated in vitro. In addition, we evaluated the efficacy and safety of free and encapsulated tobramycin in liposomal formulations administered intratracheally to rats chronically infected with P. aeruginosa. LipoBiEDT-TOB significantly reduced the production of quorum sensing signaling molecules and virulence factor secretion compared to free tobramycin. The LipoBiEDT-TOB formulation significantly reduced the bacterial count in lungs, modulated the IL-8 level in blood and minimized the nephrotoxicity that is associated with aminoglycoside treatment. These results support the hypothesis that aerosolization of liposomal aminoglycosides may enhance the management of chronic lung infections caused by resistant P. aeruginosa in patients with cystic fibrosis.