An Anti-Persister Strategy for the Treatment of Chronic Pseudomonas aeruginosa Infections [PublishAheadOfPrint]

Bacterial persisters are a quasi-dormant sub-population of cells that are tolerant to antibiotic treatment. The combination of the aminoglycoside tobramycin with fumarate as an antibacterial potentiator utilizes an anti-persister strategy that is aimed at reducing recurrent Pseudomonas aeruginosa infections by enhancing the killing of P. aeruginosa persisters. Stationary phase cultures of P. aeruginosa were used to generate persister cells. A range of tobramycin concentrations was tested with a range of metabolite concentrations to determine the potentiation effect of the metabolite under a variety of conditions, including a range of pH values and in the presence of azithromycin or cystic fibrosis (CF) patient sputum. In addition, 96-well dish biofilm and colony biofilm assays were performed, and the cytotoxicity of the tobramycin-fumarate combination was determined utilizing an LDH assay. Enhanced killing of up to 6 orders of magnitude of P. aeruginosa persisters over a range of CF isolates including mucoid and non-mucoid strains was observed for the tobramycin-fumarate combination compared to tobramycin alone. Furthermore, significant fumarate-mediated potentiation was seen in the presence of azithromycin or CF patient sputum. Fumarate also reduced the cytotoxicity of tobramycin treated P. aeruginosa to human epithelial airway cells. Finally, in mucoid and non-mucoid CF isolates, complete eradication of P. aeruginosa biofilm was observed in the colony biofilm assay due to fumarate potentiation. These data suggest that a combination of tobramycin with fumarate as an antibacterial potentiator may be an attractive therapeutic for eliminating recurrent P. aeruginosa infections in CF patients through the eradication of bacterial persisters.

http://ift.tt/2xtJiRR