MDR Bacterial Infections Our Treatment Option

Attenuation of Colistin Bactericidal Activity byHigh Inoculum of Pseudomonas aeruginosaIn vitro time-kill experiments using 8-64 x the MIC of colistinP. aeruginosa PAO1 at initial CFUo of 10 6 , 10 8 , and 10 9 CFU/ml.Against PAO Killing rate of the susceptible population- at the 10 9 CFUo 23-fold slower- at the 10 8 CFUo 6-fold slower- at the 10 6 CFUo 1-fold (for comparison)Bacteria were assumed to release signal molecules stimulating aphenotypic change that inhibits killing.The extent and rate of killing of P. aeruginosa were markedlydecreased at high CFUo compared to those at low CFUo.Bulitta JB, Yang JC, Yohonn L, Ly NS, Brown SV, D'Hondt RE, et al. Attenuation of colistin bactericidal activity by high inoculum of Pseudomonasaeruginosa characterized by a new mechanism-based population pharmacodynamic model. Antimicrob Agents Chemother 2010;54:2051-62.