Increased antimicrobial susceptibility rates for Pseudomonas aeruginosa bloodstream isolates across the Veterans Affairs Healthcare System

This study sought to characterize the trends in antimicrobial susceptibility rates for Pseudomonas aeruginosa causing bacteremias across the US Veterans Healthcare Administration from 2007 through 2013 utilizing a national clinical database. Data were gathered from 107 Veterans Affairs medical centers involving 4418 patients with 4826 blood cultures with positive growth of P. aeruginosa. Susceptibility rates of β-lactam antimicrobials, carbapenems, fluoroquinolones, and aminoglycosides all significantly increased throughout the 7-year period, closely corresponding to a significant decline in the incidence of P. aeruginosa blood cultures of nosocomial origin. Several statistically significant increases in susceptibility rates were found for antimicrobial agents across different geographic regions of the United States. There were no statistically significant decreases in susceptibility rates for any antimicrobial agents for any region. Levels of multidrug resistance significantly declined throughout the study period in 2 regions and increased in 1. Additional efforts should evaluate variables associated with these improvements.