Development of a combination antibiogram for Pseudomonas aeruginosa bacteremia in an oncology population

PurposeDevelopment of a combination antibiogram to identify combinations of antibiotics that have the highest likelihood of attaining one active agent in the empiric management of presumed Pseudomonas aeruginosa bacteremia.MethodsPatients with cancer and P. aeruginosa bacteremia from January 1 to December 31, 2012 were included in this analysis. The primary outcome was identification of effective combinations of beta-lactam and non-betalactam agents. An effective combination was defined as one which achieved in-vitro activity to greater than or equal to 85% of isolates collected. Furthermore, the addition of the non-beta-lactam agent was required to increase the in-vitro activity by at least 5% over beta-lactam monotherapy. Multiple secondary outcomes were evaluated.ResultsOne hundred and twenty-three P. aeruginosa isolates were included from 99 patients. Single agent beta-lactam sensitivities ranged from 72.4 to 79.7%. Combination regimen sensitivities ranged from 73.5 to 96.7%. All combination regimens ...