Assessment of Susceptibility, Pharmacodynamics, and Therapeutic Response for Interpretation of Piperacillin-Tazobactam in Vitro Activity in the Treatment of Pseudomonas aeruginosa Infection

This is the authors' abstract. We don't add key points for this paper.

Pseudomonas aeruginosa remains an important pathogen. Our purpose was to determine the minimum inhibitory con-centration (MIC) and pharmacodynamic (PD) parameters predicting a positive response to therapy with piperacil-lin-tazobactam. Medical records were retrospectively reviewed at 3 centers. Data were recorded to assess age, type of disease, renal function, weight (body mass), MIC, antimicrobial treatment, and clinical outcome. Success was response to piperacillin-tazobactam alone, or in combination with another active agent; failure was lack of response. Of 78 eva-luable patients, 63 responded (7 UTI; 56 non-UTI) and 15 did not; 26 responding received combination therapy and 37 monotherapy. Piperacillin-tazobactam treatment was successful in 53 of 63 of non-UTI disease with a MIC of ≤64/4 μg/mL, but in only 3 of 7 with a MIC of >64/4 μg/mL (P = 0.023); overall 9 of 10 infections by strains with MICs = 32 - 64 μg/mL had a successful outcome. Piperacillin estimated time above MIC at 20% separated those responding from those that did not (P = 0.019).