Relation of %T >MIC of piperacillin to the clinical outcome in the treatment of Gram-negative bacterial infections

摘要

There are few reports of direct assessment of the percent duration of the dosing interval for which the concentration of the antibiotic in the blood remains above the minimum inhibitory concentration (MIC) (time above the MIC% [%fT>MIC]) and the clinical outcome for piperacillin (PIPC). Therefore, we investigated the relationship between the %fT>MIC and the outcomes in patients receiving PIPC therapy. In patients treated with PIPC at Kitasato University East Hospital, the %fT >MIC for the antibiotic was determined retrospectively for each patient from the serum concentrations of the drug plotted over time, and the relationship between the %fT>MIC and the therapeutic response rate was calculated by logistic regression analysis. Evaluation of the efficacy of the drug was carried out on the basis of its bacteriological effects (elimination of the bacterial pathogen). The analysis revealed that a response rate of >90% was achieved when the %fT>MIC was >60%. Assessment of the relationship between the emergence of resistant organisms and the %fT>MIC in the non-responders revealed that the emergence of resistant organisms can be prevented if a %fT>MIC of 60% can be achieved, at which the drug is known to exert maximal bactericidal effect. In conclusion, this study suggested that maintaining the %fT>MIC at a target of 60% in the dosage design of PIPC therapy would result in improved clinical outcomes.