Effect of De-escalation Facilitated by Antimicrobial Stewardship Activities on Blood Culture Positive Patient Outcomes

To evaluate changes in the efficacy and safety of antimicrobial therapy through de-escalation improved by the antimicrobial stewardship (AS) activities, which started from 2013 in Kagawa University Hospital, we analyzed changes in the de-escalation rate and the patient outcomes. The number of carbapenem-treated cases evaluated as ‘improper use’ had decreased from 2013 to 2017. In most of these cases, improper use of blood culture was indicated. The AS team directed the proper use of carbapenem through weekly rounds, focusing on “intervention and feedback” according to the guideline. This activity was performed with emphasis on the appropriate use of blood culture results and the process of target therapy. As a result, it was shown that the number of blood culture orders and the rates of hospitalized cases, for which multiple sets of blood cultures were ordered, were increased. Also, the de-escalation rate of blood culture-positive cases treated with carbapenem was improved from 13.1％ in 2011 to 29.9％ in 2017. Furthermore, as a patient outcome, the 90-day mortality rate was decreased from 24.3％ in 2011 to 15.6％ in 2017. Similarly, the recurrent bloodstream infections rate was decreased from 5.6％ to 0％. On the other hand, in 2011 vs 2017, there was no significant difference in the detection rate of resistant bacteria. Taken together, most of the changes in the indicators related to patient outcome analyzed in the present study suggest that AS activities improved the de-escalation rate, and that the de-escalation contributed to the efficacy and safety of antimicrobial therapy.