The effect of an antimicrobial stewardship programme in two intensive care units of a teaching hospital: an interrupted time series analysis

Abstract

Objectives: To evaluate the effect of an antimicrobial stewardship programme in two intensive care units (ICUs) of a teaching hospital.

Methods: Between January 2017 and June 2018 we conducted a prospective, interventional, interrupted time-series study, based on Prospective Audit and Feedback in two ICUs of an acute-care teaching hospital. The primary outcomes were the difference in the antibiotic consumption, and the incidence of bloodstream infections (BSI) caused by multidrug-resistant (MDR) organisms. The secondary outcomes included the hospital mortality rate, the mean length of stay and the antibiotic expense.

Results: During the study, 231 audits were performed, evaluating 693 antibiotic prescriptions. The programme led to a global reduction in antibiotic consumption, with a change in level (CL) of -324.8 defined daily doses (DDD)/100 patient-days (PD), p 0.04, and particularly in the use of fluoroquinolone: (CL: -63.48 DDD/100 PD, p < 0.001). A non-significant reduction was obtained for the consumption of carbapenems (CL: -34.7 DDD/100 PD, p 0.25) and third- and fourth-generation cephalosporins (CL: -27.3 DDD/100 PD, p 0.102). Furthermore, we registered a significant decrease in all BSI (CL: -5.8 events/100 PD, p 0.026) and in BSI due to MDR Gram-negative organisms (CL: -2.96 events/100 PD, p 0.043). No difference was observed in the hospital mortality and length of stay.

Conclusions: Our study demonstrated that implementation of an antimicrobial stewardship programme in two ICUs of a teaching hospital induced a significant reduction in antibiotic consumption and in the incidence of BSI due to MDR Gram-negative organisms, without any impact on the mortality rate.

Keywords: Antibiotics; Antimicrobial stewardship; Bacteraemia; Bacterial resistances; Defined daily dose; Intensive care units.