January 6, 2016



Effective antimicrobial stewardship in the Intensive Care Unit (ICU) avoids any potential morbidity and mortality associated with inadequate antimicrobial therapy among critically ill patients, and may prevent the development of resistant pathogens. To date there is no consensus on how ICUs should best approach this challenge. Taggart et al. has conducted a single centre audit and feedback intervention based in a Canadian teaching hospital, which has provided insight into effective antimicrobial stewardship. 

This study involved weekday antimicrobial therapy reviews by a pharmacist and a physician, both with special infectious diseases backgrounds. They provided antimicrobial recommendations to the ICU team, but the ICU team retained prescribing autonomy. This was performed in a trauma/neurosurgery ICU (TNICU) and a medical/surgical ICU (MSICU). The control group was comprised of a cardiovascular surgery ICU (CVICU) and cardiac ICU (CICU). In this group, antibiotic selection was performed at the discretion of the respective ICU team.

The programme ran for one year pre-intervention and one year after the intervention was initiated. This method of interrupted time series was used to compare the intervention and control groups. Patients with cystic fibrosis were excluded from this trial.

The study’s primary outcome was total systemic antimicrobial use, measured as ‘defined daily doses’ (DDD) per 1000 patient days per month. In the TNICU antimicrobial use decreased by 28% (p=0.0009) after the intervention. There was no significant decrease in antimicrobial use in the MSICU or either control groups. This may be partly attributable to an unexpected and significant 4-fold increase in cystic fibrosis patients in the MSICU.

Furthermore the TNICU significantly decreased the mean total cost of antimicrobials by 29% (p=0.0001), the use of fluoroquinolones by 80% (p<0.0001) and the use of antibacterials with activity against pseudomonas by 44% (p<0.0001). However, there was no significant change in mortality, length of stay on ICU or proportion of patients re-admitted to the ICU.

Strengths & Limitations

Restricting the study to weekdays may have lead to an underestimation of the effectiveness of audit and feedback stewardship, limiting any potential improvements to mortality, length of stay on ICU or proportion of patients re-admitted to ICU that would potentially be seen if this was a 7 day service.

Using total systemic antimicrobial use as a primary outcome may establish a reduction in the antibiotic usage, but does not reveal anything about the appropriateness of the therapy. The authors acknowledge that a longer period of observation would be required to see the effects of such a stewardship program on preventing the development of resistant pathogens

This study investigates overall antibiotic use rather than looking at specific antimicrobials thereby avoiding substitution of specific antimicrobials by others, keeping the overall antibiotic use the same.

Take Home Message

The audit and feedback programme showed different outcomes within the intervention group. In the TNICU the observed significant decrease in systemic antimicrobial use led to a decrease in spending, but this conferred no clinical benefit. There was no significant decrease in antimicrobial use in the MSICU. More evidence is necessary to determine an optimal system for stewarding antimicrobials in ICU.

This article review was prepared and submitted by John Batty, Charing Cross Hospital, London


Taggart LR, Leung E, Muller MP, Matukas LM, Daneman N. Differential outcome of an antimicrobial stewardship audit and feedback program in two intensive care units: a controlled interrupted time series study. BMC infectious diseases. 2015;15:480.

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