Impact of a Change in Antibiotic Prophylaxis on Total Antibiotic Use in a Surgical Intensive Care Unit

Objective: The aim of this study was to evaluate the impact of reducing the length of antibiotic prophylaxis for cerebrospinal shunts on total antibiotic use and key resistant pathogens. Methods: In January 2004, the use of antibiotic prophylaxis was reduced to a single shot dose with cefuroxime in an intensive care unit (ICU). Prior to this intervention, prophylaxis with second-generation cephalosporins was administered during the entire period of external cerebrospinal fluid (CSF) drainage. The effect on the antibiotic use density (AD: DDD [defined daily doses] per 1,000 patient-days [pd]) was calculated prior to (January 2002-December 2003) and following implementation of the intervention (January 2004-December 2006) by segmented regression analysis of an interrupted time series. Resistance proportions (RP) and resistance densities (RD), defined as resistant pathogen/1,000 pd of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis or E faecium, third-generation-resistant (3GC) Escherichia coli and Kebsiella pneumoniae, and imipenem-resistant Pseudomonus aeruginosa, were compared by the Fisher's exact test before and after the intervention. Results: Total antibiotic use by 147 DDD/1,000 pd decreased after the intervention when pre-operative prophylaxis was changed into single shot prophylaxis, from an estimated mean of 1,036 DDD/1,000 pd before the intervention to 887 DDD/1,000 pd post-intervention. This decrease was primarily due to a significant reduction in the amount of cefuroxime used for prophylaxis. The reduction in total antibiotic consumption was sustainable, and it did not increase again during the next 36 months. The RR and RD of third-generation cephalosporin-resistant E. coli increased after January 2004, whereas the percentage of MRSA significantly decreased. Conclusion: Change to single shot prophylaxis along with an ongoing antibiotic stewardship program resulted in a cut-back in total antibiotic use amounting to as much as 15%. It would therefore appear that targeting interventions aimed at reducing antibiotic prophylaxis in surgical ICUs may be very worthwhile.