Hospital acquired infections in the ICU are associated with serious morbidity and mortality. Our institution has had two major outbreaks of multi-drug resistant Acinetobacter (MDRA) in our general surgery (GS) and trauma ICUs in 2004 and 2011, requiring implementation of maximal infection control strategies including intense deep cleaning efforts.
We hypothesized that this outbreak response subsequently decreased the rates of other resistant pathogens such as MRSA, VRE and C. difficile.
Incidence of nosocomial MRSA, VRE, and C.difficile were calculated from a prospectively collected database for 6 months before and after the 2004 and 2011 MDRA outbreaks in the GS and trauma ICUs, and in two unaffected control ICUs: thoracic surgery and MICU. We created a composite endpoint of “any resistant pathogen” defined as MRSA, or VRE, or C.difficile and used the Wilcoxon’s signed rank test to compare rates across time.
The incidence rate of ‘any resistant pathogen’ decreased in the GS ICU in 2004 and 2011 after the infection control strategies to control MDRA (from 21 to 10 cases/1000 patient days in 2004, p=0.07 and from 6.7 to 2.7 cases/1000 patient days in 2011, p=0.04). However, in the Trauma ICU, rates of acquiring MRSA, or VRE, or C.difficile did not change in either year despite implementation of maximal infection control strategies (15.9 vs. 20.7 cases/1000 patient days in 2004, p=0.44 and 5.0 vs. 4.2 cases/1000 patient days in 2011, p=0.41). The Medical & Thoracic ICUs, which were unaffected by the MDRA outbreaks, had no change in rates in either period.
Conventional infection control strategies to address MDRA outbreaks seem to reduce the rates of other resistant pathogens in critically ill patients in the General Surgery ICU although not in the Trauma ICU. This suggests that a scheduled, periodic, infection control strategy may be useful in limiting the rates of resistant pathogens in certain patient populations. Cost-effective analysis of our outbreak response is under way.
Brigham and Women’s Hospital
Brigham & Women’s Hospital
Dept of Population Medicine