Reduction of Methicillin Resistant Staphylococcus Aureus Infections in Medical Intensive Care Unit with Active Surveillance Cultures and Chlorhexidine Wipes

Background: Methicillin Resistant Staphylococcus Aureus (MRSA) is highly endemic in Singapore hospitals. As part of our efforts to reduce MRSA, we started active surveillance cultures (ASC) in our medical intensive care unit (MICU) and decolonization of positive patients. Objective: Our objectives were to see if ASC and decolonization with chlorhexidine wipes would reduce MRSA acquisition and infections in MICU

Methods: This is a before-after interventional study. All patients admitted to MICU were screened for MRSA within 24 hours unless they were already known to be positive. Surveillance cultures were taken from nasal, axilla, groin, and any open wounds. During the baseline period, patients who had negative cultures had a repeat screen on discharge from MICU. Positive patients underwent decolonization with nasal mupirocin and chlorhexidine baths. During the study period, 1^st Nov 08 – 30^th Sep 09, screening cultures were repeated at 2-day intervals if earlier cultures were negative. MRSA-positive patients underwent decolonization with nasal mupirocin and daily wipes with chlorhexidine impregnated wash-cloths. We collected data on compliance with screening, as well as results of screening and clinical cultures done by managing physicians.

Results: From 1^st Nov 08 – 30^th Sep 09, screening swab specimens for MRSA were obtained from 920 patients on admission to MICU, giving a compliance rate of 99%. 150 patients (16.3%) were found to be colonized with MRSA. Of those screened negative for MRSA on entry to MICU, 40 patients (5.2%) were subsequently observed to be colonized with MRSA on interval-screening and 43 patients (5.6%) on exit screening. 77 patients (40.5%) underwent decolonization. The remaining patients were not started on the decolonization programme, as they had either been transferred out of MICU or had demised when the MRSA results were received. 48 patients (62.3%) completed the decolonization protocol. The remaining 29 patients  were either discharged or had died mid-way through the decolonization. 22 patients (45.8%) were successfully decolonized in the first round of decolonization. Another 2 patients were successfully decolonized in a second round. Overall, decolonization was successful in 24 of the 48 patients (50%) within the prescribed decolonization protocol.
MRSA infection rate in MICU was 1.5 per 1,000 discharges and deaths and 0.5 per 1,000 patient-days respectively, a significant reduction from a baseline of 8.3 per 1,000 discharges and deaths and 1.8 per 1,000 patient-days respectively in the baseline period. (P<0.05)
Conclusions: Active surveillance and decolonization with chlorhexidine wipes resulted in a significant reduction in MRSA infection rates in MICU.