The hospital performed active surveillance for MRSA,
which included nasal swabs for MRSA upon ICU admission,
weekly, and upon discharge in the cardiothoracic,
medical, and surgical/burn/trauma ICUs for several years
before this project. This surveillance continued throughout
this study. We defined MRSA acquisition in these 3
units as a nasal swab or clinical culture that was positive
for MRSA 48 hours after admission in any patient who
had a negative result or no nasal swab at admission.