Figure 1From: Colonization with antibiotic-susceptible strains protects against methicillin-resistant Staphylococcus aureus but not vancomycin-resistant enterococci acquisition: a nested case-control studyIdentification of methicillin-resistant Staphylococcus aureus (MRSA) cases and controls following intensive care unit (ICU) admission. All patients were required to have an initial MRSA-negative bilateral nares screening culture. Controls had a subsequent MRSA-negative screening culture (Interval A) whereas cases had a subsequent MRSA-positive screening or clinical culture (Interval B).Back to article page