Ward-Specific Rates of Nasal Cocolonization with Methicillin-Susceptible and -Resistant Staphylococcus spp. and Potential Impact on Molecular Methicillin-Resistant Staphylococcus aureus Screening Tests

We report that the rates of nasal cocolonization with methicillin-susceptible Staphylococcus aureus and methicillin-resistant coagulase-negative staphylococci can vary widely between patients admitted to different wards within a single hospital. Such cocolonization can greatly influence the performance of molecular methicillin-resistant S. aureus (MRSA) screening tests depending on the methods used and targets selected.