Diagnostic accuracy of methicillin-resistant Staphylococcus aureus nasal colonization to predict methicillin-resistant S aureus soft tissue infections.

Nasal methicillin-resistant Staphylococcus aureus (MRSA) testing at admission to the hospital was found to have a positive likelihood ratio of 8.5 and a negative likelihood ratio of 0.41 for predicting MRSA soft tissue infections. The clinical utility of this test depends on the prevalence of MRSA infection. In high prevalence populations, nasal MRSA is useful to rule in MRSA infections. In low prevalence populations it may be useful to rule out infections.