Origin of methicillin-resistant Staphylococcus aureus health care-associated infections: Evaluation of the role of anterior nares

Methicillin-resistant Staphylococcus aureus (MRSA) health care-associated infections (HAIs) are a cause of extended hospitalizations and escalating health care costs. We typed 49 MRSA HAIs and their corresponding admission nasal MRSA isolates to determine strain-relatedness and better define the role of anterior nares in the causation of HAI and the value of decolonization. Based on repetitive extragenic palindromic sequencing polymerase chain reaction results, the majority of our patients possibly acquired MRSA HAI from nonnasal sources (36 out of 49; 74%). Among the remaining patients (13 out of 49; 26%) the nasal and clinical HAI isolates matched, indicating potential benefit of decolonization among this subsegment of patients. These findings may be relevant to institutions such as Veterans Health Administration hospitals that already have universal screening programs but are looking at ways to further reduce MRSA HAI incidence.