Selective screening of carriers for control of methicillin-resistant Staphylococcus aureus (MRSA) in high-risk hospital areas with a high level of endemic MRSA.

Screening for methicillin-resistant Staphylococcus aureus (MRSA) carriage in patients at risk was evaluated as part of a control program in a 26-bed medical intensive care unit (ICU) of a university hospital with a high level of endemic MRSA. Control measures included isolation and barrier precautions, skin decolonization with chlorhexidine of patients from whom MRSA was recovered, and mupirocin treatment of nasal carriers of MRSA. Of 3,686 patients admitted during a 4-year period, 44% were screened, which occurred during admission for 38%; MRSA was recovered from 293 patients (8%). There were 150 imported cases and 143 ICU-acquired cases, of which 51% and 45%, respectively, were first identified through screening. Nasal swab cultures identified 84% of MRSA carriers. The incidence of all ICU-acquired cases and of acquired colonization or infection decreased from 5.8% and 5.6% to 2.6% and 1.4% (P = .002 and P < .001), respectively, whereas that of imported cases remained unchanged (range, 3.8% to 4.3%; P = .8). Selective screening for nasal carriage during admission to high-risk areas may contribute to identification of a substantial proportion of cases of MRSA and to early implementation of effective control measures.