Prevalence of Staphylococcus aureus nasal colonization in emergency department personnel

Nasal colonization with Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) can precede infection in patients and contacts. Although general population S aureus/MRSA rates are well described, the prevalence of S aureus and MRSA nasal colonization in emergency department health care workers is not defined. We seek to determine the prevalence of S aureus and MRSA nasal colonization among ED health care workers without evidence of an active site of staphylococcal infection and identify variables associated with colonization.

We prospectively studied a convenience sample of ED health care workers from 5 urban teaching hospitals in Pittsburgh, PA. Each participant completed a questionnaire and nasal culturing. We tested susceptibility with the oxacillin disc diffusion method. We analyzed data with descriptive statistics and univariate regression, with alpha set at 0.05.

Of 255 subjects, 23% were physicians; 62% were nurses, nursing assistants, or patient care technicians; and 15% were clerical staff or social service workers. Of 81 (31.8%) S aureus isolates, 11 (13.6%) were MRSA, an overall prevalence of 4.3%. All positive MRSA samples were from nurses, nursing assistants, or patient care technicians. No other covariate had an association with S aureus or MRSA colonization.

In this urban ED health care worker population, the prevalence of S aureus is similar but MRSA nasal colonization is higher than previously reported estimates in the general population of the United States. Physicians and nonpatient contact ED health care workers did not have MRSA colonization.