Methicillin-Resistant Staphylococcus aureus Colonization Among Health Care Personnel in the Emergency Department: What Does It Tell Us?

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) remains an important cause of health care–associated infections and has now emerged as a major cause of community-associated skin and soft tissue infections in the United States. Hospitalizations for MRSA disease increased 2 to 3 times between 1999 and 2005 in the United States, and much of this trend appears to be attributable to increases in skin and soft tissue infections. Many patients with MRSA infection are initially evaluated and treated in emergency departments (EDs); in 2004, 59% of all purulent skin infections evaluated in US EDs were caused by MRSA. In addition, about two thirds of severe health care– associated MRSA infections have their onset outside of hospitals, and it is likely that a substantial proportion of these patients return to care through EDs. The frequency with which EDs currently encounter MRSA-colonized or -infected patients suggests there may be a high risk for MRSA transmission between patients and health care personnel in this setting unless appropriate infection control practices are in place. In this issue of Annals of Emergency Medicine, 2 separate studies examined the prevalence of MRSA carriage among ED health care personnel. In the study by Suffoletto et al, anterior nares cultures were performed in a convenience sample of ED personnel in 5 hospitals in Pittsburgh, PA. Of 255 subjects studied, 81 (31.8%) had S aureus detected and 11 (13.5%) carried MRSA, for an overall MRSA colonization prevalence of 4.3% (95% confidence interval [CI] 0% to 9.3%). The prevalence of MRSA carriage was similar across the 5 study sites, ranging from 3.1% to 7.0%. Bisaga et al used polymerase chain reaction to screen for the presence of MRSA among swabs taken from the anterior nares of 105 ED workers in a Chicago hospital. A total of 16 (15%; 95% CI 9.6% to 23%) health care personnel were found to carry MRSA. The authors of both studies point out that the observed MRSA carriage rate among their ED personnel was higher than in the general US