Risk factors for Staphylococcus aureus colonization in a general emergency department patient cohort–results of an observational cohort study

Abstract

Background: Testing for Staphylococcus aureus (SA) colonization in emergency department (ED) patients may guide prevention strategies against hospital acquired infections (HAIs). This study determined the prevalence of SA carriers in a general ED population, characterized the population, and identified predictors for SA colonization. Methods: A prospective monocentric observational cohort study in a tertiary care hospital collected nasopharyngeal swabs in 1000 adult patients. Polymerase chain reaction (PCR) testing for methicillin resistant and methicillin sensitive SA (MRSA/MSSA) was performed. Risk factor questionnaires and routine data from the clinical information system were captured. Descriptive statistics and binary logistic regression models were applied to report prevalence and outcomes and to identify predictors. Results: The prevalence for SA was 33.7% (n = 328; 95%-CI: 30.7–36.8): MSSA 30.9% (n = 301; 95%-CI: 28.0–34.0) and MRSA 2.8% (n = 27; 95%-CI: 1.8–4.0). Key predictors of SA colonization included having a catheter (OR 2.0, 95%-CI 1.0–4.0, p = 0.044) and requiring nursing care (OR 1.9, 95%-CI: 1.2–2.9, p =.007), even after adjusting for age and sex. Conclusion: Testing strategies for SA detection in ED need to focus on vulnerable populations with an elevated risk for HAIs and associated adverse outcomes. Individuals requiring nursing care could be a key target population for screening efforts.