Major article Evaluation of screening risk and nonrisk patients for methicillin-resistant Staphylococcus aureus on admission in an acute care hospital Eilish Creamer MSc a, * , Sandra Galvin PhD a , Anthony Dolan PhD a , Orla Sherlock PhD a , Borislav D. Dimitrov PhD b , Deirdre Fitzgerald-Hughes PhD a , Toney Thomas MBA c , John Walsh BSc c , Joan Moore FAMLS d , Edmond G. Smyth MD d , Anna C. Shore PhD e , Derek Sullivan PhD e , Peter Kinnevey PhD e , Piaras O’Lorcain PhD f , Robert Cunney MD f, g , David C. Coleman PhD e , Hilary Humphreys MD a, d a Department of Clinical Microbiology, Education and Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland b Department of General Practice, Royal College of Surgeons in Ireland, Dublin, Ireland c Department of Infection Prevention and Control, Beaumont Hospital, Dublin, Ireland d Department of Microbiology, Beaumont Hospital, Dublin, Ireland e Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, Trinity College Dublin, University of Dublin, Dublin, Ireland f Health Protection Surveillance Centre, Dublin, Ireland g Children’s University Hospital, Temple Street, Dublin, Ireland Key Words: Admission screening Universal MRSA screening Infection control MRSA epidemiology MRSA screening costs Background: Screening for methicillin-resistant Staphylocccus aureus (MRSA) is advocated as part of control measures, but screening all patients on admission to hospital may not be cost-effective. Objective: Our objective was to evaluate the additional yield of screening all patients on admission compared with only patients with risk factors and to assess cost aspects. Methods: A prospective, nonrandomized observational study of screening nonrisk patients 72 hours of admission compared with only screening patients with risk factors over 3 years in a tertiary referral hospital was conducted. We also assessed the costs of screening both groups. Results: A total of 48 of 892 (5%) patients was MRSA positive; 28 of 314 (9%) during year 1,12 of 257 (5%) during year 2, and 8 of 321 (2%) during year 3. There were significantly fewer MRSA-positive patients among nonrisk compared with MRSA-risk patients: 4 of 340 (1%) versus 44 of 552 (8%), P  .0001, respectively. However, screening nonrisk patients increased the number of screening samples by 62% with a propor- tionate increase in the costs of screening. A backward stepwise logistic regression model identified age > 70 years, diagnosis of chronic pulmonary disease, previous MRSA infection, and admission to hospital during the previous 18 months as the most important independent predictors to discriminate between MRSA- positive and MRSA-negative patients on admission (94.3% accuracy, P < .001). Conclusion: Screening patients without risk factors increased the number of screenings and costs but resulted in few additional cases being detected. In a hospital where MRSA is endemic, targeted screening of at-risk patients on admission remains the most efficient strategy for the early identification of MRSA- positive patients. Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. Methicillin-resistant Staphylococcus aureus (MRSA) is prevalent worldwide, and prevention and control include early identification, patient isolation, decolonization regimens, improved hygiene, and antimicrobial stewardship. 1,2 Screening on hospital admission of at- risk patients is recommended in most countries, 1 although universal screening, ie, screening all patients, is now mandated in the United Kingdom. 3 The application of admission screening on acute care hospital admission varies from study to study and includes screening all admissions 4 and selected patient groups, eg, intensive care unit (ICU) patients, 5 surgical patients, 6 and MRSA-risk patients. 7 The value of admission screening, however, in reducing MRSA rates is variable. 4,6,8-11 * Address correspondence to Eilish Creamer, MSc, Department of Clinical Microbiology, RCSI Education and Research Centre, Beaumont Hospital, PO Box 9063, Beaumont Road, Dublin 9, Ireland. E-mail address: eilishcreamer@rcsi.ie (E. Creamer). Supported by the Health Research Board, Ireland (TRA/2006/4). Conflicts of interest: None to report. Contents lists available at ScienceDirect American Journal of Infection Control journal homepage: www.ajicjournal.org American Journal of Infection Control 0196-6553/$36.00 - Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.ajic.2011.07.008 American Journal of Infection Control 40 (2012) 411-5