Modelling the usefulness of a dedicated cohort facility to prevent the dissemination of MRSA D. Talon a , P. Vichard b , A. Muller a , M. Bertin a , L. Jeunet b , X. Bertrand a, * a Service d’Hygie `ne hospitalie `re et d’Epide ´miologie mole ´culaire, Centre Hospitalier Universitaire Jean Minjoz, Besanc ¸on Cedex 25030, France b Service de chirurgie orthope ´dique, traumatique et plastique, Centre Hospitalier Universitaire Jean Minjoz, Besanc ¸on Cedex 25030, France Received 11 June 2002; accepted 31 January 2003 KEYWORDS Dedicated cohort facility; MRSA; Isolation; Colonization pressure Summary The aim of this retrospective study was to determine whether or not a surgical dedicated cohort facility, mainly dedicated to the care of orthopaedic patients, can control the risk of infection caused by methicillin-resistant Staphylo- coccus aureus (MRSA). We tested this hypothesis on the orthopaedic surgery ward of a university-affiliated public hospital with 1228 beds by determining whether there was a significant correlation between the colonization pressure exerted by MRSA and the number of cases of acquired MRSA. This was then used as a tool to predict the number of patients contaminated with MRSA in hospitals with and without dedicated cohort facilities. We found that the relative risk of MRSA acquisition increased with the colonization pressure exerted by MRSA imported cases. This statistical model enabled us to predict that the risk of MRSA acquisition would increase by 160% per year in the absence of a dedicated cohort facility. We conclude that these units are useful to control the spread of MRSA in hospitals. Q 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved. Introduction Methicillin-resistant Staphylococcus aureus (MRSA) is a major hospital-acquired pathogen, which causes severe morbidity and mortality in hospitals in France and worldwide. 1–4 Colonized and infected inpatients are the major reservoir of this pathogen. These inpatients are responsible for the coloniza- tion of their environment. Contact with colonized inpatients and the environment may then lead to the contamination of nurses’ hands or gloves. 5 The transient carriage of MRSA on the hands of hospital personnel is the most common mechanism of patient-to-patient transmission. 6 Consequently, the incidence of hospital-acquired MRSA in inpati- ents can be used to assess the quality of infection control measures. 7 There is therefore a require- ment to separate patients colonized or infected with MRSA from other patients. 8 The need for dedicated cohort facility, including beds, an operating area, nursing and consultation facilities, is often contested. However, this may partly be due to the associated costs, both in terms of the workload and staff. 9 Two reasons for not 0195-6701/03/$ - see front matter Q 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved. doi:10.1016/S0195-6701(03)00086-0 Journal of Hospital Infection (2003) 54, 57–62 www.elsevierhealth.com/journals/jhin *Corresponding author. Tel.: þ 33-3-81-66-82-86; fax: þ33-3- 81-66-89-14. E-mail address: daniel.talon@ufc-chu.univ-fcomte.fr