Authors' objectives:

- To review the evidence for the effectiveness of different isolation policies and screening practices in reducing the incidence of methicillin-resistant Staphylococcus aureus (MRSA): colonisation and infection in hospital inpatients.

- To develop transmission models to study the effectiveness and cost-effectiveness of isolation policies in controlling MRSA.

Authors' results and conclusions: Results - Systematic review: - No conclusions could be drawn about the effect of isolation in one-third of studies. In studies with multiple simultaneous interventions it was not possible to assess the relative contribution of individual measures. - Most others provided evidence consistent with reduction of MRSA. In half of these, the evidence was considered weak because of poor design, major confounders and/or risk of systematic biases. - Two studies presented evidence consistent with immediate isolation reducing transmission. - Stronger evidence was presented in the larger and longer time series, with large changes in MRSA numbers, detailed information on interventions and relative absence of plausible alternative explanations. - There were six such studies: (a) Three presented conflicting evidence of the effectiveness of isolation wards (with other measures) in reducing MRSA infection hospital wide: one reduced infection, one did not and one resulted in control for many years until a change in strain and/or an increase in the number of patients colonised on admission overwhelmed the institution. (b) One presented evidence that single-room isolation with screening, eradication and an extensive hand-hygiene programme reduced MRSA infection and colonisation hospital wide. (c) One provided evidence that NC in single rooms with screening and eradication reduced infection hospital wide. One paediatric intensive care unit study provided evidence that single-room isolation and patient cohorting in bays (with screening, feedback of infection rates and hand-hygiene education) reduced infection. - It was not possible to draw any conclusions about the cost-effectiveness of the interventions because of the poor quality of the economic evaluative work presented. The costs included were not comprehensive many items were omitted and they were not consistent as the items included in the studies varied widely. Results - Modelling: - Equilibrium endemic prevalences of MRSA in hospitals with fixed-capacity isolation facilities were shown to be dependent on the detection rate of MRSA patients, the number of isolation beds available and the transmissibility of the organism. - Improving either the detection rate or isolation capacity was shown to decrease endemic levels provided that the other was not the limiting factor. - The final endemic level often depended on when the isolation ward opened, with ultimate eradication often possible only when the isolation ward was opened early. - In many scenarios, long-term control failure occurred owing to saturation of isolation facilities as the numbers colonised on admission rose. However, even when such control failure occurred, the isolation ward delayed the rate at which prevalence increased and reduced the ultimate endemic level. Saturation of isolation facilities can be prevented by ensuring sufficient capacity. - A paucity of reliable information on key parameter values hampered economic evaluations. However, under a wide range of plausible parameter values estimated independently, substantial savings could be achieved over 10 years compared with a policy of no isolation, provided that the burden of unused isolation ward capacity and staff time was not too great. Assumptions were made about the unused capacity on the isolation wards that had implications for the estimates of opportunity costs. Our assumptions possibly overestimated the opportunity costs. The opportunity costs in practice may have been less and would depend crucially upon what the alternative uses would have been and what would have been the cost of maintaining unused capacity. We lacked data to estimate these costs.

Authors' recommendations: There was evidence that intensive concerted interventions that include isolation can substantially reduce MRSA, even in settings with a high level of endemic MRSA. Little evidence was found to suggest that current isolation measures recommended in the UK are ineffective, and these should continue to be applied until further research establishes otherwise.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.hta.ac.uk/1108

Year Published: 2003

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: England, United Kingdom

Organisation Name: NIHR Health Technology Assessment programme

Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK

Contact Name: journals.library@nihr.ac.uk

Contact Email: journals.library@nihr.ac.uk

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