What is the size and nature of the current need for single room isolation in hospital, and how does success or 'failure to isolate' patients affect the control of meticillin-resistant Staphylococcus aureus (MRSA)?

Healthcare-associated infections, in particular those caused by antibiotic-resistant organisms, are a major cause of morbidity, mortality and increased cost to healthcare providers and MRSA are, in terms of prevalence, by far the most significant resistant organisms in the United Kingdom as well as many other countries worldwide. Isolation of hospital patients, usually in single rooms, is intended to interrupt the transmission of potential pathogens between patients and/or staff. Risk assessment is used to determine whether individual patients with potentially transmissible pathogens, including MRSA, should be isolated in single rooms. However, limited isolation room availability and/or operational needs may compromise this process and this has contributed to a general perception that although isolation may be recommended, in many cases it is not achieved due to a lack of facilities and conflicting priorities for the use of those facilities. Despite it being considered as standard practice the evidence for the efficacy of isolation in a single room in preventing the transmission of MRSA is limited. An initial study examined, prospectively, the incidence of isolation failure in a large UK National Health Service hospital and the relationship between the rate of 'failure to isolate' of patients from whose clinical samples MRSA had been identified and the rate of MRSA identified from samples sent for clinical purposes, per ward. A subsequent study compared the transmission of MRSA from index cases who were isolated and those who were not isolated with a cohort of contacts who were immediately adjacent to them. The results of these studies demonstrate that 'failure to isolate' is a frequent occurrence; isolation requirements were not met in 22% of cases and that there was a significant correlation between failing to isolate patients with MRSA, and rates of MRSA identified from samples sent for clinical purposes (Spearman's p=0.596, p<0.001). Conversely there was no significant difference in the MRSA acquisition rates in the contacts of people with MRSA who were not isolated vs. index cases who were isolated. Risk factors for MRSA acquisition in multivariate analysis were: exposure to antibiotics(quinolones and macrolides),presence of a nasogastric tube, dermatological conditions and the index case being risk-assessed as requiring isolation. Further research is needed into the efficacy of isolation in preventing the hospital transmission of MRSA.