The lowest prevalence was in obstetrics (0.9%). The most common types of HAI were urinary tract infection (17.9%), surgical site infection (15.9%) and gastrointestinal infections (15.4%). The most frequently occurring organisms were Staphylococcus aureus (141 cases, of which MRSA was present in 93 cases), and Clostridium difficile (95 cases). The management of Clostridium difficile is an issue in itself but perhaps that can await another letter.
   Due to the problem that MRSA poses in Scotland, the organization for which I work (NHS Quality Improvement Scotland or NHS QIS) was asked by the Scottish Executive (now Scottish Government) HAI Task Force to undertake a health technology assessment (HTA) on the clinical- and cost-effectiveness of screening patients admitted to hospital for MRSA. The report was published in September 20073 and looks not just at the clinical- and cost-effectiveness of MRSA screening but also organizational issues, i.e. what does the health service need to do if screening is to be implemented, and patient issues, i.e. what are the perspectives of patients and their carers on MRSA screening. Essentially, the study has attempted to answer the question: ‘Which strategy for screening for MRSA colonization of patients admitted to Scottish hospitals is most clinically and cost-effective?’
   Staphylococcus aureus is a common bacterium and is carried by about 30% of the healthy population in the UK. If Staphylococcus aureus enters the body then it can cause a spectrum of infection from the trivial to potentially life-threatening. Due to the development of resistance of Staphylococcus aureus to the antibiotics used against infections caused by it, MRSA appeared in 1961 and since the 1990s MRSA has become endemic in healthcare facilities. One method of controlling the spread of MRSA is to identify colonized (those carrying the organism) or infected patients and then to manage them to reduce the risk of MRSA transmission to others.
   In Scotland, a variety of methods of identifying and managing patients with MRSA have been used to date. A survey of practice in Scotland (as part of the HTA) showed that 60% of hospital infection control units reported carrying out some assessment of MRSA colonization risk at the time of admission to hospitals. A few services reported screening all non-emergency patients or all patients admitted to orthopaedics or cardiac surgery.
   The details of the study are in the report but suffice it to say that the systematic review and the economic modelling undertaken have taken forward the issue for Scotland. So what does the HTA conclude and recommend? The conclusions include:

• There was a lack of robust data to populate the economic model and the model used is, by definition, a simplified representation of what happens in real hospitals and wards. However, the modelling indicates that screening of patients would reduce the prevalence of MRSA.

• At present, chromogenic agar testing is the most clinically and cost-effective method of screening.

• Being identified as MRSA-positive has implications for patients such as being nursed in isolation and so the consequences of this need to be addressed by health professionals.

The recommendations are as follows:

• On the basis of the lack of robust evidence to inform the economic model, it has been recommended that a primary (pilot) study be set up on a regional basis to test whether the benefits predicted by the economic modelling can be realized in real life. A key aspect of testing the recommendation in real life is to understand how the flow of emergency and non-emergency patients admitted to hospital will work.

• There is insufficient evidence at present to change the UK policy regarding staff screening, i.e. to undertake staff screening only in unexplained MRSA outbreaks.

• There need to be systems to collect patient-based data on MRSA colonization and infection.

• Patients and their relatives need good quality information on MRSA, screening and reasons for infection control procedures so that they understand what is happening and why.

   The eagle-eyed (and not so eagle-eyed) among the readers will note the caveats around the conclusions and recommendations. Clearly the information and data underlying the work on MRSA screening is not as robust and as reliable as we would like because the primary studies are methodologically weak or because the studies simply do not exist. But as a public health physician I would argue that we do not always have all the evidence (nor evidence in the form we would like) before we need to act. As an author of the HTA report I would argue that we have gone as far as the evidence allows us to.
   What happens now here in Scotland? Nicola Sturgeon, the new Scottish Government Cabinet Secretary for Health and Wellbeing, has indicated her support for MRSA screening of patients admitted to hospital. Consequently, there will be monies set aside for the primary study to be undertaken in Scotland and planning for the primary study has now started. That change is happening as a direct result of the HTA report is heartening. This will help us understand the issue of MRSA screening for patients in Scotland much better and holds out the hope of dealing with this form of HAI.

REFERENCES

1. Tinning W. Wards closed after five patients fall ill with MRSA bug. The Herald (newspaper), Glasgow, 24 October 2007; p. 1.

2. Reilly J, Stewart A, Allardice G, Noone A, Robertson C, Walker A, et al. NHS Scotland National HAI prevalence survey Final Report. Health protection Scotland, Edinburgh, 2007. http://www.documents.hps.scot.nhs.uk/hai/sshaip/publications/national-prevalence-study/report/full-report.pdf (accessed on 18 November 2007)

3. Ritchie K, Bradbury I, Craig J, Eastgate J, Foster L, Kohli H, et al. The clinical and cost effectiveness of screening for methicillin-resistant Staphylococcus aureus MRSA. NHS QIS, Glasgow, 2007. http://www.nhshealthquality.org/nhsqis/controller?p_service=Content.show&p_applic=CCC&pContentID=3780 (accessed on 18 November 2007)