Can we reduce incidence of hospital acquired infection?

Hospital acquired infection is at an all-time high in UK hospitals. Whilst the cleanliness or otherwise of our hospitals has been highlighted by the media as a serious source of concern, we should remember that the patients occupying hospital beds and the bacterial and viral causes of infection today are very different from 10 or 15 years ago. More and more patients are entering hospital with increasingly complex underlying medical conditions making them more susceptible to infection. In addition many of the bacterial causes of HAI have developed resistance to antibiotics (MRSA, vancomycin resistant enterococci or VRE, and enterobacteria resistant to several beta-lactamases or ESBL). The incidence of HAI in UK hospitals has been estimated at between 1 in 8 and 1 in 10 admissions. In recent years we have seen the development and in-use testing of a variety of disinfection practices to control HAI outbreaks ranging from alcohol-containing gels for hand cleansing, steam deep cleaning regimens and ozone or hydrogen peroxide fumigation of individual isolation rooms or whole ward areas after a serious outbreak. Increased attention is now paid to infection prevention rather than infection control and the measures included have been developed into a ‘bundle’ which if rigorously implemented and maintained should lead to a significant reduction in HAI. Rather than trying to achieve impossible ‘targets’ we should be trying to manage down levels of HAI especially in high risk areas of our hospitals before attempting to eliminate HAI throughout our healthcare system.

Staphylococcal infection including that due to MRSA, often results in outbreaks within a hospital ward and their subsequent closure until the problem is resolved. Transmission is mainly via hands and fomites touched by the patient and healthcare worker. The introduction of alcohol gel as a major component of the infection prevention ‘bundle’ has reduced the contagious spread of staphylococci. However prolonged reduction of the incidence of cross infection requires close to 100% compliance in the use of the gel by doctors, nurses, patients and their visitors. In addition it does not afford protection in the longer-term nor does it kill spores of Clostridium difficile. Sole reliance on alcohol gel use will not maintain any reduction in incidence of HAI.

Hitherto not enough attention has been paid to the cleanliness of the ward environment. Routine cleaning by domestic cleaning staff removes superficial grime but may not involve the use of disinfectants to kill invisible bacteria and viruses some of which can survive for several hours or even days. Three of the major causes of HAI (MRSA, Clostridium difficile and Norovirus) can survive in the hospital environment. A real step forward in our fight to control HAI would be to eliminate the environmental source of these micro-organisms. Most disinfectants have been developed to kill bacteria but not all kill bacterial spores or viruses. An effective disinfectant needs to work (i.e. be bactericidal) in both clean and dirty conditions. It also should not display any toxicity or irritancy to skin or cause damage to inanimate surfaces such as flooring or metal appliances. Chlorine-releasing agents have been introduced to combat the threat posed by C.difficile and its spores. However its use has some side-effects suggesting that it should not be used long-term. It is important that alternatives are available which are capable of decontaminating efficiently the ward environment without damaging the fabric of the ward. Combinations of a detergent and a disinfectant displaying a degree of residual activity (up to 48 hours) should offer the prospect of eliminating environmental contamination as a cause of HAI. Together with better personal hygiene and careful nursing practice the problem of HAI in our hospitals can be tackled successfully.

Professor Curtis G.Gemmell | October 2009