Skin preparation: the evidence

Healthcare-associated infections (HCAIs) are the cause of considerable patient harm, increased length of hospital stay and other linked costs, as well as disability, loss of productivity or even death. This crisis can be reduced and impacted by the education of healthcare workers and patients, as well as the adherence to existing frameworks which are known to prevent and reduce the potential of transmission and subsequent patient harm. There are many campaigns, strategies, new laws and preventative policies already in existence; but as new evidence emerges how long does it take to change practice? Surgical Site Infections (SSIs) have recently become a new focus of attention. A prevalence survey undertaken in 2006, identified that approximately 8% of patients in hospital in UK have an HCAI. SSIs accounted for 14% of those infections and nearly 5% of the 10.6 million people undergoing surgery each year, go on to develop an infection. The severity of the infection may vary from a relatively minor wound discharge to a life threatening condition.1 Only healthcare workers who have been on another planet for the last few years, will not have reviewed their personal hand hygiene processes and changed their practice. It is possible that surgical teams, since the publication of the NICE guidance in October 2008, have also worked together to monitor their practice and amend it in the light of new evidence. However, it is possible that they have not yet found an opportunity to do so. One of the seemingly obvious reviews which surgical teams might undertake is that of the methodology of reducing the numbers of endogenous and exogenous microorganisms on every patient prior to surgery.

Pathogenesis and microbiology

Bacterial contamination is a necessary precursor to surgical site infection. Most surgical wounds are contaminated by bacteria but only a minority proceed to cause the patient a clinical infection. The main bacteria which causes more than 50% of surgical site infections is Staphylococcus aureus. Innate host defences efficiently defend the patient against contaminants which go on to cause an infection. Three key determinants are thought to be the basis of an infection – the dose of bacterial contamination, the virulence of the bacteria and the resistance of the patient.2 Skin bacteria are always present and, in addition, in some types of surgery, additional contaminants are exposed – such as in the bowel or GI tract. It is widely recognised that the main source of potential contaminants for surgical wounds are endogenous i.e. from the patients’ own skin, mucous membranes or hollow viscera. When skin or mucous membranes are incised, the tissues exposed are at risk of contamination.3 In addition, exogenous pathogens which may contaminate the incision may be from the surgical team , equipment within the sterile field and the air of the operating theatre. Patient’s skin may be the source of both resident flora and transient microorganisms. The transient bacteria are those acquired by contact or touch, and are easily removed by washing with soap or alcohol gel. Indeed, some hospitals ask their patients to use an alcohol rub on their hands immediately prior to their transport to the operating theatre, to remove just such microorganisms. Resident flora that normally inhabit the patient’s skin and hair are less readily removed although their numbers can be reduced by antiseptics.