Some traditional antiseptics, used in hospitals and clinics, are actually ineffective at killing bacteria, according to research due to be presented at the British Association of Dermatologists’ Annual Conference in Liverpool this week (July 8th-11th).

The study, conducted by researchers from the Department of Dermatology at the Royal Infirmary of Edinburgh and the University of Edinburgh’s Centre for Inflammation Research, sought to test the largely anecdotal evidence supporting various antiseptics’ efficacy.

The researchers tested the bactericidal activity against Staphylococcus aureus, a bacterium commonly found on the skin, of four frequently used topical antiseptics. To do this they used a modified version of the European Standard EN 1276 for evaluation of bacteria killing activity. To meet this standard there has to be a very significant reduction in microbial count within five minutes of exposure to the antiseptic.

Two of the four antiseptics chosen met the standard: 0.1% benzalkonium chloride and 6% hydrogen peroxide, but two did not: 2% aqueous eosin and 1 : 10 000 potassium permanganate.

Dr Claire Leitch, one of the study’s authors from the Royal Infirmary of Edinburgh, said: “Although these antiseptics are commonly used in the treatment of skin complaints, there has been a dearth of scientific evidence to support their bactericidal effectiveness. Whilst some of these antiseptics may have desirable astringent properties, these results suggest they lack effective antiseptic activity.

“This is preliminary research, relating specifically to Staphylococcus aureus, and so it is too early to draw wider conclusions. However, this study is an important step for future research to build on”.

Both aqueous eosin and potassium permanganate are used in primary and secondary care, primarily for the treatment of superficial skin infections, atopic dermatitis and chronic leg ulcers. However, their use in atopic dermatitis and chronic leg ulcers is not just for an antiseptic effect but also for their astringent properties.
Hydrogen peroxide and benzalkonium chloride are components of many commercially manufactured antiseptic creams, lotions and washes.

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Notes to editors:

If using this study, please ensure you mention that the study was released at the British Association of Dermatologists’ Annual Conference.
The conference will be held at ACC Liverpool from July 9th to 11th 2013, and is attended by approximately 1,300 UK and worldwide dermatologists and dermatology nurses.

For more information please contact: Nina Goad, Head of Communications, 0207 391 6094 (or mobile 07825567717 during conference week only) or Deborah Mason, Communications Manager, Phone: 0207 391 6355, Email: comms@bad.org.uk, Website: www.bad.org.uk

Study details: “Traditional antiseptics show ineffective antistaphylococcal bactericidal activity”; C.S. Leitch, A. Leitch and M.J. Tidman/Department of Dermatology, Royal Infirmary of Edinburgh, Edinburgh, U.K. and Centre for Inflammation Research, Queen’s Medical Research Institute.

Abstract: Topical antiseptics are frequently used in dermatological management, yet evidence for the efficacy of traditional generic formulations is often largely anecdotal. We tested the in vitro bactericidal activity against Staphylococcus aureus of four commonly used topical antiseptics using a modified version of the European Standard, EN 1276, a quantitative suspension test for the evaluation of bactericidal activity of chemical disinfectants and antiseptics. To meet the standard for antiseptic effectiveness of EN 1276, at least a 105-fold reduction in bacteria counts within 5 min of exposure is required. While 0 1% benzalkonium chloride and 6% hydrogen peroxide both achieved this 105-fold reduction in S. aureus counts, neither 2% aqueous eosin nor 1 : 10 000 potassium permanganate showed significant bactericidal activity, when compared with controls, at exposure periods of up to 1 hour. Aqueous eosin and potassium permanganate may have desirable astringent properties, but these results suggest they lack effective antiseptic activity, at least against S. aureus.

The British Association of Dermatologists is the central association of practising UK dermatologists. Our aim is to continually improve the treatment and understanding of skin disease.