For hygienic hand disinfection, residual substances in alcoholic hand disinfectants are no longer recommended. This advisory has been in effect since the KRINKO guideline “Hand Hygiene in Health Care Facilities" was published in autumn 2016. The benefit of residual active ingredients for surgical hand disinfection was still unclear at the time of publication of the directive. A recent study has now closed this gap.
Residual active agents show no better antimicrobial long-term effect in surgical hand disinfection than comparable alcohol-based hand disinfectants without these additives. This is the conclusion of a study published in the ”Journal of Hospital Infection” in 2017. Residual active ingredients are substances that remain on the skin after the alcohol has evaporated, and are intended to develop their effect over a longer period of time.
For his analysis, the author of the study, Professor Dr Günter Kampf, self-employed specialist for hygiene and environmental medicine, compared three propanol-based products: a formulation containing 45% propan-2-ol and 30% propan-1-ol without a residual active ingredient; a disinfectant with the identical propanolic formulation and additionally 0.2% of the residual active ingredient Mecetroniumetilsulfate (MES); as well as a market-leading product, also containing 45% propan-2-ol, 30% propan-1-ol and 0.2% MES. All three products were tested according to EN 12791 for surgical hand disinfection.
With an application time of 1.5 minutes, “there was no significant difference” between the products tested, writes Kampf. All three showed comparable long-term efficacy after three hours under sterile surgical gloves. Kampf concludes that it is “more than questionable whether 0.2% MES actually makes a measurable contribution to antimicrobial effectiveness.”
This assessment follows Kampf’s previous 2016 study on the efficacy of residual substances. For that survey, also published in the Journal of Hospital Infection, he compared several studies on alcoholic hand disinfectants containing the residual active ingredients MES, chlorhexidine (CHG) and phenylphenol (OPP). Two sets of data analysed alcoholic disinfectants containing 0.5% or 1% CHG. Another 23 data sets dealt with propanolic disinfectants containing 0.2% MES.
None of these showed a lasting effect when the application lasted one minute, one and a half minutes or two minutes. Only after an application time of three minutes did three of seven data sets show a better long-term effect. Even an ethanolic hand rub with 0.1% OPP could not achieve an improved long-term effect.
The study shows that with the standard application time of 1.5 minutes, none of the hand disinfectants has a superior long-term effect for surgical hand disinfection. Given the lack of benefits, potential risks weigh significantly more heavily. For CHG, for example, an increased risk of acquired bacterial resistance, skin irritation and anaphylactic reactions has been described. “These possible side effects should not be underestimated with daily, multiple use of hand disinfectants," explains Professor Kampf. Recent findings on the effectiveness of residual active ingredients in surgical hand disinfection support the view that here, too, primarily products without residual active ingredients should be used.