A new Afnor standard evaluates the effectiveness of bactericidal surfaces
PARIS, June 3, 2019 (TecHopital) – In order to strengthen the fight against nosocomial diseases in the hospital, Afnor announced at the Paris Healthcare Week that the publication of a new standard (NF S90-700) on the efficacy of biocidal surfaces.
To evaluate the effectiveness of bactericidal surfaces, until now there was only one standard, ISO 22196, based on “tests in the dark, with a long contact time (24 hours), at 35°C and 80% humidity”, “which is a far cry from the conditions of a hospital door handle,” explained Stéphane Pénari, creator of MetalSkin®*, a bactericidal surface that won an innovation prize with its product in 2014 (see box and this TecHopital dispatch).
As a result, surfaces declared as antimicrobial may prove to be totally ineffective in real conditions of use.
“There was a normative void in France,” explained François Thomassin, health project manager at Afnor (French Standards Association). The idea of this NF S90-700 standard, entitled Method for evaluating the basic bactericidal activity of a non-porous surface, is to enable the bactericidal capacities of the materials tested to be assessed under real operating conditions.
This standard was drawn up by a committee of experts after a public inquiry – i.e. a consultation open to any interested party who wishes to give its opinion and transmit proposals for improvement -. and after a feasibility study. It is “a performance-based standard, not an techniques” used, he stressed.
“The interest of having a standard is to have a common repository (French, European, global), to facilitate exchanges and interoperability,” added the project leader. A standardization committee has been formed, made up of experts and chaired by Afnor. Professor Christine Roques, hygienist of the CHU of Toulouse, was appointed chairperson of this commission.
The test is based on 4 bacterial strains: Staphylococcus aureus, Enterococcus hirae, Escherichia coli and Pseudomonas aeruginosa, “representative of problematic bacteria families”. “The test is very simple” and fast since it is speaking after 2 to 3 minutes of drying.
Thus, if 99% of surfaces are bactericidal, the surface is classified as bactericidal.
The standard, published at the end of April, “has received a very positive reception from hygienists,” said François Thomassin.
A bactericidal copper resin
Applied to handles, elevator knobs, handrails, taps, access ramps, etc., the MetalSkin®* solution makes it possible to obtain the properties of copper without the disadvantages. It was a Montpellier-based start-up company that developed this copper-based resin, which makes any surface bactericidal. It is protected by patents in France, Europe and worldwide.
A clinical study, validated in 2013, proved the effectiveness of the innovation, which inhibits the growth of bacteria. The effect “is very rapid with a 3-log reduction in 3 minutes”, reports Stéphane Pénari. Bacterial reduction is expressed on a logarithmic scale in base 10. Thus, a 3-log reduction corresponds to a division by 1,000 of the number of bacteria, i.e. an efficiency of 99.9%.
Finally, the additional cost generated by the use of MetalSkin® is between 10% and 20%, according to Stéphane Pénari.