EN 16615: 2015. Quantitative test method for the evaluation of bactericidal and yeasticidal activity on non-porous surfaces with mechanical action in the medical area (4-field test). Test method and requirements (phase 2, step 2).
Test accredited by ENAC (Spanish National Accreditation Entity), for standard mandatory microorganisms and additional bacteria or fungi.
Test with the certificate of Good Laboratory Practices (GLPs).
This is a carrier test to know if one chemical disinfectant applied with wipes, shows bactericidal and/or yeasticidal activity. The product of assay must provide a homogeneous mixture, physically stable when diluted in hard water, or with distilled water for products ready to use. The product is used on non-porous surfaces, including surfaces of sanitary elements where disinfection is required (hospitals, Community health Institutions, Dental clinics, Schools clinics, Children schools, work installations, domestic areas, laundries and kitchen that provide products for patients, …). The application of the disinfectant product is through rubbing with wipes, following some specific time of contact, temperature and interfering substances, including the previous dryness of the assay microorganisms over the surface of assay used as carrier and rubbing the disinfectant product on the surface using the wipe. Ready-to-use wipes or liquid products that must be applied by mechanical action can be used. The wipes are impregnated with 16 mL of the product during 30 minutes, but the customer can choose other volumes and time for impregnation. The conditions are thought to cover general purposes, but other recommendations can be followed as additional assay conditions. Besides, the bactericidal or yeasticidal activities can be tested following other times of contact or other organisms of assay for specific applications of use.
The assays can be performed under clean simulated conditions (in the presence of bovine albumin solution 0.3 g/L) or under dirty simulated conditions (in the presence of bovine albumin solution 3.0 g/L de + 3.0 mL/L sheep erythrocytes) according with the practical application for the product. The test must include four microorganisms of assay (for bactericidal activity Staphylococcus aureus, Enterococcus hirae and Pseudomonas aeruginosa; and for the yeasticidal activity one yeast Candida albicans); one temperature between 4ºC and 30ºC; and one time of contact between 1 min and 5 min or 60 min. The time of contact for surface disinfectants are selected depending of the practical conditions for applications of the product. The time of contact recommended for surfaces is selected by the manufacturer. The products for disinfection of surfaces that can go in contact with patients and/or health personnel and the surfaces that are touched by different persons and has the risk of transmission of microorganisms to the patient must be assayed using a time of contact of 5 minutes, maximum. The same considerations are applicable when the time of contact should be limited due to practical reasons. The products for surfaces others than previously mentioned can be assayed with a time of contact of 60 minutes, maximum. The assay should be performed at two concentrations, one in the active range and one in the non-active range. To be consider bactericidal, the product must show in the field of assay #1, at least a logarithm reduction of the number of bacteria viable counts (log10R) of 5 (Staphylococcus aureus, Enterococcus hirae, Pseudomonas aeruginosa), and to be considered yeasticidal a logarithmic reduction of 4 for the number of viable yeasts (Candida albicans). The mean of UFC in the fields of assay #2 and #4 must be equal or lower than 50, and the mean of the UFC in the water control must be equal or higher to 10.
To perform the test, ready-to-use wipes or liquid disinfectant products whose application requires mechanical action can be sent. For a basic test (two concentrations, a contact time, a test temperature and selected soil conditions) for determining the bactericidal and yeasticidal activity, a minimum of 20 wipes or 400 mL of liquid disinfectant product is required. It is always recommended to send a larger quantity of sample in case a result needs to be confirmed.