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International audience; Many studies emphasize the need for effective surface disinfection of the patient environment [1,2,3,4]. Thus, standardized tests for disinfectant evaluation under simulated practical conditions are of utmost importance to evaluate effective measures to prevent transmission of infectious agents from contaminated surfaces. Within the framework of CEN/TC 216, the 4-field test EN 16615 provides a phase 2/step 2 test simulating practical conditions to test microbicidal efficacy of surface disinfectants applied by wiping, i.e. with mechanical action [ 5]. Employing EN 16615, practical conditions of application are simulated. This includes contact time, temperature, organic soiling, and application of the disinfectant/wipe as well as pre-drying of specified test organisms on a test surface as carrier.

Recently, new insights into the persistence of pathogens, their transfer from inanimate surfaces to humans and the risk of contamination and dissemination of pathogens by detergents have been gained. Furthermore, new experimental data on the interruption of chains of infection by disinfectants as well as results of outbreak-control studies are now available. Hence it has become necessary to reassess the potential benefits using disinfectants to prevent and control nosocomial infections. Based on the new findings and in view of the increasing incidence of nosocomial infections and antibiotic resistances, the German Robert-Koch-Institut has issued completely revised recommendations on Household Cleaning and Surface Disinfection. With respect to these recommendations we developed a new test method, which allows comparison of the efficacy of disinfection in reducing the microbial loads and their dissemination with that of cleaning procedures under practical conditions. In a multi-factor approach, mechanical properties (wet mop technique), utensils (different mop materials) and active agents (disinfectant, detergent) were taken into consideration. We found that under the given conditions, dissemination of the test organism Staphylococcus aureus did not take place when using aldehydes and peroxides, it did take place, however, when water, surfactants, and the disinfectants glycol derivatives, quaternary ammonium compounds and alkylamines were used.

The pathogenic bacterium Helicobacter pylori, which has infected more than one-half of the world's human population, exists in two morphological forms; the viable helical form and the disputed viable-but-not-culturable coccoid form. Infection by the helical form proceeds through the oral-oral route, while that by the coccoid form, if possible at all, is by the faecal-oral and/or the oral-oral route. The present pilot study addresses the question of disinfectant efficacy against both forms of the bacterium.

The Children's Clinic in Giessen, Germany recently reported several severe infections with Klebsiella oxytoca resulting in deaths of two neonates. The putative source of the infections was a contaminated infusion solution. The resistance to disinfectant of the K. oxytoca isolates was investigated in three independent laboratories and was indeed found to be significantly increased. Comparative tests with standard strains of K. oxytoca and other recommended bacterial surrogates showed the disinfection procedures used were fully effective. The higher resistance of the nosocomial isolates may have developed due to improper handling and storage of the cleaning utensils. This report describes the events and draws conclusions concerning the use of disinfectants, the treatment of cleaning utensils, the reliability of procedures for testing disinfectants, and suggests additional measures.