[Experimental study of the antibacterial activity of cloth impregnated with a disinfectant solution]

Disinfecting cloths were commercialized for several years. The solutions of disinfectant used are generally active in vitro in the conditions required by the french standards published by AFNOR, but it is also necessary to know the effectiveness of disinfecting cloths in conditions of use. We describe in this paper a method for this determination. Four bacterial stains recommended in the french standards were used: Staphylococcus aureus ATCC 9144, Enterococcus hirae ATCC 10541, Pseudomonas aeruginosa CIP A 22 and Escherichia coli ATCC 10536. The bacteria were layed on a test watch-glass and the disinfecting cloth was applied on it following the conditions recommended by the manufacturer. 15 minutes after using the disinfecting cloth, the bacteria on the watch-glass and those which were recovered on the disinfecting cloth during application were collected in a neutralising agent suitable for the disinfecting solution used and the surviving bacteria were counted. A similar test was performed using cloth impregnated with sterile distilled water. We studied the activity of unweaved cloths impregnated with a mixture of quaternary ammonium compounds (0.5%) and peroxides (0.1%). The results show that the method allows us to estimate the proper activity of the disinfectant used. In this study, a much higher decontamination of the watch-glass was observed with impregnated cloths than with cloths containing distilled water only. The mean reduction of the number of bacteria layed on the watch-glass was 5.95 log10 in 15 minutes in the first case and only 2.4 log10 in the second case. In addition, the disinfectant leads to the destruction of the bacteria recovered on the cloth during application.