Evaluation of three disinfectants after in-use stress.

Solutions of 2.0% and 3.4% glutaraldehyde, and of 0.5% phenate with 0.18% glutaraldehyde were stressed with a microbial and organic soil load for the periods advocated by the respective manufacturers. The disinfecting efficacy of the stressed solutions was challenged with Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Mycobacterium bovis (BCG), a water Mycobacterium sp. and Candida albicans. The three disinfectants were active against the fast-growing bacteria in appropriate dilutions; lesser dilutions of the glutaraldehyde solutions killed the mycobacteria and the yeast, while stressed phenate with glutaraldehyde did not. One hour exposure of the stressed disinfectants failed to kill the spore preparations while reducing the number of survivors.