[Microbiological investigations with decentral dosing apparatuses for disinfectants. Part 2: Resistance-behaviour of isolated bacteria (author's transl)].

When bacteria were isolated from disinfectant solutions of dosing apparatuses their resistance observed in those solutions is rapidly lost during few passages on nutrient agar (Table 1). Bacteria in tap-water, too, show an increased resistance against that disinfectant (Table 2) but it could be reversed by EDTA (Table 3). Therefore, the resistance of bacteria observed in tap-water and disinfectant solution is not determined genetically but results from a temporary adaptation which may be caused by an increased secretion of slime. This resistance is only observed in solution but not after application of the disinfectant to surfaces; it is not dependent from the dosing apparatus but from the product used. Only one species (Corynebacterium rubrum) which occasionally was found showed a primarily increased resistance which is stable during isolation.