[The effect of the synthetic detergents on the formazan formation of various environmental bacteria (author's transl)].

The authors studied the changes in activity of the dehydrogenase enzyme purifier of in the hygiene important bacteria, caused by different concentrations of various detergents with the aid of the triphenyl-tetrazolium chloride test (TTC) (Simmons-Williams test). The cation-active CTAB, in a contentration of only -0.008%, inhibited the enzymatic activity in all bacteria tested, whereas the non-ionic detergents (Praewozell and G 3707), even in high concentrations (5%) produced no inhibiting effect. The anion-active detergents (DBSNa-LSNa) differed in their action on the test bacteria, but Str. faecalis appears to be the most sensitive species, but Micrococcus was also sensitive. In the case of Str. faecalis a 0.03% DBSNa concentration and a 0.008% LSNa concentration was needed to produce the same effect in micrococci. E. coli pathogens proved relatively resistant to anionic detergents; a complete inhibition of the enzymatic activity was brought about by a 1% DBSNa and 0.63% LSNa concentrations. The results suggest that the TTC testing method is suitable for the evaluation of the action of ionic detergents in the organism.