[Sensitivity to sodium dodecyl benzene sulfonate: a supplementary test for bacterial identification]

The susceptibility to sodium dodecylbenzene sulfonate, an anion-active detergent, was studied with 10 Gram-positive and 18 Gram-negative bacterial cultures. According to this susceptibility, the cultures were subdivided into two groups identical in their tinctorial properties. The bacteria growing at a 0.05% concentration of sodium dodecylbenzene sulfonate or at its higher concentrations were Gram-negative. The threshold concentration of this compound in the medium at which Gram-positive cultures could grow was 0.008%; some of the bacteria ceased growing even at a 0.002% concentration. The bacteria varied in their susceptibility to the detergent also within one and the same group, and even within one and the same species. The subdivision of bacteria on the basis of their susceptibility to sodium dodecylbenzene sulfonate may be considered as a taxonomic feature.