The Use of the Selective Inhibitory Action of Toluene on Coliform Bacilli in Routine Cultures

Abstract

Toluene inhibits the growth of Gram-negative bacteria. The exposure of infected material to 10% of toluene for 15-20 sec. prior to culture reduces the proportion of colonies of coliform bacilli in the plate cultures. Gentian violet, which inhibits the growth of staphylococci, can be used to determine the numbers of Gram-negative bacteria present. The use of a plate half of which contains gentian violet and a suspension of bacteria, and half of which is treated with toluene, can be used to demonstrate the proportions of different bacteria present.