[Activity of an antiseptic against mycobacteria]

Since the publication of Afnor standards for the determination of bactericidal activity we have studied different antiseptics. Most were inactive on the test strains of Mycobacteria, M. smegmatis. We investigated one antiseptic that did exhibit bactericidal activity against M. smegmatis to find out whether this product's spectrum included other mycobacteria such as those responsible for skin diseases (M. marinum, M. ulcerans, M. chelonei and M. fortuitum). We used the dilution-neutralization method (NF T 72-150) according to all the Afnor requisites, changing only the strains (5 mycobacterial strains recently recovered from clinical specimens), culture conditions, and, for some studies, temperature (21 degrees C and 32 degrees C) and time of contact (5 and 30 minutes). Under Afnor standard conditions (5 mn at 21 degrees C), the tested antiseptic in a concentration of 90% was bactericidal only for M. smegmatis. For the other strains, inhibition was limited (M. fortuitum) or nearly non-existent (M. chelonei). Another series of tests at 32 degrees C showed bactericidal activity (5 log reduction) in 5 minutes for all strains including M. marinum. Despite the fact that these results are of limited practical usefulness, they show 1) that trials under strict conditions can be carried out with all Mycobacteria (including slow growing species), and 2) that broad spectrum bactericidal antiseptics are available.