The Distinction of Licheniformin from Subtilin by Cross Reactions with Antibiotic-Resistant Strains of Mycobacterium phlei

Abstract

SUMMARY: Under standard conditions of subculturing in increasing drug concentrations, lichenifonnin and subtih (polypeptide-containing antibiotics from the genus Bacyiuus) induced resistance in Mycobacterium phlei more slowly and to a much smaller degree than did streptomycin. Strains resistant to licheniformin and subtilin tended to revert, whereas streptomycin-resistance was stable. Licheniformin resistance w w somewhat more difficult to induce and less stable than subtilin resistance.Cross-resistance tests of bacteriostatic activity between the resistant strains and the three antibiotics distinguished completely lichenifonnin from both subtilin and streptomycin. Although the difference between licheniformin and subtilin was largely confirmed by a more sensitive bactericidal test, making viable counts after varying periods of exposure of the resistant strains to the antibiotics in nutrient medium, the test, nevertheless, revealed a minor overlap between the two antibiotics, which was either the result of contamination of one by the other or, more probably, the expression of some common chemical property. Licheniformin and subtilin differed in the speed of their lethal action on M. phlei, subtilin being much the slower.When M. phlei was exposed to mixtures of streptomycin and licheniformin in certain proportions, the rapid development of high streptomycin resistance was prevented.

Drug Resistance in Protozoa

“…But although a triple resistance to compounds of such different chemical constitution could be produced, each compound alone produced resistance only to substances belonging to the same chemical group (Ehrlich, 1908, 1 9 0 9~) . Although further work has shown that resistance is not as specific as the early experiments upon trypanocidal compounds suggested, cross-resistance tests have proved of value in indicating a relationship in mode of action, hitherto unsuspected, not only between certain trypanocidal drugs, but between drugs inhibitory to the malaria parasite (p. 465); they have also been used to distinguish between and to classify antibiotics (Eisman, Marsh & Mayer, 1946;Hart & Moss, 1950;Szybalski, 1954). chemical substances which are effective in the treatment of parasitic diseases) might be classified.…”

“…chemical substances which are effective in the treatment of parasitic diseases) might be classified. Although further work has shown that resistance is not as specific as the early experiments upon trypanocidal compounds suggested, cross-resistance tests have proved of value in indicating a relationship in mode of action, hitherto unsuspected, not only between certain trypanocidal drugs, but between drugs inhibitory to the malaria parasite (p. 465); they have also been used to distinguish between and to classify antibiotics (Eisman, Marsh & Mayer, 1946;Hart & Moss, 1950;Szybalski, 1954).…”