Mode of Action of Polymyxin B: Physiological Studies with a Bacillus subtilis -Resistant Mutant

Abstract

Polymyxin B resistance in Bacillus subtilis can be suppressed by the synergistic action of lysozyme or of an analogous cell wall lytic activity released by B. subtilis spores during germination. Such a synergistic effect is probably due to partial cell-wall digestion by lysozyme that allows polymyxin to reach its site of action and is therefore distinct from the analogous synergistic effect described by other authors in Escherichia coli . In the latter case polymyxin B probably damaged the outer membrane, allowing lysozyme to reach and digest the cell wall.