Production of sodium azide inactivating substance by resistant mutants of Salmonella typhimurium and other bacteria

We have found that azide-resistant mutants of Salmonella typhimurium and of other bacteria studied produce a substance which inactivates the azide. The production of this substance was proved by the demonstration of a satellite growth of azide-sensitive cells around colonies of azide-resistant mutants and by testing azide inactivating properties of culture filtrates of the azide-resistant strains. The same substance was found to be present in lower concentrations in culture filtrates of wild-type sensitive strains, In broth cultures of sensitive strains, it was apparently produced by the resistant mutants and not by the sensitive cells. The substance does not pass across a dialysis membrane and is heat stable. It has a high molecular weight but is nora protein.