Janthinobacterium lividum

Janthinobacterium lividum is an aerobic, Gram-negative, soil-dwelling bacterium that has a distinctive dark-violet (almost black) color, due to a compound called violacein, which is produced when glycerol is metabolized as a carbon source. Violacein has antibacterial, antiviral, and antifungal properties. Its antifungal properties are of particular interest, since J. lividum is found on the skin of certain amphibians, including the red-backed salamander (Plethodon cinereus), where it prevents infection by the devastating chytrid fungus (Batrachochytrium dendrobatidis).