Bacteria from the Janthinobacterium genus

Janthinobacteria are some of the most colourful bacteria known since they produce a shiny violet pigment and antibiotic. And this antibiotic even helps the bacterium Janthinobacterium lividum make friends with animals.

Indeed, Janthinobacterium lividum lives on the skins of frogs or salamanders in symbiosis. The animal gives the bacterium a place to live and food and the bacterium protects the host animal from a toxic and deadly fungus. To fight off the fungus, Janthinobacterium lividum produces the purple antibiotic violacein, which not only gives the bacterium its shiny purple colour but also thus saves the frogs and salamanders.