A 39183A is a rare 9,9’-bianthryl antibiotic related to setomimycin isolated from a strain of Streptomyces by researchers at Eli Lilly, USA, in 1981. A 39183A has broad spectrum antibiotic activity against both susceptible and resistant isolates including many anaerobic species. The patent reported that A 38183A acts as an ionophore, aiding the partitioning of Mg+ and Ca+ ions into organic solvents and transport of ferric ions into mitochondria.