Any of the group of cationic polypeptide antibiotics produced by the bacterium Bacillus polymyxa. Although these antibiotics are toxic to the brain and kidney and are poorly absorbed from the gastrointestinal tract, they are occasionally used to treat resistant infections caused by gram-negative microorganisms.
A set of antibiotic medications originating from the bacterium Bacillus Polymyxa is known as polymyxins. This group, which encompasses the drug colistin, is prescribed for treating eye and skin infections.