What is Tyrothricin?
Tyrothricin is a cyclic polypeptide-antibiotic mixture from Bacillus brevis. It is a locally effective antibiotic effective against gram-positive bacteria. It is sometimes combined with benzocaine 5 mg to provide relief from sore throats. In systemic intake it can lead to severe side effects, therefore, the use is limited to topical application.
Tyrothricin belongs to the pharmacologically related group of polypeptide antibiotic compounds including colistin, polymyxin B and bacitracin. There is no cross-resistance to these three agents.