an antibiotic obtained from a strain of bacteria (Bacillus subtilis) and used in the treatment of certain bacterial infections, esp. of the body surfaces
See bacitracin in American Heritage Dictionary 4
(băsˌĭ-trāˈsĭn)
noun
A polypeptide antibiotic obtained from a strain of a bacterium (Bacillus subtilis) and used as a topical ointment in the treatment of certain bacterial infections, especially those caused by cocci.