n :  an antibiotic mixture that consists chiefly of tyrocidine and gramicidin, is usu. extracted from a soil bacterium of the genus Bacillus (B. brevis) as a gray to brown powder, and is used for local applications esp. for infection caused by gram-positive bacteria .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2004.