lincomycin , penicillins , chloramphenicol , tetracyclines , cephalosporins , three peptides ( virginiamycin , thiopeptin , and bacitracin ) , and one aminoglycoside ( gentamicin ) exhibited intermediate levels of activity ranging from 0.39 to 50 mug/ml .
C0002556
aminoglycoside
C0017436
gentamicin