the rapid fixed-time assay for penicillinase was modified for measuring beta-lactamase activity with twelve substrates , i.e. , benzylpenicillin , ampicillin , cloxacillin , methicillin , carbenicillin , cefazolin , cephalothin , cephaloglycin , cephalexin , cephalosporin c , 7-aminocephalosporanic acid , and cefoxitin .
C0030827
benzylpenicillin
C0002680
ampicillin