title: Disk susceptibility studies with cefazolin and cephalothin.
abstract: Cefazolin and cephalothin disk susceptibility and minimal inhibitory concentration determinations were conducted on 591 clinical isolates. Cefazolin demonstrated superior activity, as shown by lower minimal inhibitory concentrations, and a greater percentage of isolates inhibited in the disk susceptibility test. The cephalothin antibiotic class disk by the standard Bauer-Kirby method failed to detect susceptibility to cefazolin in a significant percentage of Escherchia coli, Enterobacter species, and Enterococcus isolates. A separate cefazolin disk with a susceptibility cut-off point of 18 mm is recommended. An alternative to a separate cefazolin disk would be a reinterpretation of the cephalothin susceptibility disk zone diameters so that it would more adequately predict cefazolin activity.
mesh_terms: D002511:Cephalosporins / Q000494:pharmacology*; D002512:Cephalothin / Q000494:pharmacology*; D004058:Diffusion; D004755:Enterobacteriaceae / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D013210:Staphylococcus / Q000187:drug effects; D013440:Sulfides / Q000494:pharmacology; D013777:Tetrazoles / Q000494:pharmacology; D013830:Thiadiazoles / Q000494:pharmacology
chemical_list: D002511:Cephalosporins; D013440:Sulfides; D013777:Tetrazoles; D013830:Thiadiazoles; D002512:Cephalothin