FIG. 1.
Biological assay comparing the efficacy of CMY-30 (A) with CMY-2 (B) against aztreonam. Suspensions of E. coli DH5α (105 CFU per ml) and disks of aztreonam were applied in MH agar. Solution containing 700 ng of purified cephalosporinase in 10 μl of phosphate buffer was then placed on the culture as shown by the thin white lines. Plates were read after incubation for 18 h at 35°C. A distortion of the inhibition zone was seen with CMY-30. Control aztreonam disks are on the right in each panel.