Canadian Multicenter Susceptibility Study, with a focus on cephalosporins, from 15 Canadian medical centers. The Canadian Multicenter Study Group.

We have previously reported on the in vitro susceptibilities of 4,482 microorganisms to 10 antimicrobial agents tested as part of a Canadian multicenter study. We now report on the remaining 10 agents tested in that study. Of the cephalosporins reported here, ceftriaxone had the greatest activity (82 to 100% susceptible isolates) against Enterobacteriaceae, compared to ceftizoxime (78 to 100%) and cefoperazone (78 to 100%). Cefoperazone activity against Pseudomonas aeruginosa was 87%, compared to 92% for ticarcillin-clavulanate. All agents had 97% or greater activity against Staphylococcus aureus.