In vitro comparison of GR69153, a novel catechol-substituted cephalosporin, with ceftazidime and ceftriaxone against 5,203 recent clinical isolates.

The activity of GR69153, a novel catechol-substituted cephalosporin, was compared with those of ceftazidime and ceftriaxone in a multicenter study against 5,203 fresh clinical isolates of gram-negative and gram-positive bacteria. GR69153 was generally very active at concentrations equivalent to or two- to fourfold lower than those of ceftazidime and ceftriaxone against gram-negative bacilli other than Citrobacter freundii, Enterobacter cloacae, and Xanthomonas maltophilia. Against Pseudomonas aeruginosa, MICs of GR69153 and ceftazidime for 50% of isolates tested (MIC50s) were, respectively, 1 and 2 micrograms/ml; the corresponding MIC90s were 4 and 16 micrograms/ml. Although MIC50s of GR69153 for staphylococci were two- to eightfold lower than those of ceftazidime or ceftriaxone, MIC90s against staphylococci and enterococci were greater than or equal to 16 micrograms/ml for all three compounds. Quality control MIC ranges for reference strains are proposed for the broth microdilution method on the basis of the GR69153 data derived from this multicenter study.