title: Ceftriaxone: a summary of in vitro antibacterial qualities including recommendations for susceptibility tests with 30-micrograms disks.
abstract: The new aminothiazoyl-cephalosporin, ceftriaxone (Ro 13-9904), was found to have excellent inhibitory activity against the Enterobacteriaceae (minimum inhibitory concentration needed to inhibit 50% of isolates (MIC50) less than or equal to 0.004-0.5 microgram/ml, Haemophilus influenzae (MIC50 less than or equal to 0.004 micrograms/ml), Neisseria species (MIC50 less than or equal to 0.001 microgram/ml), pneumococci (MIC50 0.25 micrograms/ml), Staphylococcus aureus (MIC50 2.0 micrograms/ml), and Streptococcus pyogenes (MIC50 0.015 micrograms/ml). Ceftriaxone was less effective against Acinetobacter species, Pseudomonas aeruginosa, and other Pseudomonas species (MIC50 8.0-16 micrograms/ml). Methicillin-resistant S. aureus and enterococci were not significantly inhibited by ceftriaxone. Ceftriaxone was very resistant to beta-lactamase hydrolysis, although the type IV cephalosporinase minimally destroyed the compound at 16.4-19.9% of the rates for cephaloridine. Type I cephalosporinases were inhibited by ceftriaxone and related enzyme-stable cephalosporins. Based on analysis of disk-MIC regression statistics, tentative recommendations for the disk test of the National Committee for Clinical Laboratory Standards are 21 mm or more = susceptible, 14-20 mm = moderately susceptible, and 13 mm or less = resistant. These criteria produce interpretive accuracy of more than 92%, with very rare major errors. Ceftriaxone was comparable to cefotaxime in spectrum and activity, thus allowing the use of the "spectrum-class" concept (for example, cefotaxime tests in vitro to predict ceftriaxone susceptibility, and vice versa).
mesh_terms: D000150:Acinetobacter / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects*; D002435:Cefamandole / Q000494:pharmacology; D002438:Cefoperazone / Q000494:pharmacology; D002439:Cefotaxime / Q000031:analogs & derivatives* / Q000494:pharmacology; D002440:Cefoxitin / Q000494:pharmacology; D002443:Ceftriaxone; D002463:Cell Membrane Permeability / Q000187:drug effects; D004352:Drug Resistance, Microbial; D004755:Enterobacteriaceae / Q000187:drug effects; D006193:Haemophilus influenzae / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D009070:Moxalactam / Q000494:pharmacology; D009343:Neisseria / Q000187:drug effects; D011549:Pseudomonas / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D002435:Cefamandole; D002440:Cefoxitin; D002443:Ceftriaxone; D002438:Cefoperazone; D001618:beta-Lactamases; D002439:Cefotaxime; D009070:Moxalactam