title: In vitro activity evaluations of cefdinir (FK482, CI-983, and PD134393). A novel orally administered cephalosporin.
abstract: Cefdinir, a so-called third-generation oral cephalosporin was tested in vitro against over 700 pathogens from patients with bacteremia. Cefdinir was very active against the Enterobacteriaceae with a 50% minimum inhibitory concentration (MIC50) value range of less than or equal to 0.03-8 micrograms/ml. The enteric species having the highest MIC90S (greater than or equal to 16 micrograms/ml) were Citrobacter freundii, and the enterobacters, Morganella morganii, Proteus vulgaris, and Serratia marcescens. Cefdinir was generally two- to fourfold less active than cefixime, but markedly more potent with a wider spectrum compared with older oral cephalosporins, cefaclor or cefuroxime. In contrast to cefixime, cefdinir inhibited Staphylococcus aureus (MIC90, 1 micrograms/ml) and other staphylococci. Pneumococci, beta-hemolytic streptococci, Haemophilus influenzae, Moraxella catarrhalis, and pathogenic Neisseria spp. (MIC90S, 0.12-0.5 micrograms/ml) were cefdinir susceptible, but Pseudomonas aeruginosa, oxacillin-resistant staphylococci and Bacteroides fragilis gr. strains were resistant. Cefdinir was generally bactericidal with a minimal inoculum effect at 10(6) colony-forming units per spot. Cefdinir beta-lactamase hydrolysis by some recently described extended broad spectrum beta-lactamases was suspected. Cefdinir exhibited a wide, balanced spectrum for an oral cephalosporin indicating possible clinical use against susceptible pathogens in respiratory tract, urinary tract, genital and cutaneous infections.
authors.affiliation: Department of Pathology, University of Iowa College of Medicine, Iowa City.
authors.forename: B M
authors.initials: BM
authors.lastname: Briggs
authors.forename: R N
authors.initials: RN
authors.lastname: Jones
authors.forename: M E
authors.initials: ME
authors.lastname: Erwin
authors.forename: M S
authors.initials: MS
authors.lastname: Barrett
authors.forename: D M
authors.initials: DM
authors.lastname: Johnson
mesh_terms: D000077525:Cefdinir; D002511:Cephalosporins / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D004352:Drug Resistance, Microbial; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D002511:Cephalosporins; D000077525:Cefdinir; D001618:beta-Lactamases