title: In vitro activity of RU29246. The metabolite of a new HR916 cephalosporin ester.
abstract: Compound RU29246 (RU) is the active metabolite of an orally absorpted cephalosporin ester HR916. The RU spectrum of activity includes the majority of Enterobacteriaceae species, Haemophilus influenzae, pathogenic Neisseria spp., Moraxella catarrhalis, Acinetobacter antiratus, staphylococci, and Streptococcus spp. Pseudomonas species and enterococci were routinely resistant to RU. The RU spectrum was most similar to cefixime against the Gram-negative bacilli and to cefuroxime against the Gram-positive organisms. RU was bactericidal and its mean inhibitory concentrations (MICs) were not greatly increased by high inoculum concentrations. Many strains producing various beta-lactamases generally remained susceptible to RU by MIC tests. However, isolates with extended broad spectrum beta-lactamases capable of hydrolyzing cefotaxime and ceftazidime were also resistant to RU. Broth and agar RU MICs were comparable. Its activity was increased against enterococci in the presence of blood products.
authors.affiliation: Department of Pathology, University of Iowa College of Medicine, Iowa City 52242.
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: B M
authors.initials: BM
authors.lastname: Briggs
authors.forename: D M
authors.initials: DM
authors.lastname: Johnson
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002511:Cephalosporins / Q000737:chemistry / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000201:enzymology; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; C073743:RU 29246; D001618:beta-Lactamases