title: Activity of cefditoren against beta-lactamase-positive and -negative Haemophilus influenzae and Moraxella catarrhalis.
abstract: Cefditoren is a novel broad-spectrum oral cephalosporin. To determine the influence of beta-lactamase production on cefditoren activity, 1,170 H. influenzae and 641 M. catarrhalis isolated during 2000 were tested by NCCLS broth microdilution methodology (M7-A5, 2000). Against H. influenzae the potency of cefditoren (MIC(90,) 0.015 microg/mL) was similar to that of ceftriaxone (MIC(90,) < or = 0.015 microg/mL) and levofloxacin (MIC(90,) 0.015 microg/mL), and its MIC distribution was unaffected by beta-lactamase production. In comparison, the beta-lactamase status of M. catarrhalis affected the potency of all beta-lactams tested, including cefditoren, as well as trimethoprim-sulfamethoxazole. However, regardless of the presence of beta-lactamase, cefditoren demonstrated potent activity, as concentrations of 0.5 and 1 microg/mL inhibited 93.1 and 100% of M. catarrhalis isolates, respectively. We conclude that cefditoren is highly active in vitro against beta-lactamase-positive H. influenzae and M. catarrhalis.
authors.affiliation: Focus Technologies, Inc., 13665 Dulles Technology Drive, Herndon, Virginia 20171, USA. jkarlowsky@focusanswers.com
authors.forename: James A
authors.initials: JA
authors.lastname: Karlowsky
authors.forename: Ian A
authors.initials: IA
authors.lastname: Critchley
authors.forename: Deborah C
authors.initials: DC
authors.lastname: Draghi
authors.forename: Mark E
authors.initials: ME
authors.lastname: Jones
authors.forename: Clyde
authors.initials: C
authors.lastname: Thornsberry
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Sahm
mesh_terms: D002511:Cephalosporins / Q000494:pharmacology*; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects* / Q000201:enzymology; D011446:Prospective Studies; D001618:beta-Lactamases
chemical_list: D002511:Cephalosporins; C073460:cefditoren; D001618:beta-Lactamases