Activity of cefditoren against beta-lactamase-positive and -negative Haemophilus influenzae and Moraxella catarrhalis.
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.
Karlowsky
James A
JA
Focus Technologies, Inc., 13665 Dulles Technology Drive, Herndon, Virginia 20171, USA. jkarlowsky@focusanswers.com
Critchley
Ian A
IA
Draghi
Deborah C
DC
Jones
Mark E
ME
Thornsberry
Clyde
C
Sahm
Daniel F
DF
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
D002511:Cephalosporins; C073460:cefditoren; D001618:beta-Lactamases