title: Activities of ceftobiprole, a novel broad-spectrum cephalosporin, against Haemophilus influenzae and Moraxella catarrhalis.
abstract: Ceftobiprole, a broad-spectrum pyrrolidinone-3-ylidenemethyl cephem currently in phase III clinical trials, had MICs between 0.008 microg/ml and 8.0 microg/ml for 321 clinical isolates of Haemophilus influenzae and between < or =0.004 microg/ml and 1.0 microg/ml for 49 clinical isolates of Moraxella catarrhalis. Ceftobiprole MIC(50) and MIC(90) values for H. influenzae were 0.06 microg/ml and 0.25 microg/ml for beta-lactamase-positive strains (n = 262), 0.03 microg/ml and 0.25 microg/ml for beta-lactamase-negative strains (n = 40), and 0.5 microg/ml and 2.0 microg/ml for beta-lactamase-negative ampicillin-resistant strains (n = 19), respectively. Ceftobiprole MIC(50) and MIC(90) values for beta-lactamase-positive M. catarrhalis strains (n = 40) were 0.12 microg/ml and 0.5 microg/ml, respectively, whereas the ceftobiprole MIC range for beta-lactamase-negative M. catarrhalis strains (n = 9) was < or =0.004 to 0.03 microg/ml. Ceftriaxone MICs usually were generally at least twofold lower than those of ceftobiprole, whereas amoxicillin-clavulanate MICs usually were higher than those of ceftobiprole. Azithromycin and telithromycin had unimodal MIC distributions against H. influenzae, with MIC(90) values of azithromycin and telithromycin of 2 microg/ml and 4 microg/ml, respectively. Except for selected quinolone-nonsusceptible H. influenzae strains, moxifloxacin proved highly active, with MIC(90) values of 0.12 microg/ml. Time-kill analyses showed that ceftobiprole, ceftriaxone, cefpodoxime, amoxicillin-clavulanate, azithromycin, telithromycin, and moxifloxacin were bactericidal at 2x MIC by 24 h against all 10 H. influenzae strains surveyed. Only modest increases in MICs were found for H. influenzae or M. catarrhalis clones after 50 serial passages in the presence of subinhibitory concentrations of ceftobiprole, and single-passage selection showed that the selection frequency of H. influenzae or M. catarrhalis clones with elevated ceftobiprole MICs is quite low.
authors.affiliation: Department of Pathology, Hershey Medical Center, PA 17033, USA.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Bogdanovich
authors.forename: Catherine
authors.initials: C
authors.lastname: Clark
authors.forename: Lois
authors.initials: L
authors.lastname: Ednie
authors.forename: Gengrong
authors.initials: G
authors.lastname: Lin
authors.forename: Kathy
authors.initials: K
authors.lastname: Smith
authors.forename: Stuart
authors.initials: S
authors.lastname: Shapiro
authors.forename: Peter C
authors.initials: PC
authors.lastname: Appelbaum
mesh_terms: D019980:Amoxicillin-Potassium Clavulanate Combination / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001372:Aza Compounds / Q000494:pharmacology; D017963:Azithromycin / Q000494:pharmacology; D015296:Ceftizoxime / Q000031:analogs & derivatives / Q000494:pharmacology; D002443:Ceftriaxone / Q000494:pharmacology; D002511:Cephalosporins / Q000493:pharmacokinetics* / Q000494:pharmacology*; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial / Q000235:genetics; D024841:Fluoroquinolones; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D006801:Humans; D066298:In Vitro Techniques; D048628:Ketolides / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D000077266:Moxifloxacin; D011804:Quinolines / Q000494:pharmacology; D012641:Selection, Genetic; D001618:beta-Lactamases / Q000378:metabolism; D000097623:Cefpodoxime
chemical_list: D019980:Amoxicillin-Potassium Clavulanate Combination; D000900:Anti-Bacterial Agents; D001372:Aza Compounds; D017963:Azithromycin; D015296:Ceftizoxime; D002443:Ceftriaxone; D002511:Cephalosporins; D024841:Fluoroquinolones; D048628:Ketolides; D000077266:Moxifloxacin; D011804:Quinolines; D001618:beta-Lactamases; D000097623:Cefpodoxime; C443755:ceftobiprole; C106791:telithromycin