In vitro activity of ABT-773 versus macrolides and quinolones against resistant respiratory tract pathogens.
ABT-773, a novel ketolide, was compared to erythromycin, azithromycin, clarithromycin, ciprofloxacin, ofloxacin, levofloxacin, moxifloxacin, gatifloxacin, and gemifloxacin against antibiotic-resistant strains recently isolated from patients with respiratory tract infections. MICs were determined by agar dilution using standard NCCLS methodology. ABT-773 (MIC(90) 0.06 mg/L) was more active than the macrolides (MIC(90) > or = 2 mg/L) and fluoroquinolones (MIC(90) > or = 0.5 mg/L) against penicillin-resistant Streptococcus pneumoniae. The fluoroquinolones were the most active agents tested against beta-lactamase-positive Haemophilus influenzae (MIC(90) < or = 0.01-0.06 mg/L), against which ABT-773 (MIC(90) 4 mg/L) was comparable to azithromycin and two- and four-fold more active than erythromycin and clarithromycin, respectively. Against beta-lactamase positive Moraxella catarrhalis, the activity of ABT-773 (MIC(90) 0.06 mg/L) was comparable to gemifloxacin, trovafloxacin, levofloxacin, and ciprofloxacin (MIC(90) 0.03-0.06 mg/L) and 4- to eightfold greater than that of clarithromycin, gatifloxacin, and erythromycin. These data suggest ABT-773 could be a valuable compound for the treatment of respiratory tract infections, including those resistant to usual oral therapy.
Dubois
J
J
Centre Hospitalier Universitaire de Sherbrooke, Site Bowen, 1335 King Quest, Sherbrooke, Quebec J1J 2B8, Canada. jdubois@novabyss.com
St -Pierre
C
C
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D001424:Bacterial Infections / Q000382:microbiology; D004352:Drug Resistance, Microbial; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D024841:Fluoroquinolones; D006193:Haemophilus influenzae / Q000187:drug effects; D006801:Humans; D048628:Ketolides; D008826:Microbial Sensitivity Tests; D001936:Moraxella catarrhalis / Q000187:drug effects; D012141:Respiratory Tract Infections / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000187:drug effects; D013297:Streptococcus pyogenes / Q000187:drug effects
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D048628:Ketolides; D004917:Erythromycin; C405499:cethromycin