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In Vitro Activities of ABT-773 and Other Antimicrobials against Human Mycoplasmas

By Ken B. Waites, Donna M. Crabb and Lynn B. Duffy


The in vitro susceptibilities of 103 Mycoplasma pneumoniae isolates, 14 Mycoplasma hominis isolates, 12 Mycoplasma fermentans isolates, and 24 Ureaplasma species to ABT-773, an investigational ketolide, and seven other agents were determined. For M. pneumoniae, the ABT-773 MIC at which 90% of isolates are inhibited (MIC(90); ≤0.001 μg/ml) was comparable to those of azithromycin, clarithromycin, and erythromycin and at least 128-fold lower than those of levofloxacin, gatifloxacin, moxifloxacin, and doxycycline. For M. fermentans, the ABT-773 MIC(90) (≤0.008 μg/ml) was 2- to 128-fold lower than those of all other agents tested. For M. hominis, the ABT-773 MIC(90) (0.031 μg/ml) was equivalent to that of moxifloxacin, 2-fold lower than those of gatifloxacin and clindamycin, and 16-fold lower than that of levofloxacin. ABT-773 was equally active against doxycycline-susceptible and doxycycline-resistant organisms. The ABT-773 MICs (0.016 μg/ml) for Ureaplasma species were the lowest of those of any drug tested. The MIC(90) was 4- to 64-fold lower than those of clarithromycin, azithromycin, and erythromycin and ≥16-fold lower than those of all three fluoroquinolones. Minimal bactericidal concentrations determined for a subgroup of organisms were ≤0.063 μg/ml for M. pneumoniae and 0.25 μg/ml for M. fermentans, but they were several dilutions higher for M. hominis and Ureaplasma spp. ABT-773 has great potential for further study for the treatment of infections due to mycoplasmas and ureaplasmas

Topics: Susceptibility
Publisher: American Society for Microbiology
Year: 2003
DOI identifier: 10.1128/AAC.47.1.39-42.2003
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Provided by: PubMed Central
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