In vitro activities of ABT-773 and other antimicrobials against human mycoplasmas.
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); <or=0.001 microg/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) (<or=0.008 microg/ml) was 2- to 128-fold lower than those of all other agents tested. For M. hominis, the ABT-773 MIC(90) (0.031 microg/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 microg/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 >or=16-fold lower than those of all three fluoroquinolones. Minimal bactericidal concentrations determined for a subgroup of organisms were <or=0.063 micro g/ml for M. pneumoniae and 0.25 microg/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.
Waites
Ken B
KB
Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35249, USA. waites@path.uab.edu
Crabb
Donna M
DM
Duffy
Lynn B
LB
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006801:Humans; D048628:Ketolides; D008826:Microbial Sensitivity Tests; D009174:Mycoplasma / Q000187:drug effects* / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D048628:Ketolides; D004917:Erythromycin; C405499:cethromycin