Susceptibilities of Mycoplasma hominis, Mycoplasma pneumoniae, and Ureaplasma urealyticum to new glycylcyclines in comparison with those to older tetracyclines.
The glycylcyclines are new tetracycline derivatives that include the N,N-dimethylglycylamido derivative of minocycline (DMG-MINO) and the N,N-dimethylglycylamido derivative of 6-demethyl-6-deoxytetracycline (DMG-DMDOT). The susceptibilities of Mycoplasma pneumoniae, Mycoplasma hominis, and Ureaplasma urealyticum to DMG-MINO, DMG-DMDOT, tetracycline, doxycycline, and minocycline were determined by the agar dilution method. The glycylcyclines with MICs at which 50% of the isolates are inhibited of 0.25 to 0.5 micrograms/ml for M. pneumoniae were two- to fourfold more active than tetracycline and had the same activity as minocycline and doxycycline. Tetracycline-susceptible M. hominis strains were four- to eightfold more susceptible to the glycylcyclines (0.12 to 0.25 micrograms/ml) than to tetracycline. Strains of M. hominis known to be resistant to tetracycline, doxycycline, and minocycline because of the tet(M) determinant were as susceptible to the glycylcyclines as the tetracycline-susceptible strains. For tetracycline-susceptible U. urealyticum strains, the glycylcyclines showed the same activity as tetracycline (MICs at which 50% of the isolates are inhibited of 1 to 2 micrograms/ml). Tetracycline-resistant strains of U. urealyticum were resistant to doxycycline and minocycline and showed variable susceptibility to the glycylcyclines (range, 0.5 to 32 micrograms/ml). In view of the increasing resistance of M. hominis and U. urealyticum strains to tetracyclines, the glycylcyclines have promise, pending assessment of their pharmacokinetic and safety profiles.
Kenny
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GE
Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle 98195.
Cartwright
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FD
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004318:Doxycycline / Q000494:pharmacology; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D008911:Minocycline / Q000031:analogs & derivatives / Q000494:pharmacology; D009174:Mycoplasma / Q000187:drug effects*; D009177:Mycoplasma pneumoniae / Q000187:drug effects*; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance; D013754:Tetracyclines / Q000494:pharmacology; D014509:Ureaplasma / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D013754:Tetracyclines; C085305:9-(N,N-dimethylglycylamido)minocycline; C085306:6-demethyl-9-(N,N-dimethylglycylamido)-6-deoxytetracycline; D013752:Tetracycline; D008911:Minocycline; D004318:Doxycycline