Minimal inhibitory concentration of omadacycline and doxycycline against bacterial isolates with known tetracycline resistance determinants.

Omadacycline is an aminomethylcycline derived from the tetracycline class. The minimum inhibitory concentration of 115 Enterobacteriaceae and Staphylococcus aureus isolates with known tetracycline resistance determinants against omadacycline and doxycycline was determined by broth microdilution. Omadacycline is, on a weight basis, more active than doxycycline for nearly all isolates, and differences in activity correlated with organism rather than resistance mechanism.