Activity of Minocycline and Other Tetracyclines Against Tetracycline-Sensitive and -Resistant Staphylococci

Minocycline was more active than doxycycline, demethylchlortetracycline, methacycline, and tetracycline in vitro against 101 clinical staphylococcal isolates. It was the only analog active against all 48 tetracycline resistant strains at concentrations of 4 μg/ml or less. In mice, minocycline was the most potent analog against a tetracycline-sensitive staphylococcal infection and the only drug effective against a tetracycline-resistant staphylococcal infection. The results show that minocycline has a potential clinical advantage over tetracycline.