Doxycycline is a bacteriostatic agent that acts by interfering with the bacterial protein synthesis of sensitive species. Doxycycline is a semi-synthetic tetracycline derived from oxytetracycline. It acts on the subunit 30S of the bacterial ribosome, to which it is linked reversibly, blocking the union between aminoacyl-tRNA (transfer RNA) to the mRNA-ribosome complex, preventing the addition of new amino acids into the growing peptide chain and thus interfering with protein synthesis. Doxycycline is active against Gram-positive and Gram-negative bacteria, such as
Streptococcus spp.,
Staphylococcus aureus,
Chlamydia spp.,
Mycoplasma spp.,
Salmonella spp.,
Pasteurella multocida and
Bordetella bronchiseptica.