Doxycycline, a member of the tetracycline group, exerts a bacteriostatic effect against numerous Grampositive
and Gram-negative bacteria. This includes Bordetella, Campylobacter, E. coli, Haemophilus,
Pasteurella, Salmonella, Staphylococcus, and Streptococcus spp. It is also effective against Chlamydia,
Mycoplasma, and Rickettsia spp. Its mode of action involves inhibiting bacterial protein synthesis. Doxycycline
displays a strong affinity for the lungs, making it particularly valuable for treating bacterial respiratory
infections.
Gentamicin sulphate, an aminoglycoside, acts bactericidally, primarily against Gram-negative bacteria like E.
coli, Klebsiella, Pasteurella, and Salmonella spp. Its bactericidal action is based on the inhibition of bacterial
protein synthesis. When administered orally, gentamicin is poorly absorbed, primarily acting within the
gastrointestinal tract.