Marbofloxacin is a synthetic bactericidal antimicrobial belonging to the fluoroquinolone group which acts by inhibition of DNA gyrase. It is effective against a wide range of Gram positive bacteria (in particular Staphylococci, Streptococci) and Gram negative bacteria (Escherichia coli, Salmonella typhimurium, Citrobacter freundii, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Proteus spp, Klebsiella spp, Shigella spp, Pasteurella spp, Haemophilus spp, Moraxella spp, Pseudomonas spp, Brucella canis) as well as Mycoplasma spp.

Marbofloxacin is not effective against anaerobes, yeasts or fungi.

Resistance to fluoroquinolones occurs by chromosomal mutation with three mechanisms: decrease of the bacterial wall permeability, expression of the efflux pump or mutation of the enzymes responsible for molecule binding. No significant evolution of resistance to marbofloxacin has been observed in the target pathogenic strains isolated from companion animals since the launch of the molecule on the veterinary market. The occurrence and rate of transfer of a genetic resistance is therefore considered to be very low.

Cross-resistance with ß-lactam antibiotics, aminoglycosides, tetracyclines, macrolide and polypeptide antibiotics, sulfonamides, diaminopyrimidines, and nitrofurans does not generally occur. However, certain mutations conferring resistance to fluoroquinolones can also confer resistance to cephalosporins, tetracyclines, macrolides and chloramphenicol.

After oral administration in dogs and cats at the recommended dose of 2 mg/kg, Marbofloxacin is readily absorbed and reaches maximal plasma concentrations of 1.5 µg/ml within 2 hours. Its bioavailability is close to 100%. It is weakly bound to plasma proteins (<10%), extensively distributed and in most tissues (liver, kidney, skin, lung, bladder, digestive tract) it achieves higher concentrations than in plasma. Marbofloxacin is eliminated slowly (t1/2β= 14h in dogs and 10h in cats) predominately in the active form, in urine (2/3) and faeces (1/3).