Duphatrim IS is a broad-spectrum antibacterial indicated in the treatment of a wide range of Gram-positive and Gram-negative organisms. The two active ingredients, trimethoprim and sulfadiazine, sequentially block bacterial and protozoal synthesis of folinic acid, thus greatly potentiating the activity obtained when either ingredient is used alone. In vitro antibacterial activity of Duphatrim IS is extensive, including Actinobacillus spp, Actinomyces spp, Bordetella spp, Brucella spp, Corynebacterium spp, E. coli, Haemophilus spp, Klebsiella spp, Pasteurella spp, Pneumococcus spp, Proteus spp, Salmonella spp, Staphylococcus spp (including penicillin-sensitive and penicillin-resistant), Streptococcus spp. Duphatrim IS is indicated for use in horses, cattle, pigs, dogs and cats, for the treatment of acute, subacute and chronic bacterial infections sensitive to trimethoprim/sulfadiazine therapy such as: Bacterial infections of the respiratory tract, including rhinitis, pneumonia, bronchitis and in bacterial infections secondary to viral disease such as viral pneumonia or mycoplasma infections. Urogenital tract infections, including cystitis, vaginitis, urethritis, nephritis and metritis. Alimentary tract infections, including neonatal diarrhoea and salmonellosis. Other infections, such as foul-in-the-foot, severe mastitis, bacterial agalactia of sows, infections of the eye, ear or mouth.