EN
There have been done a wide review on the physico-chemical properties of colistin and its antibacterial activity. The antibiotic of peptide nature is very effective against the majority of gram-negative bacterial cells. Colistin is not absorbed from the alimentary tract and therefore it should be given in case of intestine infections caused by E. coli or Salmonella spp instead of sulfamides or tetracyclines (usually not effective). On the other hand chloramphenicol is not allowed to use because of its side effects. Since spiramycin is effective against gram-positive bacteriac and mycoplasms therefore given together with colistin has a wide spectrum of activity. Besides, spiramycin inhibits the process of intestine colonisation by E. coli and colistin kills these bacteriae. According to the data of literature the effectiveness of the two antibiotics administered together has been confirmed in mycoplasmatic infections of the respiratory tract of chickens complicated by pathogenic strains of E. coli. In the studies performed by the authors there was found a high effectiveness of these antibiotics combination in a perihatching period infections (Belcospira orale — Rhone Merieux), in colibacteriosis of piglets and in secondary infections of influenza in horses (Belcospira injectable — Rhone Merieux).