PROPERTIES

Spiramycin is an antibiotic of the macrolides group. It is bacteriostatic and can be bactericidal at high concentrations. Macrolides inhibit protein synthesis by binding to the 50S ribosomal sub-units of bacterial ribosomes and preventing peptide formation. Moreover,
spiramycin inhibits the adhesion of the bacteria to the epithelial cells (particularly for gram positive cocci like Staphylococcus and Streptococcus) and stimulates the phagocytosis capacity of the polynuclear neutrophils. Spiramycin has post-antibiotic effects.

Spiramycin has some antimicrobial activity against Gram-positive bacteria and mycoplasmas, as well as certain Gram-negative germs, particularly Legionella and Actinobacillus. The spectrum of activity of spiramycin includes Staphylococcus sp., Streptococcus sp.,
Enterococcus, Streptococcus pneumoniae, Neisseria intracellularis, Listeria monocytogenes, Corynebacterium diphteriae, Mycoplasma sp., Clostridium sp., Bacteroides sp., Haemophilus sp., Treponema pallidum, Treponema microdentium, Leptospira ictero-hemorragiae,
Toxoplasma, Miyagawanella, Brucella, Pasteurella, Rickettsia sp. and Amoeba sp. Spiramycin is widely distributed into tissues and secretions, in particular genital tissues, respiratory system and milk. It presents good intracellular penetration. The spiramycin half life is very
long: 20.9 hours after intramuscular injection. It is extensively metabolised through the biliary system, which contributes to its enteric effect. Spiramycin toxicity is very low.