Streptococcus suis is an important pathogen in swine that causes, among other conditions, meningites and endocardites. Antibiotic treatment can be efficient against this pathogenic bacteria when it is administrated soon enough. However, more and more strains of S. suis that are resistant to penicillin and other antibiotics are observed. At the same time, some non-pathogenic strains of S. suis are known to produce antibacterial substances of proteic nature called bacteriocins. This research project explored that antibacterial property in the context of fighting virulent strains of S. suis. The results showed that the non-pathogenic strain of S. suis 90-1330 can produce an antibacterial substance exhibiting the classical characteristics of bacteriocins, that is, low molecular weight, resistance to heat and susceptibility to proteolytic enzymes. This bacteriocin proved to be active against pathogenic isolates of S. suis, as well as other bacteria, both Gram positive and negative. Also, been found that adding yeast extract to the culture medium significantly simulated the producion of this bacteriocin by S. suis 90-1330. A purification procedure permitting to obtain an enriched fraction of bacteriocin 90-1330 have also been developed. Electrophoretic analysis on polyacrylamide gel suggests the molecular weight of bacteriocin 90-1330 to range between 4 and 5kDa. The results support potential utility of the non-pathogenic S. suis strain 90-1330 or its bacteriocin to prevent and fight infections in swine caused by virulent strains of S. suis. However, further research is needed before applying this new therapeutic principle.