[Differentiation of the streptococci isolated from the milk of cows with mastitis].

Differentiation was carried out of a total of 170 strains of streptococci that caused mastitis, which were isolated from 3200 milk samples taken from a farm. Ouchterlony's agar gel precipitation method was employed for the serologic typing of the strains along with the Jonagar No. 2 Oxoid and group antisera. The biochemical behaviour of the strains was followed up with regard to the hydrolysis of esculin and sodium hippurate, the fermentation of lactose, sucrose, glucose, trehalose, mannite, and salicin, and the breakdown of arginine. It was found that 17.05 per cent of the isolated mastitis streptococci belonged to group B, 17.64 per cent belonged to group C, and 62.94 per cent--to group C. Untypeable were as many as 2.37 per cent. The behaviour of these three groups of mastitis causative agents with regard to esculin and sodium hippurate proved most stable in the biochemical differentiation of the strains. In this respect the selective TKT agar medium could be used in a mass scale diagnosis for the rapid differentiation of the most frequently isolated mastitis streptococci on the base of the characteristic morphologic traits.