[Coagulase-negative staphylococci isolated from the milk of cows with subclinical mastitis]

Studied were a total of 450 strains of coagulase-negative staphylococci, 60.2 per cent of which were sensitive to novobiocin, and 37.1 per cent were producing delta toxin, 35.2 per cent were yielding lysosime, and 27.8 per cent - fibrinolysin. As compared to staphylococci isolated from normal cows they showed higher protease, DN-ase, and lecitinase activity. A scheme is suggested for the differentiation of the coagulase-negative mastitis staphylococci, of primary importance being the evaluation of their virulence to chick embryos or cell cultures.