Coagulase-negative staphylococci (CNS) as an aetiological factor of mastitis in cows.

The aim of the present study was to determine the proportions of individual coagulase-negative Staphylococcus species in clinical and subclinical mastitis. The material consisted of 100 CNS isolates obtained from 223 milk samples collected from cows with clinical and subclinical mastitis. Coagulase-negative staphylococci constituted 44.8% of all isolated microorganisms. CNS were isolated from the mammary gland secretions of 86 cows from farms in the Lublin region (Poland). Clinical mastitis was found in 20 whereas subclinical mastitis in 66 study cows (23.3% and 76.7%, respectively). The symptoms of clinical mastitis were mild. The clinical forms of mastitis concerned mainly the first or second lactation. Subclinical mastitis was most commonly observed during the second lactation. Four CNS species (S. xylosus, S. chromogenes, S. haemolyticus and S. sciuri) were isolated from clinical and subclinical mastitis. S. xylosus was the commonest CNS species isolated from cows with clinical mastitis whereas S. chromogenes was the most prevalent one in subclinical mastitis cases. The three CNS species (S. warneri, S. hominis and S. saprophyticus) caused only subclinical mastitis.