Haemolytic properties and titration of haemolysins of Staphylococcus aureus of milk origin from cattle and goat with clinical mastitis

Thirty Staphylococcus aureus isolates used in the study obtained from cattle (20) and goat (10) were haemolytic on blood agar. Twenty one of the isolates (14 from cattle, 7 from goats) produced ahaemolysis, 3 producedb-haemolysis (2 from cattle and 1 from goats), and 6 isolates (4 from cattle and 2 from goats) produced botha- and b-haemolysis. The haemolysins tested against erythrocytes from rabbit, cattle and horse in order to demonstrate a-, b- and d-toxins, respectively revealed that a- and b-toxins were produced by all the isolates but b toxin was produced by only 7 isolates from cattle and by 3 from goats. On titration it was recorded that highest titre was recorded for a-toxins (for cattle, 1:2560 and for goat, 1:1280) whereas the highest titres for b and d-toxins was similar (1:160) for cattle as well as goat isolates. The result obtained for qualitative and quantitative haemolysin assays correlated well with the haemolysis pattern seen on the blood agar plates.