Characteristics of Staphylococci isolated from mastitic goat milk in Iranian dairy herds

ne hundred and fifteen cases of sub clinical mastitis were detected in a study on 510 goats from 5 herds in west central, Iran. From positive milk samples, 23 Staphylococcus spp. strains were isolated. Fourteen isolates were determined as Staphylococcus aureus (12.17%), and the other 9 (7.82%) as Staphylococcus epidermidis. Eleven and six isolates of S. aureus and S. epidermidis produced combined form of hemolysins a/13/d, while 13/d hemolysins produced by 2 and 3 isolates respectively . Only one isolate of S. aureus produced single type d hemolysin. The sensitivity of all strains to 10 chemotherapeutics was tested through the disk diffusion method, 6 strains (26.08%) were determined as methicillin-resistant: out of them 4 isolates were S. aureus and 2 S.epidermidis. S. aureus and S. epidermidis isolates were 100% resistant to Cloxaciline and Kanamycin while the resistance to Penicillin was 100% in S. aureus and 33.33% in S. epidermidis isolates