Resistance to antibiotics in Staphylococcus aureus isolated from dairy cow mastitis, milk, udder smears, and milking installation.

摘要

During the period from 1993 to 1997, the sensitivity of 320 strains of Staphylococcus aureus to 8 antibiotics was studied by the disc diffuse method. The S. aureus strains had been isolated from both clinical and latent cases of mastitis, milk samples, smears taken from the udder skin, milking installations, and environment. The occurrence of resistant S. aureus strains was as follows: 22.5% to penicillin, 6.9% to ampicillin, 1.9% to oxacillin, 7.2% to tetracycline, 2.2% to chloramphenicol, 14.7% to streptomycin, 1.6% to neomycin, and 0.6% to erythromycin. A total of 63.4% of S. aureus strains were sensitive to the antibiotics observed. 24.7% of the strains, however, were resistant only to one antibiotic, 5.6% of strains were resistant to two antibiotics, 4.1% of strains to three, 1.6% to four, and 0.3% of strains were resistant to five and six antibiotics.