[Sensitivity of agents of mastitis to various antibiotics]

Studied was the sensitivity to antibiotics of a total of 328 strains of mastitis-causative agents, employing the agar-diffusion method. Staphylococcus aureus proved most sensitive to cephacetril (100%), gentamycin (85.3%), and erythromycin (75.2%). Of the pathogenic streptococci Str. agalactiae was most sensitive to cephacetril (100%), chloramphenicol (100%), and tetracycline (92,8%), while Str. uberis and Str. dysgalactiae ranked second - cephacetril (88,2%), tetracycline (77.4%), and gentamycin (74.5%). Coliform bacteria were found to be most sensitive to streptomycin (75-77%), gentamycin (69-74%), and chloramphenicol (66-73%), and completely resistant to penicillin and ampicillin. Corynebacteria were sensitive to most of the antibiotics - cephacetril (100%), chloramphenicol (83.8%), erythromycin (78.3%), gentamycin (75.6%), and ampicillin (72.9%). Usually, the mastitis causative agents showed polyresistance at one and the same time mostly to three (36.3%) and four (19%) antibiotics.