EN
There was determined the antibiotic sensitivity of 1777 bacterial strains isolated from subclinical and clinical mastitis in cows from 20 farms. The assessment was performed by the paper disc method. It was found that Str. agalactiae was most sensitive to ampicillin (93.7%), erythromycin (88.8%), and penicillin (86.7%), Str. dysgalactiae — to chloramphenicol (96.5%), erythromycin (91.8%) and penicillin (84.6%), Str. uberis to chloramphenicol (95.6%), erythromycin (91.8%) and penicillin (88.5%), Staph. aureus to neomycin (87.0%), chloramphenicol (85.8%) and erythromycin (84.7%), Staph. epidermidis to chloramphenicol (98.1%), neomycin (87.6%) and streptomycin (77.7%), Micrococcus spp to neomycin (91.2%) and streptomycin (77.5%), E. coli to streptomycin (78.9%) and neomycin (75.0%). However, 10.1% of the strains under study appeared to be resistant to Nafpenzal.