Rates of resistance of mastitis pathogens from cows in Switzerland

1215 strains of bacteria isolated from cows suffering from acute or chronic clinic mastitis were tested in the antibiogram according to the Kirby-Bauer method. The germ spectrum included: 304 DNase-positive strains of Staphylococci 304 DNase-negative strains of Staphylococci 304 CAMP-negative strains of Streptococci 303 Strains of Enterobacteriaceae The antibiotics selected were Penicillin, Cloxacillin, Neomycin und Gentamicin, then the combinations Penicillin/Neomycin, Cloxacillin/Gentamicin and Nafcillin/Penicillin/Dihydrostreptomycin. Gentamicin showed excellent action against Staphylococci and Enterobacteriaceae. Further on, the present investigations show, that the combination Cloxacillin/Gentamicin is fully effective in the gram-positive spectrum (against Streptococci and Staphylococci), as in the gram-negative spectrum (against E. coli).