| Popis: |
We have shown the results of routine microbiological testing and susceptibility of Staphylococcus aureus isolates that were isolated from cows with inflammation of mammary gland during a five year period. Totally, 2719 strains identified as Staphylococcus aureus were routinely tested to twelve antimicrobial agents by the agar-disc diffusion technique. The strains were isolated from 45, 000 samples of udder secretion on Columbia agar plates containing 5% of defibrinated ovine blood (0.01 ml on a quarter of culture medium). They were identified on the basis of colony morphology, catalase and coagulase tests, a tube coagulase test and the strains from 2002 were identified by the API ID 32 Staph system. Of strains isolated in 2002, 70.77% were penicillin-susceptible, higher than any other year, after that 39.13% of strains in 2007, 37.54% in 2008, 37.96% in 2009, and 44.65% in 2010. Totally, 66.66% of oxacillin-susceptible strains were found in 2007, 67.45% in 2008, 71.52% in 2009 and 88.56% in 2010. For potentiated penicillins like amoxicillin and clavulanic acid 93.85% to 95.65% of susceptible strains were found. For first-generation cephalosporins 36.66%-85.98% of strains demonstrated susceptibility, while for third-generation cephalosporins 100% of strains were susceptible in 2002 and 2007, but 91.07% of isolated strains were susceptible in 2009 and 95.94% in 2010. The strains have shown various susceptibility to tetracyclines, lincosamides, aminoglycosides, fluroquinolone and sulfonamides. The results show the resistance of strains to all groups of antibiotics. |
