Antibiotic susceptibility and β-lactamase prevalence for staphylococci isolated from bovine mastitic milk samples

Abstract

In this study, it was aimed to investigate the mastitis pathogens and to determine the β-lactamase activities of staphylococci isolated from bovine mastitic milk samples and the sensitivities of these isolates to various antibiotics. For this purpose, 1180 dairy cows On 131 farms were examined for mastitis and 496 mastitic milk samples were taken from 249 cows. Staphylococcus aureus was present in 33.16%, coagulase negative staphylococci in 31.10%, Escherichia coli in 11.57%, Streptococcus uberis in 6.43%, Streptococcus dysgalactiae in 5.39%, Streptococcus agalactiae and Streptococcus spp. in 3.86%, Candida spp. in 1.29%, Pseudomonas aeruginosa in 1.03%, Bacillus spp. in 0.77%, Citrobacter freundii and Proteus vulgaris in 0.51%, Actinomyces pyogenes and Enterobacter aerogenes in 0.26% of the samples. The resistance rates of 250 staphylococci to amoxi-cillin +clavulanic acid, danofloxacin, enrofloxacin, cloxacillin, gentamycin, neomycin, amoxicillin, ampicillin, oxytetracycline, penicillin, erythromycin and trimethoprim + sulphamethoxazole were 4%, 10%, 10.4%, 18.8%, 40%, 40.8%, 42%, 45.6%, 48%, 50.4% and 60.4%, respectively. β-lactamase was produced by 65.1% of S. aureus isolates and 29.8% of coagulase negative staphylococci. The most effective antibiotics for β-lactamase producing isolates were amoxicillin+clavulanic acid, danofloxacin, enrofloxacin and cloxacillin.