Isolation of aerobic bacteria in cows with subclinical mastitis in Turkey and evaluation of their antimicrobial suspectibility

Abstract

This study was conducted to determine the presence and prevalence of aerobic bacteria in cattle with subclinical mastitis (SCM) and evaluation of their antimicrobial suspectibility. In this study, a total of 394 unmedicated cows from 13 dairy farms were randomly selected and screened for SCM using California Mastitis test (CMT) were used. Overall, 294 agents were isolated and identified from milk samples by classic bacteriological methods. Isolated bacteria were tested by Kirby-Bauer antibiogram disc diffusion test to determinate antimicrobial resistance profile. A total of 294 (74.6%) agents were isolated from 394 milk samples; 100 (25.4%) of the milk samples, neither bacteria nor yeast were isolated. Staphylococcus spp and Streptococcus spp. were the most frequently isolated bacteria, found in 106 (36%), 90 (31%) of the samples, respectively. Among the samples, 68 (23.1%) were positive for S. aureus, 34 (11.5%) for Coagulase negative Staphylococcus, 34 (11.5%) for Escherichia coli, 22 (7.5%) for Bacillus spp., 18 (6.1%) for Corynebacterium spp., 8 (2.7%) Corynebacterium bovis and Pseudomonas aeruginosa, 6 (2%) for Streptococcus dysagalactiae sp. dysagalactiae, 4 (1.3%) for Staphylococcus chromogenes, Klebsiella pneumonia, Actinomyces spp. The most sensitive 3 antibiotic were Amicasin (78%), Tobramicin (73%) and Gentamicin (72%) against isolated bacteria. In conclusion, because of a high percentage isolation of Staphylococcus and Streptoccocus from cows with subclinical mastitis, we are especially struggle for this two bacteria to prevent cows from mastitis and it is important to test the antimicrobial sensitivity of aetiological agents of mastitis before treatment so as to prevent the development of antibiotic resistance in bacteria.