tailieunhanh - Báo cáo khoa học: "Etiology and antimicrobial susceptibility of udder pathogens from cases of subclinical mastitis in dairy cows in Sweden"

Tuyển tập các báo cáo nghiên cứu về bệnh học thý y được đăng trên tạp chí Acta Veterinaria Scandinavica cung cấp cho các bạn kiến thức về bệnh thú yđề tài: Etiology and antimicrobial susceptibility of udder pathogens from cases of subclinical mastitis in dairy cows in Sweden. | Persson et al. Acta Veterinaria Scandinavica 2011 53 36 http content 53 1 36 AVS ACTAVETERINARIA SCANDINAVICA RESEARCH Open Access Etiology and antimicrobial susceptibility of udder pathogens from cases of subclinical mastitis in dairy cows in Sweden Ylva Persson1 2 Ann-Kristin J NymanH and Ulrika Gronlund-Andersson1t Abstract Background A nationwide survey on the microbial etiology of cases of subclinical mastitis in dairy cows was carried out on dairy farms in Sweden. The aim was to investigate the microbial panorama and the occurrence of antimicrobial resistance. Moreover differences between newly infected cows and chronically infected cows were investigated. Methods In total 583 quarter milk samples were collected from 583 dairy cows at 226 dairy farms from February 2008 to February 2009. The quarter milk samples were bacteriological investigated and scored using the California Mastitis Test. Staphylococci were tested for betalactamase production and presence of resistance was evaluated in all specific udder pathogens. Differences between newly infected cows and chronically infected cows were statistically investigated using logistic regression analysis. Results The most common isolates of 590 bacteriological diagnoses were Staphylococcus S aureus 19 and coagulase-negative staphylococci CNS 16 followed by Streptococcus Str dysgalactiae 9 Str. uberis 8 Escherichia E. coli and Streptococcus spp. . Samples with no growth or contamination constituted 22 and 18 of the diagnoses respectively. The distribution of the most commonly isolated bacteria considering only bacteriological positive samples were S. aureus - 31 CNS - 27 Str. dysgalactiae - 15 Str. uberis - 14 E. coli and Streptococcus spp. - . There was an increased risk of finding S. aureus Str. uberis or Str. dysgalactiae in milk samples from chronically infected cows compared to findings in milk samples from newly infected cows. Four percent of the S. aureus isolates and