Adhikari B, Besser T E, Gay J M, Fox L K, Davis M A, Cobbold R N, Berge A C, McClanahan R, Hancock D D
Department of Veterinary Clinical Sciences, Washington State University, Pullman, Washington 99164, USA.
J Dairy Sci. 2009 Sep;92(9):4218-28. doi: 10.3168/jds.2008-1493.
A longitudinal observational study of 59 dairy herds was conducted in Washington State to estimate the rate of introduction of new multidrug-resistant (MDR) Salmonella enterica strains onto commercial dairy herds. Samples were collected on these herds over 7 visits separated by intervals of 2 to 4 mo over a period of 15 to 21 mo. Samples were cultured for Salmonella spp. and serogroup, serovar, and antimicrobial susceptibility patterns were identified for MDR Salmonella isolates. Fingerprinting generated by pulsed-field gel electrophoresis (PFGE) using XbaI restriction enzyme digestion generated genotyping profiles for all MDR isolates identified in the study. The rate of new MDR Salmonella strain introduction was 0.9 per herd-year (95% confidence interval: 0.6-1.4). The rates for the most commonly introduced MDR Salmonella serovars were 0.4/herd-year for Typhimurium, 1.2/herd-year for Newport, and 0.1/herd-year for Dublin. Thirty-three of 59 herds (56%) had at least one new MDR Salmonella introduction during the study period. The number of new MDR Salmonella strains acquired by dairy herds ranged from zero to 8. Thirteen of the 59 herds had a history of clinical salmonellosis. Among these 13 herds, 6 herds acquired new MDR Salmonella strains, although these strains were different than historical clinical strains. These data indicate that acquisition of new MDR Salmonella strains by dairy herds was a common event in participating herds, although the number of strains introduced varied greatly among herds.
在华盛顿州对59个奶牛场进行了一项纵向观察研究，以估计新的多重耐药性肠炎沙门氏菌菌株引入商业奶牛场的比率。在15至21个月的时间里，对这些奶牛场进行了7次采样，每次采样间隔2至4个月。对样本进行沙门氏菌属培养，并对多重耐药性沙门氏菌分离株进行血清群、血清型和抗菌药物敏感性模式鉴定。使用XbaI限制性内切酶消化通过脉冲场凝胶电泳（PFGE）生成指纹图谱，为研究中鉴定的所有多重耐药性分离株生成基因分型图谱。新的多重耐药性沙门氏菌菌株引入率为每牛群年0.9（95%置信区间：0.6 - 1.4）。最常引入的多重耐药性沙门氏菌血清型的引入率分别为：鼠伤寒血清型每牛群年0.4，新港血清型每牛群年1.2，都柏林血清型每牛群年0.1。在59个奶牛场中，有33个（56%）在研究期间至少有一次新的多重耐药性沙门氏菌引入。奶牛场获得的新的多重耐药性沙门氏菌菌株数量从零到8不等。59个奶牛场中有13个有临床沙门氏菌病病史。在这13个奶牛场中，有6个奶牛场获得了新的多重耐药性沙门氏菌菌株，尽管这些菌株与历史临床菌株不同。这些数据表明，参与研究的奶牛场获得新的多重耐药性沙门氏菌菌株是一个常见事件，尽管不同奶牛场引入的菌株数量差异很大。
