Rodriguez-Rivera Lorraine D, Cummings Kevin J, Loneragan Guy H, Rankin Shelley C, Hanson Devin L, Leone William M, Edrington Thomas S
1 Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University , College Station, Texas.
2 International Center for Food Industry Excellence, Texas Tech University , Lubbock, Texas.
Foodborne Pathog Dis. 2016 Apr;13(4):205-11. doi: 10.1089/fpd.2015.2037. Epub 2016 Mar 8.
Dairy cattle are a reservoir of several Salmonella serovars that are leading causes of human salmonellosis. The objectives of this study were to estimate the environmental prevalence of Salmonella on dairy farms in Texas and to characterize the antimicrobial susceptibility of the isolates. Eleven dairy farms throughout Texas were sampled from August through October 2013, using a cross-sectional approach. Samples were collected from four locations within each farm (hospital pen, maternity pen, cow housing area, and calf housing area), and feces were collected from cull cows as available. Environmental and fecal samples were processed for Salmonella, and isolates were tested for susceptibility to 15 antimicrobial agents. Serovar characterization was performed on a subset of these isolates. Salmonella was isolated from 67.0% (236/352) of the environmental samples and 64.2% (43/67) of the cull cow fecal samples. Environmental samples from the maternity pen were significantly more likely to be Salmonella positive than samples from the cow and calf housing areas. Multidrug resistance was evident in 11.9% (27/226) of environmental isolates and 19.5% (8/41) of fecal isolates. Salmonella isolates from the calf housing area and maternity pen were significantly more likely to be multidrug resistant (MDR) than isolates from the cow housing area. The most common serovars found among the MDR isolates were Newport, Muenchen, and Typhimurium. These results help provide a focus for efforts to mitigate the burden of antimicrobial-resistant Salmonella at the preharvest level.
奶牛是几种沙门氏菌血清型的宿主，这些血清型是人类沙门氏菌病的主要病因。本研究的目的是估计德克萨斯州奶牛场沙门氏菌的环境流行率，并对分离株的抗菌药物敏感性进行表征。2013年8月至10月，采用横断面方法对德克萨斯州的11个奶牛场进行了采样。从每个农场的四个地点（医院围栏、产房、奶牛饲养区和犊牛饲养区）采集样本，并在可行时从淘汰奶牛中采集粪便。对环境和粪便样本进行沙门氏菌检测，并对分离株进行15种抗菌药物的敏感性测试。对这些分离株的一个子集进行血清型鉴定。从67.0%（236/352）的环境样本和64.2%（43/67）的淘汰奶牛粪便样本中分离出沙门氏菌。产房的环境样本比奶牛和犊牛饲养区的样本沙门氏菌阳性的可能性显著更高。11.9%（27/226）的环境分离株和19.5%（8/41）的粪便分离株表现出多重耐药性。犊牛饲养区和产房的沙门氏菌分离株比奶牛饲养区的分离株多重耐药（MDR）的可能性显著更高。在多重耐药分离株中发现的最常见血清型是纽波特、慕尼黑和鼠伤寒。这些结果有助于为在收获前减轻耐抗菌药物沙门氏菌负担的努力提供重点。
