McConnel Craig S, Stenkamp-Strahm Chloe M, Rao Sangeeta, Linke Lyndsey M, Magnuson Roberta J, Hyatt Doreene R
Department of Clinical Sciences, Colorado Veterinary Diagnostic Laboratory, Colorado State University, Fort Collins, Colorado 80523, USA.
Department of Microbiology, Immunology and Pathology, Colorado Veterinary Diagnostic Laboratory, Colorado State University, Fort Collins, Colorado 80523, USA.
J Food Prot. 2016 Mar;79(3):484-7. doi: 10.4315/0362-028X.JFP-15-321.
Escherichia coli O157 (EcO157) infections can lead to serious disease and death in humans. Although the ecology of EcO157 is complex, ruminant animals serve as an important reservoir for human infection. Dairy cattle are unique because they may be a source of contamination for milk, meat, and manure-fertilized crops. Foodborne dairy pathogens such as EcO157 are of primary importance to public health. Antimicrobial resistance (AMR) is a complex phenomenon that complicates the treatment of serious bacterial infections and is of increasing concern. In the face of recommended use restrictions for antimicrobial agents in livestock operations, current AMR patterns in known foodborne pathogens should be documented. The objective of this study was to document AMR patterns in EcO157 isolates from dairies in northern Colorado using antimicrobial agents commonly found on dairies and representative of medically important antimicrobial drug classes. Seventy-five EcO157 isolates were recovered from three dairies. Six isolates were resistant to at least 1 of the 10 tested antimicrobial agents: four were resistant to streptomycin, sulfisoxazole, and tetracycline; one was resistant to streptomycin and tetracycline; and one was resistant to only tetracycline. All resistant isolates were from a single dairy. Overall, a low prevalence (8%) of AMR was observed among the 75 EcO157 isolates. No significant effects on AMR profiles due to virulence genes, parity, or previous antimicrobial treatments within the current lactation period were detected. The results of this study provide background information for future comparative studies investigating AMR trends. Future studies should include more participating farms and more samples and should control for potential confounding factors of AMR that may underlie individual farm variation.
大肠杆菌O157（EcO157）感染可导致人类严重疾病甚至死亡。尽管EcO157的生态环境复杂，但反刍动物是人类感染的重要宿主。奶牛具有独特性，因为它们可能是牛奶、肉类和粪肥施肥作物的污染源。诸如EcO157等食源性奶牛病原体对公众健康至关重要。抗菌药物耐药性（AMR）是一种复杂现象，它使严重细菌感染的治疗变得复杂，且日益受到关注。面对家畜养殖中抗菌药物使用的推荐限制，应记录已知食源性病原体当前的AMR模式。本研究的目的是使用奶牛场常见且代表医学上重要抗菌药物类别的抗菌药物，记录科罗拉多州北部奶牛场EcO157分离株的AMR模式。从三个奶牛场分离出75株EcO157分离株。6株分离株对10种测试抗菌药物中的至少1种耐药：4株对链霉素、磺胺异恶唑和四环素耐药；1株对链霉素和四环素耐药；1株仅对四环素耐药。所有耐药分离株均来自单个奶牛场。总体而言，在75株EcO157分离株中观察到较低的AMR患病率（8%）。未检测到毒力基因、胎次或当前泌乳期内先前抗菌治疗对AMR谱有显著影响。本研究结果为未来调查AMR趋势的比较研究提供了背景信息。未来的研究应纳入更多参与农场和更多样本，并应控制可能是单个农场差异基础的AMR潜在混杂因素。
