The streptomycin-sulfadiazine-tetracycline antimicrobial resistance element of calf-adapted Escherichia coli is widely distributed amona isolates from Washington State cattle
The streptomycin-sulfadiazine-tetracycline antimicrobial resistance element of calf-adapted Escherichia coli is widely distributed amona isolates from Washington State cattle
复制标题
DOI：
10.1128/aem.01534-07
复制
发表时间：
2008-01-01
影响因子：
4.4
通讯作者：
Call, Douglas R.
中科院分区：
文献类型：
--
作者：
Khachatryan, Artashes R.;Besser, Thomas E.;Call, Douglas R.
长期以来，特定的抗菌素耐药性模式与无关的选择性性状之间的关联一直与人群中抗菌素耐药性的维持有关。之前，我们证明了具有特定抗性模式（对链霉素、磺胺嘧啶和四环素[SSuT]具有抗性）的大肠杆菌菌株在奶牛小牛肠道环境中以及在存在通常饲喂小牛的牛奶补充剂的情况下具有选择性优势。在本研究中，我们确定了赋予SSuT表型的遗传元件的序列，并表明该元件存在于遗传多样性的E.大肠杆菌分离株，通过宏观限制性酶切消化和脉冲场凝胶电泳评估。在E.从华盛顿州18个不同的养牛场分离的大肠杆菌。使用体外竞争实验，我们进一步证明，SSuT菌株从18个农场中的17个能够胜过泛敏感菌株。在一组单独的实验中，我们能够通过电穿孔将抗微生物剂抗性表型转移到实验室E. coli（DH10B）中，使新菌株在与亲本DH10B菌株的体外竞争中更具竞争力。这些数据表明，一个相对较大的遗传元件赋予SSuT表型广泛分布在E。从华盛顿州的牛身上提取的大肠杆菌。此外，我们的研究结果表明，这个元素是负责维护这些性状，由于连锁遗传性状，赋予选择性优势，在奶牛的肠腔。
Association of specific antimicrobial resistance patterns with unrelated selective traits has long been implicated in the maintenance of antimicrobial resistance in a population. Previously we demonstrated that Escherichia coli strains with a specific resistance pattern (resistant to streptomycin, sulfadiazine, and tetracycline [SSuT]) have a selective advantage in dairy calf intestinal environments and in the presence of a milk supplement commonly fed to the calves. In the present study we identified the sequence of the genetic element that confers the SSuT phenotype and show that this element is present in a genetically diverse group of E. coli isolates, as assessed by macrorestriction digestion and pulsed-field gel electrophoresis. This element was also found in E. coli isolates from 18 different cattle farms in Washington State. Using in vitro competition experiments we further demonstrated that SSuT strains from 17 of 18 farms were able to outcompete pansusceptible strains. In a separate set of experiments, we were able to transfer the antimicrobial resistance phenotype by electroporation to a laboratory strain of E. coli (DH10B), making that new strain more competitive during in vitro competition with the parental DH10B strain. These data indicate that a relatively large genetic element conferring the SSuT phenotype is widely distributed in E. coli from cattle in Washington State. Furthermore, our results indicate that this element is responsible for maintenance of these traits owing to linkage to genetic traits that confer a selective advantage in the intestinal lumens of dairy calves.