PDF(Pubmed)
Abstract：
Escherichia coli has been attributed to playing a major role in a cascade of events that affect the prevalence and severity of uterine disease in cattle. The objectives of this project were to (i) define the association between the prevalence of specific antimicrobial resistance and virulence factor genes in E. coli with the clinical status related to uterine infection, (ii) identify the genetic relationship between E. coli isolates from cows with diarrhea, with mastitis, and with and without metritis, and (iii) determine the association between the phenotypic and genotypic antimicrobial resistance identified on the E. coli isolated from postpartum cattle. Bacterial isolates (n = 148) were obtained from a larger cross-sectional study. Cows were categorized into one of three clinical groups before enrollment: metritis, cows with purulent discharge, and control cows. For genomic comparison, public genomes (n = 130) from cows with diarrhea, mastitis, and metritis were included in a genome-wide association study, to evaluate differences between the drug classes or the virulence factor category among clinical groups. A distinct E. coli genotype associated with metritis could not be identified. Instead, a high genetic diversity among the isolates from uterine sources was present. A virulence factor previously associated with metritis (fimH) using PCR was not associated with metritis. There was moderate accuracy for whole-genome sequencing to predict phenotypic resistance, which varied depending on the antimicrobial tested. Findings from this study contradict the traditional pathotype classification and the unique intrauterine E. coli genotype associated with metritis in dairy cows.IMPORTANCEMetritis is a common infectious disease in dairy cattle and the second most common reason for treating a cow with antimicrobials. The pathophysiology of the disease is complex and is not completely understood. Specific endometrial pathogenic Escherichia coli have been reported to be adapted to the endometrium and sometimes lead to uterine disease. Unfortunately, the specific genomic details of the endometrial-adapted isolates have not been investigated using enough genomes to represent the genomic diversity of this organism to identify specific virulence genes that are consistently associated with disease development and severity. Results from this study provide key microbial ecological advances by elucidating and challenging accepted concepts for the role of Intrauterine E. coli in metritis in dairy cattle, especially contradicting the existence of a unique intrauterine E. coli genotype associated with metritis in dairy cows, which was not found in our study.
摘要：
大肠杆菌被认为在一系列影响牛子宫疾病患病率和严重程度的事件中起主要作用。该项目的目的是（i）定义大肠杆菌中特定抗生素耐药性和毒力因子基因的患病率与子宫感染相关的临床状态之间的关联。(ii)鉴定腹泻奶牛大肠杆菌分离株之间的遗传关系，乳腺炎,有和没有子宫炎，和(iii)确定在从产后牛分离的大肠杆菌上鉴定的表型和基因型抗微生物剂抗性之间的关联。细菌分离物(n=148)获自较大的横断面研究。纳入前将奶牛分为三个临床组之一：子宫炎，有脓性分泌物的奶牛，控制奶牛。对于基因组比较，来自腹泻奶牛的公共基因组（n=130），乳腺炎,和子宫炎被纳入了一项全基因组关联研究，评估临床组之间药物类别或毒力因子类别之间的差异。无法鉴定与子宫炎相关的独特的大肠杆菌基因型。相反，来自子宫来源的分离株之间存在高度遗传多样性。先前使用PCR与子宫炎（fimH）相关的毒力因子与子宫炎无关。全基因组测序预测表型抗性的准确性中等，这取决于所测试的抗菌剂。这项研究的结果与传统的病理类型分类和与奶牛子宫炎相关的独特的子宫内大肠杆菌基因型相矛盾。IMPORTANCEMetritis是奶牛的一种常见传染病，也是用抗生素治疗奶牛的第二大常见原因。该疾病的病理生理学是复杂的，尚未完全了解。据报道，特定的子宫内膜致病性大肠杆菌适应子宫内膜，有时会导致子宫疾病。不幸的是,尚未使用足够的基因组来研究适应子宫内膜的分离株的特定基因组细节,以代表该生物体的基因组多样性,从而鉴定与疾病发展和严重程度一致相关的特定毒力基因.这项研究的结果通过阐明和挑战公认的关于子宫内大肠杆菌在奶牛子宫炎中的作用的概念，提供了关键的微生物生态学进展。特别是与奶牛子宫炎相关的独特子宫内大肠杆菌基因型的存在相矛盾，这在我们的研究中没有发现。
