The interaction of typical host adapted enteric bacterial pathogens with fresh produce grown in fields is complex. These interactions can be more pronounced in co-managed or sustainable farms where animal operations are, by design, close to fresh produce, and growers frequently move between the two production environments. The primary objectives of this study were to 1) determine the transmission of STEC or enteric pathogens from small and large animal herds or operations to fresh produce on sustainable farms in TN and NC, 2) identify the possible sources that impact transmission of AMR E. coli, specifically STEC on these systems, and 3) WGS to characterize recovered E. coli from these sources. Samples were collected from raw and composted manure, environment, and produce sources. The serotype, virulence, and genotypic resistance profile were determined using the assembled genome sequences sequenced by Illumina technology. Broth microdilution was used to determine the antimicrobial susceptibility of each isolate against a panel of fourteen antimicrobials. The prevalence of E. coli increased during the summer season for all sources tested. ParSNP trees generated demonstrated that the transmission of AMR E. coli is occurring between animal feeding operations and fresh produce. Ten isolates were identified as serotype O45, a serotype that is associated with the "Big Six" group that is frequently linked with foodborne outbreaks caused by non-O157 E. coli. However, these isolates did not possess the stx gene. The highest frequency of resistance was detected against streptomycin (n = 225), ampicillin (n = 190) and sulfisoxazole FIS (n = 140). A total of 35 (13.7%) isolates from two TN farms were positive for the blaCMY (n = 5) and blaTEM (n = 32) genes. The results of this study show the potential of AMR E. coli transmission between animal feeding operations and fresh produce, and more studies are recommended to study this interaction and prevent dissemination in sustainable farming systems.

中文翻译：

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在可持续的农业环境中，抗兽药性非O157大肠杆菌在动物新鲜产品界面上的传播。

典型的宿主适应性肠道细菌病原体与田间生长的新鲜农产品之间的相互作用是复杂的。这些相互作用在共同管理或可持续的农场中更为明显，在这些农场中，动物设计使之接近新鲜农产品，且种植者经常在两种生产环境之间移动。这项研究的主要目的是：1）确定STEC或肠道病原体从小型和大型动物群或运营向田纳西州和北卡罗来纳州可持续农场的新鲜农产品的传播，2）确定影响AMR E传播的可能来源。大肠杆菌，特别是这些系统上的STEC，以及3）WGS来表征从这些来源回收的大肠杆菌。从原始和堆肥，环境和生产来源中收集样品。血清型，毒力，使用通过Illumina技术测序的组装的基因组序列确定基因型和基因型抗性谱。肉汤微稀释用于确定每种分离物对一组十四种抗微生物药的抗药性。在所有测试来源中，大肠杆菌的流行率在夏季都增加了。生成的ParSNP树表明，在动物饲养操作和新鲜农产品之间正在发生AMR大肠杆菌的传播。鉴定出十个分离株为O45血清型，该血清型与“六大”人群相关，该人群经常与非O157大肠杆菌引起的食源性暴发有关。但是，这些分离株不具有stx基因。检测到对链霉素（n = 225），氨苄青霉素（n = 190）和磺胺异恶唑FIS（n = 140）的耐药率最高。来自两个TN农场的总共35个（13.7％）分离株的blaCMY（n = 5）和blaTEM（n = 32）基因呈阳性。这项研究的结果表明，动物饲养和新鲜农产品之间存在AMR大肠杆菌传播的潜力，建议进行更多研究以研究这种相互作用并防止其在可持续农业系统中传播。