Gutiérrez Sebastián, Díaz Leonela, Reyes-Jara Angélica, Yang Xun, Meng Jianghong, González-Escalona Narjol, Toro Magaly
Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Macul, Santiago, Chile.
Department of Nutrition and Food Science, University of Maryland, College Park, College Park, MD, United States.
Front Microbiol. 2021 Jan 18;11:622663. doi: 10.3389/fmicb.2020.622663. eCollection 2020.
Shiga toxin-producing (STEC) causes foodborne outbreaks that can lead to complications such as hemolytic uremic syndrome. Their main reservoir is cattle, and ground beef has been frequently associated with disease and outbreaks. In this study, we attempted to understand the genetic relationship among STEC isolated in Chile from different sources, their relationship to STEC from the rest of the world, and to identify molecular markers of Chilean STEC. We sequenced 62 STEC isolated in Chile using MiSeq Illumina. typing was determined using tools of the Center Genomic Epidemiology, Denmark University (CGE/DTU). Genomes of our local STEC collection were compared with 113 STEC isolated worldwide through a core genome MLST (cgMLST) approach, and we also searched for distinct genes to be used as molecular markers of Chilean isolates. Genomes in our local collection were grouped based on serogroup and sequence type, and clusters were formed within local STEC. In the worldwide STEC analysis, Chilean STEC did not cluster with genomes of the rest of the world suggesting that they are not phylogenetically related to previously described STEC. The pangenome of our STEC collection was 11,650 genes, but we did not identify distinct molecular markers of local STEC. Our results showed that there may be local emerging STEC with unique features, nevertheless, no molecular markers were detected. Therefore, there might be elements such as a syntenic organization that might explain differential clustering detected between local and worldwide STEC.
产志贺毒素大肠杆菌（STEC）可引发食源性疾病暴发，进而导致诸如溶血性尿毒症综合征等并发症。它们的主要宿主是牛，而碎牛肉常与疾病及暴发事件相关。在本研究中，我们试图了解智利不同来源分离出的STEC之间的遗传关系、它们与世界其他地区STEC的关系，并识别智利STEC的分子标记。我们使用Illumina MiSeq对智利分离出的62株STEC进行了测序。分型是使用丹麦大学基因组流行病学中心（CGE/DTU）的工具确定的。我们将本地STEC菌株的基因组与通过核心基因组多位点序列分型（cgMLST）方法从全球分离出的113株STEC进行了比较，并且我们还寻找了可作为智利分离株分子标记的独特基因。本地收集的基因组根据血清群和序列类型进行分组，并且在本地STEC中形成了簇。在全球STEC分析中，智利STEC并未与世界其他地区的基因组聚类，这表明它们在系统发育上与先前描述的STEC无关。我们的STEC菌株集合的泛基因组有11,650个基因，但我们未识别出本地STEC的独特分子标记。我们的结果表明，可能存在具有独特特征的本地新兴STEC，然而，未检测到分子标记。因此，可能存在诸如共线性组织等因素，这或许可以解释本地和全球STEC之间检测到的差异聚类。
