Abstract
Escherichia coli (E. coli) carrying the transmissible locus of stress tolerance (tLST) are able to overcome numerous environmental challenges. In our in-silico study, we aimed to characterize tLST in terms of its variants in 793 genomes of E. coli from Brazil originating from food, environmental and clinical (animal and human) sources, and to perform a temporal analysis in order to identify the historical moment of its emergence. We also analyzed the presence of two Yersinia high pathogenicity island (HPI) variants in E. coli genomes, describing other genes and accessory for resistance, persistence, mobile elements (plasmids) and sequence types. The prevalence of the tLST was 10% in E. coli from Brazil, predominantly observed in milk-originating genomes, within the prevalent tLST(CP010237) variant. In E. coli from other sources (clinical/environmental), only part of the tLST was present. Remarkably, our temporal analysis pinpointed the emergence of tLST back to around 1914, coinciding with major societal events. Regarding virulence genes, we found a prevalence of 38.5% for HPI of Y. pestis across genomes from all sources. Our global analysis also showed a high diversity of other virulence genes for milk E. coli (+ 100 genes). These genomes also stood out from the overall metadata for presenting a greater variety of resistance genes to other stresses, such as metals, biocides and acids, as well as persistence genes (biofilm formation). This study demonstrated the historical background of E. coli with tLST genes dating back more than 100 years, and the acquisition of a wide range of virulence and resistance genes that allow it to circulate in different environments: from food to clinic or from clinic to food, making this bacterium a pathogen that requires rigorous surveillance and strategic interventions to mitigate potential risks.