Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle
Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 is an enteric pathogen that causes life-threatening disease in humans, with cattle being major natural reservoirs. A group of STEC O157:H7 with a dramatic combination of high virulence potentials and super-shedder bovine origin have been is...
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doaj-808e818760d2438eaf8b7277c6474d6f2020-11-25T03:14:57ZengFrontiers Media S.A.Frontiers in Cellular and Infection Microbiology2235-29882020-06-011010.3389/fcimb.2020.00271520007Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder CattleLin Teng0Lin Teng1Shinyoung Lee2Shinyoung Lee3Dongjin Park4Kwangcheol Casey Jeong5Kwangcheol Casey Jeong6Emerging Pathogens Institute, University of Florida, Gainesville, FL, United StatesDepartment of Animal Sciences, University of Florida, Gainesville, FL, United StatesEmerging Pathogens Institute, University of Florida, Gainesville, FL, United StatesDepartment of Animal Sciences, University of Florida, Gainesville, FL, United StatesFood Science and Technology Department, University of Nebraska-Lincoln, Lincoln, NE, United StatesEmerging Pathogens Institute, University of Florida, Gainesville, FL, United StatesDepartment of Animal Sciences, University of Florida, Gainesville, FL, United StatesShiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 is an enteric pathogen that causes life-threatening disease in humans, with cattle being major natural reservoirs. A group of STEC O157:H7 with a dramatic combination of high virulence potentials and super-shedder bovine origin have been isolated. Here, an STEC O157:H7 isolate, JEONG-1266, was analyzed by comparative genomics, stx genotyping, and phenotypic analyses. The phylogenetic typing and whole-genome comparison consistently showed that JEONG-1266 is genetically close to EC4115 (one of 2006 Spinach outbreak isolates) and SS17 (an isolate from super-shedder cattle) strains, all of which belong to lineage I/II and Clade 8. Both lineage I/II and Clade 8 are known to be mostly associated with clinical strains with high virulence and severe clinical symptoms. Further, JEONG-1266, like EC4115 and SS17, harbors stx2a/stx2c genes, and carries Stx-encoding prophages, specifically the φstx2a-γ subtype. Possession of the φstx2a-γ subtype of Stx-encoding prophages and production of Stx2a have been shown to be a key signature associated with hypervirulent STEC O157:H7 strains. In silico virulence typing elucidated JEONG-1266, EC4115, and SS17 shared a highly conserved profile of key virulence genes at the nucleotide sequence level. Consistently, phenotypic data showed that JEONG-1266 expressed a high level of Stx2 toxins and had the full capacity of adhesion in vitro. Taken together, our study suggests that JEONG-1266 may represent an emerging STEC O157:H7 group, which are hypervirulent strains that originate from super-shedders, that can be a threat to food safety and public health.https://www.frontiersin.org/article/10.3389/fcimb.2020.00271/fullvirulencecomparative genomicssuper-shedderfunctional analysisE. coli O157:H7 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Lin Teng Lin Teng Shinyoung Lee Shinyoung Lee Dongjin Park Kwangcheol Casey Jeong Kwangcheol Casey Jeong |
spellingShingle |
Lin Teng Lin Teng Shinyoung Lee Shinyoung Lee Dongjin Park Kwangcheol Casey Jeong Kwangcheol Casey Jeong Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle Frontiers in Cellular and Infection Microbiology virulence comparative genomics super-shedder functional analysis E. coli O157:H7 |
author_facet |
Lin Teng Lin Teng Shinyoung Lee Shinyoung Lee Dongjin Park Kwangcheol Casey Jeong Kwangcheol Casey Jeong |
author_sort |
Lin Teng |
title |
Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle |
title_short |
Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle |
title_full |
Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle |
title_fullStr |
Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle |
title_full_unstemmed |
Genetic and Functional Analyses of Virulence Potential of an Escherichia coli O157:H7 Strain Isolated From Super-Shedder Cattle |
title_sort |
genetic and functional analyses of virulence potential of an escherichia coli o157:h7 strain isolated from super-shedder cattle |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Cellular and Infection Microbiology |
issn |
2235-2988 |
publishDate |
2020-06-01 |
description |
Shiga toxin (Stx)-producing Escherichia coli (STEC) O157:H7 is an enteric pathogen that causes life-threatening disease in humans, with cattle being major natural reservoirs. A group of STEC O157:H7 with a dramatic combination of high virulence potentials and super-shedder bovine origin have been isolated. Here, an STEC O157:H7 isolate, JEONG-1266, was analyzed by comparative genomics, stx genotyping, and phenotypic analyses. The phylogenetic typing and whole-genome comparison consistently showed that JEONG-1266 is genetically close to EC4115 (one of 2006 Spinach outbreak isolates) and SS17 (an isolate from super-shedder cattle) strains, all of which belong to lineage I/II and Clade 8. Both lineage I/II and Clade 8 are known to be mostly associated with clinical strains with high virulence and severe clinical symptoms. Further, JEONG-1266, like EC4115 and SS17, harbors stx2a/stx2c genes, and carries Stx-encoding prophages, specifically the φstx2a-γ subtype. Possession of the φstx2a-γ subtype of Stx-encoding prophages and production of Stx2a have been shown to be a key signature associated with hypervirulent STEC O157:H7 strains. In silico virulence typing elucidated JEONG-1266, EC4115, and SS17 shared a highly conserved profile of key virulence genes at the nucleotide sequence level. Consistently, phenotypic data showed that JEONG-1266 expressed a high level of Stx2 toxins and had the full capacity of adhesion in vitro. Taken together, our study suggests that JEONG-1266 may represent an emerging STEC O157:H7 group, which are hypervirulent strains that originate from super-shedders, that can be a threat to food safety and public health. |
topic |
virulence comparative genomics super-shedder functional analysis E. coli O157:H7 |
url |
https://www.frontiersin.org/article/10.3389/fcimb.2020.00271/full |
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