Skip to main content
ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Publications at this Location » Publication #409093

Research Project: Identification, Genomic Characterization, and Metabolic Modeling of Foodborne Pathogens in the Meat Production Continuum

Location: Meat Safety and Quality

Title: Escherichia coli O157:H7 tir 255 T > A allele strains differ in chromosomal and plasmid composition

item Weinroth, Margaret - Maggie
item Clawson, Michael - Mike
item Harhay, Gregory
item EPPINGER, MARK - University Of Texas At San Antonio
item Harhay, Dayna
item Smith, Timothy - Tim
item Bono, James - Jim

Submitted to: Frontiers in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2023
Publication Date: 12/15/2023
Citation: Weinroth, M.D., Clawson, M.L., Harhay, G.P., Eppinger, M., Harhay, D.M., Smith, T.P.L., Bono, J.L. 2023. Escherichia coli O157:H7 tir 255 T > A allele strains differ in chromosomal and plasmid composition. Frontiers in Microbiology. 14:1303387.

Interpretive Summary: Escherichia coli O157:H7 is a bacterium that causes foodborne illness and is naturally occurring in cattle. Changes in bacterial genomes over time can provide valuable information about a bacteria’s features. In this study, we compared the genomes of E. coli O157:H7 strains that did or did not have a genome change that was associated with the ability to cause disease in human. This study demonstrated that there were differences between the two groups in the size and content of the genome, the number and types of genetic elements that can move between bacteria and antimicrobial resistance genes. None of the differences between the two groups completely explained why one group has a greater frequency of causing disease in humans. Further investigation is needed to provide a better explanation for the difference in these E. coli O157:H7 strains’ ability to cause disease in humans.

Technical Abstract: Shiga toxin-producing Escherichia coli (STEC) O157:H7 strains with a T allele in the translocated intimin receptor (tir 255 A > T) gene associate with human disease more than strains with an A allele, however the allele is not thought to be the direct cause of this difference. We sequenced a diverse set of STEC O157:H7 strains (26% A allele, 74% T allele) to identify linked differences that might underlie disease association. The average chromosome and pO157 plasmid size and gene content was greater within the tir 255 A allele strains. Eighteen coding sequences were unique to tir 255 A allele chromosomes and three were unique to tir 255 T allele chromosomes. There also were non-pO157 plasmids that were unique to each tir 255 allele variant. The overall average number of prophages did not differ between tir 255 allele strains, however, there were different types between the strains. Genomic and mobile element variation linked to the tir 255 polymorphism did not appear to individually account for the increased frequency of the T allele isolates in human disease.