Rates of evolutionary change of resident Escherichia coli O157:H7 differ within the same ecological niche.

ABSTRACT:

Background

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a pathogen known to reside in cattle feedlots. This retrospective study examined 181 STEC O157:H7 strains collected over 23 years from a closed-system feedlot. All strains were subjected to short-read sequencing, with a subset of 36 also subjected to long-read sequencing.

Results

Over 96% of the strains fell into four phylogenetically distinct clades. Clade membership was associated with multiple factors including stx composition and the alleles of a well-characterized polymorphism (tir 255 T > A). Small plasmids (2.7 to 40 kb) were found to be primarily clade specific. Within each clade, chromosomal rearrangements were observed along with a core phageome and clade specific phages. Across both core and mobil

SUBMITTER: Weinroth MD 

PROVIDER: S-EPMC8991562 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature