In Silico Analysis of Shiga Toxin-Producing Escherichia coli O157:H7 Strains from Presumptive Super- and Low-Shedder Cattle

Cattle are the primary reservoir for STEC O157, with some shedding >10 CFU/g in feces, a phenomenon known as super-shedding (SS). The mechanism(s) responsible for SS are not understood but have been attributed to the environment, host, and pathogen. This study aimed to compare genetic characteris...

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Bibliographic Details
Published in:Toxins 2024-02, Vol.16 (2), p.86
Main Authors: Bumunang, Emmanuel W, Castro, Vinicius S, Alexander, Trevor, Zaheer, Rahat, McAllister, Tim A, Guan, Le Luo, Stanford, Kim
Format: Article
Language:English
Subjects:
Animals
Bacteriophages - genetics
Cattle
Cattle Diseases
Cluster analysis
comparative genomics
E coli
Escherichia coli Infections - veterinary
Escherichia coli O157
Escherichia coli O157:H7
Feces
Feedlots
Food contamination & poisoning
Genes
Genomes
Genomics
hybrid sequence analysis
Insertion
Mutation
Pathogens
Pens
Phages
Phylogenetics
Phylogeny
Polymorphism
Shedding
Shiga toxin
Shiga Toxin - genetics
Shiga toxin producing E. coli
Shiga-Toxigenic Escherichia coli
super shedding
Toxins
Virulence
Virulence - genetics
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Summary:Cattle are the primary reservoir for STEC O157, with some shedding >10 CFU/g in feces, a phenomenon known as super-shedding (SS). The mechanism(s) responsible for SS are not understood but have been attributed to the environment, host, and pathogen. This study aimed to compare genetic characteristics of STEC O157 strains from cattle in the same commercial feedlot pens with SS or low-shedding (LS) status. Strains from SS (n = 35) and LS (n = 28) collected from 11 pens in three feedlots were analyzed for virulence genes, Shiga toxin-carrying bacteriophage insertion sites, and phylogenetic relationships. In silico analysis showed limited variation regarding virulence gene profiles. -encoding prophage insertion sites and for and , respectively, were all occupied, but two isolates had fragments of the -carrying phage in and loci without and . All strains screened for lineage-specific polymorphism assay (LSPA-6) were 111111, lineage I. Of the isolates, 61 and 2 were clades 1 and 8, respectively. Phylogenetic analysis revealed that pens with more than one SS had multiple distantly related clusters of SS and LS isolates. Although virulence genes and lineage were largely similar within and across feedlots, multiple genetic origins of strains within a single feedlot pen illustrate challenges for on-farm control of STEC.
ISSN:2072-6651
2072-6651
DOI:10.3390/toxins16020086