Evolution of Enterohemorrhagic Escherichia coli O26 Based on Single-Nucleotide Polymorphisms

ABSTRACT Escherichia coli O157:H7 (O157) strains demonstrate varied pulsed-field gel electrophoresis patterns following XbaI digestion, which enable epidemiological surveillance of this important human pathogen. The genetic events underlying PFGE differences between strains, however, are not defined. We investigated the mechanisms for strain variation in O157 by recovering and examining nucleotide sequences flanking each of the XbaI restriction enzyme sites in the genome. Our analysis demonstrated that differences between O157 strains were due to discrete insertions or deletions that contained the XbaI sites polymorphic between strains rather than single-nucleotide polymorphisms in the XbaI sites themselves. These insertions and deletions were found to be uniquely localized within the regions of the genome that are specific to O157 compared to E. coli K-12 (O islands), suggesting that strain-to-strain variation occurs in these O islands. These results may be utilized to devise novel strain-typing tools for this pathogen.

Download Full-text

Canonical Single Nucleotide Polymorphisms (SNPs) for High-Resolution Subtyping of Shiga-Toxin Producing Escherichia coli (STEC) O157:H7

PLoS ONE ◽

10.1371/journal.pone.0131967 ◽

2015 ◽

Vol 10 (7) ◽

pp. e0131967 ◽

Cited By ~ 5

Author(s):

Sean M. Griffing ◽

Duncan R. MacCannell ◽

Amber J. Schmidtke ◽

Molly M. Freeman ◽

Eija Hyytiä-Trees ◽

...

Keyword(s):

Escherichia Coli ◽

High Resolution ◽

Single Nucleotide Polymorphisms ◽

Shiga Toxin ◽

Nucleotide Polymorphisms ◽

Single Nucleotide

Download Full-text

Genotypic analyses of uropathogenic Escherichia coli based on fimH single nucleotide polymorphisms (SNPs)

Journal of Medical Microbiology ◽

10.1099/jmm.0.47262-0 ◽

2007 ◽

Vol 56 (10) ◽

pp. 1363-1369 ◽

Cited By ~ 25

Author(s):

Sara Y. Tartof ◽

Owen D. Solberg ◽

Lee W. Riley

Keyword(s):

Escherichia Coli ◽

Single Nucleotide Polymorphisms ◽

Screening Test ◽

Epidemiological Studies ◽

Discriminatory Power ◽

Snp Analysis ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Discriminatory Ability ◽

E Coli

The application of genotyping techniques for subtyping uropathogenic Escherichia coli has contributed to better understanding of the epidemiology of community-acquired urinary tract infection (UTI). However, the current techniques are hampered by limited reproducibility, poor discriminatory power, labour-intensive performance or high cost. A screening test that is sequence-based would provide an inexpensive, reproducible way to subtype E. coli isolates. Such a test, if also discriminatory, would be highly useful for epidemiological studies. The discriminatory ability of 12 putative virulence genes (fimH, fliD, fliM, iha, motA, papA/H, kpsMTII, fepE, fimA, flgA, malG, purD) was evaluated based on single nucleotide polymorphisms (SNPs) in nine uropathogenic E. coli isolates, all previously found to belong to a single multilocus sequence type (MLST) complex (ST69). An additional 25 epidemiologically well-characterized E. coli isolates belonging to 12 distinct MLST clonal complexes were analysed for fimH SNP. None of the 12 genes except fimH were able to further discriminate the nine ST69-complex strains. Isolates belonging to the 12 non-ST69 MLST groups were separated into 10 fimH SNP subgroups. While fimH SNP analysis may not be an appropriate phylogenetic method, it offers discriminatory power similar to that of MLST and could be used as a simple, inexpensive screening test for epidemiological studies of uropathogenic E. coli.

Download Full-text