Multilocus sequence typing reveals a lack of diversity among Escherichia coli O157: H7 isolates that are distinct by pulsed-field gel electrophoresis

Anna C. Noller, M. Catherine McEllistrem, O. Colin Stine, J. Glenn Morris, David J. Boxrud, Bruce Dixon, Lee H. Harrison

Research output: Contribution to journalArticlepeer-review

Abstract

Escherichia coli O157:H7 is a major cause of foodborne illness in the United States. Pulsed-field gel electrophoresis (PFGE) is the molecular epidemiologic method mostly commonly used to identify food-borne outbreaks. Although PFGE is a powerful epidemiologic tool, it has disadvantages that make a DNA sequence-based approach potentially attractive. Multilocus sequence typing (MLST) analyzes the internal fragments of housekeeping genes to establish genetic relatedness between isolates. We sequenced selected portions of seven housekeeping genes and two membrane protein genes (ompA and espA) of 77 isolates that were diverse by PFGE to determine whether there was sufficient sequence variation to be useful as an epidemiologic tool. There was no DNA sequence diversity in the sequenced portions of the seven housekeeping genes and espA. For ompA, all but five isolates had sequence identical to that of the reference strains. E. coli O157:H7 has a striking lack of genetic diversity in the genes we explored, even among isolates that are clearly distinct by PFGE. Other approaches to identify improved molecular subtyping methods for E. coli O157:H7 are needed.

Original languageEnglish (US)
Pages (from-to)675-679
Number of pages5
JournalJournal of Clinical Microbiology
Volume41
Issue number2
DOIs
StatePublished - Feb 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology (medical)
  • Microbiology

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