Relationship between <i>stx</i> Genotype and Stx2 Expression Level in Shiga Toxin-Producing <i>Escherichia coli</i> O157 Strains

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Abstract

To determine the expression level of Shiga toxin (Stx) 2-related toxins (Stx2 and Stx2c) produced by each of 33 Stx-producing <i>Escherichia coli</i> (STEC) O157 strains, <i>stx2</i> and <i>stx2c</i> mRNAs (<i>stx2</i>-related mRNA) were measured using real-time PCR with primers that recognize sequences common to <i>stx2</i> and <i>stx2c</i>. The amount of Stx2 and Stx2c protein was measured using a reversed passive latex agglutination (RPLA) kit. Expression of <i>stx2</i>-related mRNA was significantly higher in STEC O157 strains carrying the <i>stx2</i> gene (i.e., <i>stx2</i>, <i>stx1/stx2</i>, or <i>stx2/stx2c</i>) than in most strains that carried the <i>stx2c</i> gene but not the <i>stx2</i> gene (i.e., <i>stx2c</i> or <i>stx1/stx2c</i>). RPLA might not measure the precise amount of each toxin variant; nevertheless, <i>stx2</i>-inclusive strains had 40-fold higher mean toxin titers than did strains that carried the <i>stx2c</i> gene but not the <i>stx2</i> gene, with the exception of 1 <i>stx2c</i> strain. Interestingly, 1 <i>stx2c</i> strain that was isolated from a patient with severe hemorrhagic diarrhea had the highest <i>stx2</i>-related mRNA expression and the highest toxin titer of all 33 STEC O157 strains. Taken together, these findings indicated that measurement of <i>stx2</i>-related mRNA expression could reflect differences in production levels of toxins among STEC strains.

Journal

  • Japanese Journal of Infectious Diseases

    Japanese Journal of Infectious Diseases 65(4), 322-325, 2012

    National Institute of Infectious Diseases, Japanese Journal of Infectious Diseases Editorial Committee

Codes

  • NII Article ID (NAID)
    130001931831
  • NII NACSIS-CAT ID (NCID)
    AA1132885X
  • Text Lang
    ENG
  • ISSN
    1344-6304
  • NDL Article ID
    023840639
  • NDL Call No.
    Z53-C450
  • Data Source
    NDL  J-STAGE 
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