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Journal of Environmental Quality Abstract -

Mortality of Escherichia coli O157:H7 in Two Soils with Different Physical and Chemical Properties


This article in JEQ

  1. Vol. 29 No. 6, p. 1821-1825
    Received: Feb 17, 2000

    * Corresponding author(s): mscoyn00@pop.uky.edu
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  1. D. N. Mubiru,
  2. M. S. Coyne * and
  3. J. H. Grove
  1. Department of Agronomy, Univ. of Kentucky, Lexington, KY 405460091.



Wild and domesticated animals can harbor a pathogenic Escherichia coli strain designated as O157:H7. Potential health problems could occur if strain O157:H7 is a more robust survivor in defecated waste than commonly used indicator bacteria. A laboratory study was conducted to assess E. coli O157:H7 survival relative to a nonpathogenie E. coli strain in two soils with different physical and chemical characteristics. Bacteria in the inoculated soils were enumerated on a weekly basis for 8 wk using a most probable number (MPN) technique. First-order decay models were used to describe bacteria mortality in the soils. Decay series were described slightly better by a two-stage function than by a single-stage function. Strain O157:H7 exhibited similar mortality patterns to the nonpathogenic E. coli in the same soil environment. Both E. coli strains had greater mortality rates in Pope silt loam (coarse-loamy, mixed, active, mesic Fluventic Dystrudept) than Zanesville silt loam (fine-silty, mixed, active, mesic Oxyaquic Fragiudalf). Differences in available soil water probably were the overriding factor in E. coli survival. Escherichia coli O157:H7 survival could be modeled in the same way as nonpathogenic E. coli and appears to have a slightly higher mortality rate.

Contribution (Paper no. 00-06-33) of the Kentucky Agric. Exp. Stn., published with the approval of the director.

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