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

• Published in: Journal of environmental quality 2000-11, Vol.29 (6), p.1821-1825
• Main Authors: Mubiru, D. N., Coyne, M. S., Grove, J. H.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Bacteriology; Biological and medical sciences; Chemical properties; E coli; Epidemiology; Escherichia coli; Fundamental and applied biological sciences. Psychology; Growth kinetics; Manures; Microbial ecology; Microbiology; Soil
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2000.00472425002900060012x

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.