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This article in JEQ

  1. Vol. 37 No. 6, p. 2299-2310
    Received: Jan 17, 2008

    * Corresponding author(s): trevisan@thonon.inra.fr


Persistence of Culturable Escherichia coli Fecal Contaminants in Dairy Alpine Grassland Soils

  1. Stéphanie Texierab,
  2. Claire Prigent-Combaretb,
  3. Marie Hélène Gourdona,
  4. Marie Andrée Poirierb,
  5. Pierre Faivrea,
  6. Jean Marcel Dorioza,
  7. Jérome Poulenarda,
  8. Lucile Jocteur-Monrozierb,
  9. Yvan Moënne-Loccozb and
  10. Dominique Trevisan *a
  1. a UMR42 CARRTEL, INRA F74203, Thonon-les-Bains, France; Université de Savoie, F73376 Le Bourget du Lac, France
    b Université de Lyon, F69003, Lyon France; CNRS, UMR5557, Ecologie Microbienne, F69622, Villeurbanne, France


Our knowledge of Escherichia coli (E. coli) ecology in the field is very limited in the case of dairy alpine grassland soils. Here, our objective was to monitor field survival of E. coli in cow pats and underlying soils in four different alpine pasture units, and to determine whether the soil could constitute an environmental reservoir. E. coli was enumerated by MPN using a selective medium. E. coli survived well in cow pats (107 to 108 cells g−1 dry pat), but cow pats disappeared within about 2 mo. In each pasture unit, constant levels of E. coli (103 to 104 cells g−1 dry soil) were recovered from all topsoil (0–5 cm) samples regardless of the sampling date, that is, under the snow cover, immediately after snow melting, or during the pasture season (during and after the decomposition of pats). In deeper soil layers below the root zone (5–25 cm), E. coli persistence varied according to soil type, with higher numbers recovered in poorly-drained soils (103 to 104 cells g−1 dry soil) than in well-drained soils (< 102 cells g−1 dry soil). A preliminary analysis of 38 partial uidA sequences of E. coli from pat and soils highlighted a cluster containing sequences only found in this work. Overall, this study raises the possibility that fecal E. coli could have formed a naturalized (sub)population, which is now part of the indigenous soil community of alpine pasture grasslands, the soil thus representing an environmental reservoir of E. coli

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Copyright © 2008. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyAmerican Society of Agronomy, Crop Science Society of America, and Soil Science Society of America