This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Franz, E.
Right arrow Articles by van Bruggen, A. H. C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Franz, E.
Right arrow Articles by van Bruggen, A. H. C.
Agricola
Right arrow Articles by Franz, E.
Right arrow Articles by van Bruggen, A. H. C.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, April 2007, p. 2180-2190, Vol. 73, No. 7
0099-2240/07/$08.00+0     doi:10.1128/AEM.01950-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Prevalence of Shiga Toxin-Producing Escherichia coli stx1, stx2, eaeA, and rfbE Genes and Survival of E. coli O157:H7 in Manure from Organic and Low-Input Conventional Dairy Farms{triangledown}

Eelco Franz,1* Michel M. Klerks,2 Oscar J. De Vos,1 Aad J. Termorshuizen,1 and Ariena H. C. van Bruggen1

Wageningen University and Research Centre, Biological Farming Systems Group, Marijkeweg 22, 6709 PG Wageningen, The Netherlands,1 Wageningen University and Research Centre, Plant Research International BV, Droevendaalsesteeg 1, 6709 PB Wageningen, The Netherlands2

Received 17 August 2006/ Accepted 21 January 2007

Manure samples were collected from 16 organic (ORG) and 9 low-input conventional (LIC) Dutch dairy farms during August and September 2004 to determine the prevalence of the STEC virulence genes stx1 (encoding Shiga toxin 1), stx2 (encoding Shiga toxin 2), and eaeA (encoding intimin), as well as the rfbE gene, which is specific for Escherichia coli O157. The rfbE gene was present at 52% of the farms. The prevalence of rfbE was higher at ORG farms (61%) than at LIC farms (36%), but this was not significant. Relatively more LIC farms were positive for all Shiga toxin-producing E. coli (STEC) virulence genes eaeA, stx1, and stx2, which form a potentially highly virulent combination. Species richness of Enterobacteriaceae, as determined by DGGE, was significantly lower in manure positive for rfbE. Survival of a green fluorescent protein-expressing E. coli O157:H7 strain was studied in the manure from all farms from which samples were obtained and was modeled by a biphasic decline model. The time needed to reach the detection limit was predominantly determined by the level of native coliforms and the pH (both negative relationships). Initial decline was faster for ORG manure but leveled off earlier, resulting in longer survival than in LIC manure. Although the nonlinear decline curve could theoretically be explained as the cumulative distribution of an underlying distribution of decline kinetics, it is proposed that the observed nonlinear biphasic pattern of the survival curve is the result of changing nutrient status of the manure over time (and thereby changing competition pressure), instead of the presence of subpopulations differing in the level of resistance.

* Corresponding author. Mailing address: Wageningen University and Research Centre, Biological Farming Systems Group, Marijkeweg 22, 6709 PG Wageningen, The Netherlands. Phone: 31-317-478202. Fax: 31-317-478213. E-mail: Eelco.Franz{at}wur.nl.

{triangledown} Published ahead of print on 2 February 2007.

Applied and Environmental Microbiology, April 2007, p. 2180-2190, Vol. 73, No. 7
0099-2240/07/$08.00+0     doi:10.1128/AEM.01950-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»