Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: April 1, 2003
Publication Date: May 18, 2003
Citation: Ibekwe, A.M., Papiernik, S.K., Grieve, C.M. 2003. Impact of fumigants on the survival of escherichia coli o157:h7 in animal manure. Abstract. 103rd General Meeting of the American Society for Microbiology, Washington, DC. May 18-22, 2003. P. 596.
Agricultural soils are typically fumigated to provide effective control of nematodes and soil-borne pathogens in preparation for planting of high value cash crops. In the past, animal manure has been applied to agricultural land with little or no regulation. Many groups have voiced concerns about the safety of land application of manure and their potential for food and water contamination by Escherichia coli (E. coli) from agricultural runoffs. In this study, a multiplex fluorogenic PCR assay was used to quantify E. coli O157:H7 in soil and manure after soil fumigation with methyl bromide and methyl iodide. Primers and probes were designed to amplify and quantify the Shiga-like toxin 1 (stx1) and 2 (stx2) genes and the intimin (eae) gene of E. coli O157:H7 in a single reaction. A direct correlation was determined between the fluorescence threshold cycle (CT) and the starting quantity of E. coli O157:H7 DNA. A detection limit of approximately 6.4 X 1,000 CFU ml/1 E. coli O157:H7 based on plate counts was determined. Both fumigants were effective in reducing pathogen concentrations in soil and manure before planting, with MeBr having the highest impact.