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Loss of virulence genes in Escherichia coli populations during manure storage on a commercial swine farm.
Loss of virulence genes in Escherichia coli populations during manure storage on a commercial swine farm.
- Source :
-
Applied and environmental microbiology [Appl Environ Microbiol] 2008 Jul; Vol. 74 (13), pp. 3935-42. Date of Electronic Publication: 2008 Apr 25. - Publication Year :
- 2008
-
Abstract
- Confined livestock production farms typically store their wastes prior to land application. Here, we employed three complementary approaches to evaluate changes in the population structure and stability of virulence genes in Escherichia coli during manure storage on a commercial farm that housed healthy swine. Isolates were genotyped by repetitive extragenic palindromic PCR using the BOXA1R primer and evaluated for the presence of selected virulence genes by PCR. Isolates obtained from the manure holding tank (n = 392) carried estB, fedA, stx(2e), astA, paa, aida-I, and sepA at lower frequencies than isolates obtained from fresh feces (n = 412). Fresh fecal material from the barn was added into diffusion chambers and immersed in the manure holding tank for 7 weeks. The fecal E. coli population was initially dominated by a single genotype, all isolates of which carried fedA and aida-I. After 7 weeks, a genotype that did not carry any virulence genes dominated the surviving population. In a second experiment, 48 fecal isolates of E. coli that varied in their genotypes and virulence gene complement were incubated in diffusion chambers in the manure holding tank for 3 weeks. Over 95% of the inoculum population carried at least one virulence gene, whereas after 3 weeks 90% of the recovered isolates carried no virulence genes. Taken together, these results indicate that during commercial manure storage, there was a significant reduction in the carriage of these virulence genes by E. coli. We propose that loss of virulence genes from enteric pathogens in the farm and in natural environments may, if generalized, contribute to the attenuation of a public health risk from contamination with agricultural wastes.
- Subjects :
- Animals
Computational Biology methods
Escherichia coli genetics
Escherichia coli growth & development
Feces microbiology
Genotype
Image Processing, Computer-Assisted
Polymerase Chain Reaction
Swine
Virulence
Animal Husbandry methods
Escherichia coli pathogenicity
Escherichia coli Proteins genetics
Manure microbiology
Virulence Factors genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1098-5336
- Volume :
- 74
- Issue :
- 13
- Database :
- MEDLINE
- Journal :
- Applied and environmental microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 18441108
- Full Text :
- https://doi.org/10.1128/AEM.02710-07