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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR MICROBIOLOGY AND CONTROL OF ENTERIC PATHOGENS THAT CONTAMINATE FRESH PRODUCE

Location: Produce Safety and Microbiology Research

Title: Effects of Environmental Stress on Stability of Tandem Repeat in Escherichia coli O157:H7

Authors
item Cooley, Michael
item Carychao, Diana
item Nguyen, Kimberly
item Whitehand, Linda
item Mandrell, Robert

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 10, 2010
Publication Date: May 6, 2010
Citation: Cooley, M.B., Carychao, D.K., Nguyen, K.M., Whitehand, L.C., Mandrell, R.E. 2010. Effects of Environmental Stress on Stability of Tandem Repeat in Escherichia coli O157:H7. Applied and Environmental Microbiology. 76(10)3398-3400

Interpretive Summary: Observation of survival and spread of the pathogen E. coli O157 in pastures, fields and streams requires methods to distinguish one bacterium from another. One such method uses repeated DNA structures commonly found in all bacteria. The research reported here shows that stress causes mutations in these repeat units and also the loss of a small, circular piece of DNA called pO157.

Technical Abstract: Multilocus variable-number tandem-repeat analysis (MLVA) is used for source tracking Escherichia coli O157:H7 in agricultural environments. Tandem repeats were stable after limited replication but changed after exposure to irradiation, elevated temperatures, and starvation conditions. The pO157 plasmid was frequently lost under these stress conditions. Environmental stresses may increase phylogenetic diversity as measured by MLVA.

Last Modified: 7/31/2014
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