%0 Journal Article
%T Gene Expression during Survival of Escherichia coli O157:H7 in Soil and Water
%A Ashley D. Duffitt
%A Robert T. Reber
%A Andrew Whipple
%A Christian Chauret
%J International Journal of Microbiology
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/340506
%X The in vitro survival of Escherichia coli O157:H7 at under two experimental conditions (sterile soil and sterile natural water) was examined. DNA microarrays of the entire set of E. coli O157:H7 genes were used to measure the genomic expression patterns after 14 days. Although the populations declined, some E. coli O157:H7 cells survived in sterile stream water up to 234 days and in sterile soil for up to 179 days. Cells incubated in soil microcosms for 14 days expressed genes for antibiotic resistance, biosynthesis, DNA replication and modification, metabolism, phages, transposons, plasmids, pathogenesis and virulence, antibiotic resistance, ribosomal proteins, the stress response, transcription, translation, and transport and binding proteins at significantly higher levels than cells grown in Luria broth. These results suggest that E. coli O157:H7 may develop a different phenotype during transport through the environment. Furthermore, this pathogen may become more resistant to antibiotics making subsequent infections more difficult to treat. 1. Introduction Escherichia coli O157:H7 is an enterohemorrhagic strain of E. coli that produces a powerful shiga-like toxin. It is capable of causing bloody stools, hemorrhagic colitis, and hemolytic uremic syndrome [1]. Nearly 75,000 cases of O157:H7 infection occur every year in the US [2]. Most outbreaks have been associated with the consumption of contaminated, undercooked, bovine food products [1]. There also have been reports of E. coli O157:H7 outbreaks associated with both drinking and recreational water [3¨C7]. E. coli O157:H7 is ubiquitous on farms where healthy cattle and sheep harbor the pathogen in their gastrointestinal tracts [8]. As a consequence, farm animal manure is a source for spreading E. coli O157:H7 into the environment and potentially to the human food chain. One of the most common modes by which E. coli O157:H7 is introduced onto food crops is through contaminated irrigation water [9]. In addition, the propagation of this pathogen through the environment has been linked to runoff contaminated with bovine manure or by use as soil amendment [10]. The contamination of surface and ground water in rural areas of the United States is becoming increasingly more common as a result of concentrated animal feeding operations [9]. Escherichia coli O157:H7 can survive in varying habitats under a wide range of conditions. In the environment, cells are exposed to rapidly changing conditions such as changes in pH, nutrient availability, temperature, oxidative stress, and osmotic challenge [11]. E. coli
%U http://www.hindawi.com/journals/ijmicro/2011/340506/