Factors influencing the persistence of escherichia coli O157:H7 lineages in feces from cattle fed grain versus grass hay diets
Lowe, R.M.S., Munns, K., Selinger, L.B., Kremenik, L., Baines, D., McAllister, T.A., Sharma, R. (2010). Factors influencing the persistence of escherichia coli O157:H7 lineages in feces from cattle fed grain versus grass hay diets, 56(8), 667-675. http://dx.doi.org/10.1139/W10-051
Escherichia coli O157:H7 is a pathogenic, gram-negative bacterium that causes diarrhea, hemorrhagic colitis, and can lead to fatal hemolytic uremic syndrome in humans. We examined the persistence of E. coli O157:H7 lineages I and II in feces held at 4, 12, and 25°C, from animals fed either grain or hay diets. Three strains of each lineage I and II were inoculated into grain-fed or hay-fed feces, and their persistence was monitored over 28 days. No significant differences in E. coli O157:H7 survival between the 2 lineages in both fecal types was found at the examined temperatures. Volatile fatty acids were higher in grain-fed than in hay-fed feces, resulting in consistently lower pH in the grain-fed feces at 4,12 and 25°C. Regardless of lineage type, E. coli O157:H7 CFUs were significantly higher in grain-fed than in hay-fed feces at 4 and 25°C. Escherichia coli O157:H7 survival was highest in grain-fed feces at 25°C up to 14 days. Our results indicate that the 2 lineages of E. coli O157:H7 do not differ in their persistence; however, it appears that temperature and feces type both affect the survival of the pathogen.
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