title: Factors influencing the persistence of Escherichia coli O157:H7 lineages in feces from cattle fed grain versus grass hay diets.
abstract: 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 degrees 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 degrees 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 degrees C. Escherichia coli O157:H7 survival was highest in grain-fed feces at 25 degrees 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.
authors: Agriculture and Agri-Food Research Centre, P.O. Box 3000, Lethbridge, AB T1J 4B1, Canada.
authors: Ross M S
authors: RM
authors: Lowe
authors: Krysty
authors: K
authors: Munns
authors: L Brent
authors: LB
authors: Selinger
authors: Linda
authors: L
authors: Kremenik
authors: Danica
authors: D
authors: Baines
authors: Tim A
authors: TA
authors: McAllister
authors: Ranjana
authors: R
authors: Sharma
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D057138:Bacterial Shedding; D002417:Cattle / Q000382:microbiology*; D002418:Cattle Diseases / Q000382:microbiology; D003967:Diarrhea / Q000382:microbiology; D004032:Diet / Q000662:veterinary*; D002523:Edible Grain / Q000737:chemistry; D004927:Escherichia coli Infections / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000302:isolation & purification / Q000472:pathogenicity*; D005232:Fatty Acids, Volatile / Q000032:analysis; D005243:Feces / Q000737:chemistry / Q000382:microbiology*; D006109:Poaceae / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry
chemical_list: D005232:Fatty Acids, Volatile