Suppression of the human pathogen, Escherichia coli 0157:H7, by dung beetles (Coleoptera:Scarabaeidae) using the lowbush blueberry (Vaccinium angustifolium) agroecosystem as a conceptual model system
Monday, November 11, 2013: 11:12 AM
Meeting Room 9 C (Austin Convention Center)
Matthew Jones
,
Entomology, Washington State University, Pullman, WA
Frank Drummond
,
School of Biology and Ecololgy, University of Maine, Orono, ME
Vivian Wu
,
Food Science & Human Nutrition, School of Food and Agriculture, University of Maine, Orono, ME
Shravani tadepalli
,
Food Science & Human Nutrition, School of Food and Agriculture, University of Maine, Orono, ME
Wildlife as a source of microbial contamination is a concern among public health and food safety agencies. Deer feces have, on multiple occasions, been determined as the point source of
Escherichia coli 0157:H7
contamination of produce. We used the lowbush blueberry agroecosystem as a conceptual model system in which to test multiple, broadly applicable, food safety questions. In this project, the ecological role of a generalist dung beetle species,
Onthophagus hecate, was explored as a potential natural biological control agent of feces-borne pathogens, and alternatively as a pathogen vector between feces and food. Understanding the ecological role of dung beetles in agriculture has strong implications for any system in which food crops are at risk of wildlife fecal contamination. We conducted a laboratory study to elucidate aspects of dung beetle feeding ecology as they relate to suppression and/or transmission of
E. coli 0157:H7 from white tailed deer feces to pre-harvest lowbush blueberry fruit.
Dung beetles were fed white tailed deer scat, intentionally inoculated with E. coli 0157:H7, within a microcosm including fruiting lowbush blueberry plants. Beetles were allowed 10 days to consume and bury scat, after which the harvestable fruit, soil, and feces were tested for the pathogen of concern.
Data from a large-scale field survey indicate that pathogenic E. coli does naturally occur, at low prevalence, in the Maine lowbush blueberry agroecosystem. Dung beetles buried the same percentage (29.1%) of feces whether or not it was artificially inoculated with the pathogen (F(1,6) < 0.001; P = 0.99). Beetles were found to vector no detectable amount of the pathogen to the fruit. Lastly, dung beetles lowered the amount of pathogenic E. coli persisting in the soil (F(2,9) = 7.75; P = 0.01). Therefore, our study suggests that the generalist dung beetle species, Onthophagus hecate, when present in agroecosystems, has the potential to contribute to the suppression of E. coli 0157:H7.
