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Title: IN VITRO DISAPPEARANCES OF E. COLI AND ENTEROCOCCI RELATED TO LIGHT, PREDATION, AND SEDIMENTATION

Author
item Fisher, Dwight
item Jenkins, Michael
item Lowrance, Robert
item Hubbard, Robert
item Strickland, Timothy
item VELLIDIS, G - UGA, TIFTON, GA
item NEWTON, G - UGA, TIFTON, GA

Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/20/2003
Publication Date: 10/20/2003
Citation: Fisher, D.S., Jenkins, M., Lowrance, R.R., Hubbard, R.K., Strickland, T.C., Vellidis, G., Newton, G.L. 2003. In vitro disappearances of E. coli and enterococci related to light, predation, and sedimentation [Abstract]. American Society of Agronomy Abstracts. A05-fisher927072-oral.

Interpretive Summary:

Technical Abstract: Recent experiments indicated that when large numbers of E. coli and enterococci from fresh bovine feces entered a pond, the numbers of these organisms exiting the pond were negligible. This study examined the relative importance of ultraviolet light, pond organisms, and sedimentation in reducing the numbers of fecal indicator organisms. Fresh bovine feces were used as a source of E. coli and enterococci. The feces were mixed with deionized water to inoculate small containers filled with either deionized water, autoclaved pond water, or raw pond water. Half the containers were in shelters that provided similar ambient temperatures but blocked ultraviolet light. The other containers were exposed to sunlight without shelter. To test for sedimentation, a sample was removed with pipette from the surface of the container and then the container was stirred and another sample collected. The E. coli and enterococci were enumerated using IDEXX methodology. Enterococci did not persist more than 48 to 72 hours under any conditions. Both microbe species were extinct in less than 48 hours when exposed to UV radiation. When E. coli were sheltered from radiation but placed in raw pond water they died off over 2 to 5 days. The E. coli that were sheltered from radiation and placed in autoclaved pond water were still present at the end of the experiment (up to 7 weeks).