title: Comparison of the transport of Bacteroides fragilis and Escherichia coli within saturated sand packs.
abstract: Pathogens in groundwater accounted for ∼50% of waterborne disease outbreaks in the United States between 1971 and 2006. The fast and reliable detection of groundwater microbial contamination and the identification of the contamination sources are of critical importance to the protection of public health. Recent studies suggested that fecal anaerobe Bacteriodes spp. could be employed as an effective tool for surface water microbial source tracking (MST). The usefulness of Bacteroides spp. for groundwater MST depends strongly on its mobility within the subsurface system. This research provides laboratory results comparing transport and attachment of E. coli K12 and B. fragilis within packed quartz sands. The results indicate that at low ionic strengths both E. coli K12 and B. fragilis are readily transported through saturated sand packs. At higher ionic strengths such as may be found near concentrated sources of fecal contamination, B. fragilis displayed significantly higher mobility than E. coli K12. Analysis of the extended Derjaguin-Landau-Verweu-Overbeek (XDLVO) energy interactions for both types of bacteria showed a significant repulsive energy barrier exists between the sand surface and the bacteria, precluding attachment directly to the sand surface. However a secondary minimum energy level exists under higher ionic strength conditions. The depth of this energy low is greater for E. coli K12, which results in greater attachment of E. coli K12 than of B. fragilis. The high mobility of B. fragilis suggests that it represents a promising tool for the detection of groundwater fecal contamination as well as the identification of the microbial sources.
authors.affiliation: Department of Geosciences, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Johanson
authors.affiliation: Department of Geosciences, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America.
authors.forename: Lucia
authors.initials: L
authors.lastname: Feriancikova
authors.affiliation: Department of Biological Sciences, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America.
authors.forename: Areen
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Department of Biological Sciences, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America.
authors.forename: Daâd A
authors.initials: DA
authors.lastname: Saffarini
authors.affiliation: Civil & Environmental Engineering Department, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America.
authors.forename: Lixia
authors.initials: L
authors.lastname: Wang
authors.affiliation: Civil & Environmental Engineering Department, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Geosciences, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Grundl
authors.affiliation: Department of Geosciences, University of Wisconsin Milwaukee, Milwaukee, WI 53211, United States of America. Electronic address: xus@uwm.edu.
authors.forename: Shangping
authors.initials: S
authors.lastname: Xu
mesh_terms: D001441:Bacteroides fragilis / Q000502:physiology*; D004926:Escherichia coli / Q000502:physiology*; D060587:Groundwater; D014871:Water Microbiology; D014876:Water Pollution
keywords: Bacterial transport; Groundwater microbial contamination; Microbial source tracking; Transport of Bacteroides fragilis; Transport of E. coli