ARS | Publication request: Correlating Transport Behavior with Cell Properties for Eight Porcine Escherichia coli Isolates

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 26, 2010
Publication Date: July 1, 2010
Repository URL: http://hdl.handle.net/10113/44605
Citation: Bolster, C.H., Cook, K.L., Marcus, I.M., Haznedaroglu, B.Z., Walker, S.L. 2010. Correlating Transport Behavior with Cell Properties for Eight Porcine Escherichia coli Isolates. Environmental Science and Technology. 44(13):5008–5014.

Interpretive Summary: Infiltration of fecal material into the subsurface can result in the contamination of ground water supplies by pathogenic microorganisms such as bacteria, viruses, and protozoa, thereby posing a threat to public health. To assess whether a ground water source is at risk for fecal contamination, agencies responsible for monitoring water supplies generally test for the presence of nonpathogenic as indicator organisms. One of the most commonly used indicator organisms in ground water systems is E coli. To improve our understanding of the mechanisms controlling E. coli movement in the environment, we conducted a set of transport studies to better understand the factors that control E. coli attachment to sediment surfaces. For quartz sand we found that E .coli attachment, and thus transport, was controlled by the surface charge of the cell. For Fe-coated sand a mild correlation between cell width and attachment was observed. These findings will help improve our understanding of the mechanisms controlling E .coli in the environment.

Technical Abstract: In this study we investigate how growth stage and depositional environment affect variability of cell properties and transport behavior of eight porcine E. coli isolates. We compared the surface properties and transport behavior for cells harvested at two different growth stages (exponential and stationary) and depositional environments (favorable and unfavorable). We then investigated correlations between measured cell properties and fitted bacterial attachment efficiencies. For both growth stages we found that bacterial attachment efficiencies to negatively-charged quartz sand varied among the eight different isolates by over an order of magnitude whereas attachment efficiencies to the positively-charged Fe-coated sands varied by a factor of less than two. With the exception of one isolate, growth condition had minimal impact on attachment efficiencies to the uncoated sands. A strong and statistically significant inverse relationship was observed between bacterial attachment to uncoated quartz sand and log-transformed zeta potential whereas a mild yet statistically significant relationship between bacterial attachment to the Fe-coated soils and cell width was observed. For the experimental conditions used in our study, we found that variability in E. coli transport was more dependent on the depositional environment than on growth conditions.