Agricultural and Biosystems Engineering Publications

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

12-2014

Journal or Book Title

Journal of Applied Microbiology

Volume

117

Issue

6

First Page

1730

Last Page

1739

Research Focus Area(s)

Land and Water Resources Engineering

DOI

10.1111/jam.12660

Abstract

Aim: A standard procedure does not exist to distinguish between attached and unattached micro-organisms. In this study, we compared two methods to quantify between Escherichia coli attached to clay particles and E. coli freely suspended in solution: flow cytometry (attachment assay and viability assay) and settling (or centrifugation followed by settling).

Methods and Results: Methods were tested using three environmental strains collected from swine facilities (A, B and C) and one purchased modified pathogenic strain (ATCC 43888); four clay particles: Hectorite, Kaolinite, Ca-Montmorillonite, Montmorillonite K-10; and a range of surface area ratios (particle surface area to E. coli surface area). When comparing the two methods, the per cent attached obtained from the flow cytometry was lower, but not significantly different from the per cent attached obtained from the settling method for all conditions except when the particle was Hectorite or Montmorillonite K-10; when the strain was C; and when the surface area ratio was below 100. Differences between the methods are likely because traditional culture-based methods cannot detect the viable but nonculturable (VBNC) population, whereas flow cytometry can detect the fraction of VBNC with intact membranes.

Conclusion: Our results indicate that flow cytometry is a rapid and culture-independent method for differentiating between attached and unattached micro-organisms.

Significance and Impact of the Study: Flow cytometry is useful for laboratory-based studies of micro-organism–particle interactions.

Comments

This is the peer reviewed version of the following article: Liang, X., Soupir, M. L., Rigby, S., Jarboe, L. R., and Zhang, W. (2014). Journal of Applied Microbiology 117, 1730–1739, which has been published in final form at http://dx.doi.org/ 10.1111/jam.12660. This article may be used for non-commercial purposed in accordance with Wiley Terms and Conditions for Self-Archiving.

Copyright Owner

The Society for Applied Microbiology

Language

en

File Format

application/pdf