Premium
Flow cytometry is a promising and rapid method for differentiating between freely suspended E scherichia coli and E . coli attached to clay particles
Author(s) -
Liang X.,
Soupir M.L.,
Rigby S.,
Jarboe L.R.,
Zhang W.
Publication year - 2014
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12660
Subject(s) - escherichia coli , flow cytometry , microbiology and biotechnology , flow (mathematics) , enterobacteriaceae , bacteria , chemistry , biology , biochemistry , physics , genetics , gene , mechanics
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.