Current Microbiology

, Volume 25, Issue 1, pp 9–17

Demonstration of exopolysaccharide production by enterohemorrhagicEscherichia coli

  • Alan D. Junkins
  • Michael P. Doyle
Article

DOI: 10.1007/BF01570076

Cite this article as:
Junkins, A.D. & Doyle, M.P. Current Microbiology (1992) 25: 9. doi:10.1007/BF01570076

Abstract

EnterohemorrhagicEscherichia coli O157∶H7 produces visibly slimy colonies when grown on Sorbitol/MacConkey or Maloney's agar plates at room temperature, indicative of exopolysaccharide (EPS) production. Eighteen of 27 (67%) wild-typeE. coli O157∶H7 isolates produced enough EPS to be visually distinguishable. Of five strains that showed no visible EPS production on these media, four (80%) did produce slimy colonies on media containing higher salt concentrations. Measurements of EPS production by colorimetric determination of uronic acid indicated that EPS production was affected by growth temperature, atmosphere, and medium. Wild-typeE. coli O157∶H7 strain 932 produced the greatest amounts of EPS when grown anaerobically at 37°C, whereas its plasmid-cured derivative 932P produced large quantities of EPS when grown aerobically at room temperature. Electron micrographs revealed thin, flexible fibers extending from the bacterial cell surface. Cells of strain 932P grown aerobically at room temperature were completely encased in a thick EPS matrix. Chemical analysis of purified EPS revealed that it is very similar or identical to colanic acid.E. coli O157∶H7 adheres better to INT 407 cells when grown under conditions that favor high EPS production than when grown under conditions that repress EPS production.

Copyright information

© Springer-Verlag New York Inc. 1992

Authors and Affiliations

  • Alan D. Junkins
    • 1
  • Michael P. Doyle
    • 1
  1. 1.Food Research Institute and Department of BacteriologyUniversity of Wisconsin-MadisonMadisonUSA
  2. 2.Department of Medical Laboratory SciencesMedical University of South CarolinaCharlestonUSA
  3. 3.Food Safety and Quality Enhancement LaboratoryUniversity of GeorgiaGriffinUSA

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