Water, Air, and Soil Pollution

, Volume 177, Issue 1, pp 367–382

Survival of various ERIC-genotypes of Shiga toxin-producing Escherichia coli in well water

  • Leigh Watterworth
  • Bruce Rosa
  • Heidi Schraft
  • Edward Topp
  • Kam Tin Leung
Article

DOI: 10.1007/s11270-006-9179-x

Cite this article as:
Watterworth, L., Rosa, B., Schraft, H. et al. Water Air Soil Pollut (2006) 177: 367. doi:10.1007/s11270-006-9179-x

Abstract

Recently, there has been a surge of interest in understanding the survival of Shiga toxin-producing Escherichia coli (STEC) in aquatic environments. Fifteen strains of STEC were monitored, individually, in untreated well water samples incubated at 10 and 22^C for 56 days. The strains were selected from three serogroups (O26, Ol11 and O157) and represented five distinct ERIC (enterobacterial repetitive intergenic concensus)-genotypes. The microcosms were prepared in triplicate and inoculated at an initial cell density of about 7.0 log CFU/ml well water. At 10^C, the cell density of five STEC strains fell below the detection limit of 0.8 log CFU/ml by day 56. Of the ten persisting strains, four showed superior survival with cell densities decreasing to an average of about 5 log CFU/ml while the remaining six strains showed moderate levels of survival, decreasing to an average cell density of about 3 log CFU/ml. At 22^C, strain H32 (genotype I) and H15 (genotype B) persisted at 1.1 log CFU/ml and 2.2 log CFU/ml in 56 days, respectively. The other 13 STEC strains dropped below the detection limit between weeks 3 to 8. The 15 strains demonstrated highly variable levels of survival with no correlation between ERIC-genotypes or serogroups and the strains' ability to persist in the well water samples. Although strain H32 (O157:H7) persisted significantly longer than strain H22 (O157:H7) in natural well water at both 10 and 22^C, both strains survived equally well in sterile well water, indicating that individual STEC strains vary in their ability to compete with background microbial populations.

Keywords

Shiga toxin-producing Escherichia coliERIC-genotypeSurvivalWell water

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Leigh Watterworth
    • 1
  • Bruce Rosa
    • 1
  • Heidi Schraft
    • 1
  • Edward Topp
    • 2
  • Kam Tin Leung
    • 1
  1. 1.Department of BiologyLakehead UniversityOntarioCanada
  2. 2.Agriculture and Agri-Food CanadaLondonCanada