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β ‐ d ‐glucuronidase activity assay to assess viable Escherichia coli abundance in freshwaters
Author(s) -
GarciaArmisen T.,
Lebaron P.,
Servais P.
Publication year - 2005
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2005.01670.x
Subject(s) - escherichia coli , biology , most probable number , microbiology and biotechnology , bacteria , abundance (ecology) , contamination , food science , ecology , biochemistry , genetics , gene
Aims: The relationships between the β ‐ d ‐glucuronidase (GLUase) activity, the abundance of culturable Escherichia coli and the number of viable E. coli were investigated in river and wastewater samples. Methods and Results: GLUase activity was measured as the rate of hydrolysis of 4‐methylumbelliferyl‐ β ‐ d ‐glucuronide. Culturable E. coli were enumerated by the most probale number (MPN) microplate method. Viable E. coli were estimated by fluorescent in situ hybridization (FISH) coupled with a procedure of viability testing (DVC‐FISH procedure). Significant correlations were found between the log of GLUase activity and both, the log culturable E. coli and the log of viable E. coli . Conclusions: GLUase activity per viable E. coli gave a broadly constant value from low to highly contaminated waters while GLUase activity per culturable E. coli strongly increased at low contaminated waters because of an underestimation of the number of active E. coli by the culture‐based method. Significance and Impact of the Study: GLUase activity is a reliable parameter for the rapid quantification of viable E. coli in waters.