Contribution of polymerase chain reaction (PCR) to improve assessment of drinking water quality: a comparison study

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Companies that offer services in the domain of drinking water quality surveillance and monitoring continuously attempt to improve the quality and the rapidity of their services. In the field of microbiological water quality monitoring, molecular technologies are very promising. This could be the case for the rapid identification of presumptive E. coli colonies isolated from water by culture-based techniques. In Quebec, new technologies for microbiological water quality monitoring must be approved by the provincial authorities (CEAEQ). Exova is a company based in Québec City specializing in water quality testing that uses the mFC medium to detect the presence of thermotolerant coliforms in drinking water with the mFC agar method. However, this method is not totally specific and non-fecal origin microorganisms can be detected with this method as false-positive results and supplementary time-consuming test must be performed to confirm the result. Consequently, the Quebec authorities recently proposed modifying their guidelines to require the measurement of the presence of E. coli instead of thermotolerant coliforms.To ensure compliance with the CEAEQ proposition, Exova have to validate a new procedure able to detect the presence of E. coli rather than thermotolerant coliforms in drinking water. The objective of this project is to compare various methods to detect the presence of E. coli in water and, to identify the one that offers the best cost/benefit advantages. In collaboration with Exova, we will simultaneously analyze 1000 water samples of well water using three different methods: 1) the Colilert method 2) the MI agar culture-based method and, 3) the mFC agar culture-based method coupled with a rapid E. coli-specific real-time PCR assay proposed by Maheux et al. (2011a). It is our hope that at the conclusion of this project, the collaboration with Exova will have proven successful and profitable collaboration by improving drinking water monitoring and the quality of services offered to assess the microbiological quality.