AWWA WQTC71416

In this study, different approaches based on the real-time amplification of different molecular markers (DNA, rRNA, mRNA) were compared in order to assess the viability status of Pseudomonas aeruginosa and Escherichia coli cells after heat-killing and chlorine treatments. The analysis of residual DNA and RNA extracted from water samples after lethal treatment by electrophoresis bioanalyzer, demonstrated that DNA molecules can survive for up to 24 hours post death, although RNA (mainly rRNA molecules) started to disappear immediately after treatment. Disappearance of 48 transcripts was analyzed by two-steps reverse transcription and real-time PCR (RT-PCR) in starved and not-starved P. aeruginosa and E. coli population. Results showed rplP, rplV, rplE and rpsD as the most labile transcripts after P. aeruginosa death, although groEL was the most labile transcript in E. coli. Moreover, some opposite results were obtained between starved and freshly cultivated E. coli cells. Includes 21 references, table, figures.