AWWA WQTC55148

The objective of this study is to expand molecular biology-based monitoring of microorganisms to include measurements of viability in addition to identification, localization, and enumeration. Although ribosomal RNA-targeted techniques have replaced culture-based methods as the preferred technology for assessing microbial diversity, culture-based methods remain the "gold standard" for screening for microorganisms because culture-based methods detect viable microorganisms while ribosomal RNA-targeted techniques can detect "naked" nucleic acid released from dead microorganisms. The authors have improved the capabilities of ribosomal RNA-targeted techniques by expanding the methods to simultaneously measure ribosomal RNA as well as precursor ribosomal RNA--a key intermediate in the production of ribosomes. Ribosomal RNA and precursor ribosomal RNA were measured simultaneously in whole cells of Acinetobacter calcoaceticus T exposed to chlorine. The results demonstrate that precursor ribosomal RNA is a sensitive measure of viability in whole cells. The authors believe this approach holds tremendous promise for verifying disinfection efficacy for pathogenic microorganisms using molecular biology-based monitoring. In the future, coupling the rapid developments in molecular biology-based technology with the critical measurement of cellular viability via detection of ribosome genesis may change the way disinfectants are evaluated. Includes 9 references, figures.