Flow cytometric examination of bacterial growth in a local drinking water network

Bacterial growth in drinking water networks can result in health-based implications, affect network hydrology and induce customer complaints. In this study, cultivation-based methods were compared to flow cytometric methods for the study of growth in a local drinking water network. Comparison of flow cytometric cell concentrations indicated growth in several samples, while further data analysis with fingerprinting algorithms showed the different origin of this growth; low similarity between samples with elevated cell counts indicated that growth occurred mainly in the sampled household plumbing installations instead of centrally in the water network. Fast obtained flow cytometric data made this thorough analysis possible, while cultivation-based methods were yielding too scarce information. Flow cytometry showed to be more rapid, complete, and accurate than cultivation-based methods for a network growth study. It is proposed as a future useful tool for the fast detection of microbial point contaminations in drinking water networks.