Polyvalent fingerprint based molecular surveillance methods for drinking water supply systems

Despite the relevance for public health, surveillance of drinking water supply systems (DWSS) in Europe is mainly achieved by cultivation based detection of indicator bacteria. The study presented here demonstrates the use of molecular analysis based on fingerprints of DNA extracted from drinking water bacteria as a valuable monitoring tool of DWSS and was exemplified for a DWWS in Northern Germany. The analysis of the bacterial community of drinking water was performed by a set of 16S rRNA gene based fingerprints, sequence analysis of relevant bands and phylogenetic assignment of the 16S rRNA sequences. We assessed the microflora of drinking water originating from two reservoirs in the Harz Mountains. The taxonomic composition of the bacterial communities from both reservoirs was very different at the species level reflecting the different limnological conditions. Detailed analysis of the seasonal community dynamics of the tap water revealed a significant influence of both source waters on the composition of the microflora and demonstrated the relevance of the raw water microflora for the drinking water reaching the consumer. According to our experience, molecular analysis based on fingerprints of different degrees of resolution can be considered as a valuable monitoring tool of DWSS.