On the way to identify microorganisms in drinking water distribution networks via DNA analysis of the gut content of freshwater isopods

• Freshwater isopods are ubiquitary. They graze the biofilm in drinking water systems.
• The intestinal content of fresh water isopods reflects the biocenosis of their habitat, here drinking water systems.
• The DNA in the guts of fresh water isopods are extracted, amplificated and subject to 16S DNA and 18S rDNA analysis.
• The evaluation of the DNA sequencing is based on comparison of the experimental gained sequences with those allocated in the data bank of the internet tool BLAST.
• The presented first steps on the way to identify microorganisms in drinking water networks are suitable to judge water quality.

Pure drinking water is the basis for a healthy society. In Germany the drinking water regulations demand for analysis of water via detection of certain microbiological parameters by cultivation only. However, not all prokaryotes can be detected by these standard methods. How to gain more and better information about the bacteria present in drinking water and its distribution systems? The biofilms in drinking water distribution systems are built by bacteria and therefore represent a valuable source of information about the species present. Unfortunately, these biofilms are badly accessible. We thus exploited the circumstance that a lot of metazoans graze the biofilms, so that the content of their guts partly reflects the respective biofilm biocenosis. Therefore, we collected omnivorous isopods, prepared their guts and examined and characterized their contents based on 16S und 18S rDNA analysis. These molecularbiological investigations provide a profound basis for the characterization of the biocenosis and thereby biologically assess the drinking water ecosystems. Combined with a thorough identification of the species and the knowledge of their habitats, this approach can provide useful indications for the assessment of drinking-water quality and the early detection of problems in the distribution system.