[Microbial contamination of water by pipe and tube materials. 3. Behavior of E. coli, Citrobacter freundii and Klebsiella pneumoniae].

Materials water comes into contact with can promote the microbial growth as it could be shown before. The reaction of an unspecific microorganism flora and of Legionella pneumophila in pipes and hoses has been described in the two previous communications. The investigation with L. pneumophila has shown that even a pathogen organism can grow upon the materials. Therefore it was of special interest to prove whether indicator organisms for the testing of drinking water can grow in pipes and hoses as well. Escherichia coli, Citrobacter freundii and Klebsiella pneumoniae grew after the experimental contamination for many weeks on the rubber hose until the test was finally stopped, in the other pipes and hoses (glass, high-grade steel, PVC, PE, PA, PTFE and silicone) E. coli could be found for maximal 7 weeks, Citrobacter freundii for 1 week and Klebsiella pneumoniae for maximal 3 weeks. In the copper pipe the organisms could be found only for a few days.