title: Bacterial communities in the collection and chlorinated distribution sections of a drinking water system in Budapest, Hungary.
abstract: Bacterial communities of a bank-filtered drinking water system were investigated by aerobic cultivation and clone library analysis. Moreover, bacterial communities were compared using sequence-aided terminal restriction fragment length polymorphism (T-RFLP) fingerprinting at ten characteristic points located at both the collecting and the distributing part of the water supply system. Chemical characteristics of the samples were similar, except for the presence of chlorine residuals in the distribution system and increased total iron concentration in two of the samples. Assimilable organic carbon (AOC) concentration increased within the collection system, it was reduced by chlorination and it increased again in the distribution system. Neither fecal indicators nor pathogens were detected by standard cultivation techniques. Chlorination reduced bacterial diversity and heterotrophic plate counts. Community structures were found to be significantly different before and after chlorination: the diverse communities in wells and the collection system were dominated by chemolithotrophic (e.g., Gallionella and Nitrospira) and oligocarbophilic-heterotrophic bacteria (e.g., Sphingomonas, Sphingopyxis, and Bradyrhizobium). After chlorination in the distribution system, the most characteristic bacterium was related to the facultative methylotrophic Methylocella spp. Communities changed within the distribution system too, Mycobacterium spp. or Sphingopyxis spp. became predominant in certain samples.
authors.affiliation: Department of Microbiology, Eötvös Loránd University, Budapest, Hungary.
authors.forename: Zalán G
authors.initials: ZG
authors.lastname: Homonnay
authors.forename: György
authors.initials: G
authors.lastname: Török
authors.forename: Judit
authors.initials: J
authors.lastname: Makk
authors.forename: Anikó
authors.initials: A
authors.lastname: Brumbauer
authors.forename: Eva
authors.initials: E
authors.lastname: Major
authors.forename: Károly
authors.initials: K
authors.lastname: Márialigeti
authors.forename: Erika
authors.initials: E
authors.lastname: Tóth
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D015373:Bacterial Typing Techniques; D002713:Chlorine / Q000494:pharmacology*; D060766:Drinking Water / Q000382:microbiology*; D054879:Halogenation; D006814:Hungary; D059013:Microbial Consortia / Q000187:drug effects / Q000235:genetics*; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D060766:Drinking Water; D002713:Chlorine
keywords: Bank filtration; Clone library analysis; Cultivation; Drinking water; Terminal restriction fragment length polymorphism (T-RFLP)