title: Environmental factors shaping cultured free-living amoebae and their associated bacterial community within drinking water network.
abstract: Free-living amoebae (FLA) constitute an important part of eukaryotic populations colonising drinking water networks. However, little is known about the factors influencing their ecology in such environments. Because of their status as reservoir of potentially pathogenic bacteria, understanding environmental factors impacting FLA populations and their associated bacterial community is crucial. Through sampling of a large drinking water network, the diversity of cultivable FLA and their bacterial community were investigated by an amplicon sequencing approach, and their correlation with physicochemical parameters was studied. While FLA ubiquitously colonised the water network all year long, significant changes in population composition were observed. These changes were partially explained by several environmental parameters, namely water origin, temperature, pH and chlorine concentration. The characterisation of FLA associated bacterial community reflected a diverse but rather stable consortium composed of nearly 1400 OTUs. The definition of a core community highlighted the predominance of only few genera, majorly dominated by Pseudomonas and Stenotrophomonas. Co-occurrence analysis also showed significant patterns of FLA-bacteria association, and allowed uncovering potentially new FLA - bacteria interactions. From our knowledge, this study is the first that combines a large sampling scheme with high-throughput identification of FLA together with associated bacteria, along with their influencing environmental parameters. Our results demonstrate the importance of physicochemical parameters in the ecology of FLA and their bacterial community in water networks.
authors.affiliation: Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, France; Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, 94200 Ivry sur Seine, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Delafont
authors.affiliation: Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Bouchon
authors.affiliation: Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipes Microbiologie de l'Eau & Ecologie, Evolution, Symbiose, France.
authors.forename: Yann
authors.initials: Y
authors.lastname: Héchard
authors.affiliation: Eau de Paris, Direction de la Recherche et du Développement pour la Qualité de l'Eau, R&D Biologie, 33, Avenue Jean Jaurès, 94200 Ivry sur Seine, France. Electronic address: laurent.moulin@eaudeparis.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Moulin
mesh_terms: D000656:Amoeba; D001419:Bacteria; D060766:Drinking Water / Q000382:microbiology*; D004463:Ecology; D056890:Eukaryota
chemical_list: D060766:Drinking Water
keywords: Amoebae; Bacteria; Co-occurrences; Drinking water; Environment