title: Novel Chlamydiales strains isolated from a water treatment plant.
abstract: Chlamydiae are obligate intracellular bacteria infecting free-living amoebae, vertebrates and some invertebrates. Novel members are regularly discovered, and there is accumulating evidence supporting a very important diversity of chlamydiae in the environment. In this study, we investigated the presence of chlamydiae in a drinking water treatment plant. Samples were used to inoculate Acanthamoeba monolayers (Acanthamoeba co-culture), and to recover autochthonous amoebae onto non-nutritive agar. Chlamydiae were searched for by a pan-chlamydia 16S rRNA gene PCR from both Acanthamoeba co-cultures and autochthonous amoebae, and phylotypes determined by 16S rRNA gene sequencing. Autochthonous amoebae also were identified by 18S rRNA gene amplification and sequencing. From a total of 79 samples, we recovered eight chlamydial strains by Acanthamoeba co-culture, but only one of 28 amoebae harboured a chlamydia. Sequencing results and phylogenetic analysis showed our strains belonging to four distinct chlamydial lineages. Four strains, including the strain recovered within its natural host, belonged to the Parachlamydiaceae; two closely related strains belonged to the Criblamydiaceae; two distinct strains clustered with Rhabdochlamydia spp.; one strain clustered only with uncultured environmental clones. Our results confirmed the usefulness of amoeba co-culture to recover novel chlamydial strains from complex samples and demonstrated the huge diversity of chlamydiae in the environment, by identifying several new species including one representing the first strain of a new family.
authors.affiliation: Center for Research on Intracellular Bacteria, Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne, Bugnon 46, 1011 Lausanne, Switzerland.
authors.forename: Daniele
authors.initials: D
authors.lastname: Corsaro
authors.forename: Veronica
authors.initials: V
authors.lastname: Feroldi
authors.forename: Gemma
authors.initials: G
authors.lastname: Saucedo
authors.forename: Ferran
authors.initials: F
authors.lastname: Ribas
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Loret
authors.forename: Gilbert
authors.initials: G
authors.lastname: Greub
mesh_terms: D000656:Amoeba / Q000235:genetics / Q000382:microbiology; D000818:Animals; D002695:Chlamydiales / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D016000:Cluster Analysis; D018920:Coculture Techniques; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D016053:RNA, Protozoan / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D016053:RNA, Protozoan; D012336:RNA, Ribosomal, 16S; D012337:RNA, Ribosomal, 18S