title: Clinical and environmental isolates of Legionella pneumophila serogroup 1 cannot be distinguished by sequence analysis of two surface protein genes and three housekeeping genes.
abstract: We used gene sequencing to determine whether clinical (sporadic, epidemic, and endemic) and environmental isolates of Legionella pneumophila serogroup (sg) 1 belong to specific lineages. A total of 178 clinical and environmental L. pneumophila sg 1 isolates, defined by pulsed-field gel electrophoresis and epidemiological data as sporadic, epidemic, or endemic, were analyzed for polymorphisms in five gene fragments. The fragments belonged to three housekeeping genes (coding for aconitase [acn], aspartate-beta-semialdehyde dehydrogenase [asd], and RNA polymerase beta subunit [rpoB]) and two surface protein genes (coding for the macrophage infectivity potentiator [mip] and the major outer membrane protein [mompS]). The phylogenetic tree inferred from sequence polymorphisms of the five genes identified two large clusters, one consisting of 133 poorly differentiated strains and containing two smaller clusters (10 and 2 strains) unrelated to each other and the other consisting of 42 strains. Clinical and environmental isolates could not be distinguished on this basis, and no link between genetic background and epidemiological type was found, suggesting that other factors are responsible for differences in pathogenicity.
authors.affiliation: Centre National de Référence des Legionella, INSERM E-0230, Laboratoire de Bactériologie, Faculté de Médecine Laennec IFR 62, 7 rue Guillaume Paradin, 69372 Lyon cedex 08, France.
authors.forename: Helena
authors.initials: H
authors.lastname: Aurell
authors.forename: Pierre
authors.initials: P
authors.lastname: Farge
authors.forename: Hélène
authors.initials: H
authors.lastname: Meugnier
authors.forename: Manolo
authors.initials: M
authors.lastname: Gouy
authors.forename: Françoise
authors.initials: F
authors.lastname: Forey
authors.forename: Gérard
authors.initials: G
authors.lastname: Lina
authors.forename: François
authors.initials: F
authors.lastname: Vandenesch
authors.forename: Jerome
authors.initials: J
authors.lastname: Etienne
authors.forename: Sophie
authors.initials: S
authors.lastname: Jarraud
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D006761:Hospitals; D006801:Humans; D016952:Legionella pneumophila / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D007877:Legionnaires' Disease / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014871:Water Microbiology; D014881:Water Supply
chemical_list: D001426:Bacterial Proteins