title: New endemic Legionella pneumophila serogroup I clones, Ontario, Canada.
abstract: The water-borne pathogen Legionella pneumophila serogroup 1 (Lp1) is the most commonly reported etiologic agent of legionellosis. To examine the genetic diversity, the long-term epidemiology, and the molecular evolution of Lp1 clinical isolates, we conducted sequence-based typing on a collection of clinical isolates representing 3 decades of culture-confirmed legionellosis in Ontario, Canada. Analysis showed that the population of Lp1 in Ontario is highly diverse and combines lineages identified worldwide with local strains. Identical types were identified in sporadic and outbreak-associated strains. In the past 15 years, the incidence of some lineages distributed worldwide has tended to decrease, and local endemic clones and lineages have emerged. Comparative geographic distribution analysis suggests that some lineages are specific to eastern North America. These findings have general clinical implications for the study of Lp1 molecular evolution and for the identification of Lp1 circulating strains in North America.
authors.affiliation: Ontario Agency for Health Protection and Promotion, Toronto, Ontario, Canada.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Tijet
authors.forename: Patrick
authors.initials: P
authors.lastname: Tang
authors.forename: Mya
authors.initials: M
authors.lastname: Romilowych
authors.forename: Carla
authors.initials: C
authors.lastname: Duncan
authors.forename: Victoria
authors.initials: V
authors.lastname: Ng
authors.forename: David N
authors.initials: DN
authors.lastname: Fisman
authors.forename: Frances
authors.initials: F
authors.lastname: Jamieson
authors.forename: Donald E
authors.initials: DE
authors.lastname: Low
authors.forename: Cyril
authors.initials: C
authors.lastname: Guyard
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D019353:Endemic Diseases; D019143:Evolution, Molecular; D014644:Genetic Variation; D006801:Humans; D016952:Legionella pneumophila / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D007876:Legionellosis / Q000453:epidemiology* / Q000382:microbiology; D007877:Legionnaires' Disease / Q000453:epidemiology* / Q000382:microbiology; D017720:Molecular Epidemiology; D009864:Ontario / Q000453:epidemiology; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012703:Serotyping
chemical_list: D004269:DNA, Bacterial