Molecular typing of a Legionella pneumophila outbreak in Ontario, Canada

Matthew W. Gilmour, Kathryn Bernard, Dobryan M. Tracz, Adam B. Olson, Cindi R. Corbett, Tamara Burdz, Betty Ng, Deborah Wiebe, George Broukhanski, Peter Boleszczuk, Patrick Tang, Frances Jamieson, Gary Van Domselaar, Francis A. Plummer, Jody D. Berry

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


An outbreak of Legionnaires' disease at a long-term care facility in Ontario, Canada from September to October 2005 resulted in the death of 23 residents and the illness of 112 other people. In response, molecular methods were developed to detect Legionella pneumophila in clinical lung samples and to subtype isolates from clinical and environmental samples. The targeted genetic loci included Legionella-specific virulence determinants (mip, icmO, sidA and lidA) and core bacterial determinants (ftsZ, trpS and dnaX). An established amplified fragment length polymorphism typing method provided the first indication of genetic relatedness between strains recovered from clinical samples and strains cultured from environmental samples taken from the outbreak site. These associations were verified using the European Working Group for Legionella Infections sequence-based typing protocol targeting the flaA, pilE, asd, mip, mompS and proA loci. These molecular typing methods confirmed the outbreak source as a contaminated air conditioning cooling tower.

Original languageEnglish
Pages (from-to)336-341
Number of pages6
JournalJournal of Medical Microbiology
Issue number3
Publication statusPublished - Mar 2007

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