Epidemiology and Infection

Original Papers

Pneumonia and other respiratory infections

Outbreak of Legionnaires' disease associated with a supermarket mist machine

I. BARRABEIGa1 c1, A. ROVIRAa1, M. GARCIAa2a3, J. M. OLIVAa1, A. VILAMALAa4, M. D. FERRERa5, M. SABRIÀa2a3 and A. DOMÍNGUEZa6a7

a1 Epidemiological Surveillance Unit of Costa Ponent, Department of Health, Generalitat of Catalonia, Barcelona, Spain

a2 Study Group of Legionnaires' Disease, Hospital Germans Trias i Pujol of Badalona, Barcelona, Spain

a3 CIBER Enfermedades Respiratorias (CIBERES), Instituto Carlos III, Madrid, Spain

a4 Department of Microbiology, Catalan Institute of Health, Vilafranca del Penedès, Barcelona, Spain

a5 Laboratory Public Health Agency of Barcelona, Spain

a6 Department of Public Health, School of Medicine, University of Barcelona, Spain

a7 CIBER Epidemiologia y Salud Pública (CIBERESP), Instituto Carlos III, Madrid, Spain

SUMMARY

An outbreak of Legionnaires' disease affected 12 customers of a supermarket in a town in Catalonia, Spain, between August and November 2006. An epidemiological and environmental investigation was undertaken. Preliminary investigation showed that all patients had visited the same supermarket in this town where a mist machine was found in the fish section. Water samples were collected from the machine and from the supermarket's water distribution system when high-risk samples were excluded. Environmental samples from the mist machine and clinical samples from two patients tested positive for L. pneumophila serogroup 1 and had the same molecular pattern. The PFGE pattern detected in the clinical and mist-machine isolates had never previously been identified in Catalonia prior to the outbreak and has not been identified since. Four days after turning off the machine, new cases ceased appearing. Molecular study supports the hypothesis that the mist machine from the fish section of the supermarket was the source of infection. We believe it is essential to include exposure to mist machines in any legionellosis epidemiological survey.

(Accepted March 23 2010)

(Online publication April 15 2010)

Correspondence:

c1 Author for correspondence: I. Barrabeig M.D., Epidemiological Surveillance Unit of Costa Ponent, Department of Health, Generalitat de Catalonia, Av. de la Granvia, 8-10, 5th floor, 08902 l'Hospitalet de Llobregat, Barcelona. (Email: ibarrabeig@catsalut.cat)

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