Brote comunitario de neumonía por Legionella pneumophila: Importancia del control de las torres de refrigeración en los centros sanitarios

OBJECTIVE. Description of an outbreak of legionnaires' disease originating in one of the cooling towers of a hospital. PATIENTS AND METHODS. This study included patients with confirmed pneumonia caused by Legionella pneumophila serogroup 1 and related to the Vallcarca neighborhood of Barcelona (Spain) in August 2004. Exposure was determined by a standardized questionnaire. An environmental investigation was carried out to identify the source of the outbreak. A descriptive analysis including incidence rates estimation was performed, as well as molecular study to document the genetic identity among human and environmental strains. RESULTS. Thirty-three cases of L. pneumophila pneumonia were detected. Median age was 68 years and 70% of the affected patients were men. Incidence rate among residents in less than 200 meters of the source and older than 65 was 888.9 cases/100,000 inhabitants. Lethality rate was 6%. Four seasonal cooling towers that were not registered with the authorities were identified in a health care center. L. pneumophila was isolated from all four and at least one colony in each tower had the same genetic profile as the strains isolated from patients. CONCLUSIONS. An association was demonstrated between a community outbreak of legionellosis and unregistered seasonal cooling towers located in a hospital. All risk facilities should be registered and inspected to ensure that they fulfill current legislation requirements.