[Community outbreak of pneumonia due to Legionella pneumophila: importance of monitoring hospital cooling towers]. / 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.

Brote comunitario de neumonía por Legionella pneumophila: importancia del control de las torres de refrigeración en los centros sanitarios / Outbreak of legionnaires’ disease linked to hospital cooling towers

Objetivo. Describir la investigación de un brote comunitario de legionelosis originado en unas torres de refrigeración de un hospital. Pacientes y métodos. Pacientes diagnosticados de neumonía por Legionella pneumophila serogrupo 1 (L. pneumophila) asociados con el barrio de Vallcarca (Barcelona) en agosto de 2004. La exposición se determinó mediante una encuesta estandarizada. Se llevó a cabo una investigación ambiental para identificar el foco emisor. Se realizó un análisis descriptivo con cálculo de tasas de incidencia, así como el estudio molecular para documentar la identidad genética entre las cepas humanas y ambientales aisladas. Resultados. Se detectaron 33 casos de neumonía por L. pneumophila. La edad media fue de 68 años y el 70% de los afectados eran varones. La tasa de incidencia en los mayores de 65 años residentes a una distancia menor o igual a 200 m del foco emisor fue de 888,9 casos/100.000 habitantes. La tasa de letalidad fue del 6%. Se identificaron cuatro torres de refrigeración estacionales no censadas ubicadas en un centro sanitario. En todas se aisló L. pneumophila y al menos una colonia de cada instalación compartía perfil genético con las cepas aisladas en los pacientes. Conclusiones. Se muestra la asociación de un brote comunitario de neumonía por Legionella y las torres de refrigeración de un centro sanitario que no estaban censadas. Se remarca la necesidad de notificar cualquier instalación de riesgo y de realizar un seguimiento para asegurar que cumplen con la legislación (AU)

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 (AU)