Legionnaires' disease in a newly constructed long-term care facility.

Objectives: To determine whether a newly-constructed long-term care facility would become colonized with Legionella and whether Legionnaires' disease would occur in residents of this new facility.
Design: Prospective environmental surveillance of the hospital's water distribution system for the presence of Legionella pneumophila during construction. Utilization of diagnostic tests for Legionnaires' disease in cases of nosocomial pneumonia.
Setting: The Pittsburgh VA Health Care System, Aspinwall Division, a two-building 400-bed complex.
Participants: Six patients who acquired Legionnaires' disease while in the facility.
Intervention: Installation of copper-silver ionization systems.
Measurements: Isolation of L. pneumophila from potable water and the occurrence of Legionnaires' disease.
Results: L. pneumophila serogroup 1 was recovered from the water distribution system within 1 month of operation; 74% (61/82) of distal sites were positive during construction. In the first 2 years of occupancy, six cases of legionellosis were diagnosed. Both clinical isolates of L. pneumophila were identical to environmental isolates by pulsed field gel electrophoresis (PFGE). Copper-silver ionization systems were installed to control Legionella in the water system.
Conclusions: We conclude that long-term care residents are at risk for acquiring nosocomial Legionnaires' disease in the presence of a colonized water system, even in a newly constructed building.