Mark Holodniy
Publication Details
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Role of Environmental Surveillance in Dtermining the Risk of Hospital-Acquired Legionellosis: A National Surveillance Study With Clinical Correlations
Infection Control and Hospital Epidemiology. 2007; (7): 818-824
Objective: Hospital-acquired Legionella pneumonia has a fatality rate of 28% and the source is the water distribution system. Two prevention strategies have been advocated. One approach to prevention is clinical surveillance for disease without routine environmental monitoring. Another approach recommends environmental monitoring even in the absence of known cases of Legionella pneumonia. We determined the Legionella colonization status of water systems hospitals to establish whether the results of environmental surveillance correlated with discovery of disease. None of these hospitals had previously experienced endemic hospital-acquired Legionella pneumonia. Design: Cohort study. Setting: 20 US hospital in 13 states. Interventions: Hospitals performed clinical and environmental surveillance for Legionella from 2000 through 2002. All specimens were shipped to the Special Pathogens Laboratory, VA Pittsburgh Medical Center. Results: L. pneumophila and L. anisa were isolated from 70% (14/20) of hospital water systems. 29% (198/676) of environmental samples were positive for Legionella spp. High-level colonization of the water system (> 30% of distal outlets were positive for L. pneumophila) was demonstrated in 43% (6/14) of the hospitals. L. pneumophila, serogroup 1 (L. pneumophila-1) was detected in 5/6 of these hospitals, while 1/6 hospitals was colonized with L. pneumophila serogroup 5. 633 patients were evaluated for Legionella pneumonia from 60% (12/20) of hospitals: 377 by urinary antigen and 577 by sputum culture. Hospital-acquired Legionella pneumonia was identified in 4 hospitals, and only in hospitals with L. pneumophila-1 in >30% of distal outlets. No cases of disease due to other serogroups or species (L. anisa) were identified. Conclusion:Environmental monitoring followed by clinical surveillance was successful in uncovering previously unrecognized cases of hospital-acquired Legionella pneumonia.
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