BACKGROUND: Legionella, the bacterium causing Legionnaires’ disease (LD), a severe pneumonia, can be transmitted through a building’s water system. However, transmission is preventable through environmental infection control. Healthcare facilities with vulnerable populations pose known risks for Legionella transmission, but the burden of healthcare-associated LD is unknown. We used national reporting data to describe the burden and outcomes of potentially healthcare-associated LD.
METHODS: We analyzed data from 12 states that included comprehensive exposure data for ≥95% of legionellosis cases reported to CDC in 2014. We defined confirmed cases as those meeting Council of State and Territorial Epidemiologists criteria. Potentially healthcare-associated cases reported inpatient, outpatient, visitor/volunteer, or work-related exposures to healthcare facilities during some portion of the ten days before illness onset. Case-fatality rates (CFRs) were compared using Fisher’s exact test.
RESULTS: We identified 1,181 confirmed cases (1.8/100,000 population), of which 243 (20.6%) were potentially healthcare-associated. CFR was higher for potentially healthcare-associated cases (10.3%) than for non-healthcare-associated cases (5.3%; P < .01). Among potentially healthcare-associated cases, 112 (46.1%) reported inpatient exposures (CFR 14.3%); 77 (31.7%) reported outpatient visits (CFR 9.1%); 25 (10.3%) reported visitor/volunteer visits (CFR 0.0%); and 16 (6.6%) reported employee visits (CFR 0.0%). Ten (4.1%) reported >1 type of exposure (CFR 10.0%).
CONCLUSIONS: LD in those with healthcare exposures accounted for a substantial proportion of the total reported LD burden. Among persons with potentially healthcare-associated LD, patients experienced higher mortality than non-patients. New guidance for water management practices is available to reduce the risk of Legionella transmission in buildings with complex water systems including healthcare facilities.