BACKGROUND: Healthcare-associated cases of legionellosis can fatally impact many patients or residents due to the vulnerable population who seek care or reside in healthcare facilities. Rapid identification of the disease, investigation to determine the potential source, and prevention of further legionellosis cases are essential. In New Jersey, while all legionellosis cases are assessed for various exposures and risk factors, cases suspected of having healthcare setting exposure require more intensive investigation.
METHODS: Single cases of legionellosis are reportable to public health and are investigated by the local health department where the case resides, to confirm symptoms, establish an illness onset date and incubation period, and assess potential inhalation exposures. Confirmed cases who spent the entire incubation period in a healthcare facility (acute care, long-term care, assisted living, etc.), a full epidemiological and environmental investigation is conducted. Investigations from 2010-2015 were summarized and compared over time.
RESULTS: From 2010-2015, approximately 70 of the 1,175 (6%) legionellosis cases in New Jersey were associated with an exposure in 57 healthcare facilities. There was an increase in the proportion of healthcare-associated cases in 2013-2015 (13.7%) when compared to 2010-2012 (5.3%). For 2014-2015, the median age for healthcare-associated cases is 79 years and 70% are male, whereas for community-acquired cases the median age is 60 years and 61% are male. While both healthcare-associated and community-acquired cases of legionellosis occur throughout the year, there is an increase in frequency in summer months. Several cases of legionellosis have involved exposures to numerous facilities during the incubation period, which led to complicated investigations into various locations without a definitive facility association. The potable water system is the primary water exposure for healthcare-associated confirmed cases, which included use in showering, bathing, drinking, ice production, hand-washing, and inappropriate use of tap water in the oxygen concentrating machines or nebulizers. The majority of the healthcare facility investigations have led to full-building environmental assessments and remediation of the potable water system by either superheating or hyperchlorination methods.
CONCLUSIONS: While healthcare-associated legionellosis represents a small proportion of cases of legionellosis in NJ, the number of these cases has increased over the last several years and may be under-detected. Physicians should make sure to test patients with new onset of healthcare-associated pneumonia or respiratory distress for legionellosis. The occurrence of these healthcare-associated cases also highlights the importance of establishing an active preventive maintenance program for the potable water system within a healthcare facility given the immunocompromised population they serve.