More than 10 Years of Unrecognized Nosocomial Transmission of Legionnaires' Disease among Transplant Patients

Abstract

Legionella can colonize hospital potable water systems for long periods of time, resulting in an ongoing risk for patients, especially those who are immunocompromised. In this hospital, nosocomial transmission possibly occurred for more than 17 years and was interrupted in 1996, after a sudden increase in incidence led to its recognition. Hospitals specializing in the care of immunocompromised patients (eg, transplant centers) should prioritize surveillance for cases of legionnaires' disease. Aggressive control measures can interrupt transmission of this disease successfully.

Guidelines for Preventing Infectious Complications among Hematopoietic Cell Transplantation Recipients: A Global Perspective

“…HCT physicians should always include Legionnaires' disease (LD) in the differential diagnosis of pneumonia among HCT recipients (AIII) [531,534]. Legionella outbreaks have occurred on transplant wards [615][616][617]. Appropriate tests to confirm LD include culture of sputum, BAL, and tissue specimens; testing BAL specimens for Legionella by direct fluorescent antibody; and testing for Legionella pneumophila serogroup 1 antigen in urine.…”

“…Appropriate tests to confirm LD include culture of sputum, BAL, and tissue specimens; testing BAL specimens for Legionella by direct fluorescent antibody; and testing for Legionella pneumophila serogroup 1 antigen in urine. However, several of the Legionella outbreaks in immunocompromised patients described in the literature were because of species other than L. pneumophila serogroup 1 species, and therefore would not have been detected by the urine antigen assay [615][616][617]. Currently, sufficient evidence is lacking to make recommendations regarding Legionella PCR testing.…”

“…Thus, laboratory-confirmed legionellosis that occurs in a patient who has been hospitalized continuously for $10 days before the onset of illness is regarded as a definite case of nosocomial LD, and a laboratory-confirmed infection that occurs 2 to 9 days after hospital admission is a possible case of nosocomial LD [531,534]. When a definite or possible case of laboratory-confirmed nosocomial LD [615,618] is identified in a person who was in the inpatient HCT center during all or part of the 2 to 10 days before illness onset, or if 2 or more cases of laboratory-confirmed LD occur among patients who had visited an outpatient HCT center, the case(s) should be reported to the local or state health department if the disease is reportable in that state or country or if assistance is needed (AIII) [531,534]. Additionally, in consultation with the hospital infection control team, a thorough epidemiologic and environmental investigation should be conducted to determine the likely environmental source(s) of Legionella species (eg, showers, tap water faucets, cooling towers, and hot water tanks) (AI) [531,534].…”

Current and Emerging Legionella Diagnostics for Laboratory and Outbreak Investigations

“…In addition, case-fatality rates for LD are higher among older males and the immunosuppressed (121). In the first half of 1996, a cluster of health care-associated LD cases was identified at a Southwestern U.S. regional transplant center (529,530). An initial in-house investigation and attempted remediation were unsuccessful in iden-tifying and controlling the problem, and by summer, the CDC was requested to assist state and local officials.…”

“…The problem of long-term colonization in anthropogenic water systems has arisen many times in environmental assessments, retrospective studies (183,(562)(563)(564)(565), and outbreak investigations (75,92,530,(566)(567)(568)(569)(570)(571). As illustrated in one recent outbreak report (75), ϳ35 cases of LD in condominium residents were discovered over 9 years due to the mistaken belief that low-level potable water contamination did not pose a significant disease threat; seemingly arbitrary "action levels" for remediation laid out by facility managers and defined by bacterial concentration thresholds resulted in recurrent and prolonged transmission and disease.…”