Title: Looking for Legionella – Which Test is Best?
One objective of this presentation is to educate the audience members about the variety of Legionella species (L. pneumophila and others) that are commonly detected in potable and non-potable sources in building water systems and to encourage them to screen for all Legionella species when evaluating building water sources.
Introduction / Description of the Study -- Marjorie Viskup, BS / PathCon Laboratories
Presence of L. pneumophila vs. Legionella species in the study samples -- Deborah Jaeger, MS / PathCon Laboratories
Detection of L. pneumophila vs. Legionella species in different geographic locations within the US -- Kimberly Kirkland, MPH / PathCon Laboratories
Summary / Conclusions -- Kimberly Kirkland, MPH / PathCon Laboratories
Legionnaires’ disease is on the rise and the number of cases has increased more than fivefold since 2000. Legionella bacteria is the leading cause of reported waterborne disease in the U.S. As of 2018, nearly 10,000 cases of Legionnaire’s disease (LD) have been reported in the US, and this number is likely an underestimate. With the median age of Americans increasing and US building and distribution infrastructure aging rapidly, the number of LD cases is rising. Increase in LD cases may also be due to greater surveillance and reporting as well as climate changes.
Although Legionella pneumophila serogroup 1 is most commonly associated with Legionnaires’ disease, more than 61 Legionella species and 3 subspecies have been identified. Of these species, approximately half have also been associated with disease. Detection of Legionella species in a water system likely indicates that conditions are suitable for L. pneumophila to also grow and amplify within that system. Testing methods are needed that reliably detect L. pneumophila as well as other Legionella species in building water systems to comprehensively evaluate water sources for amplification and to determine risk of exposure to Legionella-contaminated aerosols.
Other Legionella species that have been frequently isolated from patients include L. anisa, L. bozemanii, L. dumoffii, L. feeleii, L. longbeachae and L. micdadei. Most non-pneumophila infections are not detected by current clinical laboratory diagnostic tests (i.e., urine antigen test, which is specific for L. pneumophila serogroup 1) and can go undiagnosed without culturing from a patient specimen.
To date, most research has focused on the occurrence of L. pneumophila in cooling towers and premise plumbing systems. To better understand the types of Legionella prevalent in environmental sources, more data on distribution of L. longbeachae, L. micdadei, L. dumoffi and other pathogenic Legionella species is needed. In this study, water samples from a variety of environmental sources (cooling towers, potable water, hot tubs, decorative water fountains) from various geographic regions of the US were analyzed in the last several years. Samples were collected from water systems in hotels, office buildings and industrial settings, hospitals, cruise ships, and universities. Water samples were analyzed using the Legionella culture method (based on CDC methods and the ISO 11731:2017 standard). For this presentation, we are comparing the occurrence of Legionella pneumophila vs. Legionella species in environmental samples, based on sample type and geographic location.
Marjorie Viskup, BS – Microbiologist / Laboratory Group Leader, Legionella – PathCon Laboratories. BIO: Marjorie Viskup has been employed at PathCon Laboratories for 23 years. She currently serves as a Group Leader in the Legionella laboratory and provides customer technical support, prepares customer reports, summarizes project data for specific customer needs, and oversees training of new Legionella laboratory technicians and analysts. Over the years, Marjorie has supported customers in routine and outbreak investigations of Legionnaires’ disease and Legionella risk assessments.
Deborah Jaeger, MS – Director of Quality Assurance – PathCon Laboratories. BIO: Deborah Jaeger has been employed at PathCon Laboratories for 25 years. She currently serves as Director of Quality Assurance. She is responsible for overseeing laboratory quality management, microbiological media production, and PathCon laboratory accreditations. She has consulted with customers on planning indoor environmental investigations for bacteria, fungi and Legionella bacteria and interpreting microbiological data. Over the years, she has supported customers with outbreak and routine investigations of Legionnaires' disease as well as Legionella risk assessments. She has been involved in development of PathCon laboratory methods for detection of environmental mycobacteria and Legionella from environmental samples. From 1995-2000, Deborah served on the AIHA (American Industrial Hygiene Association) Environmental Microbiology Laboratory Accreditation Committee to participate in formation of the EMPAT laboratory proficiency testing program for bacteria and fungi as well as the EMLAP accreditation program for environmental microbiology laboratories. She currently volunteers on the AIHA Indoor Environmental Quality Committee Legionella subcommittee (currently updating the AIHA Legionella guidance published in 2015) and the Legionella BoK (Body of Knowledge) Task Force. Deborah earned an MS in Medical Microbiology and a BS in Microbiology from the University of Georgia.
Kimberly Kirkland, MPH – Director of Laboratory Services – PathCon Laboratories. BIO: Kimberly has been employed at PathCon Laboratories for 27 years. She currently serves as Director of Laboratory Services. Kimberly directs all laboratory activities related to the sampling, detection, and analysis of microorganisms from air, water, building materials, and other environmental sources. She coordinates and supervises a multi-talented team of microbiologists and laboratory analysts. Kimberly works with customers to develop sample collection strategies and protocols for microbial investigations and assists in interpretation of microbiological data. She manages the implementation of proactive Legionella monitoring programs for PathCon customers. Kimberly has conducted numerous indoor air quality investigations for microorganisms, including on-site support of Legionnaires’ disease outbreaks and Legionella risk assessments. She earned an MPH from Emory University in Occupational and Environmental Health Sciences and a BS in Environmental Sciences from the University of Georgia.