Even in Michigan surrounded by the Great Lakes, total groundwater usage is about 700 million gallons per day. In the U.S., groundwater withdrawal for public supply accounts for approximately 39% of the total usage. population gets its drinking water from groundwater. Legionella pneumophila is the cause of most drinking water disease outbreaks in contrast to other water-related pathogens in the U.S.Ī large percentage of the U.S. Ĭurrently, in the United States (U.S.), the incidence rate of Legionnaires’ Disease is increasing with an annual rate of 550%, corresponding to a range of 0.4 to 2.2 reported cases per 100,000 population from 2000 to 2017. longbeachae while other species such as L. Legionella pneumophila accounts for more than 90% of Legionnaires’ Disease cases followed by L. Legionella pneumophila serogroup 1 is the most well-known and studied Legionella species, as it is most often identified as the etiologic agent of Legionnaires’ Disease. Since its discovery, there have been 61 identified Legionella species, of which 28 have been isolated from human specimens associated with disease. Legionella was first described and classified over 40 years ago. pneumophila are also likely amplifying in the system thus, it is important to consider other disease relevant species in the whole water supply system-to subsequently control the growth of pathogenic Legionella in the built water environment. Other pathogenic Legionella species besides L. Based on this study, it is hypothesized that water age in the distribution system and the premise-plumbing system as well as building management plays a major role in the increase of Legionella spp., (23S rRNA) and the diversity of pathogenic species found as seen in the influent, and at the taps in the ERC building-where the building water quality was most comparable to the industrial cooling towers. pneumophila was found in 57% (24/42) of the water samples, followed by L. (23S rRNA) were found in 100% (42/42) of water samples at concentrations ranging from 2.2 to 4.5 Log10 GC/100 mL. (23S rRNA) were significantly higher in the cooling towers and ERC building ( p < 0.05) relative to the reservoir and building Fa (closest to reservoir). ![]() Results demonstrated that gene copies of Legionella spp. The approximate water age (time in the system) for all sample locations are as follows: ~4.5, 3.4, 9.2, 20.8, and 23.2 h (h) for the groundwater to the reservoir influent, reservoir influent to the reservoir effluent, reservoir effluent to building Fa (building names are abbreviated to protect the privacy of site location), building ERC and the cooling towers, respectively. A total of 42–10 L volume water samples were analyzed during this study: 12 from a reservoir (untreated groundwater and treated water storage tanks), 24 from two buildings (influents and taps), and six from cooling towers, all part of the same water system. and five specific Legionella species from source (groundwater) to exposure sites (taps and cooling towers). In this study, droplet digital PCR TM (ddPCR TM) was used to characterize total Legionella spp.
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