Most of the public health agencies and water management program guidance documents that are focused on the risk of Legionella, do not consider their host, Naegleria, and Acanthamoeba spp.
Free-living amoebae are ubiquitous protozoa that have been found in various natural and engineered water systems, such as surface water, groundwater, drinking water supply systems, hot springs, and cooling towers. Similar to free-living amoebae, Legionella spp. are also found in natural water bodies (surface water, groundwater, and hot springs) and human-made systems (swimming pools, drinking water supply systems, and cooling towers). In their natural and engineered environments, free-living amoebae serve as a host, reservoir, and vehicle of pathogenic bacteria, including Legionella species.
Researchers at Michigan State investigated raw and treated drinking water as well as cooling tower water, notorious for harboring the bacteria and its host protozoa. Using Large Volume Ultrafilter Concentration on 10 Liter water samples, and paired with instant Wet Foam Elution™ (EasyElute™) of the ultrafilters, they were able to improve the sample prep workflow as well as improve the sensitivity of their assays.
Conclusion summary -
Testing showed that N. fowleri significantly cooccurred with three pathogenic Legionella spp. (L. pneumophila, L. micdadei, and L. bozemanii) in a drinking water supply system and cooling towers. Thus, by examining large volume (10 L), water ultrafiltrate concentrates from the groundwater source to exposure sites (taps and cooling towers) using ddPCR allowed for the detection of individual-specific Legionella and N. fowleri. Most importantly, widespread occurrence of N. fowleri and Legionella species in the taps and cooling towers indicates an important health concern.
Read the Publication -
Cooccurrence of Five Pathogenic Legionella spp. and Two Free-Living Amoebae Species in a Complete Drinking Water System and Cooling Towers – Logan-Jackson, et al.
Pathogens 2021
