Quantitative Assessment of First Nations Drinking Water Distribution Systems for Detection and Prevalence of Thermophilic Species.

Water is considered a major route for transmitting human-associated pathogens. Although microbial water quality indicators are used to test for the presence of waterborne pathogens in drinking water, the two are poorly correlated. The current study investigates the prevalence of thermophilic DNA markers specific for spp. (. and ) in source water and throughout the water distribution systems of two First Nations communities in Manitoba, Canada. A total of 220 water samples were collected from various points of the drinking water distribution system (DWDS) between 2016 and 2018. Target spp. were always (100%) detected in a home with a fiberglass (CF) cistern, as well as the community standpipe (SP). The target bacteria were also frequently detected in treated water at the Water Treatment Plant (WTP) (78%), homes with polyethylene (CP) (60%) and concrete (CC) (58%) cisterns, homes with piped (P) water (43%) and water truck (T) samples (20%), with a maximum concentration of 1.9 × 10 cells 100 mL () and 5.6 × 10 cells 100 mL (). Similarly, target bacteria were detected in 68% of the source water samples with a maximum concentration of 4.9 × 10 cells 100 mL () and 8.4 × 10 cells 100 mL (). Neither target spp. was significantly associated with free and total chlorine concentrations in water. The study results indicate that there is an immediate need to monitor spp. in small communities of Canada and, particularly, to improve the DWDS in First Nations communities to minimize the risk of infection from drinking water sources. Further research is warranted in improving/developing processes and technologies to eliminate microbial contaminants from water.