Bacteria in drinking water sources of a First Nation reserve in Canada

Abstract

Approximately 20% of the 600 First Nations reserves across Canada are under a drinking water advisory, often due to unacceptable levels of bacteria. In this study, we detected fecal bacteria at an alarmingly high frequency in drinking water sources in a fly-in First Nations community, most notably in buckets/drums of homes without running water where Escherichia coli levels ranged from 20 to 62,000 CFU/100mL. The water leaving the water treatment plant was free of E. coli and its free residual chlorine concentration (0.67 mg/L) was within the range typically observed for treated water in Canada. Water samples from taps in homes served by cisterns, and those sampled from the water truck and community standpipe, always showed unacceptable levels of E. coli (1 to 2,100 CFU/100mL) and free residual chlorine concentrations below the 0.2 mg/L required to prevent bacterial regrowth. Samples from taps in homes served by piped water had lower levels of E. coli (0 to 2 CFU/100mL). DNA-and RNA-based 16S rRNA Illumina sequencing demonstrated that piped and cisterns water distribution systems showed an abundance of viable cells of Alphaproteobacteria indicative of biofilm formation in pipes and cisterns. The alpha diversity, based on observed OTUs and three other indices, was lowest in water truck samples that supplied water to the cistern and the low free residual chlorine concentration (0.07 mg/L) and predominance of Betaproteobacteria (63% of viable cells) that were immediately detected after the truck had filled up at the water treatment plant was indicative of contamination by particulate matter. Given these findings, First Nation residents living without running water and relying on inadequate water distribution systems are at higher risk of contracting water-born illnesses. We urge all governments in Canada to expand their investments in supporting and sustaining water as a human right in Canada's First Nations communities. 3 GRAPHICAL ABSTRACT

Escherichia coli Contamination across Multiple Environmental Compartments (Soil, Hands, Drinking Water, and Handwashing Water) in Urban Harare: Correlations and Risk Factors

“…Although the World Health Organization (WHO) standard for drinking water quality is < 1 CFU E. coli /100 mL, E. coli concentrations are frequently reported within the range of 0.9–3.3 log 10 CFU/100 mL E. coli . 11 , 12 , 41 , 42 , 51 – 55 In our study, 70.4% of samples ( N = 100) exceed the WHO standard. Similarly, studies are increasingly highlighting E. coli contamination in the soil of 2.1–5.5 log 10 /g of soil.…”

Investigation of Detection Limits and the Influence of DNA Extraction and Primer Choice on the Observed Microbial Communities in Drinking Water Samples Using 16S rRNA Gene Amplicon Sequencing

“…First, we investigated the influence of two DNA extraction kits commonly used with DW [the PowerWater DNA Isolation Kit (PowerWater) ( Nitzsche et al, 2015 ; Farenhorst et al, 2016 ; Fernando et al, 2016 ) and the FastDNA SPIN Kit for Soil (FastDNA) ( Li et al, 2010 ; Huang et al, 2014 ; Belila et al, 2016 )]. Then we investigated the impact of the choice of primers by using primer-sets targeting the V1-3, V3-4, and the V4 region of the 16S rRNA gene, which all have been used in previous DW studies ( Huang et al, 2014 ; Prest et al, 2014 ; Bautista-de los Santos et al, 2015 ; El-Chakhtoura et al, 2015 ; Gomez-Alvarez et al, 2015 ; Farenhorst et al, 2016 ; Liu et al, 2016 ). Finally, the detection limit of the employed 16S rRNA gene amplicon approach was estimated based on spike-in experiments using Escherichia coli ( E. coli ) cells in concentrations spanning 10 1 –10 6 cells/ml.…”

Analysis of Bacteriological Quality of Domestic Water Sources in Kabale Municipality, Western Uganda

“…The current study findings, however, disagree with [23] who reported that all water samples collected from unprotected water sources had fecal coliforms (FC), and 80% of samples had fecal coliforms ranging from 0.67 to 266.67 CFU/100 ml. A related study by [24] reported high thermotolerant E. coli levels up to 62,000 CFU/100 ml in drinking water sources in Central Gonja District.…”

“…However, some strains can cause human illness. The presence of E. coli in a drinking water sample usually is indicative of recent fecal contamination [24]. E. coli O157: H7 strain is known to cause most outbreaks [21].…”