Selection of a diagnostic tool for microbial water quality monitoring and management of faecal contamination of water sources in rural communities

Abstract

The aim of the current study was to evaluate, validate and select microbial water quality monitoring tools to establish their suitability and feasibility for use in rural communities. The monitoring of water quality was performed at three different levels: i) basic level focusing on sanitary inspection and hydrogen sulphide (H2S) test; ii) intermediate level via enumeration of faecal indicator bacteria (faecal coliforms, Escherichia coli, Enterococcus spp. and Clostridium perfringens); and iii) advanced level based on qPCR detecting host-associated genetic markers (BacHum, BacCow, Cytb, Pig-2-Bac, and BacCan) and pathogens (Vibrio cholerae, Escherichia coli O157:H7, and Shiga toxin-producing Escherichia coli). A positive correlation was recorded between sanitary risk and faecal coliforms (r = 0.613 and p < 0.002), E. coli (r = 0.589 and p < 0.003), and Enterococcus spp. (r = 0.625 and p < 0.003). The H2S test showed positive correlations with sanitary risk score (r = 0.623; p < 0.003), faecal coliforms (r = 0.809; p < 0.001), E. coli (r = 0.779; p < 0.001) and Enterococcus spp. (r = 0.799; p < 0.001). Similar correlation patterns were also found with advanced techniques used for detecting host-associated genetic markers, excepted between Clostridium perfringens, and Pig-2-Bac (pig), BacCan (dog), and V. cholerae. The H2S test and sanitary inspections are therefore suitable and cost-effective tools to capacitate rural areas at household level for the monitoring of faecal contamination and management of water sources.