Microbial Indicators and Their Use for Monitoring Drinking Water Quality—A Review

Abstract

An increase in the incidence of water-borne human diseases, such as diarrhea and emesis, has occurred due to drinking polluted water. These water-borne diseases can lead to death, if correct treatment is not provided. Assuring that drinking water quality is safe has been a crucial challenge for public health. Water contamination with pathogenic microorganisms represents a seriously increased threat to human health. Currently, different microorganisms are being used as the primary indicator to assess water quality total coliform and Escherichia coli (E. coli) being the most common. However, increasing the occurrence of water-borne illness from sources deemed safe by the microbial standard criteria has raised the question—are these microbial indicators reliable and sensitive enough to ensure water quality? Currently, other microorganisms including bacteria, enteric virus, and protozoa are being tested and used in different countries as alternative indicators to monitor water quality. It is necessary to study the diverse water quality indicator systems used throughout the world and their efficacy with the present water quality. Although water quality standards suggest adding pathogenic microorganisms such as enteric virus as an indicator, China only uses pathogenic E. coli, protozoa. Pin-pointing the shortage of the current water quality indicator system in China is crucial in order to propose changes in future water quality indicator systems.

Biofunctionalization of Cork with Moringa oleifera Seeds and Use of PMA Staining and qPCR to Detect Viability of Escherichia coli

“…Pathogenic bacteria from expanding human settlements can be an important cause of disease, giving rise to global health concerns, such as diarrhoea, episodes associated with a lack of access to safe drinking water and inadequate sanitation, which result in millions of deaths annually [1]. Escherichia coli and intestinal Enterococci are among the main bacteria used as faecal indicators and can be found frequently in irrigation and drinking water systems, groundwater, water reservoirs and rivers [2][3][4]. These water supplies, found to be contaminated with faecal bacteria due to untreated or inadequately treated water and thus considered to be unfit for human consumption, are of rising concern [5,6].…”

Coliform bacteria in San Pedro Lake, western Mexico

“…Total coliform (TC) and fecal coliform (FC) densities are typically used as fecal pollution indicators because they are invariably present in the feces of humans and other warm‐blooded animals in large numbers, can be easily detected in highly diluted bodies of water (Barraza, 2018; Barrera, Fernández, Wong‐Chang, & Romero, 2013; Bhumbla, Majumdar, Jain, & Dalal, 2020), and can be used as a microbial surrogate for water quality monitoring (Motlagh & Yang, 2019). Therefore, the presence of these microorganisms is used to evaluate and monitor water quality (Wen et al, 2020). In Mexico, the National Water Commission (CONAGUA) uses FCs to classify water quality from excellent to heavily contaminated (CONAGUA, 2015).…”

Bacterial Contamination at Whiteleg Shrimp (Litopeanaeus vannamei) in Aquaculture

“…E. coli and Salmonella bacteria usually originate in animals and humans. If these types of bacteria are found in the waters, this indicates pollution occurs in thewaters, so this bacteria can be used as an indicator of contamination (Frick et al, 2020;Wen et al, 2020). Cho et al (2020) and Wen et al (2020) stated E. coli and Salmonella are the indicator organisms of fecal contamination that are not derived from the aquatic environment (Cho et al, 2020;Wen et al, 2020).…”