New strategies for the enumeration of enteric pathogens in water

Abstract

Water quality standards for drinking water and recreational waters have long been based on the enumeration of faecal coliforms in the various water supplies, with 0 CFU Escherichia coli/100 ml for drinking water and <126 CFU generic E. coli/100 ml for recreational waters. Irrigation water will soon undergo the same scrutiny in the United States. For over 50 years the most probable number method has been used by laboratories to estimate the level of viable bacteria in a sample, but this method is labour intensive and slow, especially if large numbers of samples need to be tested. In this review, we describe some recent innovations in methods to enumerate enteric pathogens in water. These methods are based on different reasoning schemes that can be categorized as biosensors and nucleic acid-based methods. All the methods described here used natural water sources. Several were also used to survey the bacterial levels in naturally contaminated samples. The different methods vary in their limits of detection, ease of use, and potential portability. Some combine very good limits of detection with the ability to overcome technical challenges; however, there is considerable room for improvement, as none of the methods are without shortcomings.

Discovery of large molecules as new biomarkers in wastewater using environmental proteomics and suitable polymer probes

“…Species from the phylum Proteobacteria were the more abundant in the 3 sites, but Monitoring of enteric pathogens in water, such as Escherichia and Salmonella, is of interest for human health (Gorski et al, 2019). Together with other species of Firmicutes and Bacteroidetes, which are the dominant phyla in the human gut, they can reflect the level of water fecal contamination.…”

High‐throughput molecular analyses of microbiomes as a tool to monitor the wellbeing of aquatic environments

“…In fact, the quality of drinking water is routinely monitored by the determination of enterobacteria (Caruso, 2013;Jang et al, 2017;Gorski et al, 2019). Traditionally, bacteria levels in such waters have been quantified by the cultivation of samples under laboratory conditions or even microscopic counting, but these methodologies, although sensitive, are relative slow and do not allow for a quick detection and, thus, an immediate response to remediate the pollution events (Storey et al, 2011;Caruso, 2013;Gorski et al, 2019). Several bioassays to measure pollution have been developed based on the changes in physicochemical parameters triggered by one or multiple toxic chemicals.…”

“…Use of microbial parameters to monitor environmental pollution started in the 80s, mainly to analyse the quality of drinking water, as most aquatic pollution was produced by unprocessed faecal discharges or uncontrolled effluents from WWTP (Bae and Park, 2014). In fact, the quality of drinking water is routinely monitored by the determination of enterobacteria (Caruso, 2013;Jang et al, 2017;Gorski et al, 2019). Traditionally, bacteria levels in such waters have been quantified by the cultivation of samples under laboratory conditions or even microscopic counting, but these methodologies, although sensitive, are relative slow and do not allow for a quick detection and, thus, an immediate response to remediate the pollution events (Storey et al, 2011;Caruso, 2013;Gorski et al, 2019).…”

“…Wholecell biosensors devices have been designed to detect the presence of biological analytes, including pollutants, using living organisms that respond in some measurable and predictable way. Although these devices are being used widely to determine aquatic pollution, they are not pollutant-specific, and their determinations can be biased by the presence of growth inhibitory chemicals in the samples or by the microbial biosensor profile (OECD, 2010;Hassan et al, 2016;Gorski et al, 2019). Recent methodological innovations to enumerate enteric pathogens in water include sensitive nucleic acid-based methods, being quantitative PCR (qPCR) the most often used.…”

“…Nevertheless, these methodologies also have their drawbacks, the main one being the detection of false positives due to the persistence of dead cells or naked DNA in the water samples. Finally, metagenomics has significant potential for bacterial quantification, although the application of this technique for water testing is still under development (Gorski et al, 2019).…”