Development of a qPCR assay for the detection of naturalized wastewater E. coli strains

• Published in: Journal of water and health 2022-04, Vol.20 (4), p.727-736
• Main Authors: Zhi, Shuai, Banting, Graham, Neumann, Norman F
• Format: Article
• Language: English
• Subjects: Animals; Assaying; Bacteroides; Biomarkers; Cloning; Contamination; Detection; DNA; E coli; Effluent treatment; Effluents; Escherichia coli - genetics; Fecal coliforms; Feces; Genomes; Heat resistance; Human wastes; Municipal wastes; Municipal wastewater; naturalized; Nucleotide sequence; PCR; Plasmids; Polymerase chain reaction; Public health; qpcr; Sewage; Sewage - analysis; Sewage disposal; Specificity; Stormwater; Surface water; Waste Water - analysis; wastewater contamination; Wastewater pollution; Wastewater treatment; Water pollution; Water Purification; Water quality
• ISSN: 1477-8920; 1996-7829
• DOI: 10.2166/wh.2022.014

We recently demonstrated the presence of naturalized populations of Escherichia coli in municipal sewage. We wanted to develop a quantitative polymerase chain reaction (qPCR) assay targeting the uspC-IS30-flhDC marker of naturalized wastewater E. coli and assess the prevalence of these naturalized strains in wastewater. The limit of detection for the qPCR assay was 3.0 × 10 ng of plasmid DNA template with 100% specificity. This strain was detected throughout the wastewater treatment process, including treated effluents. We evaluated the potential of this marker for detecting municipal sewage/wastewater contamination in water by comparing it to other human and animal markers of fecal pollution. Strong correlations were observed between the uspC-IS30-flhDC marker and the human fecal markers Bacteroides HF183 and HumM2, but not animal fecal markers, in surface and stormwater samples. The uspC-IS30-flhDC marker appears to be a potential E. coli-based marker for human wastewater contamination.