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Performance of bacterial and mitochondrial qPCR source tracking methods: A European multi-center study
Sílvia Monteiro1, Bernardino Machado-Moreira2, Rita Linke3
1Laboratório de Análises, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal; CERIS, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001, Lisboa, Portugal; Departamento de Engenharia e Ciências Nucleares, Instituto Superior Técnico, Universidade de Lisboa, EN. 10, 2695-066, Bobadela, Portugal.
This study evaluated nine quantitative PCR (qPCR) assays for fecal source tracking (ST) across Europe. Results show these molecular assays offer high sensitivity and specificity for identifying human and animal fecal contamination in water.
Area of Science:
- Environmental microbiology
- Molecular diagnostics
- Water quality assessment
Background:
- Quantitative PCR (qPCR) assays are crucial for fecal source tracking (ST), but their specificity and sensitivity vary.
- Previous ST studies were often regional and used limited assays, hindering precise contamination source identification.
- A multicenter European study is needed to comprehensively compare bacterial and mitochondrial qPCR assays for ST.
Purpose of the Study:
- To evaluate the efficiency and performance of nine established qPCR assays for human, cow/ruminant, pig, and poultry fecal contamination.
- To compare bacterial and mitochondrial molecular assays for their accuracy in source tracking.
- To assess the geographical applicability of ST qPCR markers in diverse environmental samples.
Main Methods:
- A multicenter study involving five European countries analyzed 77 samples, including animal fecal slurry and human/non-human wastewater.
- Seven fecal indicators were measured using both culture-based methods and nine distinct qPCR assays.
- Assays targeted human-, cow/ruminant-, pig-, and poultry-associated fecal contamination, evaluating sensitivity and specificity.
Main Results:
- Fecal indicators were ubiquitous across samples, detected by both culture and qPCR.
- Most ST qPCR markers demonstrated high quantitative sensitivity (73%-100%) and specificity (53%-97%), indicating broad geographical utility.
- Animal-associated markers were generally detected at higher concentrations than human-associated markers, with Bacteroides spp. and mitochondrial DNA qPCR markers showing strong performance.
Conclusions:
- Bacterial and mitochondrial qPCR assays are effective tools for advanced pollution monitoring in aquatic environments.
- These ST markers support the development of targeted water quality management strategies.
- The study highlights the potential for improved discrimination of fecal contamination sources using molecular methods.
