Collection system investigation microbial source tracking (CSI-MST): Applying molecular markers to identify sewer infrastructure failures

Sources of faecal pollution in coastal recreational waters may be identified by analysing different host associated microorganisms or molecular markers. However, the microbial targets are often present at low numbers in moderately impacted waters, and often exhibit significant temporal and spatial variability in waters with fluctuating faecal loads. This patchy occurrence can limit successful detection of relevant targets in microbial source tracking studies. In this study, we explored the possibility for using the blue mussel (Mytilus edulis) as a biosampler for accumulation of faecal bacteria relevant for microbial source tracking. Non-contaminated blue mussels were transferred to three coastal recreational waters affected by faecal pollution of unknown origin. Molecular markers associated with animal and human waste were targeted by PCR and compared in seawater and mussel samples. The results demonstrated that transplanted mussels in simple enclosures accumulated and retained elevated levels of molecular markers associated with different types of faecal pollution. The targets included a novel putative human associated E. coli subgroup B2 VIII clone, and animal and human associated markers in enterococci (esp, M19, M66, M90, and M91). Human (sewage) associated markers including esp and M66 were sometimes not detectable in seawater samples despite known wastewater contamination, whereas the markers were detectable in mussels. We suggest that transplanted mussels should be considered as potential biosamplers in studies focusing on identifying source of faecal pollution in low or moderately impacted recreational waters. Bioaccumulation of molecular markers in mussels for several days may represent the water quality better than traditional grab samples from the water column.

Download Full-text

Synergistic Application of Molecular Markers and Community-Based Microbial Source Tracking Methods for Identification of Fecal Pollution in River Water During Dry and Wet Seasons

Frontiers in Microbiology ◽

10.3389/fmicb.2021.660368 ◽

2021 ◽

Vol 12 ◽

Author(s):

Hongxia Liang ◽

Zhisheng Yu ◽

Bobo Wang ◽

Fabrice Ndayisenga ◽

Ruyin Liu ◽

...

Keyword(s):

Molecular Markers ◽

Water Samples ◽

Fecal Contamination ◽

Microbial Source Tracking ◽

Fecal Pollution ◽

Small Sample ◽

16S Rrna Genes ◽

Rrna Genes ◽

Source Tracking ◽

Community Based

It is important to track fecal sources from humans and animals that negatively influence the water quality of rural rivers and human health. In this study, microbial source tracking (MST) methods using molecular markers and the community-based FEAST (fast expectation–maximization microbial source tracking) program were synergistically applied to distinguish the fecal contributions of multiple sources in a rural river located in Beijing, China. The performance of eight markers were evaluated using 133 fecal samples based on real-time quantitative (qPCR) technique. Among them, six markers, including universal (BacUni), human-associated (HF183-1 and BacH), swine-associated (Pig-2-Bac), ruminant-associated (Rum-2-Bac), and avian-associated (AV4143) markers, performed well in the study. A total of 96 water samples from the river and outfalls showed a coordinated composition of fecal pollution, which revealed that outfall water might be a potential input of the Fsq River. In the FEAST program, bacterial 16S rRNA genes of 58 fecal and 12 water samples were sequenced to build the “source” library and “sink,” respectively. The relative contribution (<4.01% of sequence reads) of each source (i.e., human, swine, bovine, or sheep) was calculated based on simultaneous screening of the operational taxonomic units (OTUs) of sources and sinks, which indicated that community-based MST methods could be promising tools for identifying fecal sources from a more comprehensive perspective. Results of the qPCR assays indicated that fecal contamination from human was dominant during dry weather and that fecal sources from swine and ruminant were more prevalent in samples during the wet season than in those during the dry season, which were consistent with the findings predicted by the FEAST program using a very small sample size. Information from the study could be valuable for the development of improved regulation policies to reduce the levels of fecal contamination in rural rivers.

Download Full-text

Development and application of molecular markers on microbial source tracking for avian

Acta Ecologica Sinica ◽

10.5846/stxb202003210633 ◽

2021 ◽

Vol 41 (3) ◽

Author(s):

梁红霞，余志晟，刘如铟，张洪勋，吴钢 LIANG Hongxia

Keyword(s):

Molecular Markers ◽

Microbial Source Tracking ◽

Source Tracking

Download Full-text

Assessment of the decay rates of microbial source tracking molecular markers and faecal indicator bacteria from different sources

Journal of Applied Microbiology ◽

10.1111/jam.14058 ◽

2018 ◽

Vol 125 (6) ◽

pp. 1938-1949 ◽

Cited By ~ 10

Author(s):

E. Ballesté ◽

C. García-Aljaro ◽

A.R. Blanch

Keyword(s):

Molecular Markers ◽

Microbial Source Tracking ◽

Decay Rates ◽

Indicator Bacteria ◽

Source Tracking ◽

Faecal Indicator Bacteria ◽

Different Sources

Download Full-text

Molecular Indicators Used in the Development of Predictive Models for Microbial Source Tracking

Applied and Environmental Microbiology ◽

10.1128/aem.02350-09 ◽

2010 ◽

Vol 76 (6) ◽

pp. 1789-1795 ◽

Cited By ~ 57

Author(s):

Elisenda Ballesté ◽

Xavier Bonjoch ◽

Lluís A. Belanche ◽

Anicet R. Blanch

Keyword(s):

Molecular Markers ◽

Predictive Models ◽

Microbial Source Tracking ◽

Fecal Pollution ◽

Pollution Sources ◽

Source Tracking ◽

Correct Identification ◽

Bifidobacterium Adolescentis ◽

Combined Use ◽

Molecular Indicators

ABSTRACT A number of chemical, microbial, and eukaryotic indicators have been proposed as indicators of fecal pollution sources in water bodies. No single one of the indicators tested to date has been able to determine the source of fecal pollution in water. However, the combined use of different indicators has been demonstrated to be the best way of defining predictive models suitable for determining fecal pollution sources. Molecular methods are promising tools that could complement standard microbiological water analysis. In this study, the feasibility of some proposed molecular indicators for microbial source tracking (MST) was compared (names of markers are in parentheses): host-specific Bacteroidetes (HF134, HF183, CF128, and CF193), Bifidobacterium adolescentis (ADO), Bifidobacterium dentium (DEN), the gene esp of Enterococcus faecium, and host-specific mitochondrial DNA associated with humans, cattle, and pigs (Humito, Bomito, and Pomito, respectively). None of the individual molecular markers tested enabled 100% source identification. They should be combined with other markers to raise sensitivity and specificity and increase the number of sources that are identified. MST predictive models using only these molecular markers were developed. The models were evaluated by considering the lowest number of molecular indicators needed to obtain the highest rate of identification of fecal sources. The combined use of three molecular markers (ADO, Bomito, and Pomito) enabled correct identification of 75.7% of the samples, with differentiation between human, swine, bovine, and poultry sources. Discrimination between human and nonhuman fecal pollution was possible using two markers: ADO and Pomito (84.6% correct identification). The percentage of correct identification increased with the number of markers analyzed. The best predictive model for distinguishing human from nonhuman fecal sources was based on 5 molecular markers (HF134, ADO, DEN, Bomito, and Pomito) and provided 90.1% correct classification.

Download Full-text