Microbial source tracking and spatial analysis of E. coli contaminated private well waters in southeastern Ontario

Private water supplies, which are the primary source of drinking water for rural communities in developed countries, are at risk of becoming fecally contaminated. It is important to identify the source of contamination in order to better understand and address this human health risk. Microbial source tracking methods using human, bovine and general Bacteroidales markers were performed on 716 well water samples from southeastern Ontario, which had previously tested positive for Escherichia coli. The results were then geospatially analyzed in order to elucidate contamination patterns. Markers for human feces were found in nearly half (49%) of all samples tested, and a statistically significant spatial cluster was observed. A quarter of the samples tested positive for only general Bacteroidales markers (25.7%) and relatively few bovine specific marker positives (12.6%) were found. These findings are fundamental to the understanding of pathogen dynamics and risk in the context of drinking well water and will inform future research regarding host-specific pathogens in private well water samples.

Download Full-text

Evaluation of Two Library-Independent Microbial Source Tracking Methods To Identify Sources of Fecal Contamination in French Estuaries

Applied and Environmental Microbiology ◽

10.1128/aem.03003-06 ◽

2007 ◽

Vol 73 (15) ◽

pp. 4857-4866 ◽

Cited By ~ 99

Author(s):

Michèle Gourmelon ◽

Marie Paule Caprais ◽

Raphaël Ségura ◽

Cécile Le Mennec ◽

Solen Lozach ◽

...

Keyword(s):

Water Samples ◽

Fecal Contamination ◽

Microbial Source Tracking ◽

Source Tracking ◽

Rrna Gene ◽

Specific Marker ◽

Gene Markers ◽

High Level ◽

Bird Feces

ABSTRACT In order to identify the origin of the fecal contamination observed in French estuaries, two library-independent microbial source tracking (MST) methods were selected: (i) Bacteroidales host-specific 16S rRNA gene markers and (ii) F-specific RNA bacteriophage genotyping. The specificity of the Bacteroidales markers was evaluated on human and animal (bovine, pig, sheep, and bird) feces. Two human-specific markers (HF183 and HF134), one ruminant-specific marker (CF193′), and one pig-specific marker (PF163) showed a high level of specificity (>90%). However, the data suggest that the proposed ruminant-specific CF128 marker would be better described as an animal marker, as it was observed in all bovine and sheep feces and 96% of pig feces. F RNA bacteriophages were detected in only 21% of individual fecal samples tested, in 60% of pig slurries, but in all sewage samples. Most detected F RNA bacteriophages were from genotypes II and III in sewage samples and from genotypes I and IV in bovine, pig, and bird feces and from pig slurries. Both MST methods were applied to 28 water samples collected from three watersheds at different times. Classification of water samples as subject to human, animal, or mixed fecal contamination was more frequent when using Bacteroidales markers (82.1% of water samples) than by bacteriophage genotyping (50%). The ability to classify a water sample increased with increasing Escherichia coli or enterococcus concentration. For the samples that could be classified by bacteriophage genotyping, 78% agreed with the classification obtained from Bacteroidales markers.

Download Full-text

Microbial source tracking of private well water samples across at-risk regions in southern Ontario and analysis of traditional fecal indicator bacteria assays including culture and qPCR

Journal of Water and Health ◽

10.2166/wh.2016.024 ◽

2016 ◽

Vol 14 (6) ◽

pp. 1047-1058 ◽

Cited By ~ 3

Author(s):

Julia Krolik ◽

Allison Maier ◽

Shawna Thompson ◽

Anna Majury

Keyword(s):

At Risk ◽

Water Samples ◽

Rural Areas ◽

Fecal Contamination ◽

Microbial Source Tracking ◽

Source Tracking ◽

Well Water ◽

Prevention Strategies ◽

E Coli ◽

Bacteriological Testing

Many people living in rural areas rely on privately owned wells as their primary source of drinking water. These water sources are at risk for fecal contamination of human, wildlife, and livestock origin. While traditional bacteriological testing involves culture-based methods, microbial source tracking (MST) assays present an opportunity to additionally determine the source of fecal contamination. This study investigated the main host sources of contamination in private well water samples with high levels of Escherichia coli (E. coli), using MST with human and multi-species specific markers. Fecal contamination of human origin was detected in approximately 50% of samples, indicating that current contamination prevention strategies require reconsideration. The relationship between cattle density and fecal contamination of bovine origin was investigated using a Bovine Bacteroidales specific MST assay. Regional variations of microbial sources were examined, and may inform local primary prevention strategies. Additionally, in order to assess MST and E. coli quantitative real time polymerase chain reaction (qPCR) assays as indicators of fecal contamination, these were compared to E. coli culture methods. Variation in results was observed across all assay methods investigated, suggesting the most appropriate routine bacteriological testing methodology cannot be determined without comparison to a method that directly detects the presence of fecal contamination.

Download Full-text

Performance of Two Quantitative PCR Methods for Microbial Source Tracking of Human Sewage and Implications for Microbial Risk Assessment in Recreational Waters

Applied and Environmental Microbiology ◽

10.1128/aem.01430-12 ◽

2012 ◽

Vol 78 (20) ◽

pp. 7317-7326 ◽

Cited By ~ 91

Author(s):

Christopher Staley ◽

Katrina V. Gordon ◽

Mary E. Schoen ◽

Valerie J. Harwood

Keyword(s):

Risk Assessment ◽

Quantitative Pcr ◽

Microbial Source Tracking ◽

Human Polyomavirus ◽

Source Tracking ◽

Specific Marker ◽

Environmental Waters ◽

Potential Health ◽

Microbial Risk Assessment ◽

Microbial Risk

ABSTRACTBefore new, rapid quantitative PCR (qPCR) methods for assessment of recreational water quality and microbial source tracking (MST) can be useful in a regulatory context, an understanding of the ability of the method to detect a DNA target (marker) when the contaminant source has been diluted in environmental waters is needed. This study determined the limits of detection and quantification of the human-associatedBacteroidessp. (HF183) and human polyomavirus (HPyV) qPCR methods for sewage diluted in buffer and in five ambient, Florida water types (estuarine, marine, tannic, lake, and river). HF183 was quantifiable in sewage diluted up to 10−6in 500-ml ambient-water samples, but HPyVs were not quantifiable in dilutions of >10−4. Specificity, which was assessed using fecal composites from dogs, birds, and cattle, was 100% for HPyVs and 81% for HF183. Quantitative microbial risk assessment (QMRA) estimated the possible norovirus levels in sewage and the human health risk at various sewage dilutions. When juxtaposed with the MST marker detection limits, the QMRA analysis revealed that HF183 was detectable when the modeled risk of gastrointestinal (GI) illness was at or below the benchmark of 10 illnesses per 1,000 exposures, but the HPyV method was generally not sensitive enough to detect potential health risks at the 0.01 threshold for frequency of illness. The tradeoff between sensitivity and specificity in the MST methods indicates that HF183 data should be interpreted judiciously, preferably in conjunction with a more host-specific marker, and that better methods of concentrating HPyVs from environmental waters are needed if this method is to be useful in a watershed management or monitoring context.

Download Full-text

Evaluation of Bovine Feces-Associated Microbial Source Tracking Markers and Their Correlations with Fecal Indicators and Zoonotic Pathogens in a Brisbane, Australia, Reservoir

Applied and Environmental Microbiology ◽

10.1128/aem.03234-12 ◽

2013 ◽

Vol 79 (8) ◽

pp. 2682-2691 ◽

Cited By ~ 35

Author(s):

W. Ahmed ◽

T. Sritharan ◽

A. Palmer ◽

J. P. S. Sidhu ◽

S. Toze

Keyword(s):

Host Specificity ◽

Water Samples ◽

Microbial Source Tracking ◽

Fecal Pollution ◽

Decay Rates ◽

Source Tracking ◽

Content Type ◽

Zoonotic Pathogens ◽

Maximum Value ◽

Bovine Feces

ABSTRACTThis study was aimed at evaluating the host specificity and host sensitivity of two bovine feces-associated bacterial (BacCow-UCD and cowM3) and one viral [bovine adenovirus (B-AVs)] microbial source tracking (MST) markers by screening 130 fecal and wastewater samples from 10 target and nontarget host groups in southeast Queensland, Australia. In addition, 36 water samples were collected from a reservoir and tested for the occurrence of all three bovine feces-associated markers along with fecal indicator bacteria (FIB),Campylobacterspp.,Escherichia coliO157, andSalmonellaspp. The overall host specificity values of the BacCow-UCD, cowM3, and B-AVs markers to differentiate between bovine and other nontarget host groups were 0.66, 0.88, and 1.00, respectively (maximum value of 1.00). The overall host sensitivity values of these markers, however, in composite bovine wastewater and individual bovine fecal DNA samples were 0.93, 0.90, and 0.60, respectively (maximum value of 1.00). Among the 36 water samples tested, 56%, 22%, and 6% samples were PCR positive for the BacCow-UCD, cowM3, and B-AVs markers, respectively. Among the 36 samples tested, 50% and 14% samples were PCR positive for theCampylobacter16S rRNA andE. coliO157rfbEgenes, respectively. Based on the results, we recommend that multiple bovine feces-associated markers be used if possible for bovine fecal pollution tracking. Nonetheless, the presence of the multiple bovine feces-associated markers along with the presence of potential zoonotic pathogens indicates bovine fecal pollution in the reservoir water samples. Further research is required to understand the decay rates of these markers in relation to FIB and zoonotic pathogens.

Download Full-text

Use of Bacteroidales Microbial Source Tracking To Monitor Fecal Contamination in Fresh Produce Production

Applied and Environmental Microbiology ◽

10.1128/aem.02891-13 ◽

2013 ◽

Vol 80 (2) ◽

pp. 612-617 ◽

Cited By ~ 14

Author(s):

Kruti Ravaliya ◽

Jennifer Gentry-Shields ◽

Santos Garcia ◽

Norma Heredia ◽

Anna Fabiszewski de Aceituno ◽

...

Keyword(s):

Fresh Produce ◽

Fecal Contamination ◽

Microbial Source Tracking ◽

Source Tracking ◽

Rrna Gene ◽

Specific Marker ◽

Production Environment ◽

Content Type ◽

Food Borne

ABSTRACTIn recent decades, fresh and minimally processed produce items have been associated with an increasing proportion of food-borne illnesses. Most pathogens associated with fresh produce are enteric (fecal) in origin, and contamination can occur anywhere along the farm-to-fork chain. Microbial source tracking (MST) is a tool developed in the environmental microbiology field to identify and quantify the dominant source(s) of fecal contamination. This study investigated the utility of an MST method based onBacteroidales16S rRNA gene sequences as a means of identifying potential fecal contamination, and its source, in the fresh produce production environment. The method was applied to rinses of fresh produce, source and irrigation waters, and harvester hand rinses collected over the course of 1 year from nine farms (growing tomatoes, jalapeño peppers, and cantaloupe) in Northern Mexico. Of 174 samples, 39% were positive for a universalBacteroidalesmarker (AllBac), including 66% of samples from cantaloupe farms (3.6 log10genome equivalence copies [GEC]/100 ml), 31% of samples from tomato farms (1.7 log10GEC/100 ml), and 18% of samples from jalapeño farms (1.5 log10GEC/100 ml). Of 68 AllBac-positive samples, 46% were positive for one of three human-specific markers, and none were positive for a bovine-specific marker. There was no statistically significant correlation betweenBacteroidalesand genericEscherichia coliacross all samples. This study provides evidence thatBacteroidalesmarkers may serve as alternative indicators for fecal contamination in fresh produce production, allowing for determination of both general contamination and that derived from the human host.

Download Full-text

Comparison of genotypic-based microbial source tracking methods requiring a host origin database

Journal of Water and Health ◽

10.2166/wh.2003.0019 ◽

2003 ◽

Vol 1 (4) ◽

pp. 167-180 ◽

Cited By ~ 51

Author(s):

Samuel P. Myoda ◽

C. Andrew Carson ◽

Jeffry J. Fuhrmann ◽

Byoung-Kwon Hahm ◽

Peter G. Hartel ◽

...

Keyword(s):

Water Samples ◽

False Positive ◽

Pattern Analysis ◽

Repetitive Element ◽

Microbial Source Tracking ◽

Pulsed Field Gel Electrophoresis ◽

Source Tracking ◽

Fecal Material ◽

Database Construction ◽

Host Origin

Microbial source tracking (MST) results, obtained using identical sample sets and pulsed field gel electrophoresis (PFGE), repetitive element PCR (rep-PCR) and ribotyping techniques were compared. These methods were performed by six investigators in analysis of duplicate, blind sets of water samples spiked with feces from five possible sources (sewage, human, dog, cow and seagull). Investigators were provided with samples of the fecal material used to inoculate the water samples for host origin database construction. All methods correctly identified the dominant source in the majority of the samples. Modifications of some of these methods correctly identified the dominant sources in over 90% of the samples; however, false positive rates were as high as 57%. The high false positive rates appeared to be indirectly proportional to the levels of stringency applied in pattern analysis. All the methods produced useful data but the results highlighted the need to modify and optimize these methods in order to minimize sources of error.

Download Full-text

Manganese in potable water of nine districts, Bangladesh: Human health risk

10.21203/rs.3.rs-219919/v1 ◽

2021 ◽

Author(s):

Md. Aminur Rahman ◽

Md. Abul Hashem ◽

Md. Sohel Rana ◽

Md. Rashidul Islam

Keyword(s):

Drinking Water ◽

Human Health ◽

Water Samples ◽

Potable Water ◽

Hazard Quotient ◽

Human Health Risk ◽

World Health ◽

Well Water ◽

Tube Well ◽

Health Organization

Abstract Safe drinking water is directly linked to good human health. An excessive amount of manganese (Mn) in drinking water supplies causes people show symptoms of neurotoxicity. In this study, the level of Mn in potable water sourced from tube wells located in 9 (nine) districts of Bangladesh was monitored. In total 170 (one hundred and seventy) water samples were collected and Mn was quantified by atomic absorption spectroscopy (AAS). The levels of Mn found in the tube well water samples of Sirajganj, Meherpur, Chuadanga, Jhenaidah, Magura, Faridpur, Jashore, Satkhira, and Khulna were 0.37–1.86, 0.10–4.11, 0.30–0.76, 0.26–0.94, 0.01–0.18, 0.21–1.78, 0.08–1.23, 0.05–0.27 and 0.01–2.11 mg/L, respectively. Results revealed that Mn level was beyond the highest contaminated levels of 0.1 mg/L and 0.4 mg/L, which are recommended by Bangladesh Drinking Standard (BDS) and World Health Organization (WHO), respectively. The maximum Mn contaminated level reached up to 4.11 mg/L (mean: 0.53 mg/L). The Mn level in tube well water exceeded 51.1% and 75.9% set by the recommended value of WHO and BDS, respectively. Furthermore, the calculated hazard quotient (HQ) value for Mn was observed to be greater than unity, indicating both children and adults risked potential non-carcinogenic health issues. The water supply authorities should take steps to provide Mn-free drinking water for communities.

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

Risk Perception and Human Health Risk in Rural Communities Consuming Unregulated Well Water in Saskatchewan, Canada

Risk Analysis ◽

10.1111/risa.13335 ◽

2019 ◽

Vol 39 (11) ◽

pp. 2559-2575

Author(s):

Lorelei Ford ◽

Cheryl Waldner ◽

Javier Sanchez ◽

Lalita Bharadwaj

Keyword(s):

Risk Perception ◽

Rural Communities ◽

Health Risk ◽

Human Health ◽

Human Health Risk ◽

Well Water

Download Full-text

Application of library-independent microbial source tracking methods for identifying the sources of faecal contamination in coastal areas

Water Science & Technology ◽

10.2166/wst.2010.033 ◽

2010 ◽

Vol 61 (6) ◽

pp. 1401-1409 ◽

Cited By ~ 19

Author(s):

M. Gourmelon ◽

M. P. Caprais ◽

C. Le Mennec ◽

S. Mieszkin ◽

C. Ponthoreau ◽

...

Keyword(s):

Water Samples ◽

Microbial Source Tracking ◽

Coastal Areas ◽

Source Tracking ◽

Rrna Gene ◽

Multiple Sources ◽

Gene Markers ◽

Faecal Contamination ◽

Water Courses ◽

Specific Bacteriophage

Faecal contamination sources were identified in coastal areas around the Guerande-Atlantique peninsula using two microbial source tracking (MST) methods: (i) Bacteroidales host-specific 16S rRNA gene markers measured by real-time PCR and (ii) F-specific bacteriophage (FRNAPH) genotyping. Both methods were used on 63 water samples from 7 water courses. HF183 marker and bacteriophage genogroup II (FRNAPH II) were detected in all water samples and in the majority of water samples, respectively, from La Torre stream (W5), Piriac (W2), R2000 (W3) and Mazy (W7) rain water drains, and also detected, less frequently, in Le Nau drain (W4), suggesting contamination by human faecal sources at these sites. These human markers were weakly detected in Pouliguen channel (W6). Furthermore, BacR and bacteriophage genogroup I (FRNAPH I) were also detected, but at lower concentration and frequency. So, site W6 seems to be contaminated by multiple sources, though mainly human. Finally, BacR was detected twice in Pont d'Armes channel (W1), whereas HF183 was not detected. FRNAPH I and II were detected in only 3 out of 12 water samples. Site W1 seems mainly contaminated by animal sources. As a result of our findings, actions were taken to remediate water and shellfish quality.

Download Full-text