Distributions of Fecal Markers in Wastewater from Different Climatic Zones for Human Fecal Pollution Tracking in Australian Surface Waters

Ahmed, Warish; Sidhu, J. P. S.; Smith, Kylie; Beale, David J.; Gyawali, Pradip; Toze, Simon

doi:10.1128/aem.03765-15

Cited by 48 publications

(40 citation statements)

References 48 publications

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“…Similar correlations between MST markers in raw wastewater have been reported among ENT 23S, HF183, HAdV, and HPyV (38). The lack of correlation with secondary-treated wastewater is likely due to low and varied target concentrations as a result of the treatment process.…”

Section: Discussionsupporting

confidence: 72%

Cross-Comparison of Human Wastewater-Associated Molecular Markers in Relation to Fecal Indicator Bacteria and Enteric Viruses in Recreational Beach Waters

Hughes

Beale

Dennis

et al. 2017

Appl Environ Microbiol

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Detection of human wastewater contamination in recreational waters is of critical importance to regulators due to the risks posed to public health. To identify such risks, human wastewater-associated microbial source tracking (MST) markers have been developed. At present, however, a greater understanding of the suitability of these markers for the detection of diluted human wastewater in environmental waters is necessary to predict risk. Here, we compared the process limit of detection (PLOD) and process limit of quantification (PLOQ) of six human wastewater-associated MST markers Among the six MST markers tested, HF183 was the most sensitive measure of human fecal pollution and was quantifiable up to dilutions of 10 Ϫ6 and 10 Ϫ4 for beach water samples seeded with raw and secondary-treated wastewater, respectively. Other markers and enteric viruses were detected at various dilutions (10 Ϫ1 to 10 Ϫ5 ). These MST markers, FIB, and enteric viruses were then quantified in beach water (n ϭ 12) and sand samples (n ϭ 12) from South East Queensland (SEQ), Australia, to estimate the levels of human fecal pollution. Of the 12 sites examined, beach water and sand samples from several sites had quantifiable concentrations of HF183 and PMMoV markers. Overall, our results indicate that while HF183 is the most sensitive measure of human fecal pollution, it should be used in conjunction with a conferring viral marker to avoid overestimating the risk of gastrointestinal illness.IMPORTANCE MST is an effective tool to help utilities and regulators improve recreational water quality around the globe. Human fecal pollution poses significant public health risks compared to animal fecal pollution. Several human wastewaterassociated markers have been developed and used for MST field studies. However, a head-to-head comparison in terms of their performance to detect diluted human fecal pollution in recreational water is lacking. In this study, we cross-compared the performance of six human wastewater-associated markers in relation to FIB and enteric viruses in beach water samples seeded with raw and secondary-treated wastewater. The results of this study will provide guidance to regulators and utilities on the appropriate application of MST markers for tracking the sources of human fecal pollution in environmental waters and confer human health risks.KEYWORDS microbial source tracking, human wastewater, fecal indicator bacteria, beach water, enteric viruses

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Section: Discussionsupporting

confidence: 72%

Cross-Comparison of Human Wastewater-Associated Molecular Markers in Relation to Fecal Indicator Bacteria and Enteric Viruses in Recreational Beach Waters

Hughes

Beale

Dennis

et al. 2017

Appl Environ Microbiol

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“…While absent from fecal samples, HPyV were detected in all wastewater samples tested. However, HPyV concentrations in sewage were roughly two logs lower than those found elsewhere (34,48). As concentrations of HPyV in raw sewage and effluent were lower than concentrations of other indicator organisms, such as enterococci and C. perfringens, testing of large sample volumes would be advisable.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, testing for other more specific markers, such as human viruses, in parallel is warranted. It also needs to be considered that concentrations of the HF183TaqMan marker in wastewater were roughly two logs lower than concentrations of different HF183 markers in Australia (48). This may suggest that an evaluation of alternative HF183 markers, such as the recently described HF183/BacR287 assay (49), is warranted in Hawaii.…”

Section: Discussionmentioning

confidence: 99%

Human-Associated Bacteroides spp. and Human Polyomaviruses as Microbial Source Tracking Markers in Hawaii

Kirs

Caffaro-Filho

Wong

et al. 2016

Appl Environ Microbiol

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Identification of sources of fecal contaminants is needed to (i) determine the health risk associated with recreational water use and (ii) implement appropriate management practices to mitigate this risk and protect the environment. This study evaluated human-associated Bacteroides spp. (HF183TaqMan) and human polyomavirus (HPyV) markers for host sensitivity and specificity using human and animal fecal samples collected in Hawaii. The decay rates of those markers and indicator bacteria were identified in marine and freshwater microcosms exposed and not exposed to sunlight, followed by field testing of the usability of the molecular markers. Both markers were strongly associated with sewage, although the cross-reactivity of the HF183TaqMan (also present in 82% of canine [n ‫؍‬ 11], 30% of mongoose [n ‫؍‬ 10], and 10% of feline [n ‫؍‬ 10] samples) needs to be considered. Concentrations of HF183TaqMan in human fecal samples exceeded those in cross-reactive animals at least 1,000-fold. In the absence of sunlight, the decay rates of both markers were comparable to the die-off rates of enterococci in experimental freshwater and marine water microcosms. However, in sunlight, the decay rates of both markers were significantly lower than the decay rate of enterococci. While both markers have their individual limitations in terms of sensitivity and specificity, these limitations can be mitigated by using both markers simultaneously; ergo, this study supports the concurrent use of HF183TaqMan and HPyV markers for the detection of sewage contamination in coastal and inland waters in Hawaii. IMPORTANCEThis study represents an in-depth characterization of microbial source tracking (MST) markers in Hawaii. The distribution and concentrations of HF183TaqMan and HPyV markers in human and animal fecal samples and in wastewater, coupled with decay data obtained from sunlight-exposed and unexposed microcosms, support the concurrent application of HF183TaqMan and HPyV markers for sewage contamination detection in Hawaii waters. Both markers are more conservative and more specific markers of sewage than fecal indicator bacteria (enterococci and Escherichia coli). Analysis of HF183TaqMan (or newer derivatives) is recommended for inclusion in future epidemiological studies concerned with beach water quality, while better concentration techniques are needed for HPyV. Such epidemiological studies can be used to develop new recreational water quality criteria, which will provide direct information on the absence or presence of sewage contamination in water samples as well as reliable measurements of the risk of waterborne disease transmission to swimmers. T he recently revised recreational water quality criteria (1) continue to use concentrations of fecal indicator bacteria (FIB), such as enterococci and Escherichia coli, to determine risks to swimmers and to establish recreational water quality standards. However, major limitations in the implementation of the current recreational water quality standards are related to the fact t...

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“…The concentrations of the HF183, BacHum-UCD, BacH, and Human-Bac1 were >1.0 × 10 9 gene copies per L of raw sewage, suggesting that these markers have the potential to detect diluted sewage pollution in environmental waters. A recent study determined the temporal variability of the HF183 markers in raw sewage samples from three climatic zones in Australia [76]. The concentrations of the HF183 markers in raw sewage samples showed little or no temporal variation over the course of the study.…”

Section: Human Feces and Wastewatermentioning

confidence: 99%

“…A recent study determined the temporal variability of the HF183 markers in raw sewage samples from three climatic zones in Australia [76]. The concentrations of the HF183 markers in raw sewage samples showed little or no temporal variation over the course of the study.…”

Section: Human Feces and Wastewatermentioning

confidence: 99%

Current Status of Marker Genes of Bacteroides and Related Taxa for Identifying Sewage Pollution in Environmental Waters

Ahmed

Hughes

Harwood

2016

Water

114

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Abstract:Microbial source tracking (MST) endeavors to determine sources of fecal pollution in environmental waters by capitalizing on the association of certain microorganisms with the gastrointestinal tract and feces of specific animal groups. Several decades of research have shown that bacteria belonging to the gut-associated order Bacteroidales, and particularly the genus Bacteroides, tend to co-evolve with the host, and are, therefore, particularly suitable candidates for MST applications. This review summarizes the current research on MST methods that employ genes belonging to Bacteroidales/Bacteroides as tracers or "markers" of sewage pollution, including known advantages and deficiencies of the many polymerase chain reaction (PCR)-based methods that have been published since 2000. Host specificity is a paramount criterion for confidence that detection of a marker is a true indicator of the target host. Host sensitivity, or the prevalence of the marker in feces/waste from the target host, is necessary for confidence that absence of the marker is indicative of the absence of the pollution source. Each of these parameters can vary widely depending on the type of waste assessed and the geographic location. Differential decay characteristics of bacterial targets and their associated DNA contribute to challenges in interpreting MST results in the context of human health risks. The HF183 marker, derived from the 16S rRNA gene of Bacteroides dorei and closely related taxa, has been used for almost two decades in MST studies, and is well characterized regarding host sensitivity and specificity, and in prevalence and concentration in sewage in many countries. Other markers such as HumM2 and HumM3 show promise, but require further performance testing to demonstrate their widespread utility. An important limitation of the one-marker-one-assay approach commonly used for MST is that given the complexities of microbial persistence in environmental waters, and the methodological challenges of quantitative PCR (qPCR) in such samples, the absence of a given marker does not ensure the absence of fecal pollution in the source water. Approaches under development, such as microarray and community analysis, have the potential to improve MST practices, thereby increasing our ability to protect human and ecosystem health.

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Distributions of Fecal Markers in Wastewater from Different Climatic Zones for Human Fecal Pollution Tracking in Australian Surface Waters

Cited by 48 publications

References 48 publications

Cross-Comparison of Human Wastewater-Associated Molecular Markers in Relation to Fecal Indicator Bacteria and Enteric Viruses in Recreational Beach Waters

Cross-Comparison of Human Wastewater-Associated Molecular Markers in Relation to Fecal Indicator Bacteria and Enteric Viruses in Recreational Beach Waters

Human-Associated Bacteroides spp. and Human Polyomaviruses as Microbial Source Tracking Markers in Hawaii

Current Status of Marker Genes of Bacteroides and Related Taxa for Identifying Sewage Pollution in Environmental Waters

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