Escherichia coli and Enterococcus spp. in Rainwater Tank Samples: Comparison of Culture-Based Methods and 23S rRNA Gene Quantitative PCR Assays

Ahmed, Warish; Richardson, K.; Sidhu, J. P. S.; Toze, Simon

doi:10.1021/es302222b

Cited by 30 publications

(19 citation statements)

References 39 publications

(76 reference statements)

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“…Overall, the four microbial indicators were found to be the highest at site #3 in both types of water samples. Thus, the results of our microbiological indicator analyses suggested that both the fresh rainwater and the reservoir water samples are not suitable for human consumption without any treatment similar to the findings on the roof harvested rainwater [22], [52], [54].…”

Section: Resultssupporting

confidence: 52%

“…Enterococci are a specific group of bacteria that are found in high numbers in both human and animal faeces, and are therefore a valuable indicator for determining the extent of fecal contamination of a water source [16], [52]–[53]. Enterococci were found to be in the range of 0 CFU/100 mL–11 CFU/100 mL in fresh rainwater and 0 CFU/100 mL–35 CFU/100 mL in the reservoir water (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Microbial Quality and Phylogenetic Diversity of Fresh Rainwater and Tropical Freshwater Reservoir

2014

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The impact of rainwater on the microbial quality of a tropical freshwater reservoir through atmospheric wet deposition of microorganisms was studied for the first time. Reservoir water samples were collected at four different sampling points and rainwater samples were collected in the immediate vicinity of the reservoir sites for a period of four months (January to April, 2012) during the Northeast monsoon period. Microbial quality of all fresh rainwater and reservoir water samples was assessed based on the counts for the microbial indicators: Escherichia coli (E. coli), total coliforms, and Enterococci along with total heterotrophic plate counts (HPC). The taxonomic richness and phylogenetic relationship of the freshwater reservoir with those of the fresh rainwater were also assessed using 16 S rRNA gene clone library construction. The levels of E. coli were found to be in the range of 0 CFU/100 mL – 75 CFU/100 mL for the rainwater, and were 10–94 CFU/100 mL for the reservoir water. The sampling sites that were influenced by highway traffic emissions showed the maximum counts for all the bacterial indicators assessed. There was no significant increase in the bacterial abundances observed in the reservoir water immediately following rainfall. However, the composite fresh rainwater and reservoir water samples exhibited broad phylogenetic diversity, including sequences representing Betaproteobacteria, Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, Lentisphaerae and Bacteriodetes. Members of the Betaproteobacteria group were the most dominant in both fresh rainwater and reservoir water, followed by Alphaproteobacteria, Sphingobacteria, Actinobacteria and Gammaproteobacteria.

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Section: Resultssupporting

confidence: 52%

Section: Resultsmentioning

confidence: 99%

Microbial Quality and Phylogenetic Diversity of Fresh Rainwater and Tropical Freshwater Reservoir

2014

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“…Ranges of concentrations were variable, ranging up to 10,000 colony forming units (CFU)/100 mL in a study from Malaysia 42 and 10,964 gene copies (GC)/100 mL in an Australian study. 43 High concentrations were also observed in Bangladesh (6000 CFU/ 100 mL) 44 and other Australian studies (~10 3 CFU/100 mL) 1,45,46 . The variability in E. coli concentrations observed in the studies has been linked to meteorological factors, 33 catchment location, roof and/or storage container materials, 36 the presence of wildlife near the roof, 32 laboratory method used, and location and/or timing of the sampling event relative to the previous factors.…”

Section: Rainwater Usesmentioning

confidence: 68%

A global review of the microbiological quality and potential health risks associated with roof-harvested rainwater tanks

et al. 2019

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A broad body of literature has been published regarding roof-harvested rainwater quality around the world. In particular, the presence of fecal indicator bacteria and pathogenic microorganisms has raised concerns regarding the acceptability of rainwater for potable and non-potable uses. As the use of molecular assays has improved understanding of the diverse microbial communities present in rainwater tanks and their role in providing benefits or harm to human health, a comprehensive review is needed to summarize the state of the science in this area. To provide a summary of microbial contaminants in rainwater tanks and contextual factors, a comprehensive review was conducted here to elucidate the uses of rainwater, factors affecting water quality, concentrations of fecal indicators and pathogens, the attribution of pathogens to host sources using microbial source tracking, microbial ecology, human health risks determined using epidemiological approaches and quantitative microbial risk assessment, and treatment approaches for mitigating risks. Research gaps were identified for pathogen concentration data, microbial source tracking approaches for identifying the sources of microbial contamination, limitations to current approaches for assessing viability, treatment, and maintenance practices. Frameworks should be developed to assess and prioritize these factors in order to optimize public health promotion for roof-harvested rainwater.

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“…qPCR assays. qPCR standards for E. coli 23S rRNA, Enterococcus 23S rRNA, and HAdVs were prepared from the genomic DNA of E. coli ATCC 35150, Enterococcus faecalis ATCC 19433, and HAdV strain 41 ATCC VR-930 as described elsewhere (38,39). qPCR standards for HF183 and HPyVs were prepared from the plasmid DNA (26,40).…”

Section: Methodsmentioning

confidence: 99%

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

Ahmed

Sidhu

Smith

et al. 2016

Appl Environ Microbiol

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cRecreational and potable water supplies polluted with human wastewater can pose a direct health risk to humans. Therefore, sensitive detection of human fecal pollution in environmental waters is very important to water quality authorities around the globe. Microbial source tracking (MST) utilizes human fecal markers (HFMs) to detect human wastewater pollution in environmental waters. The concentrations of these markers in raw wastewater are considered important because it is likely that a marker whose concentration is high in wastewater will be more frequently detected in polluted waters. In this study, quantitative PCR (qPCR) assays were used to determine the concentrations of fecal indicator bacteria (FIB) Escherichia coli and Enterococcus spp., HFMs Bacteroides HF183, human adenoviruses (HAdVs), and polyomaviruses (HPyVs) in raw municipal wastewater influent from various climatic zones in Australia. E. coli mean concentrations in pooled human wastewater data sets (from various climatic zones) were the highest (3.2 ؋ 10 6 gene copies per ml), followed by those of HF183 (8.0 ؋ 10 5 gene copies per ml) and Enterococcus spp. (3.6 ؋ 10 5 gene copies per ml). HAdV and HPyV concentrations were 2 to 3 orders of magnitude lower than those of FIB and HF183. Strong positive and negative correlations were observed between the FIB and HFM concentrations within and across wastewater treatment plants (WWTPs). To identify the most sensitive marker of human fecal pollution, environmental water samples were seeded with raw human wastewater. The results from the seeding experiments indicated that Bacteroides HF183 was more sensitive for detecting human fecal pollution than HAdVs and HPyVs. Since the HF183 marker can occasionally be present in nontarget animal fecal samples, it is recommended that HF183 along with a viral marker (HAdVs or HPyVs) be used for tracking human fecal pollution in Australian environmental waters. Direct monitoring of pathogenic microorganisms in water resources is likely to provide important information regarding public health risks. However, routine monitoring for a wide variety of pathogenic microorganisms can be expensive and challenging due to their uneven distribution among the host population and the affected waters. The microbiological quality of water is generally assessed by monitoring fecal indicator bacteria (FIB), such as Escherichia coli and Enterococcus spp., using culture-based methods (1, 2). These FIB are abundant in the feces of warmblooded animals. The presence of elevated levels of FIB in environmental waters indicates not only the occurrence of fecal pollution but also the likely presence of pathogenic microorganisms that are capable of causing illnesses in exposed humans. For the remediation of polluted water bodies, it is vital for water utilities and regulators to identify the source(s) of the fecal pollution. However, monitoring FIB alone does not provide information regarding their origin due to their presence in all warm-blooded animals, including humans (3, 4). This major l...

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Escherichia coli and Enterococcus spp. in Rainwater Tank Samples: Comparison of Culture-Based Methods and 23S rRNA Gene Quantitative PCR Assays

Cited by 30 publications

References 39 publications

Microbial Quality and Phylogenetic Diversity of Fresh Rainwater and Tropical Freshwater Reservoir

Microbial Quality and Phylogenetic Diversity of Fresh Rainwater and Tropical Freshwater Reservoir

A global review of the microbiological quality and potential health risks associated with roof-harvested rainwater tanks

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

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