scholarly journals Spatial variation of waterborne Escherichia coli – implications for routine water quality monitoring

2011 ◽  
Vol 9 (4) ◽  
pp. 734-737 ◽  
Author(s):  
Richard S. Quilliam ◽  
Katie Clements ◽  
Caroline Duce ◽  
Simon B. Cottrill ◽  
Shelagh K. Malham ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Spatial Variation ◽  
Water Quality Monitoring ◽  
Source Tracking ◽  
Microbial Water Quality ◽  
Physiochemical Properties ◽  
E Coli ◽  
Significant Difference

Escherichia coli are often used as faecal indicator bacteria (FIB) to provide a measure of microbial pollution in recreational and shellfish harvesting waters. However, although model forecasts for predicting the concentrations of FIB in surface waters are becoming more robust, they suffer from an inconsistency in quantification methods and an understanding of the spatial variation of FIB within a water course. The aim of this study was to investigate the transverse spatial variation in E. coli numbers (as an indicator of faecal pollution) across the estuary of the River Conwy, UK. Water samples were collected from four transverse transects across the estuary. Spatial variation of E. coli was significantly different from one side of the river to the other, although was not correlated with depth or the physiochemical properties of the water. Subsequently, microbial water quality classifications on the two opposite banks suggested very different levels of pollution coming down the river. This work has shown that the side of the river that routine water monitoring samples are taken from can make a significant difference to the classification of microbial water quality. This has important implications for sampling strategies and the use of microbial source tracking (MST) techniques.

Flood and rainfall mobilisation of E. coli and faecal source tracking markers from decomposing cowpats 

2021 ◽  
Author(s):  
Megan Devane ◽  
Brent Gilpin ◽  
Jennifer Webster-Brown ◽  
Louise Weaver ◽  
Pierre Dupont ◽  
...  
Keyword(s):  
Water Quality ◽  
Overland Flow ◽  
Quantitative Polymerase Chain Reaction ◽  
Linear Regression Analysis ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Source Tracking ◽  
Faecal Contamination ◽  
E Coli ◽  
Faecal Indicators

<p>The intensification of dairy farming on the agricultural landscape in New Zealand has raised concerns about pollution sources from dairy faecal runoff into waterways. The transport of faecal pollution from farms into waterways is facilitated by overland flow, which can result from rain and flood events, poorly designed irrigation practices and the washing down of milking sheds.</p><p>An important step for mitigation of pollution is the identification of the source(s) of faecal contamination. When elevated levels of faecal indicator bacteria (FIB) such as <em>Escherichia coli </em>are identified in a waterway, faecal source tracking (FST) tools such as microbial source tracking (MST) using quantitative polymerase chain reaction (qPCR), and faecal steroids (for example, cholesterol) provide information about the sources of faecal contamination. The understanding of the fate (degradation/persistence) and transport of these FST markers in the environment is recognised as an important requirement for the interpretation of water quality monitoring in aquatic environments.</p><p>This study investigated the effects of faecal decomposition on bovine faecal indicators (<em>E. coli </em>and FST markers: bovine-associated qPCR markers and ten faecal steroids) by monitoring the effect of flood and rainfall events on simulated cowpats over a five and a half month period under field conditions. Two separate spring/summer trials were conducted to evaluate: Trial 1) the mobilisation under simulated flood conditions of the faecal indicators from irrigated versus non-irrigated cowpats, Trial 2) the mobilisation of faecal indicators from non-irrigated cowpat flood runoff versus runoff after simulated rainfall onto non-irrigated cowpats.</p><p>The microbial community changes within the decomposing cowpat (as illustrated by amplicon-based metagenomic analysis) were expected to impact on the survival/persistence of the bacterial targets of the MST markers, and also alter the ratio between faecal sterols and their biodegradation products, the stanols. It was hypothesised, therefore, that there would be:</p><ul><li>Changes over time in the concentration of<em> E. coli </em>and the bovine-associated MST markers mobilised into the cowpat runoff</li> <li>Alterations in the FST ratio signature of the ten measured faecal steroids, resulting in a change from a bovine faecal steroid signature in fresh cowpat runoff to other animal faecal signatures in the runoff from decomposing cowpats</li> <li>A difference in the mobilisation decline rates of all FST and microbial markers within a treatment regime and between treatments.</li> </ul><p>Linear regression analysis was undertaken to establish mobilisation decline rates for each of the analytes in the mobilisable phase from the cowpat runoff treatments, with calculation of the time taken in days for reduction in 90% of the concentration (T<sub>90</sub>), and statistical comparison of the regression coefficients (slopes) of all analytes. The results will include a discussion of the impacts of the study’s observations on the interpretation of faecal indicator assessments for water quality monitoring in waterways influenced by sources of faecal contamination.</p>

scholarly journals Molecular Diagnostic Platforms for Specific Detection of Escherichia coli

2021 ◽  
Author(s):  
Rehan Deshmukh ◽  
Utpal Roy
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Water Quality Monitoring ◽  
Molecular Techniques ◽  
Quality Monitoring ◽  
Molecular Diagnostic ◽  
Water Contaminants ◽  
E Coli ◽  
Highly Sensitive ◽  
Safe Food

Developing countries due to socio-economic conditions are more prone to frequent pathogenic outbreaks; inadequate sanitation and water quality monitoring are also responsible for such conditions. Therefore, it is of paramount importance to provide microbiologically safe food/water in order to protect public health. Several flaws in traditional culturing methods have sparked a surge in interest in molecular techniques as a means of improving the efficiency and sensitivity of microbiological food/water quality monitoring. Molecular identification of water contaminants, mainly Escherichia coli, has been extensively used. Several of the molecular-based techniques are based on amplification and detection of nucleic acids. The advantages offered by these PCR-based methods over culture-based techniques are a higher level of specificity, sensitivity, and rapidity. Of late, the development of a biosensor device that is easy to perform, highly sensitive, and selective has the potential to become indispensable in detecting low CFU of pathogenic E. coli in environmental samples. This review seeks to provide a vista of the progress made in the detection of E. coli using nucleic acid-based approaches as part of the microbiological food/water quality monitoring.

scholarly journals Tracking the relative concentration between Bacteroidales DNA markers and culturable Escherichia coli in fecally polluted subtropical seawater: potential use in differentiating fresh and aged pollution

2017 ◽  
Vol 63 (3) ◽  
pp. 252-259
Author(s):  
Rulong Liu ◽  
Leo T.C. Yeung ◽  
Pui-Hei Ho ◽  
Stanley C.K. Lau
Keyword(s):  
Escherichia Coli ◽  
Dna Markers ◽  
Early Stage ◽  
Relative Concentration ◽  
Water Quality Monitoring ◽  
Source Tracking ◽  
E Coli ◽  
Sample Maximum ◽  
Pollution Events

Routine water quality monitoring practices based on the enumeration of culturable Escherichia coli provides no information about the source or age of fecal pollution. An emerging strategy is to use culturable E. coli and the DNA markers of Bacteroidales complementarily for microbial source tracking. In this study, we consistently observed in seawater microcosms of 3 different conditions that culturable E. coli decayed faster (T99 = 1.14 – 4.29 days) than Bacteroidales DNA markers did (T99 = 1.81 – 200.23 days). Concomitantly, the relative concentration between Bacteroidales DNA markers and culturable E. coli increased over time in all treatments. Particularly, the increase during the early stage of the experiments (before T99 of E. coli was reached) was faster than during the later stage (after T99 of E. coli was attained). We propose that the tracking of the relative concentration between Bacteroidales DNA markers and culturable E. coli provides an opportunity to differentiate a pollution that is relatively fresh from one that has aged. This method, upon further investigation and validation, could be useful in episodic pollution events where the surge of E. coli concentration causes noncompliance to the single sample maximum criterion that mandates high frequency follow-up monitoring.

Diurnal variability in concentrations and sources of Escherichia coli in three streams

2006 ◽  
Vol 52 (11) ◽  
pp. 1130-1135 ◽  
Author(s):  
Cindy L Meays ◽  
Klaas Broersma ◽  
Rick Nordin ◽  
Asit Mazumder ◽  
Mansour Samadpour
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Drinking Water ◽  
Scientific Data ◽  
Source Tracking ◽  
Diurnal Variability ◽  
E Coli ◽  
Monitoring Programs ◽  
Margin Of Error ◽  
Monitoring Protocols

Microbial contamination is a major concern for drinking water worldwide. Many monitoring protocols that use one or very few samples are inadequate and introduce a very large margin of error. An intensive sampling program needs to be conducted to characterize the Escherichia coli concentrations of a source water stream prior to establishing a monitoring program so that the sample frequency can be determined statistically, based on an acceptable margin of error. Developing meaningful monitoring programs for managing bacterial water quality is dependant on scientific data that determine the bacterial sources. In this study, three streams from drinking water watersheds were sampled every 15 min over a 24 h period on three different days to determine the concentrations of E. coli and to identify their sources, using ribosomal RNA finger printing (ribotyping). The concentrations of E. coli varied throughout the day in each of the three streams. Ribotyping identified many different animal sources of E. coli in the samples. The sources of E. coli varied significantly with stream (P < 0.001, df = 16). The development of monitoring programs for watersheds needs to consider the watershed, and care needs to be taken in selecting appropriate sample sites, sampling regime, and number of samples taken during each sampling period. This note provides a prescription for the development of monitoring programs for watersheds.Key words: Escherichia coli, fecal bacteria, water quality, ribotyping, source tracking, microbial source tracking, bacterial source tracking.

scholarly journals Diversity and Distribution of Escherichia coli Genotypes and Antibiotic Resistance Phenotypes in Feces of Humans, Cattle, and Horses

2006 ◽  
Vol 72 (11) ◽  
pp. 6914-6922 ◽  
Author(s):  
Matthew A. Anderson ◽  
John E. Whitlock ◽  
Valerie J. Harwood
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Antibiotic Resistance ◽  
Host Species ◽  
Model Organism ◽  
Source Tracking ◽  
Sampling Effort ◽  
Indicator Organisms ◽  
High Genetic Diversity ◽  
E Coli

ABSTRACT Escherichia coli is the most completely characterized prokaryotic model organism and one of the dominant indicator organisms for food and water quality testing, yet comparatively little is known about the structure of E. coli populations in their various hosts. The diversities of E. coli populations isolated from the feces of three host species (human, cow, and horse) were compared by two subtyping methods: ribotyping (using HindIII) and antibiotic resistance analysis (ARA). The sampling effort required to obtain a representative sample differed by host species, as E. coli diversity was consistently greatest in horses, followed by cattle, and was lowest in humans. The diversity of antibiotic resistance patterns isolated from individuals was consistently greater than the diversity of ribotypes. E. coli populations in individuals sampled monthly, over a 7- to 8-month period, were highly variable in terms of both ribotypes and ARA phenotypes. In contrast, E. coli populations in cattle and humans were stable over an 8-h period. Following the cessation of antibiotic therapy, the E. coli population in the feces of one human experienced a rapid and substantial shift, from a multiply antibiotic-resistant phenotype associated with a particular ribotype to a relatively antibiotic-susceptible phenotype associated with a different ribotype. The high genetic diversity of E. coli populations, differences in diversity among hosts, and temporal variability all indicate complex population dynamics that influence the usefulness of E. coli as a water quality indicator and its use in microbial source tracking studies.

scholarly journals Temporal Stability ofEscherichia coliConcentrations in Waters of Two Irrigation Ponds in Maryland

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Yakov Pachepsky ◽  
Rachel Kierzewski ◽  
Matthew Stocker ◽  
Kevin Sellner ◽  
Walter Mulbry ◽  
...  
Keyword(s):  
Water Quality ◽  
Irrigation Water ◽  
Temporal Stability ◽  
Water Quality Monitoring ◽  
Water Sources ◽  
Microbial Water Quality ◽  
Content Type ◽  
Environmental Covariates ◽  
E Coli ◽  
Relative Differences

ABSTRACTFecal contamination of water sources is an important water quality issue for agricultural irrigation ponds.Escherichia coliconcentrations are commonly used to evaluate recreational and irrigation water quality. We hypothesized that there may exist temporally stable spatial patterns ofE. coliconcentrations across ponds, meaning that some areas mostly have higher and other areas mostly lower than average concentrations ofE. coli. To test this hypothesis, we sampled two irrigation ponds in Maryland at nodes of spatial grids biweekly during the summer of 2016. Environmental covariates—temperature, turbidity, conductivity, pH, dissolved oxygen, chlorophylla, and nutrients—were measured in conjunction withE. coliconcentrations. Temporal stability was assessed using mean relative differences between measurements in each location and averaged measurements across ponds. Temporally stable spatial patterns ofE. coliconcentrations and the majority of environmental covariates were expressed for both ponds. In the pond interior, larger relative mean differences in chlorophyllacorresponded to smaller mean relative differences inE. coliconcentrations, with a Spearman's rank correlation coefficient of 0.819. Turbidity and ammonium concentrations were the two other environmental covariates with the largest positive correlations between their location ranks and theE. coliconcentration location ranks. Tenfold differences were found between geometric meanE. coliconcentrations in locations that were consistently high or consistently low. The existence of temporally stable patterns ofE. coliconcentrations can affect the results of microbial water quality assessment in ponds and should be accounted for in microbial water quality monitoring design.IMPORTANCEThe microbial quality of water in irrigation water sources must be assessed to prevent the spread of microbes that can cause disease in humans because of produce consumption. The microbial quality of irrigation water is evaluated based on concentrations ofEscherichia colias the indicator organism. Given the high spatial and temporal variability ofE. coliconcentrations in irrigation water sources, recommendations are needed on where and when samples of water have to be taken for microbial analysis. This work demonstrates the presence of a temporally stable spatial pattern in the distributions ofE. coliconcentrations across irrigation ponds. The ponds studied had zones whereE. coliconcentrations were mostly higher than average and zones where the concentrations were mostly lower than average over the entire observation period, covering the season when water was used for irrigation. Accounting for the existence of such zones will improve the design and implementation of microbial water quality monitoring.

scholarly journals Relative Decay of Bacteroidales Microbial Source Tracking Markers and Cultivated Escherichia coli in Freshwater Microcosms

2010 ◽  
Vol 76 (10) ◽  
pp. 3255-3262 ◽  
Author(s):  
Linda K. Dick ◽  
Erin A. Stelzer ◽  
Erin E. Bertke ◽  
Denise L. Fong ◽  
Donald M. Stoeckel
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Microbial Source Tracking ◽  
Decay Rates ◽  
Source Tracking ◽  
Rrna Gene ◽  
Fecal Indicator ◽  
Gene Markers ◽  
E Coli ◽  
Log Reduction

ABSTRACT Fecal indicator bacteria (FIB), commonly used to regulate sanitary water quality, cannot discriminate among sources of contamination. The use of alternative quantitative PCR (qPCR) methods for monitoring fecal contamination or microbial source tracking requires an understanding of relationships with cultivated FIB, as contamination ages under various conditions in the environment. In this study, the decay rates of three Bacteroidales 16S rRNA gene markers (AllBac for general contamination and qHF183 and BacHum for human-associated contamination) were compared with the decay rate of cultivated Escherichia coli in river water microcosms spiked with human wastewater. The following five sets of microcosms were monitored over 11 days: control, artificial sunlight, sediment exposure, reduced temperature, and no autochthonous predation. Decay was characterized by estimation of the time needed to produce a 2-log reduction (t 99). No treatment-associated differences in the decay of the 4 targets were evident except with reduced predation, where E. coli, qHF183, and BacHum markers had lower levels of decay by day 3. However, there were substantial target-associated differences. Decay curves for the AllBac marker indicated a larger persistent population than those of the other targets. Exposure to sunlight, sediment, and reduced predation resulted in more rapid decay of the human-associated markers relative to cultivable E. coli, but there were no differences in t 99 values among the 4 targets under control conditions or at reduced temperatures. Further evaluation of epidemiological relationships will be needed in order to relate the markers directly to health risk. These findings suggest that the tested human-associated markers can complement E. coli as indicators of the human impact on sanitary water quality under the constrained conditions described in this paper.

UAV-based imagery analysis with machine learning to facilitate microbial water quality monitoring of irrigation ponds

2020 ◽  
Author(s):  
Yakov Pachepsky ◽  
Billie Morgan ◽  
Matthew Stocker ◽  
Moon Kim
Keyword(s):  
Water Quality ◽  
Random Forest ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Unmanned Aerial Systems ◽  
Water Sampling ◽  
Microbial Water Quality ◽  
Explanatory Variables ◽  
E Coli ◽  
Spatial Coverage

&lt;p&gt;Surface waters can contain pathogenic microorganisms that may&amp;#160;&amp;#8203;be detrimental to individuals consuming produce grown with irrigation. Fecal indicator organisms, primarily Escherichia coli, are commonly used to estimate the potential presence of pathogens in irrigation waters.&amp;#160; Concentrations of E. coli in the water of irrigation ponds are often highly variable in space and time. Water sampling that is frequent in time and dense in space, is impractical. Unmanned aerial systems (drones, or UAVs) have shown the potential to provide informative imagery. We hypothesized that the UAV-based imagery can facilitate the microbial water quality monitoring in ponds by reflecting the differences in bacteria habitats. &amp;#8203;Six times over the summer, we coupled monitoring of 17 water quality parameters&amp;#160;&amp;#8203;of 23 locations across an irrigation pond in Maryland with 14 images &amp;#8203;captured by a MicaSense RedEdge M and modified GoPro cameras. The modified GoPro Images were demosaiced into red, green, and blue bands for each of the cameras. The random forest methodology was used to evaluate the accuracy and reliability of relationships between several combinations of measured &amp;#8203;explanatory variables, and the logarithm of the E. coli concentration as the variable to predict. Random forest models with only imagery data as the &amp;#8203;explanatory variables, and &amp;#8203;models with all measured data as&amp;#160;explanatory variables had coefficients of determination between 0.5&amp;#160;&amp;#8203;to 0.6, and 0.6&amp;#160;&amp;#8203;to 0.7, respectively. The most important explanatory variables for the model with only imagery input were digital numbers&amp;#160;&amp;#8203;obtained from the blue band of the &amp;#8220;visible only&amp;#8221; filter image, and from the red bands of the &amp;#8220;infrared only&amp;#8221; and &amp;#8220;visible only&amp;#8221; filter images. &amp;#160;When all measurements were used, the most important explanatory variables were concentrations of chlorophyll a and fluorescent dissolved organic matter, as well as and digital number&amp;#8203;s from the red band &amp;#8203;of the &amp;#8220;infrared only&amp;#8221; filter image. There appears to be a potential for the UAV-based imagery to provide dense spatial coverage of ponds with subsequent delineation of a small number of relatively uniform zones for informed water sampling.&amp;#160;&lt;/p&gt;

scholarly journals Distribution of Sulfonamide Resistance Genes in Escherichia coli and Salmonella Isolates from Swine and Chickens at Abattoirs in Ontario and Québec, Canada

2009 ◽  
Vol 75 (18) ◽  
pp. 5999-6001 ◽  
Author(s):  
Gosia K. Kozak ◽  
David L. Pearl ◽  
Julia Parkman ◽  
Richard J. Reid-Smith ◽  
Anne Deckert ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
E Coli ◽  
Significant Difference ◽  
Sulfonamide Resistance ◽  
Sulfonamide Resistance Genes

ABSTRACT Sulfonamide-resistant Escherichia coli and Salmonella isolates from pigs and chickens in Ontario and Québec were screened for sul1, sul2, and sul3 by PCR. Each sul gene was distributed differently across populations, with a significant difference between distribution in commensal E. coli and Salmonella isolates and sul3 restricted mainly to porcine E. coli isolates.

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