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.

scholarly journals Development of Goose- and Duck-Specific DNA Markers To Determine Sources of Escherichia coli in Waterways

2006 ◽  
Vol 72 (6) ◽  
pp. 4012-4019 ◽  
Author(s):  
Matthew J. Hamilton ◽  
Tao Yan ◽  
Michael J. Sadowsky
Keyword(s):  
Escherichia Coli ◽  
Dna Markers ◽  
Fecal Contamination ◽  
Cost Effective ◽  
Source Tracking ◽  
E Coli ◽  
Hybridization Probes ◽  
Animal Hosts ◽  
Maximum Daily Loads ◽  
Microarray Screening

ABSTRACT The contamination of waterways with fecal material is a persistent threat to public health. Identification of the sources of fecal contamination is a vital component for abatement strategies and for determination of total maximum daily loads. While phenotypic and genotypic techniques have been used to determine potential sources of fecal bacteria in surface waters, most methods require construction of large known-source libraries, and they often fail to adequately differentiate among environmental isolates originating from different animal sources. In this study, we used pooled genomic tester and driver DNAs in suppression subtractive hybridizations to enrich for host source-specific DNA markers for Escherichia coli originating from locally isolated geese. Seven markers were identified. When used as probes in colony hybridization studies, the combined marker DNAs identified 76% of the goose isolates tested and cross-hybridized, on average, with 5% of the human E. coli strains and with less than 10% of the strains obtained from other animal hosts. In addition, the combined probes identified 73% of the duck isolates examined, suggesting that they may be useful for determining the contribution of waterfowl to fecal contamination. However, the hybridization probes reacted mainly with E. coli isolates obtained from geese in the upper midwestern United States, indicating that there is regional specificity of the markers identified. Coupled with high-throughput, automated macro- and microarray screening, these markers may provide a quantitative, cost-effective, and accurate library-independent method for determining the sources of genetically diverse E. coli strains for use in source-tracking studies. However, future efforts to generate DNA markers specific for E. coli must include isolates obtained from geographically diverse animal hosts.

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>

Sequence of Colonization Determines the Composition of Mixed Biofilms by Escherichia coli O157:H7 and O111:H8 Strains†

2015 ◽  
Vol 78 (8) ◽  
pp. 1554-1559 ◽  
Author(s):  
RONG WANG ◽  
NORASAK KALCHAYANAND ◽  
JAMES L. BONO
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Early Stage ◽  
Critical Role ◽  
The United States ◽  
Food Samples ◽  
E Coli ◽  
Cell Percentage ◽  
Composition And Structure ◽  
Biofilm Development

Bacterial biofilms are one of the potential sources of cross-contamination in food processing environments. Shiga toxin–producing Escherichia coli (STEC) O157:H7 and O111:H8 are important foodborne pathogens capable of forming biofilms, and the coexistence of these two STEC serotypes has been detected in various food samples and in multiple commercial meat plants throughout the United States. Here, we investigated how the coexistence of these two STEC serotypes and their sequence of colonization could affect bacterial growth competition and mixed biofilm development. Our data showed that E. coli O157:H7 strains were able to maintain a higher cell percentage in mixed biofilms with the co-inoculated O111:H8 companion strains, even though the results of planktonic growth competition were strain dependent. On solid surfaces with preexisting biofilms, the sequence of colonization played a critical role in determining the composition of the mixed biofilms because early stage precolonization significantly affected the competition results between the E. coli O157:H7 and O111:H8 strains. The precolonizer of either serotype was able to outgrow the other serotype in both planktonic and biofilm phases. The competitive interactions among the various STEC serotypes would determine the composition and structure of the mixed biofilms as well as their potential risks to food safety and public health, which is largely influenced by the dominant strains in the mixtures. Thus, the analysis of mixed biofilms under various conditions would be of importance to determine the nature of mixed biofilms composed of multiple microorganisms and to help implement the most effective disinfection operations accordingly.

scholarly journals Identifying Host Sources of Fecal Pollution: Diversity of Escherichia coli in Confined Dairy and Swine Production Systems

2005 ◽  
Vol 71 (10) ◽  
pp. 5992-5998 ◽  
Author(s):  
Zexun Lu ◽  
David Lapen ◽  
Andrew Scott ◽  
Angela Dang ◽  
Edward Topp
Keyword(s):  
Escherichia Coli ◽  
Dairy Farm ◽  
Sampling Strategy ◽  
Farming Systems ◽  
Microbial Source Tracking ◽  
Fecal Pollution ◽  
Source Tracking ◽  
E Coli ◽  
Repetitive Extragenic Palindromic Pcr ◽  
Repetitive Extragenic Palindromic

ABSTRACT Repetitive extragenic palindromic PCR fingerprinting of Escherichia coli is one microbial source tracking approach for identifying the host source origin of fecal pollution in aquatic systems. The construction of robust known-source libraries is expensive and requires an informed sampling strategy. In many types of farming systems, waste is stored for several months before being released into the environment. In this study we analyzed, by means of repetitive extragenic palindromic PCR using the enterobacterial repetitive intergenic consensus primers and comparative analysis using the Bionumerics software, collections of E. coli obtained from a dairy farm and from a swine farm, both of which stored their waste as a slurry in holding tanks. In all fecal samples, obtained from either barns or holding tanks, the diversity of the E. coli populations was underrepresented by collections of 500 isolates. In both the dairy and the swine farms, the diversity of the E. coli community was greater in the manure holding tank than in the barn, when they were sampled on the same date. In both farms, a comparison of stored manure samples collected several months apart suggested that the community composition changed substantially in terms of the detected number, absolute identity, and relative abundance of genotypes. Comparison of E. coli populations obtained from 10 different locations in either holding tank suggested that spatial variability in the E. coli community should be accounted for when sampling. Overall, the diversity in E. coli populations in manure slurry storage facilities is significant and likely is problematic with respect to library construction for microbial source tracking applications.

scholarly journals Dynamic Changes in Antimicrobial Resistance in Fecal Escherichia coli from Neonatal Dairy Calves: An Individual Follow-Up Study

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1776
Author(s):  
Sang-Ik Oh ◽  
Seungmin Ha ◽  
Jae-Hee Roh ◽  
Tai-Young Hur ◽  
Jae Gyu Yoo
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Dairy Calves ◽  
Beta Lactams ◽  
Dynamic Changes ◽  
E Coli ◽  
Follow Up Study ◽  
Additional Resistance ◽  
Neonatal Calves

The prevalence of antimicrobial-resistant (AMR) Escherichia coli is typically higher in the feces of young dairy calves than in the feces of older cattle; however, the underlying factors contributing to this difference are poorly understood. In this study, AMR fecal E. coli from neonatal calves were characterized both at phenotypic and genotypic levels by individual follow-up sampling. Antimicrobial resistance profiles of E. coli isolates from the maternal colostrum were also determined. Most of the fecal AMR E. coli emerged in the calves at 2–3 days of age. The tetB was the most prevalent resistance gene detected among AMR fecal E. coli from <7-day-old calves, and was also detected in two isolates from the maternal colostrum. Weekly sampling revealed changes in the phenotype of AMR fecal E. coli as the calves aged. More than half of the fecal E. coli isolates acquired additional resistance to beta-lactams by 21–28 days of age, and minimum inhibitory concentrations were higher in ceftiofur-exposed calves than in unexposed calves. Our findings reveal the dynamic changes in AMR fecal E. coli from neonatal calves, and suggest that the feeding of colostrum and ceftiofur administration contribute to the higher prevalence of AMR E. coli in young dairy calves.

scholarly journals Reactive arthritis and other musculoskeletal symptoms associated with acquisition of diarrhoeagenic Escherichia coli (DEC)

2020 ◽  
Vol 79 (5) ◽  
pp. 605-611
Author(s):  
Riitta Tuompo ◽  
Tinja Lääveri ◽  
Timo Hannu ◽  
Sari H Pakkanen ◽  
Juha Kirveskari ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multivariate Analysis ◽  
Antibiotic Treatment ◽  
Reactive Arthritis ◽  
Musculoskeletal Symptoms ◽  
E Coli ◽  
Increased Risk ◽  
Stool Samples ◽  
Study Participants

ObjectivesUsing a prospective research design, we evaluated the association between acquisition of diarrhoeagenic Escherichia coli (DEC) and development of reactive arthritis (ReA) and other reactive musculoskeletal (MSK) symptoms among international travellers.MethodsA total of 526 study participants were asked to provide pretravel and post-travel stool samples and fill in questionnaires (pretravel, post-travel and 3-week follow-up). A multiplex quantitative PCR assay was deployed to detect five DEC comprising enteroaggregative E. coli, enteropathogenic E. coli, enterotoxigenic E. coli, enterohaemorrhagic E. coli and enteroinvasive E. coli and Salmonella, Shigella, Campylobacter, Yersinia, and Vibrio cholerae. Multivariate analysis was employed to identify factors predisposing to MSK symptoms. New post-travel MSK symptoms reported by participants with DEC were assessed by phone interviews and, if needed, clinically confirmed.ResultsFrom among the total of 224 volunteers who returned all questionnaires and stool specimens, 38 (17.0%) reported MSK symptoms. Multivariate analysis revealed that acquisition of DEC was associated with MSK symptoms (OR 3.9; 95% CI 1.2 to 13.3). Of the 151 with only-DEC, four (2.6%) had ReA, two (1.3%) reactive tendinitis and three (2.0%) reactive arthralgia. ReA was mostly mild, and all patients with ReA were negative for human leucocyte antigen B27. Antibiotic treatment of travellers’ diarrhoea did not prevent development of MSK symptoms.ConclusionA total of 17% of volunteers reported post-travel MSK symptoms. DEC acquisition was associated with an increased risk of developing them, yet the ReA incidence remained low and the clinical picture mild. Antibiotic treatment did not protect against development of MSK symptoms.

scholarly journals Heterogeneity of uidA gene in environmental Escherichia coli populations

2005 ◽  
Vol 3 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Clarivel Lasalde ◽  
Roberto Rodriguez ◽  
Gary A. Toranzos ◽  
Henry H. Smith
Keyword(s):  
Escherichia Coli ◽  
Genetic Heterogeneity ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Dry Weight ◽  
Source Tracking ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
E Coli ◽  
Gradient Gel Electrophoresis

Previous studies have shown that Escherichia coli can be isolated from non-polluted rivers and from bromeliad axilae in pristine areas of tropical rain forests. Finding E. coli in pristine environments is unusual because this bacterium is thought to only survive in the gut of warm-blooded animals and thus its presence should indicate recent fecal contamination. The aims of this study were 1) to determine if E. coli is part of the native soil microbiota in tropical rain forests and 2) to determine if genetic heterogeneity exists among E. coli populations. High concentrations of total coliforms (104–105 cells per 10 g of soil dry weight) and low concentrations of thermotolerant coliforms (101–102 cells per 10 g dry soil, the majority of these were found to be E. coli) were detected. PCR using uidA-specific primers was done on DNA purified from E. coli isolates and the resulting amplicons analysed by denaturing-gradient gel electrophoresis (DGGE). Out of several hundred isolates, mixtures of nine different amplicons were consistently observed. The different patterns of DGGE observed indicate that the E. coli populations in these pristine soils are genetically heterogeneous. Fecal and environmental E. coli isolates were also analysed by pulsed-field gel electrophoresis (PFGE) which showed high DNA sequence variation among the E. coli isolates. Because of these differences in the genomes, PFGE did not allow grouping of environmental versus human isolates of E. coli when compared side to side. The apparent genetic polymorphisms, as a result of genetic heterogeneity, observed in isolates from the same pristine site indicate that source tracking may be difficult to carry out using E. coli as the target organism.

Occurrence of antibiotic resistance inEscherichia colifrom surface waters and fecal pollution sources near Hamilton, Ontario

2005 ◽  
Vol 51 (6) ◽  
pp. 501-505 ◽  
Author(s):  
Thomas A Edge ◽  
Stephen Hill
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Surface Waters ◽  
Municipal Wastewater ◽  
Average Rate ◽  
Fecal Pollution ◽  
Pollution Sources ◽  
Source Tracking ◽  
E Coli ◽  
Bird Feces

Antibiotic resistance was examined in 462 Escherichia coli isolates from surface waters and fecal pollution sources around Hamilton, Ontario. Escherichia coli were resistant to the highest concentrations of each of the 14 antibiotics studied, although the prevalence of high resistance was mostly low. Two of 12 E. coli isolates from sewage in a CSO tank had multiple resistance to ampicillin, ciprofloxacin, gentamicin, and tetracycline above their clinical breakpoints. Antibiotic resistance was less prevalent in E. coli from bird feces than from municipal wastewater sources. A discriminant function calculated from antibiotic resistance data provided an average rate of correct classification of 68% for discriminating E. coli from bird and wastewater fecal pollution sources. The preliminary microbial source tracking results suggest that, at times, bird feces might be a more prominent contributor of E. coli to Bayfront Park beach waters than municipal wastewater sources.Key words: antibiotic resistance, Escherichia coli, surface water, fecal pollution.

scholarly journals Analysis of Serial Isolates of mcr-1-Positive Escherichia coli Reveals a Highly Active ISApl1 Transposon

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Erik Snesrud ◽  
Ana C. Ong ◽  
Brendan Corey ◽  
Yoon I. Kwak ◽  
Robert Clifford ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stress Responses ◽  
Single Copy ◽  
The United States ◽  
Content Type ◽  
E Coli ◽  
Highly Active ◽  
Copy Numbers ◽  
Genes Encoding

ABSTRACT The emergence of a transferable colistin resistance gene (mcr-1) is of global concern. The insertion sequence ISApl1 is a key component in the mobilization of this gene, but its role remains poorly understood. Six Escherichia coli isolates were cultured from the same patient over the course of 1 month in Germany and the United States after a brief hospitalization in Bahrain for an unconnected illness. Four carried mcr-1 as determined by real-time PCR, but two were negative. Two additional mcr-1-negative E. coli isolates were collected during follow-up surveillance 9 months later. All isolates were analyzed by whole-genome sequencing (WGS). WGS revealed that the six initial isolates were composed of two distinct strains: an initial ST-617 E. coli strain harboring mcr-1 and a second, unrelated, mcr-1-negative ST-32 E. coli strain that emerged 2 weeks after hospitalization. Follow-up swabs taken 9 months later were negative for the ST-617 strain, but the mcr-1-negative ST-32 strain was still present. mcr-1 was associated with a single copy of ISApl1, located on a 64.5-kb IncI2 plasmid that shared >95% homology with other mcr-1 IncI2 plasmids. ISApl1 copy numbers ranged from 2 for the first isolate to 6 for the final isolate, but ISApl1 movement was independent of mcr-1. Some movement was accompanied by gene disruption, including the loss of genes encoding proteins involved in stress responses, arginine catabolism, and l-arabinose utilization. These data represent the first comprehensive analysis of ISApl1 movement in serial clinical isolates and reveal that, under certain conditions, ISApl1 is a highly active IS element whose movement may be detrimental to the host cell.

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