Population dynamics and genetic variability of Escherichia coli in a mixed land-use watershed

Wijesinghe, Rasanthi U.; Feng, Yanfang; Wood, C. W.; Stoeckel, Donald M.; Shaw, Joey N.

doi:10.2166/wh.2009.105

Cited by 5 publications

(7 citation statements)

References 28 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results further indicate that the shifting of the E. coli population was also occurring on a monthly scale. In agreement with our results, season-specific clustering of E. coli genotypes was observed previously for different surface waters (35,42).…”

Section: Discussionsupporting

confidence: 93%

“…Overall, ϳ51% (n ϭ 335) of the genotypes identified in the present study were unique, and the corresponding diversity index was higher than those previously reported for different surface waters dominated by urban land use watersheds in the United States (30,31) and farming land use watersheds in Canada (56), indicating the high genetic diversity of E. coli isolates obtained in the present study. However, the diversity index recorded in the present study was lower than that for isolates from an urban river (4), the Catoma Creek watershed in Alabama (54%) (35). It has been documented that E. coli strains isolated from contaminated surface water had less diversity than isolates obtained from human and nonhuman host sources (4).…”

Section: Discussioncontrasting

confidence: 77%

“…Seasonal changes in fecal contamination sources have also been reported for spring samples originating mainly from treated wastewater effluent, whereas the percentage of E. coli strains from waterfowl increased from summer to autumn (58). Therefore, the temporal variation/association of E. coli on annual, seasonal, and monthly scales observed in the present study may be attributed to the variations in the contributing host sources (animals) from which they are originally derived, their dominance/ activity during a particular time/season (28,32,33,35), temporal variability or instability (9), and high clonal diversity from host or geographic locations (59). Overall, the results of fingerprint analyses indicated that the diversity and population structure of E. coli fluctuate on a temporal scale, reflecting the presence of diverse host sources and their behavior over time in the watershed.…”

Section: Discussionsupporting

confidence: 67%

“…Such variations have been observed among the genotypes of E. coli isolated from different animals and avian host sources in BC, Canada (21,22). Despite the large amount of data available on the genetic diversity of E. coli in the aquatic environment (4,30,31,34,35), only limited information is available on the temporal variation of the diversity and population structure of E. coli in the surface water over multiple years in Canada on annual, seasonal, and monthly scales. Therefore, the objectives of the present investigation were (i) to determine the prevalence of diarrheagenic virulence genes in E. coli isolates obtained from the drinking water intakes of Comox Lake and (ii) to determine the temporal variation (annual, seasonal, and monthly) in the genetic diversity and population structure of these isolates over multiple years by using repetitive element palindromic PCR (rep-PCR) fingerprinting.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Pathogenic Potential, Genetic Diversity, and Population Structure of Escherichia coli Strains Isolated from a Forest-Dominated Watershed (Comox Lake) in British Columbia, Canada

Chandran

Mazumder

2015

Appl Environ Microbiol

View full text Add to dashboard Cite

Escherichia coli isolates (n ‫؍‬ 658) obtained from drinking water intakes of Comox Lake (2011 to 2013) were screened for the following virulence genes (VGs): stx 1 and stx 2 (Shiga toxin-producing E. coli [STEC]), eae and the adherence factor (EAF) gene (enteropathogenic E. coli [EPEC]), heat-stable (ST) enterotoxin (variants STh and STp) and heat-labile enterotoxin (LT) genes (enterotoxigenic E. coli [ETEC]), and ipaH (enteroinvasive E. coli [EIEC]). The only genes detected were eae and stx 2 , which were carried by 37.69% (n ‫؍‬ 248) of the isolates. Only eae was harbored by 26.74% (n ‫؍‬ 176) of the isolates, representing potential atypical EPEC strains, while only stx 2 was detected in 10.33% (n ‫؍‬ 68) of the isolates, indicating potential STEC strains. Moreover, four isolates were positive for both the stx 2 and eae genes, representing potential EHEC strains. The prevalence of VGs (eae or stx 2 ) was significantly (P < 0.0001) higher in the fall season, and multiple genes (eae plus stx 2 ) were detected only in fall. Repetitive element palindromic PCR (rep-PCR) fingerprint analysis of 658 E. coli isolates identified 335 unique fingerprints, with an overall Shannon diversity (H=) index of 3.653. Diversity varied among seasons over the years, with relatively higher diversity during fall. Multivariate analysis of variance (MANOVA) revealed that the majority of the fingerprints showed a tendency to cluster according to year, season, and month. Taken together, the results indicated that the diversity and population structure of E. coli fluctuate on a temporal scale, reflecting the presence of diverse host sources and their behavior over time in the watershed. Furthermore, the occurrence of potentially pathogenic E. coli strains in the drinking water intakes highlights the risk to human health associated with direct and indirect consumption of untreated surface water. F ecal contamination is the primary contributor of pathogens to surface water and constitutes a significant public health risk. In Canada, the estimated rate of acute gastrointestinal illness attributable to water is 0.11 cases per person per year, which poses a substantial economic burden (1). Traditionally, the safety of water used for drinking and recreation as required by regulation is assessed in terms of the concentration of Escherichia coli, a dominant intestinal inhabitant of humans and warm-blooded animals, whose presence in water indicates fecal contamination and the potential presence of enteric pathogens (2). The sources of E. coli in the aquatic environment can originate from runoff from land applied with animal wastes or animal feeding operations, urban runoff, inadequate or failing septic or sewer systems, and wildlife (3). Identification of the source of fecal pollution is a high priority in order to protect and manage source water quality and also to assess the potential public health risk associated with fecal contamination from a given host source (4). To this end, many advances have been made in recent years to develop various ...

show abstract

Section: Discussionsupporting

confidence: 93%

Section: Discussioncontrasting

confidence: 77%

Section: Discussionsupporting

confidence: 67%

mentioning

confidence: 99%

See 2 more Smart Citations

Pathogenic Potential, Genetic Diversity, and Population Structure of Escherichia coli Strains Isolated from a Forest-Dominated Watershed (Comox Lake) in British Columbia, Canada

Chandran

Mazumder

2015

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Studies have revealed enormous diversity in E. coli populations in primary and various secondary habitats. These include feces from various mammalian and avian hosts (2,22), stored dairy and swine manure (39), home septic systems (19), fresh and marine surface water (35,43,56), beach sand (59), soils (7), and the freshwater macrophytic green alga Cladophora (8). Many aspects of this enormous diversity have importance for the assessment and management of water quality.…”

Section: Vol 76 2010 Distribution and Diversity Of E Coli In A Watmentioning

confidence: 99%

Distribution and Diversity of Escherichia coli Populations in the South Nation River Drainage Basin, Eastern Ontario, Canada

Lyautey

Lü

Lapen

et al. 2010

Appl Environ Microbiol

View full text Add to dashboard Cite

We investigated the prevalence and diversity of Escherichia coli strains isolated from surface waters from multiple watersheds within the South Nation River basin in eastern Ontario, Canada. The basin is composed of mixed but primarily agricultural land uses. From March 2004 to November 2007, a total of 2,004 surface water samples were collected from 24 sampling sites. E. coli densities ranged from undetectable to 1.64 ؋ 10 5 CFU 100 ml ؊1 and were correlated with stream order and proximity to livestock production systems. The diversity of 21,307 E. coli isolates was characterized using repetitive extragenic palindromic PCR (rep-PCR), allowing for the identification of as many as 7,325 distinct genotypes, without capturing all of the diversity. The community was temporally and spatially dominated by a few dominant genotypes (clusters of more than 500 isolates) and several genotypes of intermediary abundance (clustering between 10 and 499 isolates). Simpson diversity indices, assessed on a normalized number of isolates per sample, ranged from 0.050 to 0.668. Simpson indices could be statistically discriminated on the basis of year and stream order, but land use, discharge, weather, and water physical-chemical properties were not statistically important discriminators. The detection of Campylobacter species was associated with statistically lower Simpson indices (greater diversity; P < 0.05). Waterborne E. coli isolates from genotypes of dominant and intermediary abundance were clustered with isolates obtained from fecal samples collected in the study area over the same period, and 90% of the isolates tested proved to share genotypes with fecal isolates. Overall, our data indicated that the densities and distribution of E. coli in these mixed-use watersheds were linked to stream order and livestock-based land uses. Waterborne E. coli populations that were distinct from fecal isolates were detected and, on this basis, were possibly naturalized E. coli strains.Escherichia coli is ubiquitously distributed in fecal material from humans and warm-blooded animals (38). The detection of E. coli in water is an implicit indicator of recent fecal contamination and therefore of the risk of cooccurrence of enteric pathogens that can cause illness in susceptible populations (62). Many jurisdictions evaluate and mandate compliance with drinking and recreational water quality standards on the basis of the presence and abundance of E. coli (14,44). For example, Canadian recreational water quality standards stipulate that E. coli densities in excess of a geometric mean of 200 CFU per 100 ml indicate that the water is unsuitable for swimming and bathing (23).In a background of increasing occurrence of microbial contamination of surface water, a variety of methods for elucidating the sources of fecal contamination have been developed, and these microbial source tracking (MST) methods are recommended components of fecal pollution abatement strategies (16,57). So-called library-dependent MST methods compare environmental isolates to co...

show abstract

Semi-quantitative evaluation of fecal contamination potential by human and ruminant sources using multiple lines of evidence

Stoeckel

Stelzer

Stogner³

et al. 2011

Water Research

View full text Add to dashboard Cite

Population dynamics and genetic variability of Escherichia coli in a mixed land-use watershed

Cited by 5 publications

References 28 publications

Pathogenic Potential, Genetic Diversity, and Population Structure of Escherichia coli Strains Isolated from a Forest-Dominated Watershed (Comox Lake) in British Columbia, Canada

Pathogenic Potential, Genetic Diversity, and Population Structure of Escherichia coli Strains Isolated from a Forest-Dominated Watershed (Comox Lake) in British Columbia, Canada

Distribution and Diversity of Escherichia coli Populations in the South Nation River Drainage Basin, Eastern Ontario, Canada

Semi-quantitative evaluation of fecal contamination potential by human and ruminant sources using multiple lines of evidence

Contact Info

Product

Resources

About