scholarly journals Quantitative Detection of Escherichia coli O157 in Surface Waters by Using Immunomagnetic Electrochemiluminescence

2001 ◽  
Vol 67 (7) ◽  
pp. 2908-2915 ◽  
Author(s):  
Daniel R. Shelton ◽  
Jeffrey S. Karns
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Water Samples ◽  
Dynamic Range ◽  
Quantitative Detection ◽  
Raw Water ◽  
Cell Capture ◽  
O157 Strain ◽  
E Coli ◽  
Made In

ABSTRACT A protocol for the quantitative detection of Escherichia coli O157 in raw and concentrated surface waters using immunomagnetic electrochemiluminescence (IM-ECL) was developed and optimized. Three antibody sandwich formats were tested: commercial anti-O157:H7 IM beads, IM beads made in-house with a polyclonal anti-O157:H7 immunoglobulin G (IgG), or IM beads made in-house with a monoclonal anti-O157:H7 IgG coupled with a polyclonal anti-O157:H7 IgG to which an electrochemiluminescent label (TAG) was attached. The monoclonal IM bead-polyclonal TAG format was chosen for optimization because it gave lower background levels and linear regression slopes of ca. 1.0, indicative of a constant ECL signal per cell. The dynamic range was ca. 101 to 105 cells ml−1 in phosphate-buffered saline and in raw water samples. The monoclonal IM beads selectively captured E. coli O157 cells in the presence of ca. 108 cells of a non-O157 strain of E. coli ml−1. Background ECL signals from concentrated (100-fold) water samples were substantially higher and more variable than raw water samples. The background signal was partially eliminated by the addition of polyvinylpolypyrrolidone. Successive cell capture incubations, termed sequential bead capture (SBC), were optimized for establishing baseline ECL values for individual water samples. The linear dynamic range with SBC was ca. 102 to 105 E. coli O157 cells ml of concentrated water−1. To validate the protocol, 10-liter surface water samples were spiked with ca. 5,000E. coli O157 (Odwalla) cells and concentrated by vortex filtration, and 1- or 3-ml aliquots were analyzed by IM-ECL. Differential ECL signals (SBC) from 1- and 3-ml samples were statistically significant and were generally consistent with standard curves for these cell concentrations. Enrichments were conducted with aliquots of spiked raw water and concentrated water using EC broth and minimal lactose broth (MLB). All tubes with concentrated water became turbid and gave a positive ECL response for E. coli O157 (>10,000 ECL units); MLB gave a somewhat higher detection rate with spiked raw water. The potential sensitivity of the IM-ECL assay is ca. 25 E. coli O157 cells ml of raw water−1, 25 cells 100 ml of 100-fold concentrated water−1, or 1 to 2 viable cells liter−1 with concentration and enrichment. The IM-ECL assay appears suitable for routine analysis and screening of water samples.

scholarly journals Quantitative assessment of Naegleria fowleri and Escherichia coli concentrations within a Texas reservoir

2013 ◽  
Vol 11 (2) ◽  
pp. 346-357 ◽  
Author(s):  
Stephanie M. Painter ◽  
Russell S. Pfau ◽  
Jeff A. Brady ◽  
Anne M. S. McFarland
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Water Samples ◽  
Late Summer ◽  
Naegleria Fowleri ◽  
Fecal Indicator ◽  
E Coli ◽  
Environmental Surface ◽  
Polymerase Chain ◽  
Nægleria Fowleri

Previous presence/absence studies have indicated a correlation between the presence of the pathogenic amoeba Naegleria fowleri and the presence of bacteria, such as the fecal indicator Escherichia coli, in environmental surface waters. The objective of this study was to use quantitative real-time polymerase chain reaction (qPCR) methodologies to measure N. fowleri and E. coli concentrations within a Texas reservoir in late summer, and to determine if concentrations of N. fowleri and E. coli were statistically correlated. N. fowleri was detected in water samples from 67% of the reservoir sites tested, with concentrations ranging up to an estimated 26 CE (cell equivalents)/100 mL. E. coli was detected in water samples from 60% of the reservoir sites tested, with concentrations ranging up to 427 CE/100 mL. In this study, E. coli concentrations were not indicative of N. fowleri concentrations.

scholarly journals Host Species-Specific Metabolic Fingerprint Database for Enterococci and Escherichia coli and Its Application To Identify Sources of Fecal Contamination in Surface Waters

2005 ◽  
Vol 71 (8) ◽  
pp. 4461-4468 ◽  
Author(s):  
W. Ahmed ◽  
R. Neller ◽  
M. Katouli
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Water Samples ◽  
Fecal Contamination ◽  
E Coli ◽  
Individual Host ◽  
Metabolic Fingerprint ◽  
The Mean ◽  
Species Specific ◽  
Fingerprint Database

ABSTRACT A metabolic fingerprint database of enterococci and Escherichia coli from 10 host groups of animals was developed to trace the sources of fecal contamination in surface waters. In all, 526 biochemical phenotypes (BPTs) of enterococci and 530 E. coli BPTs were obtained from 4,057 enterococci and 3,728 E. coli isolates tested. Of these, 231 Enterococcus BPTs and 257 E. coli BPTs were found in multiple host groups. The remaining 295 Enterococcus BPTs and 273 E. coli BPTs were unique to individual host groups. The database was used to trace the sources of fecal contamination in a local creek. The mean diversities (Di) of enterococci (Di = 0.76 ± 0.05) and E. coli (Di = 0.88 ± 0.04) were high (maximum 1) in water samples, indicating diverse sources of fecal contamination. Overall, 71% of BPTs of enterococci and 67% of E. coli BPTs from water samples were identified as human and animal sources. Altogether, 248 Enterococcus BPTs and 282 E. coli BPTs were found in water samples. Among enterococci, 26 (10%) BPTs were identical to those of humans and 152 BPTs (61%) were identical to those of animals (animal BPTs). Among E. coli isolates, 36 (13%) BPTs were identical to those of humans and 151 (54%) BPTs were identical to those of animals. Of the animal BPTs, 101 (66%) Enterococcus BPTs and 93 (62%) E. coli BPTs were also unique to individual animal groups. On the basis of these unique Enterococcus BPTs, chickens contributed 14% of contamination, followed by humans (10%), dogs (7%), and horses (6%). For E. coli, humans contributed 13% of contamination, followed by ducks (9%), cattle (7%), and chickens (6%). The developed metabolic fingerprint database was able to distinguish between human and animal sources as well as among animal species in the studied catchment.

scholarly journals Population similarity of enterococci and Escherichia coli in surface waters: A predictive tool to trace the sources of fecal contamination

2006 ◽  
Vol 4 (3) ◽  
pp. 347-356 ◽  
Author(s):  
W. Ahmed ◽  
R. Neller ◽  
M. Katouli
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Water Samples ◽  
Animal Species ◽  
Fecal Contamination ◽  
Indicator Bacteria ◽  
Similarity Analysis ◽  
Wet Season ◽  
E Coli ◽  
Dry Seasons

A biochemical fingerprinting method (the PhPlate system) was used to compare similarities between Escherichia coli and enterococci populations from surface water samples with those found in different animal species during the wet and the dry seasons in order to predict the dominant source(s) of fecal contamination in a local creek. A significant increase in the number and diversity of enterococci was observed in the creek during the wet season. Enterococci population from water samples also showed a higher population similarity with animal species than did E. coli. A higher population similarity was found between both indicator bacteria and animal species during the wet season with highest population similarities found in dogs, horses, cows and kangaroos. In contrast, a low population similarity was found for both fecal indicator bacteria from humans with water samples during the wet and the dry seasons, indicating that humans are not a major source of contamination in the studied creek. The results also indicate that the population similarity analysis of enterococci population has an advantage over E. coli in tracing the possible source(s) of contamination in the studied creek and that population similarity analysis as used in this study can be used to predict the source(s) of fecal contamination in surface waters.

An Improved Membrane Filtration Method for Enumeration of Faecal Coliforms and E. Coli by a Fluorogenic β-Glucuronidase Assay

1993 ◽  
Vol 27 (3-4) ◽  
pp. 267-270 ◽  
Author(s):  
M. T. Augoustinos ◽  
N. A. Grabow ◽  
B. Genthe ◽  
R. Kfir
Keyword(s):  
Escherichia Coli ◽  
Water Samples ◽  
Membrane Filtration ◽  
Faecal Coliforms ◽  
Environmental Waters ◽  
Filtration Method ◽  
E Coli ◽  
Wide Range ◽  
Pure Cultures ◽  
Glucuronidase Assay

A fluorogenic β-glucuronidase assay comprising membrane filtration followed by selective enumeration on m-FC agar at 44.5°C and further confirmation using tlie 4-metliylumbelliferyl-β-D-glucuronide (MUG) containing medium was evaluated for the detection of Escherichia coli in water. A total of 200 typical blue and non-typical blue colonies were isolated from sea and fresh water samples using initial selective enumeration on m-FC agar. Pure cultures of the selected colonies were further tested using the MUG assay and identified using the API 20E method. Of the colonies tested which were shown to be positive using the MUG assay 99.4% were Escherichia coli. The results of this study indicate the combination of the m-FC method followed by the MUG assay to be highly efficient for the selection and confirmation of E. coli from a wide range of environmental waters.

scholarly journals Erosion and Subsequent Transport State of Escherichia coli from Cowpats

2005 ◽  
Vol 71 (6) ◽  
pp. 2875-2879 ◽  
Author(s):  
Richard William Muirhead ◽  
Robert Peter Collins ◽  
Philip James Bremer
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Overland Flow ◽  
Single Cells ◽  
Rainfall Event ◽  
Buffer Strips ◽  
Simulated Rainfall ◽  
E Coli ◽  
Unattached Fraction ◽  
Over Time

ABSTRACT Processes by which fecal bacteria enter overland flow and their transportation state to surface waters are poorly understood, making the effectiveness of measures designed to intercept this pathway, such as vegetated buffer strips, difficult to predict. Freshly made and aged (up to 30 days) cowpats were exposed to simulated rainfall, and samples of the cowpat material and runoff were collected. Escherichia coli in the runoff samples were separated into attached (to particles) and unattached fractions, and the unattached fraction was analyzed to determine if the cells were clumped. Within cowpats, E. coli grew for 6 to 14 days, rather than following a typical logarithmic die-off curve. E. coli numbers in the runoff correlated with numbers inside the cowpat. Most of the E. coli organisms eroded from the cowpats were transported as single cells, and only a small percentage (about 8%) attached to particles. The erosion of E. coli from cowpats and the state in which the cells were transported did not vary with time within a single rainfall event or over time as the cowpats aged and dried out. These findings indicate that cowpats can remain a significant source of E. coli in overland flow for more than 30 days. As well, most of the E. coli organisms eroded from cowpats will occur as readily transportable single cells.

scholarly journals Escherichia coli as a genetic tool

1985 ◽  
Vol 95 (3) ◽  
pp. 611-618
Author(s):  
Naomi Datta
Keyword(s):  
Escherichia Coli ◽  
Academic Research ◽  
Genetically Engineered ◽  
Cloning And Expression ◽  
Biological Research ◽  
New Techniques ◽  
E Coli ◽  
Genetic Tool ◽  
The Past ◽  
Made In

SUMMARYThe study of Escherichia coli and its plasmids and bacteriophages has provided a vast body of genetical information, much of it relevant to the whole of biology. This was true even before the development of the new techniques, for cloning and analysing DNA, that have revolutionized biological research during the past decade. Thousands of millions of dollars are now invested in industrial uses of these techniques, which all depend on discoveries made in the course of academic research on E. coli. Much of the background of knowledge necessary for the cloning and expression of genetically engineered information, as well as the techniques themselves, came from work with this organism.

scholarly journals Identification and management of microbial contaminations in a surface drinking water source

2007 ◽  
Vol 5 (S1) ◽  
pp. 67-79 ◽  
Author(s):  
J. Åström ◽  
T. J. R. Pettersson ◽  
T. A. Stenström
Keyword(s):  
Drinking Water ◽  
Water Intake ◽  
Surface Waters ◽  
Microbial Contamination ◽  
Water Source ◽  
Drinking Water Source ◽  
Raw Water ◽  
Indicator Organisms ◽  
E Coli ◽  
The City

Microbial contamination of surface waters constitutes a health risk for drinking water consumers which may be lowered by closing the raw water intake. We have evaluated microbial discharge events reported in the river Göta älv, which is used for raw water supply to the city of Göteborg. Elevated levels of faecal indicator bacteria were observed during periods of closed raw water intake. High bacteria levels were, however, also occasionally detected during periods of open intake, probably as a result of microbial discharge far upstream in the river which may be difficult to predict and manage by closing the intake. Accumulated upstream precipitations, resulting in surface runoff and wastewater contaminations in the catchment, correlated positively with the levels of total coliforms, E. coli, intestinal enterococci and sulfite-reducing clostridia. Levels of faecal indicator organisms were negatively correlated to the water temperature due to enhanced survival at lower temperatures. Wastewater discharges from a municipality located just upstream of the water intake resulted in elevated E. coli concentrations downstream at the raw water intake for Göteborg. To improve the prediction of microbial contaminations within the river Göta älv, monitoring data on turbidity and upstream precipitation are of particular importance.

scholarly journals Detection of antimicrobial resistance genes of carbapenem-resistant Enterobacteriaceae in Escherichia coli isolated from the water supply of smallholder dairy farms in Saraburi and Maha Sarakham, Thailand

2020 ◽  
Vol 6 (1) ◽  
pp. 1-5
Author(s):  
Natapol Pumipuntu ◽  
Sangkom Pumipuntu
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Water Samples ◽  
Dairy Farms ◽  
Drug Resistant ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Carbapenem Resistant Enterobacteriaceae ◽  
Smallholder Dairy Farms

Background and Aim: The problem of antimicrobial resistance of bacteria in both humans and animals is an important public health concern globally, which is likely to increase, including in Thailand, where carbapenem-resistant Enterobacteriaceae (CRE), such as Escherichia coli, are of particular concern. They are pathogens found in the gastrointestinal tract of humans and other animals as well as in the environment. They may cause opportunistic infection and are often resistant to antibiotics in various fields especially in animal husbandry, such as pets or livestock farms. This study aimed to investigate the occurrence of carbapenem-resistant E. coli from water samples of smallholder dairy farms in Saraburi and Maha Sarakham, Thailand. Materials and Methods: Sixty-four water samples were collected from 32 dairy farms in Kaeng Khoi district, Muak Lek district, and Wang Muang district of Saraburi Province, and Kantharawichai district and Mueang district of Maha Sarakham Province, Thailand. All samples were cultured and isolated for E. coli by biochemical tests. All E. coli isolates were tested for drug susceptibility using imipenem, meropenem, and drug resistance genes of carbapenemases such as blaNDM, blaIMP, and blaOXA48 of drug-resistant E. coli isolates detected by polymerase chain reaction (PCR) technique. Results: A total of 182 E. coli isolates were found (140 and 42 isolates from Saraburi and Maha Sarakham, respectively). Drug sensitivity tests found that two isolates of E. coli from water in Kaeng Khoi were resistant to imipenem; therefore, the incidence of E. coli resistance to carbapenem was 1.43% of Saraburi Province. On the other hand, there was no incidence of drug-resistant E. coli in Maha Sarakham. In addition, the detection of the drug-resistant gene of E. coli in both isolates by PCR showed the expression of blaNDM. Conclusion: This study reports E. coli resistance to antimicrobial drugs on livestock farms. It can be considered to be the first report of E. coli CRE detection in a dairy farm at Saraburi, which should be the subject of further extended study.

scholarly journals First-Time Isolation and Characterization of a Bacteriophage Encoding the Shiga Toxin 2c Variant, Which Is Globally Spread in Strains of Escherichia coli O157

2004 ◽  
Vol 72 (12) ◽  
pp. 7030-7039 ◽  
Author(s):  
Eckhard Strauch ◽  
Christoph Schaudinn ◽  
Lothar Beutin
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Phage Lambda ◽  
Wild Type ◽  
Chromosomal Locus ◽  
O157 Strain ◽  
Diagnostic Pcr ◽  
E Coli ◽  
Isolation And Characterization ◽  
K 12

ABSTRACT A bacteriophage encoding the Shiga toxin 2c variant (Stx2c) was isolated from the human Escherichia coli O157 strain CB2851 and shown to form lysogens on the E. coli K-12 laboratory strains C600 and MG1655. Production of Stx2c was found in the wild-type E. coli O157 strain and the K-12 lysogens and was inducible by growing bacteria in the presence of ciprofloxacin. Phage 2851 is the first reported viable bacteriophage which carries an stx 2c gene. Electron micrographs of phage 2851 showed particles with elongated hexagonal heads and long flexible tails resembling phage lambda. Sequence analysis of an 8.4-kb region flanking the stx 2c gene and other genetic elements revealed a mosaic gene structure, as found in other Stx phages. Phage 2851 showed lysis of E. coli K-12 strains lysogenic for Stx phages encoding Stx1 (H19), Stx2 (933W), Stx (7888), and Stx1c (6220) but showed superinfection immunity with phage lambda, presumably originating from the similarity of the cI repressor proteins of both phages. Apparently, phage 2851 integrates at a different chromosomal locus than Stx2 phage 933W and Stx1 phage H19 in E. coli, explaining why Stx2c is often found in combination with Stx1 or Stx2 in E. coli O157 strains. Diagnostic PCR was performed to determine gene sequences specific for phage 2851 in wild-type E. coli O157 strains producing Stx2c. The phage 2851 q and o genes were frequently detected in Stx2c-producing E. coli O157 strains, indicating that phages related to 2851 are associated with Stx2c production in strains of E. coli O157 that were isolated in different locations and time periods.

scholarly journals Isolation and Enumeration of Escherichia coli from Soil and Water

2020 ◽  
Vol 36 (2) ◽  
pp. 75-77
Author(s):  
Anindita Bhowmik ◽  
Sunjukta Ahsan
Keyword(s):  
Escherichia Coli ◽  
Water Samples ◽  
Gas Production ◽  
Soil Samples ◽  
Most Probable Number ◽  
Biochemical Tests ◽  
Probable Number ◽  
E Coli ◽  
Dilution Series

Majority of the population of Bangladesh depend on tap or surface water as their source of water supply. This study was carried out to examine the microbial quality of both water and soil collected from different places using the multiple tube fermentation technique to determine coliform count by the most probable number (MPN) method in brilliant green lactose broth (BGLB) media.Inoculum from positive tubes of the presumptive test were further transferred on eosinemethylene blue (EMB) and MacConkey agar.The organisms isolated were further characterized using biochemical tests. Out of 93 water samples, 30 (32.26%) indicated the presence of lactose fermenter and gas producer in all 3 tubes of dilution series using inoculum quantities of 1.0, 0.1 and 0.01 ml, whereas out of 85 soil samples, 45 (52.94%) showed acid and gas production in all 3 tubes of dilution series.Among 85 soil samples, 40 samples that contained at least one positive in each dilution series and among 93 water samples, 31 samples that contained at least one positive in each dilution series were further re-identified with biochemical tests.This study showed 30.59% soil isolates and 26.88% water isolates were Escherichia coli which highlighted the fact that both water and soil act as a major reservoir of E.coli, which indicates possible fecal contamination as well as presence of potentially pathogenic E. coli. Bangladesh J Microbiol, Volume 36 Number 2 December 2019, pp 75-77

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