scholarly journals Same-Day Detection of Escherichia coli O157:H7 from Spinach by Using Electrochemiluminescent and Cytometric Bead Array Biosensors

2010 ◽  
Vol 76 (24) ◽  
pp. 8044-8052 ◽  
Author(s):  
Kelly M. Leach ◽  
Joyce M. Stroot ◽  
Daniel V. Lim
Keyword(s):  
Escherichia Coli ◽  
Pathogen Detection ◽  
Disease Outbreaks ◽  
Cytometric Bead Array ◽  
Rapid Screening ◽  
Testing Procedures ◽  
E Coli ◽  
Food Borne Illness ◽  
Time To Detection ◽  
Immunological Assays

ABSTRACT Contamination of fresh produce with Escherichia coli O157:H7 and other pathogens commonly causes food-borne illness and disease outbreaks. Thus, screening for pathogens is warranted, but improved testing procedures are needed to allow reproducible same-day detection of low initial contamination levels on perishable foods, and methods for detecting numerous pathogens in a single test are desired. Experimental procedures were developed to enable rapid screening of spinach for E. coli O157:H7 by using multiplex-capable immunological assays that are analyzed using biosensors. Detection was achieved using an automated electrochemiluminescent (ECL) assay system and a fluorescence-based cytometric bead array. Using the ECL system, less than 0.1 CFU of E. coli O157:H7 per gram of spinach was detected after 5 h of enrichment, corresponding to 6.5 h of total assay time. Using the cytometric bead array, less than 0.1 CFU/g was detected after 7 h of enrichment, with a total time to detection of less than 10 h. These results illustrate that both biosensor assays are useful for rapid detection of E. coli O157:H7 on produce in time frames that are comparable to or better than those of other testing formats. Both methods may be useful for multiplexed pathogen detection in the food industry and other testing situations.

scholarly journals The AIDA Autotransporter System Is Associated with F18 and Stx2e in Escherichia coli Isolates from Pigs Diagnosed with Edema Disease and Postweaning Diarrhea

2001 ◽  
Vol 8 (1) ◽  
pp. 143-149 ◽  
Author(s):  
Ulla Niewerth ◽  
Andreas Frey ◽  
Thomas Voss ◽  
Chantal Le Bouguénec ◽  
Georg Baljer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Western Blot ◽  
Virulence Factors ◽  
Rapid Screening ◽  
Edema Disease ◽  
E Coli ◽  
Large Numbers ◽  
High Prevalence ◽  
Pcr Method ◽  
Postweaning Diarrhea

ABSTRACT Pathogenic Escherichia coli strains are known to cause edema disease (ED) and postweaning diarrhea (PWD) in piglets. Although the exact mechanisms of pathogenicity that lead to ED-PWD remain to be elucidated, E. coli-borne Shiga-like toxin and adhesion-mediating virulence factors such as F18 adhesin or F4 fimbriae are believed to play a central role in ED-PWD. In light of these observations we investigated whether another E. coliadhesin, the plasmid-encoded AIDA (adhesin involved in diffuse adherence) might also be present in ED-PWD-causing E. coli isolates. For rapid screening for the AIDA system in large numbers of isolates, a multiplex PCR method along with a duplex Western blot procedure was developed. When screening 104 strains obtained from pigs with or without ED-PWD, we observed a high prevalence of the AIDA operon in porcine E. coli isolates, with over 25% of all strains being AIDA positive, and we could demonstrate a significant association of the intact AIDA gene (orfB) with ED-PWD, while defects in orfB were associated with the absence of disease. Although our data hint toward a contribution of AIDA to ED-PWD, further studies will be necessary since the presence of the AIDA genes was also associated with the presence of the Shiga-like toxin and F18 adhesin genes, two reported virulence factors for ED-PWD.

scholarly journals Recent Progress on the Electrochemical Biosensing of Escherichia coli O157:H7: Material and Methods Overview

Biosensors ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 54 ◽  
Author(s):  
Nasrin Razmi ◽  
Mohammad Hasanzadeh ◽  
Magnus Willander ◽  
Omer Nur
Keyword(s):  
Escherichia Coli ◽  
Pathogen Detection ◽  
Recent Progress ◽  
Electrochemical Sensors ◽  
Solid Phase ◽  
Great Promise ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Electrochemical Biosensing ◽  
Sensitivity And Selectivity

Escherichia coli O157:H7 (E. coli O157:H7) is a pathogenic strain of Escherichia coli which has issued as a public health threat because of fatal contamination of food and water. Therefore, accurate detection of pathogenic E. coli is important in environmental and food quality monitoring. In spite of their advantages and high acceptance, culture-based methods, enzyme-linked immunosorbent assays (ELISAs), polymerase chain reaction (PCR), flow cytometry, ATP bioluminescence, and solid-phase cytometry have various drawbacks, including being time-consuming, requiring trained technicians and/or specific equipment, and producing biological waste. Therefore, there is necessity for affordable, rapid, and simple approaches. Electrochemical biosensors have shown great promise for rapid food- and water-borne pathogen detection. Over the last decade, various attempts have been made to develop techniques for the rapid quantification of E. coli O157:H7. This review covers the importance of E. coli O157:H7 and recent progress (from 2015 to 2020) in the development of the sensitivity and selectivity of electrochemical sensors developed for E. coli O157:H7 using different nanomaterials, labels, and electrochemical transducers.

A Rapid Test to Detect ST-producing Escherichia coli in Food

1992 ◽  
Vol 55 (10) ◽  
pp. 792-795
Author(s):  
KARSTEN FEHLHABER ◽  
RÜDIGER-THOMAS HESELER
Keyword(s):  
Escherichia Coli ◽  
Test Procedure ◽  
Brain Heart Infusion ◽  
Rapid Test ◽  
Food Samples ◽  
Food Sample ◽  
Rapid Screening ◽  
Infant Mouse ◽  
E Coli ◽  
Rapid Screening Test

Pasteurized milk, liquid egg, minced meat, and various salads were artificially contaminated with varying numbers of cells from six Escherichia coli (E. coli) strains able to produce heat-stable enterotoxins (ST). The ST-producing E. coli were detected by the following procedure within 24 h without isolation by cultivation. After enrichment of the food sample in GN broth (4 h at 37°C), the material was transferred to brain heart infusion broth, incubated (16–18 h at 37°C), centrifuged (20 min, 7000 g) and heated to 80°C for 10 min, the supernatant was tested with the infant mouse test. The sensitivity (= ratio of detectable E. coli per total microbial numbers in the food sample) of the test procedure was high even in many food samples with a considerable competitive microbial flora. The procedure was used to test 419 routine food samples. Enterotoxigenic bacteria were found in 7 samples of liquid egg and 4 samples of salad. The test is recommended as a rapid screening test in food control.

scholarly journals Predictive Models for Escherichia coli Concentrations at Inland Lake Beaches and Relationship of Model Variables to Pathogen Detection

2013 ◽  
Vol 79 (5) ◽  
pp. 1676-1688 ◽  
Author(s):  
Donna S. Francy ◽  
Erin A. Stelzer ◽  
Joseph W. Duris ◽  
Amie M. G. Brady ◽  
John H. Harrison ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Water Quality ◽  
Predictive Models ◽  
Pathogen Detection ◽  
Model Performance ◽  
Current Method ◽  
Content Type ◽  
E Coli ◽  
Predictive Variables ◽  
Inland Lake

ABSTRACTPredictive models, based on environmental and water quality variables, have been used to improve the timeliness and accuracy of recreational water quality assessments, but their effectiveness has not been studied in inland waters. Sampling at eight inland recreational lakes in Ohio was done in order to investigate using predictive models forEscherichia coliand to understand the links betweenE. coliconcentrations, predictive variables, and pathogens. Based upon results from 21 beach sites, models were developed for 13 sites, and the most predictive variables were rainfall, wind direction and speed, turbidity, and water temperature. Models were not developed at sites where theE. colistandard was seldom exceeded. Models were validated at nine sites during an independent year. At three sites, the model resulted in increased correct responses, sensitivities, and specificities compared to use of the previous day'sE. coliconcentration (the current method). Drought conditions during the validation year precluded being able to adequately assess model performance at most of the other sites.Cryptosporidium, adenovirus,eaeA(E. coli),ipaH(Shigella), andspvC(Salmonella) were found in at least 20% of samples collected for pathogens at five sites. The presence or absence of the three bacterial genes was related to some of the model variables but was not consistently related toE. coliconcentrations. Predictive models were not effective at all inland lake sites; however, their use at two lakes with high swimmer densities will provide better estimates of public health risk than current methods and will be a valuable resource for beach managers and the public.

The purification from Escherichia coli of a protein relaxing superhelical DNA

1976 ◽  
Vol 54 (4) ◽  
pp. 301-306 ◽  
Author(s):  
M. G. Burrington ◽  
A. R. Morgan
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Rapid Screening ◽  
Intact Protein ◽  
Winding Number ◽  
Circular Dna ◽  
E Coli ◽  
The Individual ◽  
Negative Supercoils

The Escherichia coli omega protein was first described by Wang (Wang, J.C.: J. Mol. Biol. 55, 523–533 (1971)) as having the ability to relax supercoiled covalently-closed circular DNA by changing the topological winding number, α. We have developed a rapid assay for omega activity which has allowed us to purify the protein to homogeneity. It appears to be an αβ-ype subunit protein with a molecular weight of the intact protein of about 80 000 (determined by gel filtration) and of the individual subunits of 56 000 and 31 000 (sodium dodecyl sulfate polyacrylamide gels). We have confirmed Wang's observation that it only partly relaxes negative supercoils, and is not active on positive supercoils. Its characteristics with respect to pH, salts, temperature and chromatography are described. A method for rapid screening of E. coli for omega mutants is described.

scholarly journals Transmission of Escherichia coli from Manure to Root Zones of Field-Grown Lettuce and Leek Plants

2021 ◽  
Vol 9 (11) ◽  
pp. 2289
Author(s):  
Leo van Overbeek ◽  
Marie Duhamel ◽  
Stefan Aanstoot ◽  
Carin Lombaers van der Plas ◽  
Els Nijhuis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Plant Root ◽  
Disease Outbreaks ◽  
Coli Strain ◽  
E Coli ◽  
Root Zones ◽  
Food Borne ◽  
Metagenome Library ◽  
Fresh Vegetables ◽  
Vegetables And Fruits

Pathogenic Escherichia coli strains are responsible for food-borne disease outbreaks upon consumption of fresh vegetables and fruits. The aim of this study was to establish the transmission route of E. coli strain 0611, as proxy for human pathogenic E. coli, via manure, soil and plant root zones to the above-soil plant compartments. The ecological behavior of the introduced strain was established by making use of a combination of cultivation-based and molecular targeted and untargeted approaches. Strain 0611 CFUs and specific molecular targets were detected in the root zones of lettuce and leek plants, even up to 272 days after planting in the case of leek plants. However, no strain 0611 colonies were detected in leek leaves, and only in one occasion a single colony was found in lettuce leaves. Therefore, it was concluded that transmission of E. coli via manure is not the principal contamination route to the edible parts of both plant species grown under field conditions in this study. Strain 0611 was shown to accumulate in root zones of both species and metagenomic reads of this strain were retrieved from the lettuce rhizosphere soil metagenome library at a level of Log 4.11 CFU per g dry soil.

Characterisation of multidrug resistant Escherichia coli isolated from two commercial lettuce and spinach supply chains

2021 ◽  
Author(s):  
Muneiwa T. Ratshilingano ◽  
Erika Margarete du Plessis ◽  
Stacey Duvenage ◽  
Lise Korsten
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Irrigation Water ◽  
Virulence Genes ◽  
Disease Outbreaks ◽  
Virulence Gene ◽  
Multidrug Resistant ◽  
Water Sources ◽  
Point Of Sale ◽  
E Coli

ABSTRACT Leafy green vegetables have increasingly been reported as a reservoir of multidrug-resistant pathogenic Enterobacteriaceae; with Shiga toxin- producing Escherichia coli frequently implicated in disease outbreaks worldwide.  This study aimed to determine the presence and characteristics of antibiotic resistance, diarrheagenic virulence genes and phylogenetic groupings of E. coli isolates (n=51) from commercially produced lettuce and spinach from the farm, through processing and at the point of sale.  Multidrug resistance was observed in 33 of the 51 E. coli isolates (64.7%); with 35.7% (n=10/28) being generic and 100% (n=23/23) Extended Spectrum β-lactamase/AmpC- producing.  Resistance of E. coli isolates was observed against neomycin (100%; n=51/51), ampicillin (70.6%; n=36/51), amoxycilin (68.6%; n=35/51), tetracycline (45%; n=23/51), trimethoprim/ sulfamethoxazole (43%; n=22/51), chloramphenicol (25.5%; n=13/51), augmentin (11.8%; n=6/51) and gentamicin (7.8%; n=4/51); with 100% (n=51/51) susceptibility to imipenem. Virulence gene eae was detected in two E. coli isolates from irrigation water sources only, while none of the other virulence genes tested for were detected.   Most of the E. coli strains belonged to phylogenetic group B2 (25.5%; n=13), B1 (19.6%; n=10) and A (17.6%; n=9); with D (5.9%; n=3) less distributed. Although diarrheagenic E. coli were not detected, antibiotic resistance in E. coli prevalent in the supply chain was evident. Additionally, a clear link between E. coli isolates from irrigation water sources and leafy green vegetables through DNA fingerprinting was established which indicates the potential transfer of E. coli from irrigation water to minimally processed leafy green vegetables.

Stx2 from enterohemorrhagic Escherichia coli O157:H7 promotes colonization in the intestine of cattle

2008 ◽  
Vol 88 (4) ◽  
pp. 581-584 ◽  
Author(s):  
Danica Baines ◽  
Stephanie Erb ◽  
Tim McAllister
Keyword(s):  
Escherichia Coli ◽  
Key Words ◽  
Virulence Factor ◽  
Human Disease ◽  
Disease Outbreaks ◽  
Mucosal Damage ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Colonization Process

Cattle act as the main reservoir for enterohemorrhagic Escherichia coli O157:H7, a bacterium that causes serious human disease outbreaks. It is currently not clear which bacterial or animal factors contribute to E. coli O157:H7 colonization in cattle. We recently identified mucosal hemorrhages in the jejunum, ileum and colon of persistent shedding cattle that were associated with E. coli O157:H7 colonization. This suggested that E. coli O157:H7-secreted cytotoxins may be involved in the E. coli O157:H7 colonization process. Further studies confirmed that E. coli O157:H7-secreted cytotoxins were toxic to cattle enterocytes and enhanced E. coli O157:H7 colonization of intestinal tissues. The current study examined the contribution of Stx2 to the earlier reported E. coli O157:H7- associated mucosal damage and secreted cytotoxin activity. Stx2 was not cytotoxic to enterocytes, but did enhance E. coli O157:H7 adherence to intestinal tissues in cattle. This is the first report of an E. coli O157:H7 virulence factor that can directly influence the E. coli O157:H7 colonization process in cattle. Key words: Stx2, Escherichia coli O157:H7, cattle, intestine, colonization

Development of a rapid screening method for the detection of pathogenic Escherichia coli using a combination of Colilert® Quanti-Trays/2000 and PCR

2010 ◽  
Vol 10 (1) ◽  
pp. 7-13 ◽  
Author(s):  
K. B. Omar ◽  
N. Potgieter ◽  
T. G. Barnard
Keyword(s):  
Escherichia Coli ◽  
Internal Control ◽  
Screening Method ◽  
Rapid Screening ◽  
E Coli ◽  
Toilet Seat ◽  
Pathogenic Escherichia Coli ◽  
Wide Range ◽  
Polymerase Chain ◽  
Pcr Targeting

The use of culture based methods for the detection of Escherichia coli (E. coli) only gives information on the occurrence of E. coli and not pathogenicity of the organisms detected. To detect the both indicator and diarrhoeagenic E. coli (DEC) a method was developed using the Colilert® Quanti-Tray/2000 system and polymerase chain reaction (PCR). A total of 619 samples were collected from springs (33), boreholes (24), taps (5), rivers (36), streams (8), domestic storage containers (253), raw sewage (1), final effluents (5), stool (149), soil (5) and toilet seat swab (100) samples from various provinces in South Africa. E. coli was enumerated using the Colilert® Quanti-Tray's/2000 and DNA extracted from E. coli positive wells and used as template for a multiplex-PCR targeting genes specific to entero-pathogenic- (EPEC), entero-haemorrhagic- (EHEC), entero-invasive- (EIEC), entero-toxigenic (ETEC) and entero-aggregative E. coli (EAEC). The internal control was detected in 99% of positive E. coli samples. EAEC was detected in 17%, EIEC in 4%, ETEC in 11%, EHEC in 9% and EPEC in 21% of the E. coli positive samples. It is shown that this method can be used for the detection of DEC from a wide range of samples enriched with Colilert® Quanti-Tray's/2000.

Antibody-Direct Epifluorescent Filter Technique and Immunomagnetic Separation for 10-h Screening and 24-h Confirmation of Escherichia coli O157:H7 in Beef

1996 ◽  
Vol 59 (10) ◽  
pp. 1072-1075 ◽  
Author(s):  
LAWRENCE RESTAINO ◽  
H. JEFFREY CASTILLO ◽  
DIANA STEWART ◽  
MARY LOU TORTORELLO
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Immunomagnetic Separation ◽  
Rapid Screening ◽  
Epifluorescence Microscopy ◽  
Objective Lens ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Filter Technique ◽  
Direct Epifluorescent Filter Technique

Rapid screening of beef for the presence of Escherichia coli O157:H7 was shown to be feasible using a 10-h enrichment in modified buffered peptone water and the antibody-direct epifluorescent filter technique (Ab-DEFT). The Ab-DEFT involved membrane filtration, fluorescent antibody staining and epifluorescence microscopy and was accomplished in less than 1 h. The procedure allowed detection of the pathogen artificially inoculated into beef patties at 0.1 CFU/g. The 10-h nonselective enrichment broth supported rapid growth, which provided sufficient numbers of cells for a positive determination by the Ab-DEFT after fewer than 10 microscope fields were scanned using a 40× objective lens. Immunomagnetic separation using anti-E. coli O157 Dynabeads® was used to confirm presumptively positive cultures within 24 h. The ease and rapidity of the Ab-DEFT may provide a substantial time and cost savings to the beef industry for screening beef for the presence of E. coli O157:H7.

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