Visual and quantitative detection of E. coli O157:H7 by coupling immunomagnetic separation and quantum dot-based paper strip

2021 ◽  
Author(s):  
Zhaohui Qiao ◽  
Qiqi Cai ◽  
Yingchun Fu ◽  
Chunyang Lei ◽  
Wenge Yang
Keyword(s):  
Quantum Dot ◽  
Immunomagnetic Separation ◽  
Quantitative Detection ◽  
Paper Strip ◽  
E Coli

Rapid and Simultaneous Quantitation of Escherichia coli O157:H7, Salmonella, and Shigella in Ground Beef by Multiplex Real-Time PCR and Immunomagnetic Separation†

2007 ◽  
Vol 70 (6) ◽  
pp. 1366-1372 ◽  
Author(s):  
LUXIN WANG ◽  
YONG LI ◽  
AZLIN MUSTAPHA
Keyword(s):  
Escherichia Coli ◽  
Detection Limit ◽  
Real Time ◽  
Real Time Pcr ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Quantitative Detection ◽  
Escherichia Coli O157 ◽  
The Real ◽  
E Coli

The objective of this study was to establish a multiplex real-time PCR for the simultaneous quantitation of Escherichia coli O157:H7, Salmonella, and Shigella. Genomic DNA for the real-time PCR was extracted by the boiling method. Three sets of primers and corresponding TaqMan probes were designed to target these three pathogenic bacteria. Multiplex real-time PCR was performed with TaqMan Universal PCR Master Mix in an ABI Prism 7700 Sequence Detection System. Final standard curves were calculated for each pathogen by plotting the threshold cycle value against the bacterial number (log CFU per milliliter) via linear regression. With optimized conditions, the quantitative detection range of the real-time multiplex PCR for pure cultures was 102 to 109 CFU/ml for E. coli O157:H7, 103 to 109 CFU/ml for Salmonella, and 101 to 108 CFU/ml for Shigella. When the established multiplex real-time PCR system was applied to artificially contaminated ground beef, the detection limit was 105 CFU/g for E. coli O157:H7, 103 CFU/g for Salmonella, and 104 CFU/g for Shigella. Immunomagnetic separation (IMS) was further used to separate E. coli O157:H7 and Salmonella from the beef samples. With the additional use of IMS, the detection limit was 103 CFU/g for both pathogens. Results from this study showed that TaqMan real-time PCR, combined with IMS, is potentially an effective method for the rapid and reliable quantitation of E. coli O157:H7, Salmonella, and Shigella in food.

A microfluidic impedance biosensor based on immunomagnetic separation and urease catalysis for continuous-flow detection of E. coli O157:H7

2018 ◽  
Vol 259 ◽  
pp. 1013-1021 ◽  
Author(s):  
Lan Yao ◽  
Lei Wang ◽  
Fengchun Huang ◽  
Gaozhe Cai ◽  
Xinge Xi ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Immunomagnetic Separation ◽  
E Coli ◽  
Flow Detection

Comparison of Rapid Enzyme-Linked Immunosorbent Assay and Immunomagnetic Separation Methods for Detection of Escherichia coli O157 in Fecal, Hide, Carcass, and Ground Beef Samples

2007 ◽  
Vol 70 (10) ◽  
pp. 2230-2234 ◽  
Author(s):  
T. W. THOMPSON ◽  
T. P. STEPHENS ◽  
G. H. LONERAGAN ◽  
M. F. MILLER ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Separation Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Escherichia Coli O157 ◽  
Perfect Agreement ◽  
Fecal Samples ◽  
E Coli ◽  
Beef Products

Rapid enzyme-linked immunosorbent assays (ELISAs) are approved for detection of Escherichia coli O157 in beef products. However, these kits have also been used in the industry to detect this pathogen on hides or in feces of cattle, although this use has not been validated. The objective of this study was to compare commercially available ELISAs (E. coli Now, Reveal, and VIP) with immunomagnetic separation along with selective media to detect E. coli O157 on hides, in feces, and in medium- and low-level-inoculated ground beef and carcasses (simulated by using briskets) samples. Naturally infected hide and fecal samples were subjected to both the immunomagnetic separation method and ELISAs for the detection of E. coli O157. Additionally, E. coli O157 inoculated and noninoculated ground beef and beef briskets were used to simulate meat and carcass samples. When comparing the detection results from the ELISAs (E. coli Now, Reveal, and VIP) to the immunomagnetic separation method, poor agreement was observed for fecal samples (kappa = 0.10, 0.02, and 0.03 for E. coli Now, Reveal, and VIP, respectively), and fair-to-moderate agreement was observed for hide samples (kappa = 0.30, 0.51, and 0.29 for E. coli Now, Reveal, and VIP, respectively). However, there was near-perfect agreement between the immunomagnetic separation method and ELISAs for ground beef (kappa = 1, 1, and 0.80 for E. coli Now, Reveal, and VIP, respectively) and brisket (kappa = 1, 1, and 1 for E. coli Now, Reveal, and VIP, respectively) samples. Assuming immunomagnetic separation is the best available method, these data suggest that the ELISAs are not useful in detecting E. coli O157 from hide or fecal samples. However, when ELISAs are used on ground beef and beef brisket samples they can be used with a high degree of confidence.

scholarly journals Quantum dot nanobead-based immunochromatographic assay for the quantitative detection of the procalcitonin antigen in serum samples

2020 ◽  
Vol 159 ◽  
pp. 105533
Author(s):  
Shu Zhou ◽  
Yuanli Peng ◽  
Jing Hu ◽  
Hong Duan ◽  
Tongtong Ma ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Immunochromatographic Assay ◽  
Quantitative Detection ◽  
Serum Samples

scholarly journals Electro-Optical Gas Sensor Consisting of Nanostructured Paper Coating and an Ultrathin Sensing Element

Chemosensors ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 23 ◽  
Author(s):  
Jawad Sarfraz ◽  
Emil Rosqvist ◽  
Petri Ihalainen ◽  
Jouko Peltonen
Keyword(s):  
Gas Sensor ◽  
Photoelectron Spectroscopy ◽  
Physical Vapor Deposition ◽  
Gas Sensing ◽  
Quantitative Detection ◽  
Paper Strip ◽  
Blue Color ◽  
Sensing Element ◽  
Paper Substrate ◽  
Color Deconvolution

This work describes the use of a paper substrate for electro-optical detection of toxic hydrogen sulfide (H2S) gas. For electrical detection, a chemiresistive type of gas sensor was developed. Ultrathin gold film electrodes (UTGFE) were produced by physical vapor deposition of gold on nanostructured latex-coated paper substrate. The gas-sensing film was deposited on the electrodes by inkjet printing. The sensing films were characterized by atomic force microscopy, X-ray photoelectron spectroscopy and conductometry. The sensing films showed more than seven orders of magnitude change in resistance when exposed to as low as 1 part per million (ppm) H2S gas at room temperature. Besides resistive response, the change in color of the sensing films was studied on a paper substrate, both as a function of print density of the sensing material and H2S concentration. For quantification of the analyte the red, green and blue color deconvolution was performed on the pictures of the paper strip indicator using an open source software. A clear response was obtained from the blue channel. The inexpensive disposable color strips produced on the paper substrate can be used for qualitative and quantitative detection (as low as 1.5 ppm) of H2S gas.

scholarly journals  Faecal shedding of verotoxigenic Escherichia coli in cattle in the Czech Republic

2011 ◽  
Vol 56 (No. 4) ◽  
pp. 149-155 ◽  
Author(s):  
P. Alexa ◽  
L. Konstantinova ◽  
Z. Sramkova-Zajacova
Keyword(s):  
Escherichia Coli ◽  
Czech Republic ◽  
Dairy Cattle ◽  
Age Groups ◽  
Immunomagnetic Separation ◽  
The Other ◽  
Somatic Antigen ◽  
The Czech Republic ◽  
E Coli ◽  
One Year

A survey to estimate the prevalence of verotoxigenic E. coli (VTEC) or enterohaemorrhagic E. coli (EHEC) in rectal swabs from healthy dairy cattle aged three weeks, three months and one year was conducted in three herds from the Czech Republic. Screening for the presence of the stx1, stx2 and eaeA genes in faecal swab cultures was performed by PCR, and in positive samples, isolated colonies were examined. Immunomagnetic separation was used for the isolation of the VTEC serogroup O157 from samples. VTEC were detected in animals from all three herds under study. In the group of 3-week-old calves, VTEC were only detected in samples collected in the summer months. However, in the other age-groups, VTEC were detected in both the summer and winter months. EHEC shedding was observed in 30 to 100% of the total samples collected from cattle aged three months and one year in the summer months, and in 30 to 60% of samples taken in the winter months. EHEC strains of serogroup O157 were detected in two herds. The range of verotoxins shed by VTEC isolates of serogroup O157 differed between herds. Besides serogroup O157, additional EHEC belonging to the antigen groups O26, O103, O128 and O153 have been identified, and in some of them, no somatic antigen was detected.

scholarly journals Development and Characterization of a Fluorescent-Bacteriophage Assay for Detection of Escherichia coli O157:H7

1999 ◽  
Vol 65 (4) ◽  
pp. 1397-1404 ◽  
Author(s):  
Lawrence Goodridge ◽  
Jinru Chen ◽  
Mansel Griffiths
Keyword(s):  
Escherichia Coli ◽  
Flow Cytometry ◽  
Immunomagnetic Separation ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Lower Detection ◽  
Unreliable Method ◽  
Direct Epifluorescent Filter Technique ◽  
Bacterial Concentrations

ABSTRACT In this paper we describe evaluation and characterization of a novel assay that combines immunomagnetic separation and a fluorescently stained bacteriophage for detection of Escherichia coliO157:H7 in broth. When it was combined with flow cytometry, the fluorescent-bacteriophage assay (FBA) was capable of detecting 104 cells/ml. A modified direct epifluorescent-filter technique (DEFT) was employed in an attempt to estimate bacterial concentrations. Using regression analysis, we calculated that the lower detection limit was between 102 and 103cells/ml; however, the modified DEFT was found to be an unreliable method for determining bacterial concentrations. The results of this study show that the FBA, when combined with flow cytometry, is a sensitive technique for presumptive detection of E. coliO157:H7 in broth cultures.

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