scholarly journals Bio-Specific Au/Fe3+ Porous Spongy Nanoclusters for Sensitive SERS Detection of Escherichia coli O157:H7

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 354
Author(s):  
Yuzhi Li ◽  
Fei Gao ◽  
Chang Lu ◽  
Marie-Laure Fauconnier ◽  
Jinkai Zheng
Keyword(s):  
Escherichia Coli ◽  
Food Samples ◽  
Detection Sensitivity ◽  
Quantitative Detection ◽  
Raman Signal ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Fast Detection ◽  
Sers Detection ◽  
Modified Magnetic Nanoparticles

For sensitive and fast detection of Escherichia coli O157:H7, organic and inorganic hybrid Au/Fe3+ nanoclusters (NCs) were synthesized for the first time using gold nanoparticles (GNPs), bovine serum albumin, ferric chloride, phosphate-buffered saline, and antibodies. The Au/Fe3+ porous spongy NCs with large surface area showed excellent bio-specific capability for E. coli O157:H7. GNPs in Au/Fe3+ NCs functioned as signal enhancers, significantly increasing the Raman signal via the metathesis reaction product of Prussian blue and obviously improving the detection sensitivity. We combined the novel Au/Fe3+ NCs with antibody-modified magnetic nanoparticles to create a biosensor capable of sensitive detection of E. coli O157:H7, which showed a good linear response (101 to 106 cfu/mL), high detection sensitivity (2 cfu/mL), and good recovery rate (93.60–97.50%) in spiked food samples. These results make the biosensor well-suited for food safety monitoring. This strategy achieves the goal of sensitive and quantitative detection of E. coli O157:H7.

An Aggregation-Induced Emission Material Labeling Antigen-Based Lateral Flow Immunoassay Strip for Rapid Detection of Escherichia coli O157:H7

2021 ◽  
pp. 247263032098193
Author(s):  
Cheng Liu ◽  
Shuiqin Fang ◽  
Yachen Tian ◽  
Youxue Wu ◽  
Meijiao Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rapid Detection ◽  
Foodborne Pathogen ◽  
Test Strip ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Lateral Flow Immunoassay ◽  
Escherichia Coli O157 ◽  
Aggregation Induced Emission ◽  
E Coli

Escherichia coli O157:H7 ( E. coli O157:H7) is a dangerous foodborne pathogen, mainly found in beef, milk, fruits, and their products, causing harm to human health or even death. Therefore, the detection of E. coli O157:H7 in food is particularly important. In this paper, we report a lateral flow immunoassay strip (LFIS) based on aggregation-induced emission (AIE) material labeling antigen as a fluorescent probe for the rapid detection of E. coli O157:H7. The detection sensitivity of the strip is 105 CFU/mL, which is 10 times higher than that of the colloidal gold test strip. This method has good specificity and stability and can be used to detect about 250 CFU of E. coli O157:H7 successfully in 25 g or 25 mL of beef, jelly, and milk. AIE-LFIS might be valuable in monitoring food pathogens for rapid detection.

Potential pitfalls in the quantitative molecular detection ofEscherichia coliO157:H7 in environmental matrices

2006 ◽  
Vol 52 (5) ◽  
pp. 482-488 ◽  
Author(s):  
Rebekka R.E Artz ◽  
Lisa M Avery ◽  
Davey L Jones ◽  
Ken Killham
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Detection Sensitivity ◽  
Escherichia Coli O157 ◽  
Soil System ◽  
E Coli ◽  
Animal Wastes ◽  
Pcr Assays

The detection sensitivity and potential interference factors of a commonly used assay based on real-time polymerase chain reaction (PCR) for Escherichia coli O157:H7 using eae gene-specific primers were assessed. Animal wastes and soil samples were spiked with known replicate quantities of a nontoxigenic strain of E. coli O157:H7 in a viable or dead state and as unprotected DNA. The detection sensitivity and accuracy of real-time PCR for E. coli O157:H7 in animal wastes and soil is low compared to enrichment culturing. Nonviable cells and unprotected DNA were shown to produce positive results in several of the environmental samples tested, leading to potential overestimates of cell numbers due to prolonged detection of nonviable cells. This demonstrates the necessity for the specific calibration of real-time PCR assays in environmental samples. The accuracy of the eae gene–based detection method was further evaluated over time in a soil system against an activity measurement, using the bioluminescent properties of an E. coli O157:H7 Tn5luxCDABE construct. The detection of significant numbers of viable but nonculturable (VBNC) as well as nonviable and possibly physically protected cells as shown over a period of 90 days further complicates the use of real-time PCR assays for quick diagnostics in environmental samples and infers that enrichment culturing is still required for the final verification of samples found positive by real-time PCR methods.Key words: Escherichia coli O157:H7, real-time PCR, animal waste, soil, VBNC.

Simultaneous Enrichment of Shiga Toxin–Producing Escherichia coli O157 and O26 and Salmonella in Food Samples Using Universal Preenrichment Broth

2009 ◽  
Vol 72 (10) ◽  
pp. 2065-2070 ◽  
Author(s):  
MASASHI KANKI ◽  
KAZUKO SETO ◽  
JUNKO SAKATA ◽  
TETSUYA HARADA ◽  
YUKO KUMEDA
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Food Samples ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Significant Difference ◽  
Peptone Water ◽  
Radish Sprouts ◽  
Pork Samples ◽  
Better Than

Universal preenrichment broth (UPB) was compared with modified Escherichia coli broth with novobiocin (mEC+n) for enrichment of Shiga toxin–producing E. coli O157 and O26, and with buffered peptone water (BPW) for preenrichment of Salmonella enterica. Ten strains each of the three pathogens were inoculated into beef and radish sprouts following thermal, freezing, or no treatment. With regard to O157 and O26, UPB incubated at 42°C recovered significantly more cells from inoculated beef than UPB at 35°C and from radish sprout samples than UPB at 35°C and mEC+n. With regard to Salmonella, UPB incubated at 42°C was as effective as UPB at 35°C and BPW at recovering cells from beef and radish sprout samples. No significant difference was noted between the effectiveness of UPB at 42°C and UPB at 35°C or BPW in the recovery of Salmonella from 205 naturally contaminated poultry samples. By using UPB at 42°C, one O157:H7 strain was isolated from the mixed offal of 53 beef samples, 6 cattle offal samples, and 50 pork samples all contaminated naturally, with no pathogen inoculation. The present study found that UPB incubated at 42°C was as effective as, or better than, mEC+n for enrichment of O157 and O26 and comparable to BPW for preenrichment of Salmonella. These findings suggest that a great deal of labor, time, samples, and space may be saved if O157, O26, and Salmonella are enriched simultaneously with UPB at 42°C.

Primers with 5′ Flaps Improve the Efficiency and Sensitivity of Multiplex PCR Assays for the Detection of Salmonella and Escherichia coli O157:H7

2013 ◽  
Vol 76 (4) ◽  
pp. 668-673 ◽  
Author(s):  
CHRIS TIMMONS ◽  
SHEFALI DOBHAL ◽  
JACQUELINE FLETCHER ◽  
LI MARIA MA
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Fold Increase ◽  
Detection Sensitivity ◽  
Escherichia Coli O157 ◽  
Bacterial Cells ◽  
Robust Detection ◽  
E Coli ◽  
Pcr Multiplex ◽  
Pcr Assays

Foodborne illnesses caused by Salmonella enterica and Escherichia coli O157:H7 are worldwide health concerns. Rapid, sensitive, and robust detection of these pathogens in foods and in clinical and environmental samples is essential for routine food quality testing, effective surveillance, and outbreak investigations. The aim of this study was to evaluate the effect on PCR sensitivity of adding a short, AT-rich overhanging nucleotide sequence (flap) to the 5′ end of PCR primers specific for the detection of Salmonella and E. coli O157:H7. Primers targeting the invA gene of Salmonella and the rfbE gene of E. coli O157:H7 were synthesized with or without a 12-bp, AT-rich 5′ flap (5′-AATAAATCATAA-3′). Singleplex PCR, multiplex PCR, and real-time PCR sensitivity assays were conducted using purified bacterial genomic DNA and crude cell lysates of bacterial cells. The effect of background flora on detection was evaluated by spiking tomato and jalapeno pepper surface washes with E. coli O157:H7 and Salmonella Saintpaul. When targeting individual pathogens, end-point PCR assays using flap-amended primers were more efficient than nonamended primers, with 20.4 and 23.5% increases in amplicon yield for Salmonella and E. coli O157:H7, respectively. In multiplex PCR assays, a 10- to 100-fold increase in detection sensitivity was observed when the primer flap sequence was incorporated. This improvement in both singleplex and multiplex PCR efficiency and sensitivity can lead to improved Salmonella and E. coli O157:H7 detection.

A sensitive and regenerative electrochemical immunosensor for quantitative detection of Escherichia coli O157:H7 based on stable polyaniline coated screen-printed carbon electrode and rGO-NR-Au@Pt

2019 ◽  
Vol 11 (11) ◽  
pp. 1475-1482 ◽  
Author(s):  
Xiaoyan Mo ◽  
Zunyi Wu ◽  
Jianfeng Huang ◽  
Guangying Zhao ◽  
Wenchao Dou
Keyword(s):  
Escherichia Coli ◽  
Electrochemical Immunosensor ◽  
Quantitative Detection ◽  
Carbon Electrode ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Screen Printed Carbon Electrode ◽  
Screen Printed

An electrochemical immunosensor was constructed for the detection of E. coli O157:H7 using Au@Pt, rGO and regenerative leucoemeraldine PANI/AuNPs.

Multiplex PCR for Simultaneous Detection of Salmonella spp., Listeria monocytogenes, and Escherichia coli O157:H7 in Meat Samples

2005 ◽  
Vol 68 (3) ◽  
pp. 551-556 ◽  
Author(s):  
SUSUMU KAWASAKI ◽  
NAOKO HORIKOSHI ◽  
YUKIO OKADA ◽  
KAZUKO TAKESHITA ◽  
TAKASHI SAMESHIMA ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Multiplex Pcr ◽  
Simultaneous Detection ◽  
Detection Sensitivity ◽  
Rapid Screening ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
E Coli ◽  
Meat Samples

A multiplex PCR method was developed for simultaneous detection of Salmonella spp., Listeria monocytogenes, and Escherichia coli O157:H7 in meat samples. DNA detection sensitivity for this method was 103 CFU/ml for each pathogen. When this protocol was used for the detection of each of the above pathogenic bacteria in spiked pork samples, 1 cell per 25 g of inoculated sample could be detected within 30 h. In the samples of naturally contaminated meat, Salmonella spp., L. monocytogenes, and E. coli O157:H7 were detected over the same time period. Excellent agreement was obtained for the results of multiplex PCR and the conventional culture method, which suggests that the multiplex PCR is a reliable and useful method for rapid screening of meat products for Salmonella spp., L. monocytogenes, and E. coli O157:H7 contamination.

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.

Incidence of Enterohemorrhagic Escherichia coli, Escherichia coli O157, Salmonella, and Listeria monocytogenes in Retail Fresh Ground Beef, Sprouts, and Mushrooms

2006 ◽  
Vol 69 (2) ◽  
pp. 441-443 ◽  
Author(s):  
M. SAMADPOUR ◽  
M. W. BARBOUR ◽  
T. NGUYEN ◽  
T.-M. CAO ◽  
F. BUCK ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Ground Beef ◽  
Food Samples ◽  
Enterohemorrhagic Escherichia Coli ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Pcr Assays ◽  
Retail Food

The objective of this study was to determine the prevalence of enterohemorrhagic Escherichia coli (EHEC), E. coli O157, Salmonella, and Listeria monocytogenes in retail food samples from Seattle, Wash. A total of 2,050 samples of ground beef (1,750 samples), mushrooms (100 samples), and sprouts (200 samples) were collected over a 12-month period and analyzed for the presence of these pathogens. PCR assays, followed by culture confirmation were used to determine the presence or absence of each organism. Of the 1,750 ground beef samples analyzed, 61 (3.5%) were positive for EHEC, and 20 (1.1%) of these were positive for E. coli O157. Salmonella was present in 67 (3.8%) of the 1,750 ground beef samples. Of 512 ground beef samples analyzed, 18 (3.5%) were positive for L. monocytogenes. EHEC was found in 12 (6.0%) of the 200 sprout samples, and 3 (1.5%) of these yielded E. coli O157. Of the 200 total sprout samples, 14 (7.0%) were positive for Salmonella and none were positive for L. monocytogenes. Among the 100 mushroom samples, 4 (4.0%) were positive for EHEC but none of these 4 samples were positive for E. coli O157. Salmonella was detected in 5 (5.0%) of the mushroom samples, and L. monocytogenes was found in 1 (1.0%) of the samples.

Evaluation of the VIDAS Methodology for Detection of Escherichia coli O157 in Food Samples

1998 ◽  
Vol 61 (7) ◽  
pp. 917-920 ◽  
Author(s):  
C. VERNOZY-ROZAND ◽  
C. MAZUY ◽  
S. RAY-GUENIOT ◽  
S. BOUTRAND-LOEÏ ◽  
A. MEYRAND ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Raw Milk ◽  
Immunomagnetic Separation ◽  
Food Samples ◽  
Positive Sample ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Contaminated Food ◽  
Capture And Release ◽  
Retail Food

An automated enzyme-linked fluorescence immunoassay (ELFA), the VIDAS E. coli O157 method, was compared with immunomagnetic separation (IMS) followed by culture on cefixime tellurite sorbitol MacConkey agar (CT-SMAC) for detecting Escherichia coli O157 in artificially and naturally contaminated food samples including raw milk cheeses, poultry, raw sausages, and ground beef retail samples. Confirmation of the samples positive according to the ELFA was performed by use of an automated immunoconcentration system, VIDAS ICE, which allows selective capture and release of target organisms. A total of 496 retail food samples were examined. Seventeen food samples gave positive values with the ELFA method, and among them 9 food samples were confirmed by the ICE method. Eight were shown to contain sorbitol-positive, O157-positive, H7-negative, motile, non-verotoxin-producing E. coli. The ninth positive sample contained an O157-positive, H7-negative, sorbitol-negative, non-verotoxin-producing E. coli. The IMS technique only allowed confirmation of this sorbitol-negative, non-verotoxin-producing E. coli O157.

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