scholarly journals Detection of E. coli O157:H7 in Food Using Automated Immunomagnetic Separation Combined with Real-Time PCR

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 908
Author(s):  
Ji Young Park ◽  
Min-Cheol Lim ◽  
Kisang Park ◽  
Gyeongsik Ok ◽  
Hyun-Joo Chang ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Magnetic Beads ◽  
High Sensitivity ◽  
Immunomagnetic Separation ◽  
Sample Volume ◽  
Food Samples ◽  
Automated System ◽  
Bacterial Strains ◽  
Foodborne Bacteria

In this study, we describe the development of an automated immunomagnetic separation device combined with real-time polymerase chain reaction (PCR) for detecting foodborne bacteria. Immunomagnetic separation (IMS) is a well-known method for the separation and concentration of target bacteria from a large volume of food samples. Magnetic beads functionalized with an antibody provide selectivity for target bacteria such as Escherichia coli O157:H7. Moreover, compared to conventional methods, real-time PCR enables high-sensitivity detection of target bacteria. The method proposed in this study involves three steps: (1) pre-enrichment, (2) automated IMS and concentration of target bacteria, and (3) detection of target bacteria by real-time PCR. Using food samples with a working sample volume as large as 250 mL, the whole process only requires 3 h. As a result, target bacteria in the range of 101–102 colony-forming units per mg or g of sample can be detected in food samples, such as milk, ground beef, and cabbage, by using the proposed approach. We anticipate that the automated IMS system combined with real-time PCR will contribute to the development of a fully automated system for detecting foodborne bacteria and serve as a multi-tester for a variety of bacterial strains in the capacity of a sample-to-answer device in the near future.

Validation of the Applied Food Diagnostics, Inc. Simultaneous Multiplex Real Time PCR (SIMUL-qPCR) Listeria species and monocytogenes Assay in Selected Foods and Environmental Surfaces: AOAC Performance Tested MethodSM 062001

2021 ◽  
Author(s):  
Thomas Lonczynski ◽  
Laura Cowin
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Reliable Method ◽  
Sample Volume ◽  
Food Samples ◽  
Listeria Species ◽  
Environmental Surfaces ◽  
The Matrix ◽  
Environmental Surface ◽  
One Year

Abstract Background The Simultaneous Multiplex Real Time PCR (SIMUL-qPCR) Listeria species and monocytogenes Assay is a quick, reliable method for detecting Listeria species and monocytogenes in environmental and food samples. The assay multiplexes several targets in one run to properly identify Listeria species and monocytogenes. The assay uses proprietary media, Listeria Recovery and Enrichment Broth (LREB), for enrichment purposes. LREB was specifically formulated to improve the recovery and growth of Listeria while inhibiting competing background flora. Objective This report details the method validation study to validate frankfurters, ready-to-eat sliced turkey, soft fresh raw cheese, chicken salad, ice cream, cooked eggs, pasteurized milk, and frozen/cooked shrimp, as well as environmental surface sponges and swabs for stainless steel, plastic, rubber, ceramic tile, and sealed concrete. Methods Matrix studies, inclusivity/exclusivity, product consistency/stability, and robustness testing were conducted to assess the method’s performance. Results There were no statistically significant differences found between the candidate and reference methods in the matrix studies. Inclusivity/exclusivity testing showed that the assay was able to detect both Listeria species and monocytogenes strains while excluding the non-Listeria isolates. Small variations in critical test parameters (enrichment time, extraction reagent volume and extracted sample volume) did not adversely affect the assay’s performance, and stability testing indicated consistent results for at least one year. Conclusions The data presented in this report show that this a reliable method for detecting Listeria species and monocytogenes. Highlights This assay allows for one sample to be tested for both Listeria species and monocytogenes with one PCR test.

Rapid Detection Method for Bacillus anthracis Using a Combination of Multiplexed Real-Time PCR and Pyrosequencing and Its Application for Food Biodefense

2015 ◽  
Vol 78 (2) ◽  
pp. 355-361 ◽  
Author(s):  
TIMOTHY W. JANZEN ◽  
MATTHEW C. THOMAS ◽  
NORIKO GOJI ◽  
MICHAEL J. SHIELDS ◽  
KRISTEN R. HAHN ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Real Time ◽  
Real Time Pcr ◽  
Rapid Detection ◽  
Detection Method ◽  
Immunomagnetic Separation ◽  
Food Samples ◽  
Health Concern ◽  
Sequential Method ◽  
Critical Gap

Bacillus anthracis, the causative agent of anthrax, has the capacity to form highly resilient spores as part of its life cycle. The potential for the dissemination of these spores using food as a vehicle is a huge public health concern and, hence, requires the development of a foodborne bioterrorism response approach. In this work, we address a critical gap in food biodefense by presenting a novel, combined, sequential method involving the use of real-time PCR and pyrosequencing for the rapid, specific detection of B. anthracis spores in three food matrices: milk, apple juice, and bottled water. The food samples were experimentally inoculated with 40 CFU ml−1, and DNA was extracted from the spores and analyzed after immunomagnetic separation. Applying the combination of multiplex real-time PCR and pyrosequencing, we successfully detected the presence of targets on both of the virulence plasmids and the chromosome. The results showed that DNA amplicons generated from a five-target multiplexed real-time PCR detection using biotin-labeled primers can be used for single-plex pyrosequencing detection. The combined use of multiplexed real-time PCR and pyrosequencing is a novel, rapid detection method for B. anthracis from food and provides a tool for accurate, quantitative identification with potential biodefense applications.

scholarly journals Validation of a Novel Diagnostic Approach Combining the VersaTREK™ System for Recovery and Real-Time PCR for the Identification of Mycobacterium chimaera in Water Samples

2021 ◽  
Vol 9 (5) ◽  
pp. 1031
Author(s):  
Roberto Zoccola ◽  
Alessia Di Blasio ◽  
Tiziana Bossotto ◽  
Angela Pontei ◽  
Maria Angelillo ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Detection System ◽  
Bacterial Load ◽  
Microbial Control ◽  
Hospital Setting ◽  
Sample Volume ◽  
Analytical Sensitivity ◽  
Initial Water

Mycobacterium chimaera is an emerging pathogen associated with endocarditis and vasculitis following cardiac surgery. Although it can take up to 6–8 weeks to culture on selective solid media, culture-based detection remains the gold standard for diagnosis, so more rapid methods are urgently needed. For the present study, we processed environmental M. chimaera infected simulates at volumes defined in international guidelines. Each preparation underwent real-time PCR; inoculates were placed in a VersaTREK™ automated microbial detection system and onto selective Middlebrook 7H11 agar plates. The validation tests showed that real-time PCR detected DNA up to a concentration of 10 ng/µL. A comparison of the isolation tests showed that the PCR method detected DNA in a dilution of ×102 CFU/mL in the bacterial suspensions, whereas the limit of detection in the VersaTREK™ was <10 CFU/mL. Within less than 3 days, the VersaTREK™ detected an initial bacterial load of 100 CFU. The detection limit did not seem to be influenced by NaOH decontamination or the initial water sample volume; analytical sensitivity was 1.5 × 102 CFU/mL; positivity was determined in under 15 days. VersaTREK™ can expedite mycobacterial growth in a culture. When combined with PCR, it can increase the overall recovery of mycobacteria in environmental samples, making it potentially applicable for microbial control in the hospital setting and also in environments with low levels of contamination by viable mycobacteria.

Development of Rapid Real-Time PCR and Most-Probable-Number Real-Time PCR Assays To Quantify Enterotoxigenic Strains of the Species in the Bacillus cereus Group

2007 ◽  
Vol 70 (12) ◽  
pp. 2774-2781 ◽  
Author(s):  
I-CHEN YANG ◽  
DANIEL YANG-CHIH SHIH ◽  
JAN-YI WANG ◽  
TZU-MING PAN
Keyword(s):  
Bacillus Cereus ◽  
Real Time ◽  
Real Time Pcr ◽  
Food Samples ◽  
Most Probable Number ◽  
Pcr Assay ◽  
Bacillus Cereus Group ◽  
Probable Number ◽  
Cooked Rice ◽  
Group Detection

Members of the Bacillus cereus group may produce diarrheal enterotoxins and could be potential hazards if they enter the food chain. Therefore, a method capable of detecting all the species in the B. cereus group rather than B. cereus alone is important. We selected nhe as the target and developed a real-time PCR assay to quantify enterotoxigenic strains of the B. cereus group. The real-time PCR assay was evaluated with 60 B. cereus group strains and 28 others. The assay was also used to construct calibration curves for different food matrices and feces. The assay has an excellent quantification capacity, as proved by its linearity (R2 &gt; 0.993), wide dynamic quantification range (102 to 107 CFU/g for cooked rice and chicken, 103 to 107 CFU/ml for milk, and 104 to 107 CFU/g for feces), and adequate relative accuracy (85.5 to 101.1%). For the low-level contaminations, a most-probable-number real-time PCR assay was developed that could detect as low as 100 CFU/ml. Both assays were tested with real food samples and shown to be considerably appropriate for B. cereus group detection and quantification.

scholarly journals Single-copy detection of somatic variants from solid and liquid biopsy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana-Luisa Silva ◽  
Paulina Klaudyna Powalowska ◽  
Magdalena Stolarek ◽  
Eleanor Ruth Gray ◽  
Rebecca Natalie Palmer ◽  
...  
Keyword(s):  
Real Time ◽  
Single Molecule ◽  
Real Time Pcr ◽  
Clinical Decision Making ◽  
High Sensitivity ◽  
Clinical Decision ◽  
Single Copy ◽  
Turnaround Time ◽  
Copy Detection ◽  
Allele Specific

AbstractAccurate detection of somatic variants, against a background of wild-type molecules, is essential for clinical decision making in oncology. Existing approaches, such as allele-specific real-time PCR, are typically limited to a single target gene and lack sensitivity. Alternatively, next-generation sequencing methods suffer from slow turnaround time, high costs, and are complex to implement, typically limiting them to single-site use. Here, we report a method, which we term Allele-Specific PYrophosphorolysis Reaction (ASPYRE), for high sensitivity detection of panels of somatic variants. ASPYRE has a simple workflow and is compatible with standard molecular biology reagents and real-time PCR instruments. We show that ASPYRE has single molecule sensitivity and is tolerant of DNA extracted from plasma and formalin fixed paraffin embedded (FFPE) samples. We also demonstrate two multiplex panels, including one for detection of 47 EGFR variants. ASPYRE presents an effective and accessible method that simplifies highly sensitive and multiplexed detection of somatic variants.

Diagnosis and Causative Species of Visceral Leishmaniasis in Southwest Saudi Arabia

2021 ◽  
Author(s):  
Aymen Abdelhaleem ◽  
Nabil Dhayhi ◽  
Mohamed Salih Mahfouz ◽  
Ommer Daffalla ◽  
Mansour Mubarki ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Visceral Leishmaniasis ◽  
Real Time ◽  
Real Time Pcr ◽  
Leishmania Donovani ◽  
Target Genes ◽  
Sample Volume ◽  
Pcr Products ◽  
Polymerase Chain ◽  
Robust Evidence

Visceral leishmaniasis (VL) is the most severe clinical form of the disease and has been reported in the Jazan region of southwest Saudi Arabia. This study aimed to diagnose VL by real-time polymerase chain reaction (PCR) and the direct agglutination test (DAT) and to identify the causative Leishmania species. A total of 80 participants, including 30 suspected VL patients, 30 healthy endemic control individuals, and 20 malaria disease controls, were enrolled in this study. Blood samples were collected and tested for Leishmania DNA by real-time PCR and for antibody by the DAT. Sequencing of some amplified PCR products was used to identify the causative Leishmania species. The diagnosis of VL was successfully achieved by both real-time PCR and by DAT with 100% sensitivity. Leishmania donovani and Leishmania infantum species were detected by sequencing both by the kDNA and ITS1 target genes, followed a BLASTn search. The detection of VL antibody by the DAT followed by the confirmatory detection of Leishmania DNA in patient blood by PCR could promote the adoption of the much less invasive and more sensitive methods for the routine diagnosis of VL. Further study with high sample volume to evaluate the PCR and the DAT are needed, to generate more robust evidence. Based on the sequencing results, emerging studies on VL should focus on the causative Leishmania species, reservoirs, and vectors that are important in the study area.

scholarly journals Effect of Feeding Cows Genetically Modified Maize on the Bacterial Community in the Bovine Rumen

2007 ◽  
Vol 73 (24) ◽  
pp. 8012-8017 ◽  
Author(s):  
S. Wiedemann ◽  
P. Gürtler ◽  
C. Albrecht
Keyword(s):  
Bacterial Community ◽  
Real Time ◽  
Real Time Pcr ◽  
Genetically Modified ◽  
Genetically Modified Maize ◽  
Bacterial Strains ◽  
Maize Silage ◽  
Bovine Rumen ◽  
Gm Maize ◽  
Effect Of Feeding

ABSTRACT Rumen-cannulated cows (n = 4) were fed successively silage made from either conventional or genetically modified (GM) maize. Results revealed no effects of GM maize on the dynamics of six ruminal bacterial strains (investigated by real-time PCR) compared to the conventional maize silage.

Exploring a phage-based real-time PCR assay for diagnosing Acinetobacter baumannii bloodstream infections with high sensitivity

2018 ◽  
Vol 1044 ◽  
pp. 147-153 ◽  
Author(s):  
Jun Luo ◽  
Mengwei Jiang ◽  
Jin Xiong ◽  
Junhua Li ◽  
Xiaoxu Zhang ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Real Time ◽  
Real Time Pcr ◽  
Bloodstream Infections ◽  
High Sensitivity ◽  
Pcr Assay

scholarly journals Sesame, Pistachio, and Macadamia Nut: Development and Validation of New Allergenic Systems for Fast Real-Time PCR Application

Foods ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1085
Author(s):  
Martina Torricelli ◽  
Elisa Pierboni ◽  
Cristina Rondini ◽  
Serena Altissimi ◽  
Naceur Haouet
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Food Processing ◽  
Annealing Temperature ◽  
Limit Of Detection ◽  
Food Samples ◽  
Support Tool ◽  
Macadamia Nut ◽  
Real Market ◽  
Development And Validation

Food allergy is a worldwide health problem that concerns infants to adults. The main health risk for sensitised individuals is due to the presence of traces of allergens as the result of an accidental contamination during food processing. The labelling of allergens such as sesame, pistachio, and macadamia nut on food products is mandatory according to Regulation (EU) N. 1169/2011; therefore, the development of suitable and specific analytical methodologies is advisable. The aim of this study was to perform a multi-allergen real-time PCR system that works well in fast mode at the same annealing temperature and with the same thermal profile. The real-time PCR was developed designing new, specific, and efficient primer and probe systems for the 2S albumingene for sesame and pistachio and for the vicilin precursorgene for macadamia nut. These systems were subjected to a robust intra-laboratory qualitative validation process prior to their application, by DNA extraction and fast real-time PCR, on some real market samples to reproduce a potential allergen contamination along the food chain. The developed system results were specific and robust, with a sensible limit of detection (0.005% for sesame; 0.004% for pistachio; 0.006% for macadamia nut). The performance and the reliability of the target systems were confirmed on commercial food samples. This molecular approach could be used as a screening or as a support tool, in association with the other widespread monitoring techniques (such as ELISA).

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