Development of an astrovirus RT–PCR detection assay for use with conventional, real-time, and integrated cell culture/RT–PCR

2004 ◽  
Vol 50 (4) ◽  
pp. 269-278 ◽  
Author(s):  
Ann C Grimm ◽  
Jennifer L Cashdollar ◽  
Frederick P Williams ◽  
G Shay Fout
Keyword(s):  
Cell Culture ◽  
Real Time ◽  
Real Time Pcr ◽  
Environmental Water ◽  
Positive Control ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Detection Assay ◽  
Stool Samples ◽  
Pcr Method

Astrovirus is a common cause of gastroenteritis in humans that has been determined to be responsible for outbreaks of illness in several countries. Since astrovirus can be waterborne, it is important to be able to identify this virus in environmental water. We have developed and optimized a reverse transcription – polymerase chain reaction (RT–PCR) method that was able to amplify all eight astrovirus serotypes in a single reaction. In addition, a positive control construct was designed so that any inhibitors of this astrovirus assay could be detected. The assay was adapted for use in a real-time PCR assay and the sensitivity of these two methods was compared. The real-time assay was then combined with CaCo2 cell culture to produce an integrated cell culture/RT–PCR (ICC/RT–PCR) assay that was able to detect low levels of astrovirus after an incubation of 7 days or less. Also, the sensitivity of the ICC/RT–PCR assay was compared with RT–PCR alone. The methods were used to detect astrovirus in acute phase illness stool samples as well as in a water sample spiked with astrovirus.Key words: astrovirus, RT–PCR, real-time PCR, ICC/RT–PCR, environmental water.

Rapid Detection and Differentiation of Campylobacter jejuni, Campylobacter coli, and Campylobacter lari in Food, Using Multiplex Real-Time PCR

2010 ◽  
Vol 73 (2) ◽  
pp. 241-250 ◽  
Author(s):  
A. M. MAYR ◽  
S. LICK ◽  
J. BAUER ◽  
D. THÄRIGEN ◽  
U. BUSCH ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Campylobacter Coli ◽  
Pcr Assay ◽  
Detection Assay ◽  
Thermophilic Campylobacter ◽  
Biochemical Identification ◽  
Pcr Method ◽  
Campylobacter Species ◽  
Campylobacter Lari

A multiplex real-time PCR assay based on four differently labeled TaqMan probes for detection and differentiation of the thermophilic Campylobacter species C. jejuni, C. coli, and C. lari was established and validated in food products. This assay combines two previously published PCR assays for C. jejuni and C. coli with a newly developed detection assay for C. lari and an internal amplification control system. The selectivity of the method was determined by analyzing 70 Campylobacter strains and 43 strains of other bacteria. The sensitivity was 50 fg of C. jejuni and C. lari DNA and 500 fg of C. coli DNA per PCR. It was possible to detect 1 to 10 CFU/25 g of food before preenrichment of all three species. More than 400 samples of various foods (poultry, seafood, and meat) were analyzed after 48 h of preenrichment parallel to the conventional diagnostic method of culture and biochemical identification. Using the established real-time PCR assay, 55.4% of the samples were recognized as positive for thermophilic Campylobacter species, whereas with the conventional method only 40.3% of the samples were positive. The real-time PCR assay also detected contaminations with two different Campylobacter species in 32.6% of the analyzed poultry samples, a finding of epidemiological interest. Compared with the original PCR method, which was established for the differentiation of bacterial isolates of C. jejuni and C. coli, this new method also detects and distinguishes C. lari, was validated as an analytical tool for food analysis, and provides reliable and extensive results within 2 days.

scholarly journals Differing Effects of Standard and Harsh Nucleic Acid Extraction Procedures on Diagnostic Helminth Real-Time PCRs Applied to Human Stool Samples

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 188
Author(s):  
Tanja Hoffmann ◽  
Andreas Hahn ◽  
Jaco J. Verweij ◽  
Gérard Leboulle ◽  
Olfert Landt ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Real Time ◽  
Real Time Pcr ◽  
Acid Extraction ◽  
Nucleic Acid Extraction ◽  
Pcr Assay ◽  
Bead Beating ◽  
Stool Samples ◽  
Pcr Assays ◽  
Human Stool

This study aimed to assess standard and harsher nucleic acid extraction schemes for diagnostic helminth real-time PCR approaches from stool samples. A standard procedure for nucleic acid extraction from stool and a procedure including bead-beating as well as proteinase K digestion were compared with group-, genus-, and species-specific real-time PCR assays targeting helminths and nonhelminth pathogens in human stool samples. From 25 different in-house and commercial helminth real-time PCR assays applied to 77 stool samples comprising 67 historic samples and 10 external quality assessment scheme samples positively tested for helminths, higher numbers of positive test results were observed after bead-beating-based nucleic acid extraction for 5/25 (20%) real-time PCR assays irrespective of specificity issues. Lower cycle threshold values were observed for one real-time PCR assay after the standard extraction scheme, and for four assays after the bead-beating-based scheme. Agreement between real-time PCR results after both nucleic acid extraction strategies according to Cohen’s kappa ranged from poor to almost perfect for the different assays. Varying agreement was observed in eight nonhelminth real-time PCR assays applied to 67 historic stool samples. The study indicates highly variable effects of harsh nucleic acid extraction approaches depending on the real-time PCR assay used.

scholarly journals Real-Time PCR Assay for Detection and Enumeration of Dekkera bruxellensis in Wine

2003 ◽  
Vol 69 (12) ◽  
pp. 7430-7434 ◽  
Author(s):  
Trevor G. Phister ◽  
David A. Mills
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Pcr Primers ◽  
Rrna Gene ◽  
Dekkera Bruxellensis ◽  
Pcr Assay ◽  
Specific Pcr ◽  
Spoilage Yeast ◽  
Pcr Method ◽  
26S Rrna

ABSTRACT Traditional methods to detect the spoilage yeast Dekkera bruxellensis from wine involve lengthy enrichments. To overcome this difficulty, we developed a quantitative real-time PCR method to directly detect and enumerate D. bruxellensis in wine. Specific PCR primers to D. bruxellensis were designed to the 26S rRNA gene, and nontarget yeast and bacteria common to the winery environment were not amplified. The assay was linear over a range of cell concentrations (6 log units) and could detect as little as 1 cell per ml in wine. The addition of large amounts of nontarget yeasts did not impact the efficiency of the assay. This method will be helpful to identify possible routes of D. bruxellensis infection in winery environments. Moreover, the time involved in performing the assay (3 h) should enable winemakers to more quickly make wine processing decisions in order to reduce the threat of spoilage by D. bruxellensis.

scholarly journals Detecting Heterobasidion irregulare in Minnesota and Assessment of Indigenous Fungi on Pines

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 57
Author(s):  
Eric Otto ◽  
Benjamin Held ◽  
Samuel Redford ◽  
Robert A. Blanchette
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Wood Decay ◽  
Positive Control ◽  
Red Pine ◽  
Pcr Assay ◽  
Nested Polymerase Chain Reaction ◽  
Decay Fungi ◽  
Field Surveys ◽  
Heterobasidion Irregulare

Heterobasidion irregulare is one of the most problematic forest pathogens in the northern hemisphere, but has only been found relatively recently in the north central United States. Discovered in Wisconsin in 1993, but probably established sometime before that, it quickly spread throughout the state. In November 2014, it was found in southeastern Minnesota. Field surveys were then conducted throughout Minnesota with the focus in the southeast near the initial discovery. To find additional infection sites, surveys were conducted with accompanying aerial imagery of red pine (Pinus resinosa Aiton) stands that were previously thinned. Samples were collected from selected sites with dead and dying trees as well as samples from stumps in recently thinned pine stands. These samples were processed first with a nested polymerase chain reaction (PCR) protocol, which was replaced by a real-time PCR assay after its development. No samples tested positive for H. irregulare using these methods and no cultures from isolations were obtained outside the original infection area. Other indigenous fungi were also identified. The majority were wood decay fungi in the Basidiomycota. A spore collection study was also conducted after field surveys. Automated rotary arm spore collectors were used and assayed with an ITS TaqMan real-time PCR assay. Collectors were placed strategically in different areas of Minnesota. A positive control was used in an infected red pine plantation in Wisconsin and this location had the highest number of spores trapped, with 63,776 over a week period. Spores of H. irregulare were detected at several sites in Minnesota, with the highest spore total observed in traps at 413 over a week period. All other locations sampled also had some spores collected except Itasca State Park located in northwestern Minnesota. The weekly deposition of spores ranged from 0 to 1.26 m−2 h−1. Low spore levels occurring in Minnesota indicate that some spores are present, but they are currently being detected in amounts that may not be sufficient for colonization to be successful.

scholarly journals Multiplex Real-Time PCR Method for Simultaneous Identification and Toxigenic Type Characterization of Clostridium difficile From Stool Samples

2015 ◽  
Vol 35 (3) ◽  
pp. 306-313 ◽  
Author(s):  
Abdullah Kilic ◽  
Mohammad J. Alam ◽  
Naradah L. Tisdel ◽  
Dhara N. Shah ◽  
Mehmet Yapar ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Real Time ◽  
Real Time Pcr ◽  
Stool Samples ◽  
Pcr Method ◽  
Simultaneous Identification

scholarly journals Detection of Peanut Allergen Traces with a Real Time PCR Assay - The Challenge to Protect Food-Allergic Consumers

2017 ◽  
Vol 7 (1) ◽  
pp. 32 ◽  
Author(s):  
Dimitra Houhoula ◽  
Stamatios Koussissis ◽  
Vladimiros Lougovois ◽  
John Tsaknis ◽  
Dimitra Kassavita ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Rapid Detection ◽  
Food Products ◽  
Molecular Techniques ◽  
Food Allergens ◽  
Pcr Assay ◽  
Peanut Allergen ◽  
Pcr Method ◽  
Detection And Quantification

The aim of the present study was the implementation of molecular techniques in the detection and quantification of allergic substances of peanut in various kinds of food products, e.g., breakfast cereals, chocolates and biscuits that are frequently related to allergies. In some cases, the presence of peanuts can be due to contamination during production and are not declared on the label. A total of 152 samples were collected from supermarkets and were analysed by a Real Time PCR method. The results indicated that 125 samples (83,3%) were found positive in peanut traces but the most important finding is that from the 84 samples that had no allergen declaration for peanuts, 48 (57,1%) of them were found positive. In conclusion, Real Time PCR can be a very important tool for the rapid detection and quantification of food allergens.

scholarly journals A New Highly Sensitive and Specific Real-Time PCR Assay Targeting the Malate Dehydrogenase Gene ofKingella kingaeand Application to 201 Pediatric Clinical Specimens

2018 ◽  
Vol 56 (8) ◽  
Author(s):  
Nawal El Houmami ◽  
Guillaume André Durand ◽  
Janek Bzdrenga ◽  
Anne Darmon ◽  
Philippe Minodier ◽  
...  
Keyword(s):  
Real Time ◽  
Malate Dehydrogenase ◽  
Real Time Pcr ◽  
Detection Sensitivity ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Content Type ◽  
Clinical Specimens ◽  
Specificity And Sensitivity ◽  
Pcr Assays

ABSTRACTKingella kingaeis a significant pediatric pathogen responsible for bone and joint infections, occult bacteremia, and endocarditis in early childhood. Past efforts to detect this bacterium using culture and broad-range 16S rRNA gene PCR assays from clinical specimens have proven unsatisfactory; therefore, by the late 2000s, these were gradually phased out to explore the benefits of specific real-time PCR tests targeting thegroELgene and the RTX locus ofK. kingae. However, recent studies showed that real-time PCR (RT-PCR) assays targeting theKingellasp. RTX locus that are currently available for the diagnosis ofK. kingaeinfection lack specificity because they could not distinguish betweenK. kingaeand the recently describedKingella negevensisspecies. Furthermore,in silicoanalysis of thegroELgene from a large collection of 45K. kingaestrains showed that primers and probes fromK. kingaegroEL-based RT-PCR assays display a few mismatches withK. kingae groELvariations that may result in decreased detection sensitivity, especially in paucibacillary clinical specimens. In order to provide an alternative togroEL- and RTX-targeting RT-PCR assays that may suffer from suboptimal specificity and sensitivity, aK. kingae-specific RT-PCR assay targeting the malate dehydrogenase (mdh) gene was developed for predicting no mismatch between primers and probe and 18 variants of theK. kingae mdhgene from 20 distinct sequence types ofK. kingae. This novelK. kingae-specific RT-PCR assay demonstrated high specificity and sensitivity and was successfully used to diagnoseK. kingaeinfections and carriage in 104 clinical specimens from children between 7 months and 7 years old.

Detection of dengue virus serotypes by single-tube multiplex RT-PCR and multiplex real-time PCR assay

2021 ◽  
Author(s):  
Kundan Tandel ◽  
Mahadevan Kumar ◽  
G.S. Bhalla ◽  
S.P.S. Shergill ◽  
Vijaya Swarnim ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Real Time ◽  
Real Time Pcr ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Single Tube ◽  
Dengue Virus Serotypes

scholarly journals A Simplified Quantitative Real-Time PCR Assay for Monitoring SARS-CoV-2 Growth in Cell Culture

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Christian Shema Mugisha ◽  
Hung R. Vuong ◽  
Maritza Puray-Chavez ◽  
Adam L. Bailey ◽  
Julie M. Fox ◽  
...  
Keyword(s):  
Cell Culture ◽  
Real Time ◽  
Real Time Pcr ◽  
Rna Extraction ◽  
Quantitative Real Time Pcr ◽  
Pcr Assay ◽  
Dna Viruses ◽  
Culture Supernatants ◽  
Hiv 1 ◽  
Rna And Dna

ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected millions within just a few months, causing severe respiratory disease and mortality. Assays to monitor SARS-CoV-2 growth in vitro depend on time-consuming and costly RNA extraction steps, hampering progress in basic research and drug development efforts. Here, we developed a simplified quantitative real-time PCR assay that bypasses viral RNA extraction steps and can monitor SARS-CoV-2 growth from a small amount of cell culture supernatants. In addition, we show that this approach is easily adaptable to numerous other RNA and DNA viruses. Using this assay, we screened the activities of a number of compounds that were predicted to alter SARS-CoV-2 entry and replication as well as HIV-1-specific drugs in a proof-of-concept study. We found that E64D (inhibitor of endosomal proteases cathepsin B and L) and apilimod (endosomal trafficking inhibitor) potently decreased the amount of SARS-CoV-2 RNA in cell culture supernatants with minimal cytotoxicity. Surprisingly, we found that the macropinocytosis inhibitor ethylisopropylamiloride (EIPA) similarly decreased SARS-CoV-2 RNA levels in supernatants, suggesting that entry may additionally be mediated by an alternative pathway. HIV-1-specific inhibitors nevirapine (a nonnucleoside reverse transcriptase inhibitor [NNRTI]), amprenavir (a protease inhibitor), and allosteric integrase inhibitor 2 (ALLINI-2) modestly inhibited SARS-CoV-2 replication, albeit the 50% inhibitory concentration (IC50) values were much higher than that required for HIV-1. Taking the data together, this simplified assay will expedite basic SARS-CoV-2 research, be amenable to mid-throughput screening assays (i.e., drug, CRISPR, small interfering RNA [siRNA], etc.), and be applicable to a broad number of RNA and DNA viruses. IMPORTANCE Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of the coronavirus disease 2019 (COVID-19) pandemic, is continuing to cause immense respiratory disease and social and economic disruptions. Conventional assays that monitor SARS-CoV-2 growth in cell culture rely on costly and time-consuming RNA extraction procedures, hampering progress in basic SARS-CoV-2 research and development of effective therapeutics. Here, we developed a simple quantitative real-time PCR assay to monitor SARS-CoV-2 growth in cell culture supernatants that does not necessitate RNA extraction and that is as accurate and sensitive as existing methods. In a proof-of-concept screen, we found that E64D, apilimod, EIPA, and remdesivir can substantially impede SARS-Cov-2 replication, providing novel insight into viral entry and replication mechanisms. In addition, we show that this approach is easily adaptable to numerous other RNA and DNA viruses. This simplified assay will undoubtedly expedite basic SARS-CoV-2 and virology research and be amenable to use in drug screening platforms to identify therapeutics against SARS-CoV-2.

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