Detection of meticillin-resistant Staphylococcus aureus and Panton-Valentine leukocidin directly from clinical samples and the development of a multiplex assay using real-time polymerase chain reaction

2008 ◽  
Vol 27 (9) ◽  
pp. 791-796 ◽  
Author(s):  
L. Renwick ◽  
A. Hardie ◽  
E. K. Girvan ◽  
M. Smith ◽  
G. Leadbetter ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Real Time ◽  
Multiplex Assay ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Polymerase Chain ◽  
Panton Valentine Leukocidin ◽  
Valentine Leukocidin

scholarly journals Quantitative Multiplex Real-Time Reverse Transcriptase–Polymerase Chain Reaction with Fluorescent Probe Detection of Killer Immunoglobulin-Like Receptors, KIR2DL4/3DL3

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 588
Author(s):  
Wipaporn Wongfieng ◽  
Rungtiwa Nutalai ◽  
Amonrat Jumnainsong ◽  
Chanvit Leelayuwat
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Limit Of Detection ◽  
Expression Patterns ◽  
Multiplex Assay ◽  
Clinical Samples ◽  
Lower Sensitivity ◽  
Chain Reaction ◽  
Kir Genes ◽  
Polymerase Chain

(1) Background: KIR2DL4/KIR3DL3 are the framework genes present in all KIR haplotypes, with unique expression patterns being present only in women and CD56bright NK cells. KIR genes have a high degree of DNA sequence identity. Consequently, they are one of the most challenging genes for molecular detection—especially regarding expressions; (2) Methods: We developed an effective method to determine KIR3DL3/KIR2DL4 expressions based on a multiplex quantitative real-time Reverse transcription polymerase chain reaction (qRT-PCR )with fluorescent probes using NK92; (3) Results: Standardizations of the singleplex KIR2DL4 and KIR3DL3 were performed to evaluate the sensitivity and specificity for further development of the multiplex assay. The limit of detection was at 500 copies each. There was cross-amplification with the presence of related KIR genes at a level of 5 × 107 copies. This is not biologically significant because this high level of KIR expression has not been found in clinical samples. The multiplex assay was reproducible equivalent to its singleplex (KIR2DL4; R2 = 0.995, KIR3DL3; R2 = 0.996, but lower sensitivity of 103 copies). Furthermore, the validation of the developed method on samples of blood donors showed high sensitivity (100%) and specificity (99.9%); (4) Conclusions: The developed method is reliable and highly specific suitable for evaluation of the KIR2DL4/3DL3 mRNA expressions in further applications.

scholarly journals Analysis and validation of a highly sensitive one-step nested quantitative real-time polymerase chain reaction assay for specific detection of severe acute respiratory syndrome coronavirus 2

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Quantitative Polymerase Chain Reaction ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Qrt Pcr ◽  
Highly Sensitive ◽  
One Step ◽  
Polymerase Chain

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.

Quantitative Real-Time Polymerase Chain Reaction Detection of BK Virus Using Labeled Primers

2010 ◽  
Vol 134 (3) ◽  
pp. 444-448 ◽  
Author(s):  
Zhengming Gu ◽  
Jianmin Pan ◽  
Matthew J. Bankowski ◽  
Randall T. Hayden
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Quantitative Polymerase Chain Reaction ◽  
Bk Virus ◽  
Clinical Samples ◽  
Quantitative Detection ◽  
Chain Reaction ◽  
Pcr Method ◽  
Polymerase Chain

Abstract Context.—BK virus infections among immunocompromised patients are associated with disease of the kidney or urinary bladder. High viral loads, determined by quantitative polymerase chain reaction (PCR), have been correlated with clinical disease. Objective.—To develop and evaluate a novel method for real-time PCR detection and quantification of BK virus using labeled primers. Design.—Patient specimens (n = 54) included 17 plasma, 12 whole blood, and 25 urine samples. DNA was extracted using the MagNA Pure LC Total Nucleic Acid Isolation Kit (Roche Applied Science, Indianapolis, Indiana); sample eluate was PCR-amplified using the labeled primer PCR method. Results were compared with those of a user-developed quantitative real-time PCR method (fluorescence resonance energy transfer probe hybridization). Results.—Labeled primer PCR detected less than 10 copies per reaction and showed quantitative linearity from 101 to 107 copies per reaction. Analytical specificity of labeled primer PCR was 100%. With clinical samples, labeled primer PCR demonstrated a trend toward improved sensitivity compared with the reference method. Quantitative assay comparison showed an R2 value of 0.96 between the 2 assays. Conclusions.—Real-time PCR using labeled primers is highly sensitive and specific for the quantitative detection of BK virus from a variety of clinical specimens. These data demonstrate the applicability of labeled primer PCR for quantitative viral detection and offer a simplified method that removes the need for separate oligonucleotide probes.

scholarly journals Detection and enumeration of Staphylococcus aureus from bovine milk samples by real-time polymerase chain reaction

2013 ◽  
Vol 96 (11) ◽  
pp. 6955-6964 ◽  
Author(s):  
B.G. Botaro ◽  
C.S. Cortinhas ◽  
L.V. Março ◽  
J.F.G. Moreno ◽  
L.F.P. Silva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Real Time ◽  
Bovine Milk ◽  
Chain Reaction ◽  
Milk Samples ◽  
Polymerase Chain

scholarly journals Multiplex Real-Time Reverse-Transcription Polymerase Chain Reaction Assays for Diagnostic Testing of Severe Acute Respiratory Syndrome Coronavirus 2 and Seasonal Influenza Viruses: A Challenge of the Phase 3 Pandemic Setting

2020 ◽  
Author(s):  
Fabiola Mancini ◽  
Fabrizio Barbanti ◽  
Maria Scaturro ◽  
Stefano Fontana ◽  
Angela Di Martino ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Severe Acute Respiratory Syndrome ◽  
Real Time ◽  
Reverse Transcription ◽  
Seasonal Influenza ◽  
Influenza Viruses ◽  
Activity Period ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Polymerase Chain

Abstract Background Pandemic coronavirus disease 2019 (COVID-19) disease represents a challenge for healthcare structures. The molecular confirmation of samples from infected individuals is crucial and therefore guides public health decision making. Clusters and possibly increased diffuse transmission could occur in the context of the next influenza season. For this reason, a diagnostic test able to discriminate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from influenza viruses is urgently needed. Methods A multiplex real-time reverse-transcription polymerase chain reaction (PCR) assay was assessed using 1 laboratory protocol with different real-time PCR instruments. Overall, 1000 clinical samples (600 from samples SARS-CoV-2–infected patients, 200 samples from influenza-infected patients, and 200 negative samples) were analyzed. Results The assay developed was able to detect and discriminate each virus target and to intercept coinfections. The limit of quantification of each assay ranged between 5 and 10 genomic copy numbers, with a cutoff value of 37.7 and 37.8 for influenza and SARS-CoV-2 viruses, respectively. Only 2 influenza coinfections were detected in COVID-19 samples. Conclusions This study suggests that multiplex assay is a rapid, valid, and accurate method for the detection of SARS-CoV-2 and influenza viruses in clinical samples. The test may be an important diagnostic tool for both diagnostic and surveillance purposes during the seasonal influenza activity period.

scholarly journals Evaluation of Amplification Targets for the Specific Detection ofBordetella pertussisUsing Real-Time Polymerase Chain Reaction

2014 ◽  
Vol 25 (4) ◽  
pp. 217-221 ◽  
Author(s):  
Mohammad Rubayet Hasan ◽  
Rusung Tan ◽  
Ghada N Al-Rawahi ◽  
Eva Thomas ◽  
Peter Tilley
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Target Genes ◽  
Reference Panel ◽  
Superior Performance ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Polymerase Chain

BACKGROUND:Bordetella pertussisinfections continue to be a major public health challenge in Canada. Polymerase chain reaction (PCR) assays to detectB pertussisare typically based on the multicopy insertion sequence IS481, which offers high sensitivity but lacks species specificity.METHODS: A novelB pertussisreal-time PCR assay based on the porin gene was tested in parallel with several previously published assays that target genes such as IS481,ptx-promoter, pertactin and a putative thialase. The assays were evaluated using a reference panel of common respiratory bacteria including differentBordetellaspecies and 107 clinical nasopharyngeal specimens. Discrepant results were confirmed by sequencing the PCR products.RESULTS: Analytical sensitivity was highest for the assay targeting the IS481element; however, the assay lacked specificity forB pertussisin the reference panel and in the clinical samples. False-positive results were also observed with assays targeting theptx-promoter and pertactin genes. A PCR assay based on the thialase gene was highly specific but failed to detect all reference strains ofB pertussis. However, a novel assay targeting the porin gene demonstrated high specificity forB pertussisboth in the reference panel and in clinical samples and, based on sequence-confirmed results, correctly predicted allB pertussis-positive cases in clinical samples. According to Probit regression analysis, the 95% detection limit of the new assay was 4 colony forming units/reaction.CONCLUSION: A novel porin assay forB pertussisdemonstrated superior performance and may be useful for improved molecular detection ofB pertussisin clinical specimens.

scholarly journals Evaluation of pathogen detection from clinical samples by real-time polymerase chain reaction using a sepsis pathogen DNA detection kit

Critical Care ◽  
2010 ◽  
Vol 14 (4) ◽  
pp. R159 ◽  
Author(s):  
Katsunori Yanagihara ◽  
Yuko Kitagawa ◽  
Masao Tomonaga ◽  
Kunihiro Tsukasaki ◽  
Shigeru Kohno ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Pathogen Detection ◽  
Dna Detection ◽  
Clinical Samples ◽  
Chain Reaction ◽  
Polymerase Chain ◽  
Pathogen Dna
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