scholarly journals Toward point-of-care diagnostics of Candida auris

2020 ◽  
Author(s):  
Geoffrey Mulberry ◽  
Sudha Chaturvedi ◽  
Vishnu Chaturvedi ◽  
Brian N. Kim
Keyword(s):  
New York ◽  
Real Time ◽  
Real Time Pcr ◽  
Positive Impact ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Candida Auris

AbstractCandida auris is a multidrug-resistant yeast that presents global health threat for the hospitalized patients. Early diagnostic of C. auris is crucial in control, prevention, and treatment. Candida auris is difficult to identify with standard laboratory methods and often can be misidentified leading to inappropriate management. A newly-devised real-time PCR assay played an important role in the ongoing investigation of the C. auris outbreak in New York metropolitan area. The assay can rapidly detect C. auris DNA in surveillance and clinical samples with high sensitivity and specificity, and also useful for confirmation of C. auris cultures. Despite its positive impact, the real-time PCR assay is difficult to deploy at frontline laboratories due to high-complexity set-up and operation. Using a low-cost handheld real-time PCR device, we show that the C. auris can potentially be identified in a low-complexity assay without the need for high-cost equipment. An implementation of low-cost real-time PCR device in hospitals and healthcare facilities is likely to accelerate the diagnosis of C. auris and for control of the global epidemic.

scholarly journals A rapid and automated sample-to-result Candida auris real-time PCR assay for high-throughput testing of surveillance samples with BD MAX™ open system

2019 ◽  
Author(s):  
L. Leach ◽  
A. Russell ◽  
Y. Zhu ◽  
S. Chaturvedi ◽  
V. Chaturvedi
Keyword(s):  
New York ◽  
Real Time ◽  
High Throughput ◽  
Open System ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Cross Reactivity ◽  
Pcr Assay ◽  
Candida Auris ◽  
Clinical Sensitivity

ABSTRACTThe multidrug-resistant yeast pathogen Candida auris continues to cause outbreaks and clusters of clinical cases worldwide. Previously, we developed a real-time PCR assay for the detection of C. auris from surveillance samples (Leach et al. JCM. 2018: 56, e01223-17). The assay played a crucial role in the ongoing investigations of C. auris outbreak in New York City. To ease the implementation of the assay in other laboratories, we developed an automated sample-to-result real-time C. auris PCR assay using BD MAX™ open system. We optimized sample extraction at three different temperatures and four incubation periods. Sensitivity was determined using eight pools of patient samples, and specificity was calculated using four clades of C. auris, and closely and distantly related yeasts. Three independent extractions and testing of two patient sample pools in the quadruplicate yielded assay precision. BD MAX™ optimum assay conditions were: DNA extraction at 75°C for 20 min, and the use of PerfeCTa Multiplex qPCR ToughMix. The limit of detection (LOD) of the assay was one C. auris CFU/PCR reaction. We detected all four clades of C. auris without cross-reactivity to other yeasts. Of the 110 patient surveillance samples tested, 50 were positive for C. auris using the BD MAX™ System with 96% clinical sensitivity and 94% accuracy compared to the manual assay. BD MAX™ assay allows high-throughput C. auris screening of 180 surveillance samples in a 12-hour workday.

scholarly journals Molecular Diagnosis of Leishmaniasis: Quantification of Parasite Load by a Real-Time PCR Assay with High Sensitivity

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 865
Author(s):  
Germano Castelli ◽  
Federica Bruno ◽  
Stefano Reale ◽  
Simone Catanzaro ◽  
Viviana Valenza ◽  
...  
Keyword(s):  
Real Time ◽  
Quantitative Pcr ◽  
Real Time Pcr ◽  
High Sensitivity ◽  
Parasite Load ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Predictive Values ◽  
Low Sensitivity

Real-time PCR was developed to quantify Leishmania infantum kinetoplast DNA and optimized to achieve a sensitivity of 1 parasite/mL. For this purpose, we cloned the conserved kDNA fragment of 120 bp into competent cells and correlated them with serial dilutions of DNA extracted from reference parasite cultures calculating that a parasite cell contains approximately 36 molecules of kDNA. This assay was applied to estimate parasite load in clinical samples from visceral, cutaneous leishmaniasis patients and infected dogs and cats comparing with conventional diagnosis. The study aimed to propose a real-time PCR for the detection of Leishmania DNA from clinical samples trying to solve the diagnostic problems due to the low sensitivity of microscopic examination or the low predictive values of serology and resolve problems related to in vitro culture. The quantitative PCR assay in this study allowed detection of Leishmania DNA and quantification of considerably low parasite loads in samples that had been diagnosed negative by conventional techniques. In conclusion, this quantitative PCR can be used for the diagnosis of both human, canine and feline Leishmaniasis with high sensitivity and specificity, but also for evaluating treatment and the endpoint determination of leishmaniasis.

scholarly journals Electroanalytical Biosensors for Circulating Tumor DNA Detection—A Brief Review

2021 ◽  
Author(s):  
Zhijia Peng ◽  
Xiaogang Lin ◽  
Weiqi Nian ◽  
Xiaodong Zheng ◽  
Jayne Wu
Keyword(s):  
Real Time ◽  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
High Specificity ◽  
Circulating Tumor Dna ◽  
Minimal Invasive ◽  
Diagnosis And Treatment ◽  
Detection Technology ◽  
Tumor Dna

Early diagnosis and treatment have always been highly desired in the fight against cancer, and detection of circulating tumor DNA (ctDNA) has recently been touted as highly promising for early cancer screening. Consequently, the detection of ctDNA in liquid biopsy gains much attention in the field of tumor diagnosis and treatment, which has also attracted research interest from the industry. However, traditional gene detection technology is difficult to achieve low cost, real-time and portable measurement of ctDNA. Electroanalytical biosensors have many unique advantages such as high sensitivity, high specificity, low cost and good portability. Therefore, this review aims to discuss the latest development of biosensors for minimal-invasive, rapid, and real-time ctDNA detection. Various ctDNA sensors are reviewed with respect to their choices of receptor probes, detection strategies and figures of merit. Aiming at the portable, real-time and non-destructive characteristics of biosensors, we analyze their development in the Internet of Things, point-of-care testing, big data and big health.

Performance evaluation of cobas HBV real-time PCR assay on Roche cobas 4800 System in comparison with COBAS AmpliPrep/COBAS TaqMan HBV Test

2018 ◽  
Vol 56 (7) ◽  
pp. 1133-1139 ◽  
Author(s):  
Hanah Kim ◽  
Mina Hur ◽  
Eunsin Bae ◽  
Kyung-A Lee ◽  
Woo-In Lee
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Nucleic Acid Amplification ◽  
Coefficient Of Determination ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Cobas Taqman ◽  
Limit Of Quantitation ◽  
Two Systems

Abstract Background: Hepatitis B virus (HBV) nucleic acid amplification testing (NAAT) is important for the diagnosis and management of HBV infection. We evaluated the analytical performance of the cobas HBV NAAT (Roche Diagnostics GmbH, Mannheim, Germany) on the cobas 4800 System in comparison with COBAS AmpliPrep/COBAS TaqMan HBV Test (CAP/CTM HBV). Methods: Precision was evaluated using three levels of cobas HBV/HCV/HIV-1 Control Kit, and linearity was evaluated across the anticipated measuring range (10.0–1.0×109 IU/mL) at seven levels using clinical samples. Detection capability, including limit of blank (LOB), limit of detection (LOD) and limit of quantitation (LOQ), was verified using the 4th WHO International Standard for HBV DNA for NAT (NIBSC code: 10/266). Correlation between the two systems was compared using 205 clinical samples (102 sera and 103 EDTA plasma). Results: Repeatability and total imprecision (coefficient of variation) ranged from 0.5% to 3.8% and from 0.5% to 3.5%, respectively. Linearity (coefficient of determination, R2) was 0.999. LOB, LOD and LOQ were all acceptable within the observed proportion rate (85%). Correlation was very high between the two systems in both serum and plasma samples (correlation coefficient [r]=0.995). Conclusions: The new cobas HBV real-time PCR assay on the cobas 4800 System showed reliable analytical performances.

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 A Real-Time PCR Assay for Simultaneous Detection and Differentiation of Four Common Entamoeba Species That Infect Humans

2020 ◽  
Vol 59 (1) ◽  
pp. e01986-20
Author(s):  
Ibne Karim M. Ali ◽  
Shantanu Roy
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Simultaneous Detection ◽  
Small Subunit ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Content Type ◽  
Rdna Sequences ◽  
Appropriate Treatment

ABSTRACTThere are over 40 species within the genus Entamoeba, eight of which infect humans. Of these, four species (Entamoeba histolytica, E. dispar, E. moshkovskii, and E. bangladeshi) are morphologically indistinguishable from each other, and yet differentiation is important for appropriate treatment decisions. Here, we developed a hydrolysis probe-based tetraplex real-time PCR assay that can simultaneously detect and differentiate these four species in clinical samples. In this assay, multicopy small-subunit (SSU) ribosomal DNA (rDNA) sequences were used as targets. We determined that the tetraplex real-time PCR can detect amebic DNA corresponding to as little as a 0.1 trophozoite equivalent of any of these species. We also determined that this assay can detect E. histolytica DNA in the presence of 10-fold more DNA from another Entamoeba species in mixed-infection scenarios. With a panel of more than 100 well-characterized clinical samples diagnosed and confirmed using a previously published duplex real-time PCR (capable of detecting E. histolytica and E. dispar), our tetraplex real-time PCR assay demonstrated levels of sensitivity and specificity comparable with those demonstrated by the duplex real-time PCR assay. The advantage of our assay over the duplex assay is that it can specifically detect two additional Entamoeba species and can be used in conventional PCR format. This newly developed assay will allow further characterization of the epidemiology and pathogenicity of the four morphologically identical Entamoeba species, especially in low-resource settings.

scholarly journals Development of a High-Throughput Quantitative Assay for Detecting Herpes Simplex Virus DNA in Clinical Samples

1999 ◽  
Vol 37 (6) ◽  
pp. 1941-1947 ◽  
Author(s):  
Alexander J. Ryncarz ◽  
James Goddard ◽  
Anna Wald ◽  
Meei-Li Huang ◽  
Bernard Roizman ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Real Time ◽  
High Throughput ◽  
Real Time Pcr ◽  
Genital Tract ◽  
Clinical Samples ◽  
Pcr Assay ◽  
The Mean ◽  
Simplex Virus

We have developed a high-throughput, semiautomated, quantitative fluorescence-based PCR assay to detect and type herpes simplex virus (HSV) DNA in clinical samples. The detection assay, which uses primers to the type-common region of HSV glycoprotein B (gB), was linear from <10 to 108 copies of HSV DNA/20 μl of sample. Among duplicate samples in reproducibility runs, the assay showed less than 5% variability. We compared the fluorescence-based PCR assay with culture and gel-based liquid hybridization system with 335 genital tract specimens from HSV type 2 (HSV-2)-seropositive persons attending a research clinic and 380 consecutive cerebrospinal fluid (CSF) samples submitted to a diagnostic virology laboratory. Among the 162 culture-positive genital tract specimens, TaqMan PCR was positive for 157 (97%) specimens, whereas the quantitative-competitive PCR was positive for 144 (89%) specimens. Comparisons of the mean titer of HSV DNA detected by the two assays revealed that the mean titer detected by the gel-based system was slightly higher (median, 1 log). These differences in titers were in part related to the fivefold difference in the amount of HSV DNA used in the amplicon standards with the two assays. Among the 380 CSF samples, 42 were positive by both assays, 13 were positive only by the assay with the agarose gel, and 3 were positive only by the assay with the fluorescent probe. To define the subtype of HSV DNA detected in the screening assay, we also designed one set of primers which amplifies the gG regions of both types of HSV and probes which are specific to either HSV-1 (gG1) or HSV-2 (gG2). These probes were labeled with different fluorescent dyes (6-carboxyfluorescein for gG2 and 6-hexachlorofluorescein for gG1) to enable detection in a single PCR. In mixing experiments the probes discriminated the correct subtype in mixtures with up to a 7-log-higher concentration of the opposite subtype. The PCR typing results showed 100% concordance with the results obtained by assays with monoclonal antibodies against HSV-1 or HSV-2. Thus, while the real-time PCR is slightly less sensitive than the gel-based liquid hybridization system, the high throughput, the lack of contamination during processing, the better reproducibility, and the better ability to type the isolates rapidly make the real-time PCR a valuable tool for clinical investigation and diagnosis of HSV infection.

Development of a LUX real-time PCR for the detection and quantification of human herpesvirus 7

2009 ◽  
Vol 55 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Massimiliano Bergallo ◽  
Cristina Costa ◽  
Maria Elena Terlizzi ◽  
Francesca Sidoti ◽  
Samuela Margio ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Primary Infection ◽  
Latent Infection ◽  
Dynamic Range ◽  
Human Herpesvirus ◽  
Clinical Samples ◽  
House Light ◽  
Pcr Assay ◽  
Sensitivity Specificity

Human herpesvirus 7 is a highly seroprevalent β-herpesvirus that, following primary infection, remains latent in CD4+ T cells and determines a persistent rather than a latent infection in various tissues and organs, including the lung and skin. This paper describes the development of an in-house light upon extension real-time PCR assay for quantification of human herpesvirus 7 DNA in clinical samples. The efficiency, sensitivity, specificity, inter- and intra-assay variability, and dynamic range have been determined. Subsequently, the assay has been validated by evaluating the human herpesvirus 7 load in bronchoalveolar lavages and skin specimens, chosen as 2 persistency sites, from healthy and pathological individuals. The real-time PCR assay developed in this study could be a useful tool to detect and quantify human herpesvirus 7 DNA in different clinical specimens to elucidate its epidemiological and pathogenic roles.

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