scholarly journals Simple Real-Time PCR and Amplicon Sequencing Method for Identification of Plasmodium Species in Human Whole Blood

2015 ◽  
Vol 53 (7) ◽  
pp. 2251-2257 ◽  
Author(s):  
Martina I. Lefterova ◽  
Indre Budvytiene ◽  
Johanna Sandlund ◽  
Anna Färnert ◽  
Niaz Banaei
Keyword(s):  
Real Time ◽  
Species Identification ◽  
Real Time Pcr ◽  
Whole Blood ◽  
18S Rrna ◽  
Pcr Assay ◽  
Test Species ◽  
Content Type ◽  
The Real ◽  
Two Samples

Malaria is the leading identifiable cause of fever in returning travelers. AccuratePlasmodiumspecies identification has therapy implications forP. vivaxandP. ovale, which have dormant liver stages requiring primaquine. Compared to microscopy, nucleic acid tests have improved specificity for species identification and higher sensitivity for mixed infections. Here, we describe a SYBR green-based real-time PCR assay forPlasmodiumspecies identification from whole blood, which uses a panel of reactions to detect species-specific non-18S rRNA gene targets. A pan-Plasmodium18S rRNA target is also amplified to allow species identification or confirmation by sequencing if necessary. An evaluation of assay accuracy, performed on 76 clinical samples (56 positives using thin smear microscopy as the reference method and 20 negatives), demonstrated clinical sensitivities of 95.2% forP. falciparum(20/21 positives detected) and 100% for thePlasmodiumgenus (52/52),P. vivax(20/20),P. ovale(9/9), andP. malariae(6/6). The sensitivity of theP. knowlesi-specific PCR was evaluated using spiked whole blood samples (100% [10/10 detected]). The specificities of the real-time PCR primers were 94.2% forP. vivax(49/52) and 100% forP. falciparum(51/51),P. ovale(62/62),P. malariae(69/69), andP. knowlesi(52/52). Thirty-three specimens were used to test species identification by sequencing the pan-Plasmodium18S rRNA PCR product, with correct identification in all cases. The real-time PCR assay also identified two samples with mixedP. falciparumandP. ovaleinfection, which was confirmed by sequencing. The assay described here can be integrated into a malaria testing algorithm in low-prevalence areas, allowing definitivePlasmodiumspecies identification shortly after malaria diagnosis by microscopy.

scholarly journals Development and Validation of a Real-Time PCR Assay for Rapid Detection of Candida auris from Surveillance Samples

2017 ◽  
Vol 56 (2) ◽  
Author(s):  
L. Leach ◽  
Y. Zhu ◽  
S. Chaturvedi
Keyword(s):  
Health Care ◽  
Real Time ◽  
Real Time Pcr ◽  
Multidrug Resistant ◽  
Effective Control ◽  
Pcr Assay ◽  
Candida Auris ◽  
Content Type ◽  
The Real ◽  
Positive Results

ABSTRACT Candida auris is an emerging multidrug-resistant yeast causing invasive health care-associated infection with high mortality worldwide. Rapid identification of C. auris is of primary importance for the implementation of public health measures to control the spread of infection. To achieve these goals, we developed and validated a TaqMan-based real-time PCR assay targeting the internal transcribed spacer 2 (ITS2) region of the ribosomal gene. The assay was highly specific, reproducible, and sensitive, with the detection limit of 1 C. auris CFU/PCR. The performance of the C. auris real-time PCR assay was evaluated by using 623 surveillance samples, including 365 patient swabs and 258 environmental sponges. Real-time PCR yielded positive results from 49 swab and 58 sponge samples, with 89% and 100% clinical sensitivity with regard to their respective culture-positive results. The real-time PCR also detected C. auris DNA from 1% and 12% of swab and sponge samples with culture-negative results, indicating the presence of dead or culture-impaired C. auris. The real-time PCR yielded results within 4 h of sample processing, compared to 4 to 14 days for culture, reducing turnaround time significantly. The new real-time PCR assay allows for accurate and rapid screening of C. auris and can increase effective control and prevention of this emerging multidrug-resistant fungal pathogen in health care facilities.

scholarly journals Utility of Real-Time PCR for Detection of Exserohilum rostratum in Body and Tissue Fluids during the Multistate Outbreak of Fungal Meningitis and Other Infections

2014 ◽  
Vol 53 (2) ◽  
pp. 618-625 ◽  
Author(s):  
Lalitha Gade ◽  
Dale E. Grgurich ◽  
Thomas M. Kerkering ◽  
Mary E. Brandt ◽  
Anastasia P. Litvintseva
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Response To Treatment ◽  
Pcr Assay ◽  
Content Type ◽  
The Real ◽  
Fungal Meningitis ◽  
Exserohilum Rostratum ◽  
Fungal Dna ◽  
Pcr Assays

Exserohilum rostratumwas the major cause of the multistate outbreak of fungal meningitis linked to contaminated injections of methylprednisolone acetate produced by the New England Compounding Center. Previously, we developed a fungal DNA extraction procedure and broad-range andE. rostratum-specific PCR assays and confirmed the presence of fungal DNA in 28% of the case patients. Here, we report the development and validation of a TaqMan real-time PCR assay for the detection ofE. rostratumin body fluids, which we used to confirm infections in 57 additional case patients, bringing the total number of case patients with PCR results positive forE. rostratumto 171 (37% of the 461 case patients with available specimens). Compared to fungal culture and the previous PCR assays, this real-time PCR assay was more sensitive. Of the 139 identical specimens from case patients tested by all three methods, 19 (14%) were positive by culture, 41 (29%) were positive by the conventional PCR assay, and 65 (47%) were positive by the real-time PCR assay. We also compared the utility of the real-time PCR assay with that of the previously described beta-d-glucan (BDG) detection assay for monitoring response to treatment in case patients with serially collected CSF. Only the incident CSF specimens from most of the case patients were positive by real-time PCR, while most of the subsequently collected specimens were negative, confirming our previous observations that the BDG assay was more appropriate than the real-time PCR assay for monitoring the response to treatment. Our results also demonstrate that the real-time PCR assay is extremely susceptible to contamination and its results should be used only in conjunction with clinical and epidemiological data.

Comparison of a Real-Time PCR Method with a Culture Method for the Detection of Salmonella enterica Serotype Enteritidis in Naturally Contaminated Environmental Samples from Integrated Poultry Houses

2012 ◽  
Vol 75 (4) ◽  
pp. 743-747 ◽  
Author(s):  
BWALYA LUNGU ◽  
W. DOUGLAS WALTMAN ◽  
ROY D. BERGHAUS ◽  
CHARLES L. HOFACRE
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Salmonella Enteritidis ◽  
Culture Method ◽  
Pcr Assay ◽  
Culture Methods ◽  
The Real ◽  
Selective Enrichment ◽  
Conventional Culture ◽  
Field Samples

Conventional culture methods have traditionally been considered the “gold standard” for the isolation and identification of foodborne bacterial pathogens. However, culture methods are labor-intensive and time-consuming. A Salmonella enterica serotype Enteritidis–specific real-time PCR assay that recently received interim approval by the National Poultry Improvement Plan for the detection of Salmonella Enteritidis was evaluated against a culture method that had also received interim National Poultry Improvement Plan approval for the analysis of environmental samples from integrated poultry houses. The method was validated with 422 field samples collected by either the boot sock or drag swab method. The samples were cultured by selective enrichment in tetrathionate broth followed by transfer onto a modified semisolid Rappaport-Vassiliadis medium and then plating onto brilliant green with novobiocin and xylose lysine brilliant Tergitol 4 plates. One-milliliter aliquots of the selective enrichment broths from each sample were collected for DNA extraction by the commercial PrepSEQ nucleic acid extraction assay and analysis by the Salmonella Enteritidis–specific real-time PCR assay. The real-time PCR assay detected no significant differences between the boot sock and drag swab samples. In contrast, the culture method detected a significantly higher number of positive samples from boot socks. The diagnostic sensitivity of the real-time PCR assay for the field samples was significantly higher than that of the culture method. The kappa value obtained was 0.46, indicating moderate agreement between the real-time PCR assay and the culture method. In addition, the real-time PCR method had a turnaround time of 2 days compared with 4 to 8 days for the culture method. The higher sensitivity as well as the reduction in time and labor makes this real-time PCR assay an excellent alternative to conventional culture methods for diagnostic purposes, surveillance, and research studies to improve food safety.

scholarly journals Evaluation of the New BD Max GC Real-Time PCR Assay, Analytically and Clinically as a Supplementary Test for the BD ProbeTec GC Qx Amplified DNA Assay, for Molecular Detection of Neisseria gonorrhoeae

2015 ◽  
Vol 53 (12) ◽  
pp. 3935-3937 ◽  
Author(s):  
Daniel Golparian ◽  
Stina Boräng ◽  
Martin Sundqvist ◽  
Magnus Unemo
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Real Time ◽  
Sensitivity And Specificity ◽  
Real Time Pcr ◽  
Molecular Detection ◽  
Analytical Sensitivity ◽  
Pcr Assay ◽  
Content Type ◽  
Dna Assay ◽  
Supplementary Test

The new BD Max GC real-time PCR assay showed high clinical and analytical sensitivity and specificity. It can be an effective and accurate supplementary test for the BD ProbeTec GC Qx amplified DNA assay, which had suboptimal specificity, and might also be used for initial detection ofNeisseria gonorrhoeae.

scholarly journals Performance Evaluation of the Real-Q Cytomegalovirus (CMV) Quantification Kit Using Two Real-Time PCR Systems for Quantifying CMV DNA in Whole Blood

2016 ◽  
Vol 36 (6) ◽  
pp. 603-606 ◽  
Author(s):  
Jong Eun Park ◽  
Ji-Youn Kim ◽  
Sun Ae Yun ◽  
Myoung-Keun Lee ◽  
Hee Jae Huh ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Real Time ◽  
Real Time Pcr ◽  
Whole Blood ◽  
The Real

A Real-Time PCR Assay for the Detection of Salmonella in a Wide Variety of Food and Food-Animal Matrices†

2007 ◽  
Vol 70 (5) ◽  
pp. 1080-1087 ◽  
Author(s):  
V. M. BOHAYCHUK ◽  
G. E. GENSLER ◽  
M. E. McFALL ◽  
R. K. KING ◽  
D. G. RENTER
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Culture Method ◽  
Pcr Assay ◽  
Culture Methods ◽  
The Real ◽  
Conventional Culture ◽  
Food Animal ◽  
Highly Sensitive ◽  
Field Samples

Conventional culture methods have traditionally been considered the “gold standards” for the isolation and identification of foodborne pathogens. However, culture methods are labor-intensive and time-consuming. We have developed a real-time PCR assay for the detection of Salmonella in a variety of food and food-animal matrices. The real-time PCR assay incorporates both primers and hybridization probes based on the sequence of the Salmonella invA gene and uses fluorescent resonance energy transfer technology to ensure highly sensitive and specific results. This method correctly classified 51 laboratory isolates of Salmonella and 28 non-Salmonella strains. The method was also validated with a large number of field samples that consisted of porcine feces and cecal contents, pork carcasses, bovine feces and beef carcasses, poultry cecal contents and carcasses, equine feces, animal feeds, and various food products. The samples (3,388) were preenriched in buffered peptone water and then selectively enriched in tetrathionate and Rappaport-Vassiliadis broths. Aliquots of the selective enrichment broths were combined for DNA extraction and analysis by the real-time PCR assay. When compared with the culture method, the diagnostic sensitivity of the PCR assay for the various matrices ranged from 97.1 to 100.0%, and the diagnostic specificity ranged from 91.3 to 100.0%. Kappa values ranged from 0.87 to 1.00, indicating excellent agreement of the real-time PCR assay to the culture method. The reduction in time and labor makes this highly sensitive and specific real-time PCR assay an excellent alternative to conventional culture methods for surveillance and research studies to improve food safety.

scholarly journals Abilities of the mCP Agar Method and CRENAME Alpha Toxin-Specific Real-Time PCR Assay To Detect Clostridium perfringens Spores in Drinking Water

2013 ◽  
Vol 79 (24) ◽  
pp. 7654-7661 ◽  
Author(s):  
Andrée F. Maheux ◽  
Ève Bérubé ◽  
Dominique K. Boudreau ◽  
Romain Villéger ◽  
Philippe Cantin ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Sample ◽  
Real Time ◽  
Clostridium Perfringens ◽  
Real Time Pcr ◽  
Potable Water ◽  
Alpha Toxin ◽  
Pcr Assay ◽  
Content Type ◽  
The Public

ABSTRACTWe first determined the analytical specificity and ubiquity (i.e., the ability to detect all or most strains) of aClostridium perfringens-specific real-time PCR (rtPCR) assay based on thecpagene (cpartPCR) by using a bacterial strain panel composed ofC. perfringensand non-C. perfringens Clostridiumstrains. All non-C. perfringens Clostridiumstrains tested negative, whereas allC. perfringensstrains tested positive with thecpartPCR, for an analytical specificity and ubiquity of 100%. ThecpartPCR assay was then used to confirm the identity of 116 putativeC. perfringensisolates recovered after filtration of water samples and culture on mCP agar. Colonies presenting discordant results between the phenotype on mCP agar andcpartPCR were identified by sequencing the 16S rRNA andcpagenes. Four mCP−/rtPCR+colonies were identified asC. perfringens, whereas 3 mCP+/rtPCR−colonies were identified as non-C. perfringens. ThecpartPCR was negative with all 51 non-C. perfringensstrains and positive with 64 of 65C. perfringensstrains. Finally, we compared mCP agar and a CRENAME (concentration andrecovery of microbial particles,extraction ofnucleicacids, andmolecularenrichment) procedure pluscpartPCR (CRENAME +cpartPCR) for their abilities to detectC. perfringensspores in drinking water. CRENAME +cpartPCR detected as few as oneC. perfringensCFU per 100 ml of drinking water sample in less than 5 h, whereas mCP agar took at least 25 h to deliver results. CRENAME +cpartPCR also allows the simultaneous and sensitive detection ofEscherichia coliandC. perfringensfrom the same potable water sample. In itself, it could be used to assess the public health risk posed by drinking water potentially contaminated with pathogens more resistant to disinfection.

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.

scholarly journals Susceptibility of Maize Inbreds and Incidence of Symptomless Infection by the Head Smut Pathogen, Sphacelotheca reiliana

2016 ◽  
Vol 17 (1) ◽  
pp. 1-5 ◽  
Author(s):  
S. J. Anderson ◽  
H. E. Simmons ◽  
R. D. French-Monar ◽  
G. P. Munkvold
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Field Trials ◽  
Growth Stages ◽  
High Susceptibility ◽  
Head Smut ◽  
Pcr Assay ◽  
Disease Symptoms ◽  
The Real ◽  
Seedling Infection

A real-time PCR assay was used to compare seedling infection by Sphacelotheca reiliana, the causal agent of head smut, among five inbred genotypes representing low, moderate, and high susceptibility to the disease. Seeds were coated with teliospores and planted in autoclaved field soil in a growth chamber. Incidence of seedling infection at growth stage V3 differed between an inbred genotype of low susceptibility and those of moderate and high susceptibility, but did not differ between the high and moderately susceptible groups (P < 0.05). The real-time PCR assay was also used to compare infection status at early and late vegetative stages with observable symptoms in the field. We detected infection via real-time PCR in maize at both growth stages during field trials conducted in Texas and California but observed no disease symptoms (smutted ears or tassels). Notably, the fungus was present in up to 31% of the ear shoots in plots without disease symptoms. The real-time assay can be a useful tool for screening seedling-stage host resistance, and for better understanding the progress of infection in different maize genotypes. The field data suggest that asymptomatic infection is much more common than previously thought, and may have important implications for the epidemiology of this fungus under diverse plant resistance and growing conditions. Accepted for publication 11 December 2015. Published 5 January 2016.

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.

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