scholarly journals Rapid Diagnosis of Intestinal Parasitic Protozoa, with a Focus onEntamoeba histolytica

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Anjana Singh ◽  
Eric Houpt ◽  
William A. Petri
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
High Sensitivity ◽  
Rapid Diagnosis ◽  
Amoebic Liver Abscess ◽  
Human Gut ◽  
Entamoeba Dispar ◽  
Highly Sensitive ◽  
Pcr Assays ◽  
Economic Constraints

Entamoeba histolyticais an invasive intestinal pathogenic parasitic protozoan that causes amebiasis. It must be distinguished fromEntamoeba disparandE. moshkovskii, nonpathogenic commensal parasites of the human gut lumen that are morphologically identical toE. histolytica. Detection of specificE. histolyticaantigens in stools is a fast, sensitive technique that should be considered as the method of choice. Stool real-time PCR is a highly sensitive and specific technique but its high cost make it unsuitable for use in endemic areas where there are economic constraints. Serology is an important component of the diagnosis of intestinal and especially extraintestinal amebiasis as it is a sensitive test that complements the detection of the parasite antigens or DNA. Circulating Gal/GalNac lectin antigens can be detected in the serum of patients with untreated amoebic liver abscess. On the horizon are multiplex real-time PCR assays which permit the identification of multiple enteropathogens with high sensitivity and specificity.

scholarly journals Development of Candida-Specific Real-Time PCR Assays for the Detection and Identification of Eight Medically Important Candida Species

2016 ◽  
Vol 9 ◽  
pp. MBI.S38517 ◽  
Author(s):  
Jing Zhang ◽  
Guo-Chiuan Hung ◽  
Kenjiro Nagamine ◽  
Bingjie Li ◽  
Shien Tsai ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Candida Species ◽  
Rapid Detection ◽  
Corneal Transplantation ◽  
High Sensitivity ◽  
Turnaround Time ◽  
Pcr Assays ◽  
Primer Sets ◽  
Pcr Primer

Culture-based identification methods have been the gold standard for the diagnosis of fungal infection. Currently, molecular technologies such as real-time PCR assays with short turnaround time can provide desirable alternatives for the rapid detection of Candida microbes. However, most of the published PCR primer sets are not Candida specific and likely to amplify DNA from common environmental contaminants, such as Aspergillus microbes. In this study, we designed pan- Candida primer sets based on the ribosomal DNA-coding regions conserved within Candida but distinct from those of Aspergillus and Penicillium. We demonstrate that the final two selected pan- Candida primer sets would not amplify Aspergillus DNA and could be used to differentiate eight medically important Candida pathogens in real-time PCR assays based on their melting profiles, with a sensitivity of detection as low as 10 fg of Candida genomic DNA. Moreover, we further evaluated and selected species-specific primer sets covering Candida albicans, Candida glabrata, Candida tropicalis, and Candida dubliniensis and show that they had high sensitivity and specificity. These real-time PCR primer sets could potentially be assembled into a single PCR array for the rapid detection of Candida species in various clinical settings, such as corneal transplantation.

scholarly journals Detection of Sesame Allergen Traces with Two PCR Assays - The Challenge to Protect Food-Allergic Consumers

2015 ◽  
Vol 3 (4) ◽  
pp. 210
Author(s):  
Dimitra Panagiotis Houhoula ◽  
Vasilios Belsis ◽  
Leonidas Georgopoulos ◽  
Virginia Giannou ◽  
Vasiliki R. Kyrana ◽  
...  
Keyword(s):  
Food Allergy ◽  
Real Time ◽  
Real Time Pcr ◽  
Food Industry ◽  
Food Samples ◽  
Rt Pcr ◽  
Highly Sensitive ◽  
Pcr Method ◽  
Pcr Assays ◽  
Positive Results

The purpose of this study was to investigate the possible presence of sesame in commercial foods normally carrying no warning for the allergen, but which may have been subjected to contamination during processing. One hundred units of widely consumed goods with high potential to contain allergenic substances deriving from nuts were analyzed, using sensitive and capable PCR (C-PCR) and Real Time PCR (RT-PCR) methodologies. Of the products examined, 15 (15.0%) declared the presence of sesame, 36 (36.0%) carried no food allergy label, 44 (44.0%) were marked by the phrase “may contain traces of nuts” and 5 (5.0%) carried the indication “may contain sesame traces”. The sesame-positive products detected using the C-PCR method were 15 (100%), 12 (33.3%), 14 (31.8%) and 3 (60%), respectively. Using the RT-PCR technique, positive results were obtained for 15 (100%), 18 (50.0%), 18 (20.5%) and 5 (100%) samples, respectively. The results indicate that the PCR methods applied are highly sensitive and selective, which makes them suitable for the detection of sesame traces in food samples. In addition, they can be useful for monitoring the effectiveness of cleaning processes in the production units of the food industry.

scholarly journals Clinical evaluation of real-time PCR assays for rapid diagnosis of SARS coronavirus during outbreak and post-epidemic periods

2005 ◽  
Vol 33 (1) ◽  
pp. 19-24 ◽  
Author(s):  
W.C. Yam ◽  
K.H. Chan ◽  
K.H. Chow ◽  
L.L.M. Poon ◽  
H.Y. Lam ◽  
...  
Keyword(s):  
Real Time ◽  
Clinical Evaluation ◽  
Real Time Pcr ◽  
Rapid Diagnosis ◽  
Sars Coronavirus ◽  
Pcr Assays

506 UNDETECTABLE HCV-RNA IN TELAPREVIR-TREATED PATIENTS: LOW CONCORDANCE BETWEEN TWO HIGHLY SENSITIVE REAL-TIME PCR ASSAYS

2013 ◽  
Vol 58 ◽  
pp. S208 ◽  
Author(s):  
J. Vermehren ◽  
A. Aghemo ◽  
K.-H. Peiffer ◽  
S. Susser ◽  
R. D'Ambrosio ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Hcv Rna ◽  
Highly Sensitive ◽  
Pcr Assays

DEVELOPMENT OF MULTIPLEX REAL-TIME PCR ASSAY FOR SIX PATHOGENS: RAPID TOOL FOR DIAGNOSIS OF BACTERIAL MENINGITIS

2019 ◽  
pp. 60-66
Author(s):  
Viet Quynh Tram Ngo ◽  
Thi Ti Na Nguyen ◽  
Hoang Bach Nguyen ◽  
Thi Tuyet Ngoc Tran ◽  
Thi Nam Lien Nguyen ◽  
...  
Keyword(s):  
Bacterial Meningitis ◽  
Real Time ◽  
Real Time Pcr ◽  
Diagnostic Methods ◽  
Type B ◽  
E Coli ◽  
Pcr Assays ◽  
Set Up ◽  
Etiological Agents ◽  
Suis Serotype

Introduction: Bacterial meningitis is an acute central nervous infection with high mortality or permanent neurological sequelae if remained undiagnosed. However, traditional diagnostic methods for bacterial meningitis pose challenge in prompt and precise identification of causative agents. Aims: The present study will therefore aim to set up in-house PCR assays for diagnosis of six pathogens causing the disease including H. influenzae type b, S. pneumoniae, N. meningitidis, S. suis serotype 2, E. coli and S. aureus. Methods: inhouse PCR assays for detecting six above-mentioned bacteria were optimized after specific pairs of primers and probes collected from the reliable literature resources and then were performed for cerebrospinal fluid (CSF) samples from patients with suspected meningitis in Hue Hospitals. Results: The set of four PCR assays was developed including a multiplex real-time PCR for S. suis serotype 2, H. influenzae type b and N. meningitides; three monoplex real-time PCRs for E. coli, S. aureus and S. pneumoniae. Application of the in-house PCRs for 116 CSF samples, the results indicated that 48 (39.7%) cases were positive with S. suis serotype 2; one case was positive with H. influenzae type b; 4 cases were positive with E. coli; pneumococcal meningitis were 19 (16.4%) cases, meningitis with S. aureus and N. meningitidis were not observed in any CSF samples in this study. Conclusion: our in-house real-time PCR assays are rapid, sensitive and specific tools for routine diagnosis to detect six mentioned above meningitis etiological agents. Key words: Bacterial meningitis, etiological agents, multiplex real-time PCR

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 Comparative Assessment of In-House Real-Time PCRs Targeting Enteric Disease-Associated Microsporidia in Human Stool Samples

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 656
Author(s):  
Konstantin Tanida ◽  
Andreas Hahn ◽  
Kirsten Alexandra Eberhardt ◽  
Egbert Tannich ◽  
Olfert Landt ◽  
...  
Keyword(s):  
Real Time ◽  
Indigenous People ◽  
Real Time Pcr ◽  
Latent Class ◽  
Enterocytozoon Bieneusi ◽  
Enteric Disease ◽  
Immunosuppressed Patients ◽  
Study Population ◽  
Stool Samples ◽  
Pcr Assays

Microsporidiosis is an infection predominantly occurring in immunosuppressed patients and infrequently also in travelers. This study was performed to comparatively evaluate the diagnostic accuracy of real-time PCR assays targeting microsporidia with etiological relevance in the stool of human patients in a latent class analysis-based test comparison without a reference standard with perfect accuracy. Thereby, two one-tube real-time PCR assays and two two-tube real-time PCR assays targeting Enterocytozoon bieneusi and Encephalocytozoon spp. were included in the assessment with reference stool material (20), stool samples from Ghanaian HIV-positive patients (903), and from travelers, migrants and Colombian indigenous people (416). Sensitivity of the assays ranged from 60.4% to 97.4% and specificity from 99.1% to 100% with substantial agreement according to Cohen’s kappa of 79.6%. Microsporidia DNA was detected in the reference material and the stool of the HIV patients but not in the stool of the travelers, migrants, and the Colombian indigenous people. Accuracy-adjusted prevalence was 5.8% (n = 78) for the study population as a whole. In conclusion, reliable detection of enteric disease-associated microsporidia in stool samples by real-time PCR could be demonstrated, but sensitivity between the compared microsporidia-specific real-time PCR assays varied.

scholarly journals Discriminating the eight genotypes of the porcine circovirus type 2 with TaqMan-based real-time PCR

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Ellen Kathrin Link ◽  
Matthias Eddicks ◽  
Liangliang Nan ◽  
Mathias Ritzmann ◽  
Gerd Sutter ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Porcine Circovirus Type ◽  
Porcine Circovirus Type 2 ◽  
Diagnostic Sensitivity ◽  
Locked Nucleic Acid ◽  
Porcine Circovirus ◽  
Amplification Efficiency ◽  
Pcr Assays

Abstract Background The porcine circovirus type 2 (PCV2) is divided into eight genotypes including the previously described genotypes PCV2a to PCV2f and the two new genotypes PCV2g and PCV2h. PCV2 genotyping has become an important task in molecular epidemiology and to advance research on the prophylaxis and pathogenesis of PCV2 associated diseases. Standard genotyping of PCV2 is based on the sequencing of the viral genome or at least of the open reading frame 2. Although, the circovirus genome is small, classical sequencing is time consuming, expensive, less sensitive and less compatible with mass testing compared with modern real-time PCR assays. Here we report about a new PCV2 genotyping method using qPCR. Methods Based on the analysis of several hundred PCV2 full genome sequences, we identified PCV2 genotype specific sequences or single-nucleotide polymorphisms. We designed six TaqMan PCR assays that are specific for single genotypes PCV2a to PCV2f and two qPCRs targeting two genotypes simultaneously (PCV2g/PCV2d and PCV2h/PCV2c). To improve specific binding of oligonucleotide primers and TaqMan probes, we used locked nucleic acid technology. We evaluated amplification efficiency, diagnostic sensitivity and tested assay specificity for the respective genotypes. Results All eight PCV2 genotype specific qPCRs demonstrated appropriate amplification efficiencies between 91 and 97%. Testing samples from an epidemiological field study demonstrated a diagnostic sensitivity of the respective genotype specific qPCR that was comparable to a highly sensitive pan-PCV2 qPCR system. Genotype specificity of most qPCRs was excellent. Limited unspecific signals were obtained when a high viral load of PCV2b was tested with qPCRs targeting PCV2d or PCV2g. The same was true for the PCV2a specific qPCR when high copy numbers of PCV2d were tested. The qPCR targeting PCV2h/PCV2c showed some minor cross-reaction with PCV2d, PCV2f and PCV2g. Conclusion Genotyping of PCV2 is important for routine diagnosis as well as for epidemiological studies. The introduced genotyping qPCR system is ideal for mass testing and should be a valuable complement to PCV2 sequencing, especially in the case of simultaneous infections with multiple PCV2 genotypes, subclinically infected animals or research studies that require large sample numbers.

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