scholarly journals Real-Time PCR Assays for Rapid Identification of Common Aphanomyces astaci Genotypes

2021 ◽  
Vol 9 ◽  
Author(s):  
Marco Di Domenico ◽  
Valentina Curini ◽  
Riccardo Caprioli ◽  
Carla Giansante ◽  
Agata Mrugała ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Central Italy ◽  
The United States ◽  
Wide Distribution ◽  
Cross Reactivity ◽  
Etiologic Agent ◽  
Clinical Samples ◽  
Introduction Pathways ◽  
Aphanomyces Astaci

The oomycete Aphanomyces astaci is the etiologic agent of crayfish plague, a disease that has seriously impacted the populations of European native crayfish species. The introduction of non-indigenous crayfish of North American origin and their wide distribution across Europe have largely contributed to spread of crayfish plague in areas populated by indigenous crayfish. Tracking A. astaci genotypes may thus be a useful tool for investigating the natural history of crayfish plague in its European range, as well as the sources and introduction pathways of the pathogen. In this study, we describe the development of real-time PCR TaqMan assays aiming to distinguish the five genotype groups of A. astaci (A–E) previously defined by their distinct RAPD patterns. The method was evaluated using DNA extracts from pure A. astaci cultures representing the known genotype groups, and from A. astaci-positive crayfish clinical samples collected mostly during crayfish plague outbreaks that recently occurred in Central Italy and Czechia. The assays do not cross-react with each other, and those targeting genotype groups A, B, D, and E seem sufficiently specific to genotype the pathogen from infected crayfish in the areas invaded by A. astaci (particularly Europe). The unusual A. astaci genotype “SSR-Up” documented from crayfish plague outbreaks in Czechia and chronically infected Pontastacus leptodactylus in the Danube is detected by the group B real-time PCR. The assay originally developed to detect group C (one not yet documented from crayfish plague outbreaks) showed cross-reactivity with Aphanomyces fennicus; the A. astaci genotype “rust1” described in the United States from Faxonius rusticus is detected by that assay as well. Analyses of additional markers (such as sequencing of the nuclear internal transcribed spacer or mitochondrial ribosomal subunits) may complement such cases when the real-time PCR-based genotyping is not conclusive. Despite some limitations, the method is a robust tool for fast genotyping of A. astaci genotype groups common in Europe, both during crayfish plague outbreaks and in latent infections.

scholarly journals Harmonization of Bordetella pertussis Real-Time PCR Diagnostics in the United States in 2012

2014 ◽  
Vol 53 (1) ◽  
pp. 118-123 ◽  
Author(s):  
Margaret M. Williams ◽  
Thomas H. Taylor ◽  
David M. Warshauer ◽  
Monte D. Martin ◽  
Ann M. Valley ◽  
...  
Keyword(s):  
Public Health ◽  
Real Time ◽  
Bordetella Pertussis ◽  
Real Time Pcr ◽  
The United States ◽  
Extraction Methods ◽  
Clinical Samples ◽  
Acid Extraction ◽  
Rt Pcr ◽  
Content Type

Real-time PCR (rt-PCR) is an important diagnostic tool for the identification ofBordetella pertussis,Bordetella holmesii, andBordetella parapertussis. Most U.S. public health laboratories (USPHLs) target IS481, present in 218 to 238 copies in theB. pertussisgenome and 32 to 65 copies inB. holmesii. The CDC developed a multitarget PCR assay to differentiateB. pertussis,B. holmesii, andB. parapertussisand provided protocols and training to 19 USPHLs. The 2012 performance exercise (PE) assessed the capability of USPHLs to detect these threeBordetellaspecies in clinical samples. Laboratories were recruited by the Wisconsin State Proficiency Testing program through the Association of Public Health Laboratories, in partnership with the CDC. Spring and fall PE panels contained 12 samples each of viableBordetellaand non-Bordetellaspecies in saline. Fifty and 53 USPHLs participated in the spring and fall PEs, respectively, using a variety of nucleic acid extraction methods, PCR platforms, and assays. Ninety-six percent and 94% of laboratories targeted IS481in spring and fall, respectively, in either singleplex or multiplex assays. In spring and fall, respectively, 72% and 79% of USPHLs differentiatedB. pertussisandB. holmesiiand 68% and 72% identifiedB. parapertussis. IS481cycle threshold (CT) values forB. pertussissamples had coefficients of variation (CV) ranging from 10% to 28%. Of the USPHLs that differentiatedB. pertussisandB. holmesii, sensitivity was 96% and specificity was 95% for the combined panels. The 2012 PE demonstrated increased harmonization of rt-PCRBordetelladiagnostic protocols in USPHLs compared to that of the previous survey.

scholarly journals Real-time PCR for detecting circulating dengue virus in the Guangdong Province of China in 2006

2008 ◽  
Vol 57 (12) ◽  
pp. 1547-1552 ◽  
Author(s):  
Zhijun Bai ◽  
Licheng Liu ◽  
Zeng Tu ◽  
Lisi Yao ◽  
Jianwei Liu ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Real Time ◽  
Real Time Pcr ◽  
Cross Reactivity ◽  
Clinical Samples ◽  
Sequencing Analysis ◽  
Serum Samples ◽  
Serological Tests ◽  
Wide Range ◽  
Pcr Assays

Dengue virus (DENV) causes a wide range of diseases in humans, from the acute febrile illness dengue fever (DF) to life-threatening dengue haemorrhagic fever/dengue shock syndrome. We developed four real-time quantitative PCR assays for each serotype of DENV based on computational analysis. These assays had high sensitivity and specificity without cross-reactivity for the four serotypes. To evaluate the performance of these assays in detecting and typing the virus in clinical samples, we analysed 64 serum samples from Guangdong during 2006. The results showed that 71 % of those samples were positive by the DEN-1 assay. The DENV assay results, in agreement with the serological tests and sequencing analysis, showed that the pathogen resulting in the DF explosion in Guangdong in 2006 belonged to DEN-1. Compared to the serological assays, the real-time PCR assays that we developed were much more sensitive in the 1–3 days after onset of the symptoms.

scholarly journals Emergence of Salmonella enterica serovar 4,[5],12:i:- as the primary serovar identified from swine clinical samples and development of a multiplex real-time PCR for improved Salmonella serovar-level identification

2019 ◽  
Vol 31 (6) ◽  
pp. 818-827 ◽  
Author(s):  
Samantha A. Naberhaus ◽  
Adam C. Krull ◽  
Laura K. Bradner ◽  
Karen M. Harmon ◽  
Paulo Arruda ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Salmonella Enterica ◽  
Enrichment Culture ◽  
The United States ◽  
Rapid Identification ◽  
Clinical Samples ◽  
Diagnostic Laboratory ◽  
Diagnostic Samples ◽  
Group B

Rapid identification of the infecting Salmonella serovar from porcine diagnostic samples is vital to allow implementation of appropriate on-farm treatment and management decisions. Although identification at the serogroup level can be rapidly achieved at most veterinary diagnostic laboratories, final Salmonella serovar identification often takes several weeks because of the limited number of reference laboratories performing the complex task of serotyping. Salmonella serogroup B, currently the dominant serogroup identified from swine clinical samples in the United States, contains serovars that vary from highly pathogenic to minimally pathogenic in swine. We determined the frequency of detection of individual group B serovars at the Iowa State Veterinary Diagnostic Laboratory from 2008 to 2017, and validated a multiplex real-time PCR (rtPCR) to distinguish pathogenic serogroup B serovars from those of lesser pathogenicity. Our results indicate that, since 2014, Salmonella enterica ssp. enterica serovar 4,[5],12:i:- has been the dominant serovar identified from swine clinical samples at the ISU-VDL, with S. Typhimurium now the second most common serovar identified. We developed a rtPCR to allow rapid differentiation of samples containing S. 4,[5],12:i:- and S. Typhimurium from samples containing serovars believed to be of less pathogenicity, such as S. Agona and S. Derby. When combined with enrichment culture, this rtPCR has the ability to significantly improve the time to final serovar identification of the 2 most commonly identified pathogenic Salmonella serovars in swine, and allows rapid implementation of serovar-specific intervention strategies.

Identifying the etiologic role of Parvovirus B19 in non-immune hydrops fetalis by histopathology, immunohistochemistry and nucleic acid testing: a retrospective study

Open Medicine ◽  
2007 ◽  
Vol 2 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Koray Ergunay ◽  
Gulcin Altinok ◽  
Bora Gurel ◽  
Ahmet Pinar ◽  
Arzu Sungur ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Real Time ◽  
San Francisco ◽  
Real Time Pcr ◽  
Nested Pcr ◽  
Parvovirus B19 ◽  
Etiologic Agent ◽  
Hydrops Fetalis ◽  
Nucleic Acid Detection

AbstractIntrauterine Parvovirus B19 infections may cause fetal anemia, non-immune hydrops fetalis or abortion. This study focuses on the pathogenic role of Parvovirus B19 in non-immune hydrops fetalis at Hacettepe University, a major reference hospital in Turkey. Twenty-two cases of non-immune hydrops fetalis were retrospectively selected out of a total of 431 hydrops fetalis specimens from the Department of Pathology archieves. Paraffine embedded tissue sections from placental and liver tissues from each case were evaluated by histopathology, immunohistochemistry, nested PCR and commercial quantitative Real-time PCR. Viral DNA was detected in placental tissues by Real-time PCR in 2 cases (2/22, 9.1%) where histopathology also revealed changes suggestive of Parvovirus B19 infection. No significant histopathologic changes were observed for the remaining sections. Nested PCR that targets the VP1 region of the viral genome and immunohistochemistry for viral capsid antigens were negative for all cases. As a result, Parvovirus B19 is identified as the etiologic agent for the development of non-immune hydrops fetalis for 9.1% of the cases in Hacettepe University, Turkey. Real-time PCR is observed to be an effective diagnostic tool for nucleic acid detection from paraffine embedded tissues. Part of this study was presented as a poster at XIIIth International Congress of Virology, San Francisco, USA (Abstract V-572).

scholarly journals Evaluation of mobile real-time polymerase chain reaction tests for the detection of severe acute respiratory syndrome coronavirus 2

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chukwunonso Onyilagha ◽  
Henna Mistry ◽  
Peter Marszal ◽  
Mathieu Pinette ◽  
Darwyn Kobasa ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Real Time ◽  
Point Of Care ◽  
Middle Eastern ◽  
Turnaround Time ◽  
Cross Reactivity ◽  
Clinical Samples ◽  
Diarrhea Virus ◽  
Highly Sensitive ◽  
Transmissible Gastroenteritis

AbstractThe coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), calls for prompt and accurate diagnosis and rapid turnaround time for test results to limit transmission. Here, we evaluated two independent molecular assays, the Biomeme SARS-CoV-2 test, and the Precision Biomonitoring TripleLock SARS-CoV-2 test on a field-deployable point-of-care real-time PCR instrument, Franklin three9, in combination with Biomeme M1 Sample Prep Cartridge Kit for RNA 2.0 (M1) manual extraction system for rapid, specific, and sensitive detection of SARS-COV-2 in cell culture, human, and animal clinical samples. The Biomeme SARS-CoV-2 assay, which simultaneously detects two viral targets, the orf1ab and S genes, and the Precision Biomonitoring TripleLock SARS-CoV-2 assay that targets the 5′ untranslated region (5′ UTR) and the envelope (E) gene of SARS-CoV-2 were highly sensitive and detected as low as 15 SARS-CoV-2 genome copies per reaction. In addition, the two assays were specific and showed no cross-reactivity with Middle Eastern respiratory syndrome coronavirus (MERS-CoV), infectious bronchitis virus (IBV), porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis (TGE) virus, and other common human respiratory viruses and bacterial pathogens. Also, both assays were highly reproducible across different operators and instruments. When used to test animal samples, both assays equally detected SARS-CoV-2 genetic materials in the swabs from SARS-CoV-2-infected hamsters. The M1 lysis buffer completely inactivated SARS-CoV-2 within 10 min at room temperature enabling safe handling of clinical samples. Collectively, these results show that the Biomeme and Precision Biomonitoring TripleLock SARS-CoV-2 mobile testing platforms could reliably and promptly detect SARS-CoV-2 in both human and animal clinical samples in approximately an hour and can be used in remote areas or health care settings not traditionally serviced by a microbiology laboratory.

scholarly journals Detection of Human Polyomaviruses in Urine from Bone Marrow Transplant Patients: Comparison of Electron Microscopy with PCR

2004 ◽  
Vol 50 (2) ◽  
pp. 306-312 ◽  
Author(s):  
Stefan S Biel ◽  
Andreas Nitsche ◽  
Andreas Kurth ◽  
Wolfgang Siegert ◽  
Muhsin Özel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Bone Marrow ◽  
Real Time ◽  
Bone Marrow Transplant ◽  
Real Time Pcr ◽  
Marrow Transplant ◽  
Test System ◽  
Urine Samples ◽  
Clinical Samples ◽  
Transplant Patients

Abstract Background: We studied electron microscopy (EM) as an appropriate test system for the detection of polyomavirus in urine samples from bone marrow transplant patients. Methods: We evaluated direct EM, ultracentrifugation (UC) before EM, and solid-phase immuno-EM (SPIEM). The diagnostic accuracy of EM was studied by comparison with a real-time PCR assay on 531 clinical samples. Results: The detection rate of EM was increased by UC and SPIEM. On 531 clinical urine samples, the diagnostic sensitivity of EM was 47% (70 of 149) with a specificity of 100%. We observed a linear relationship between viral genome concentration and the proportion of urine samples positive by EM, with a 50% probability for a positive EM result for urine samples with a polyomavirus concentration of 106 genome-equivalents (GE)/mL; the probability of a positive EM result was 0% for urine samples with <103 GE/mL and 100% for urine samples containing 109 GE/mL. Conclusions: UC/EM is rapid and highly specific for polyomavirus in urine. Unlike real-time PCR, EM has low sensitivity and cannot quantify the viral load.

scholarly journals A Multiplex real-time PCR for detection of Mycoplasma gallisepticum and Mycoplasma synoviae in clinical samples from Brazilian commercial poultry flocks

2013 ◽  
Vol 44 (2) ◽  
pp. 505-510 ◽  
Author(s):  
Aline Padilha Fraga ◽  
Tatiana de Vargas ◽  
Nilo Ikuta ◽  
André Salvador Kazantzi Fonseca ◽  
Álvaro José Celmer ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Mycoplasma Gallisepticum ◽  
Clinical Samples ◽  
Mycoplasma Synoviae ◽  
Commercial Poultry

scholarly journals Development and evaluation of duplex TaqMan real-time PCR assay for detection and differentiation of wide-type and MGF505-2R gene-deleted African swine fever viruses

2020 ◽  
Author(s):  
zhenhua Guo ◽  
Kunpeng Li ◽  
Songlin Qiao ◽  
Xinxin Chen ◽  
Ruiguang Deng ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Large Scale ◽  
Limit Of Detection ◽  
African Swine Fever ◽  
Economic Losses ◽  
Clinical Samples ◽  
Diagnosis Method ◽  
Pcr Method ◽  
And Control

Abstract Background: African swine fever (ASF) is the most important disease to the pigs and cause serious economic losses to the countries with large-scale swine production. Vaccines are recognized as the most useful tool to prevent and control ASF virus (ASFV) infection. Currently, the MGF505 and MGF360 gene-deleted ASFVs or combined with CD2v deletion were confirmed to be the most promising vaccine candidates. Thus, it is essential to develop a diagnosis method to discriminate wide-type strain from the vaccines used.Results: In this study, we established a duplex TaqMan real-time PCR based on the B646L gene and MGF505-2R gene. The sequence alignment showed that the targeted regions of primers and probes are highly conserved in the genotype II ASFVs. The duplex real-time assay can specifically detect B646L and MGF505-2R gene single or simultaneously without cross-reaction with other porcine viruses tested. The limit of detection was 5.8 copies and 3.0 copies for the standard plasmids containing B646L and MGF505-2R genes, respectively. Clinical samples were tested in parallel by duplex real-time PCR and a commercial ASFV detection kit. The detection results of these two assays against B646L gene were well consistent.Conclusion: We successfully developed and evaluated a duplex TaqMan real-time PCR method which can effectively distinguish the wide type and MGF505 gene-deleted ASFVs. It would be a useful tool for the clinical diagnosis and control of ASF.

scholarly journals Novel multiplex real-time PCR assays reveal a high prevalence of diarrhoeagenic Escherichia coli pathotypes in healthy and diarrhoeal children in the South of Vietnam

2020 ◽  
Author(s):  
Vu Thuy Duong ◽  
Le Thi Phuong Tu ◽  
Ha Thanh Tuyen ◽  
Le Thi Quynh Nhi ◽  
James I Campbell ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Real Time Pcr ◽  
Clinical Samples ◽  
Middle Income ◽  
Middle Income Countries ◽  
Virulence Markers ◽  
Low Middle Income Countries ◽  
High Prevalence ◽  
Pcr Assays

Abstract BackgroundDiarrhoeagenic Escherichia coli (DEC) infections are common in children in low-middle income countries (LMICs). However, detecting the various DEC pathotypes is complex as they cannot be differentiated by classical microbiology. We developed four multiplex real-time PCR assays were to detect virulence markers of six DEC pathotypes; specificity was tested using DEC controls and other enteric pathogens. PCR amplicons from the six E. coli pathotypes were purified and amplified to be used to optimize PCR reactions and to calculate reproducibility. After validation, these assays were applied to clinical samples from healthy and diarrhoeal Vietnamese children and associated with clinical data. ResultsThe multiplex real-time PCRs were found to be reproducible, and specific. At least one DEC variant was detected in 34.7% (978/2,815) of the faecal samples from diarrhoeal children; EAEC, EIEC and atypical EPEC were most frequent Notably, 41.2% (205/498) of samples from non-diarrhoeal children was positive with a DEC pathotype. In this population, only EIEC, which was detected in 34.3% (99/289) of diarrhoeal samples vs. 0.8% (4/498) non-diarrhoeal samples (p<0.001), was significantly associated with diarrhoea. Multiplex real-time PCR when applied to clinical samples is an efficient and high-throughput approach to DEC pathotypes. ConclusionsThis approach revealed high carriage rates of DEC pathotypes among Vietnamese children. We describe a novel diagnostic approach for DEC, which provides baseline data for future surveillance studies assessing DEC burden in LMICs.

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