P1.09 Diagnosingmycoplasma genitalium: comparison of four nucleic acid amplification tests and use of the speedx real-time pcr assay for azithromycin resistance

AbstractThe Mycobacterium tuberculosis complex (MTBC) remains one of the top 10 leading causes of death globally. The early diagnosis of MTBC can reduce mortality and mitigate disease transmission. However, current nucleic acid amplification diagnostic test methods are generally time-consuming and show suboptimal diagnostic performance, especially in extrapulmonary MTBC samples or acid-fast stain (AFS)-negative cases. Thus, development of an accurate assay for the diagnosis of MTBC is necessary, particularly under the above mentioned conditions. In this study, a single-tube nested real-time PCR assay (N-RTP) was developed and compared with a newly in-house-developed high-sensitivity real-time PCR assay (HS-RTP) using 134 clinical specimens (including 73 pulmonary and 61 extrapulmonary specimens). The amplification efficiency of HS-RTP and N-RTP was 99.8% and 100.7%, respectively. The sensitivity and specificity of HS-RTP and N-RTP for the diagnosis of MTBC in these specimens were 97.5% (77/79) versus 94.9% (75/79) and 80.0% (44/55) versus 89.1% (49/55), respectively. The sensitivity and specificity of HS-RTP and N-RTP for the diagnosis of MTBC in pulmonary specimens were 96.3% (52/54) versus 96.3% (52/54) and 73.7.0% (14/19) versus 89.5% (17/19), respectively; in extrapulmonary specimens, the sensitivity and specificity of HS-RTP and N-RTP were 100% (25/25) versus 92% (23/25) and 83.3% (30/36) versus 88.9% (32/36), respectively. Among the AFS-negative cases, the sensitivity and specificity of HS-RTP and N-RTP were 97.0% (32/33) versus 90.9% (30/33) and 88.0% (44/50) versus 92.0% (46/50), respectively. Overall, the sensitivity of HS-RTP was higher than that of N-RTP, and the performance was not compromised in extrapulmonary specimens and under AFS-negative conditions. In contrast, the specificity of the N-RTP assay was higher than that of the HS-RTP assay in all types of specimens. In conclusion, the HS-RTP assay would be useful for screening patients suspected of exhibiting an MTBC infection due to its higher sensitivity, while the N-RTP assay could be used for confirmation because of its higher specificity. Our results provide a two-step method (screen to confirm) that simultaneously achieves high sensitivity and specificity in the diagnosis of MTBC.

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Differing Effects of Standard and Harsh Nucleic Acid Extraction Procedures on Diagnostic Helminth Real-Time PCRs Applied to Human Stool Samples

Pathogens ◽

10.3390/pathogens10020188 ◽

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.

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Locked Nucleic Acid Probe-Based Real-Time PCR Assay for the Rapid Detection of Rifampin-Resistant Mycobacterium tuberculosis

PLoS ONE ◽

10.1371/journal.pone.0143444 ◽

2015 ◽

Vol 10 (11) ◽

pp. e0143444 ◽

Cited By ~ 6

Author(s):

Yong Zhao ◽

Guilian Li ◽

Chongyun Sun ◽

Chao Li ◽

Xiaochen Wang ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Nucleic Acid ◽

Real Time ◽

Real Time Pcr ◽

Rapid Detection ◽

Locked Nucleic Acid ◽

Pcr Assay ◽

Locked Nucleic Acid Probe

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Molecular Detection of Adenovirus in Tap Water from Coastal Areas Of Karachi Pakistan:The Real-Time PCR Assay

American Journal of Clinical Pathology ◽

10.1093/ajcp/aqab191.299 ◽

2021 ◽

Vol 156 (Supplement_1) ◽

pp. S140-S140

Author(s):

A Kalam

Keyword(s):

Nucleic Acid ◽

Real Time ◽

Low Income ◽

Water Samples ◽

Real Time Pcr ◽

Tap Water ◽

Watery Diarrhea ◽

Acid Extraction ◽

Pcr Assay ◽

Viral Contamination

Abstract Introduction/Objective Diarrhea is a major source of morbidity and mortality in low-income and middle-income countries. In underdeveloped countries, diseases caused by viruses identified in environmental samples cause major health problems. Little knowledge about the frequency and pattern of viral contamination of drinking water sources in these resource-poor settings. Adenovirus which causes watery diarrhea, particular has been recognized as important causal pathogen. Adenovirus remains a global threat to public health and an indicator of inequity and lack of social development. Tap water samples from coastal sites in Karachi between 2019 and 2020 over a period of 11 months. The total of 40 tap water sample was examined for infectious Adenovirus by a real time polymerase chain reaction (PCR) amplification. Methods/Case Report This Pilot study is conducted on tap water samples from Karachi Pakistan, n=40 are processed. Extraction of nucleic acid from all filtered water samples collected with Sterivex filter units by using Qiagen DNeasy Power Water Sterivex Kit. As per the manufacturer’s instruction. Phocine herpesvirus(PhHV) is added as an external positive control to monitor the efficiency of nucleic acid extraction and amplification. TaqMan Universal PCR Master Mix (Thermo Fisher Scientific) is being used in probe based real time PCR assay,the below 35 Ct value is considered as a positive sample. Results (if a Case Study enter NA) Results showed the total of 37.7% of the sources were positive for adenovirus.The level of viral contamination was moderate to high. Conclusion The results has been showed that no seasonal pattern for viral contaminations was found after samples obtained during the dry and wet seasons were compared. Further the Real time PCR assay increases the sensitivity and provides the high resolution of pathogen detection.

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Limited-Resource Preparable Chitosan Magnetic Particles for Extracting Amplification-Ready Zeptomole-Range Nucleic Acid from Complex Biofluid

10.26434/chemrxiv.14579127 ◽

2021 ◽

Author(s):

Sayantan Tripathy ◽

Arunansu Talukdar ◽

Goutam Pramanik ◽

P. V. Rajesh ◽

Souradyuti Ghosh

Keyword(s):

Nucleic Acid ◽

Real Time ◽

Real Time Pcr ◽

Magnetic Particles ◽

Limited Resource ◽

Nucleic Acid Amplification ◽

Acid Extraction ◽

Analytical Sensitivity ◽

Nucleic Acid Extraction ◽

Spin Column

<b>Layman Summary: </b>Nucleic acid extraction is a key prerequisite for any nucleic acid amplification test (NAAT) or isothermal NAAT (iNAAT) based molecular diagnosis assays.<b> </b>Existing methods utilizes spin column system for nucleic acid extraction which are unsuitable for limited resource settings. Our work explores two methods for chitosan coated magnetic particle preparation that can be executed within 6 h from commonly available chemicals with nothing but a magnetic stirrer and water bath and doable by a minimally trained person. We will also investigated the compatibility of the extracted nucleic acid with downstream NAATs such as real time LAMP, colorimetric LAMP, and real time PCR. In the process, we established the analytical sensitivity of the overall method.<div><br><div><b>Characterization methods</b>: SEM, XRD, EDX, FT-IR</div><div><br></div><div><b>Bioanalytical methods:</b> Real time LAMP, Colorimetric LAMP, Real time PCR</div></div>

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

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2017-1133 ◽

2018 ◽

Vol 56 (7) ◽

pp. 1133-1139 ◽

Cited By ~ 7

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.

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Paradigm for diagnosing mycobacterial disease: direct detection and differentiation of Mycobacterium tuberculosis complex and non-tuberculous mycobacteria in clinical specimens using multiplex real-time PCR

Journal of Clinical Pathology ◽

10.1136/jclinpath-2017-204945 ◽

2018 ◽

Vol 71 (9) ◽

pp. 774-780 ◽

Cited By ~ 10

Author(s):

Jeong-Uk Kim ◽

Dae-Shick Ryu ◽

Choong-Hwan Cha ◽

Seon-Hee Park

Keyword(s):

Mycobacterium Tuberculosis ◽

Real Time ◽

Real Time Pcr ◽

Predictive Value ◽

Direct Detection ◽

Positive Culture ◽

Nucleic Acid Amplification ◽

Mycobacterial Disease ◽

Pcr Assay ◽

Clinical Specimens

AimsMycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) are clinically different, and the rapid detection and differentiation of M. tuberculosis complex (MTBC) and NTM is crucial for patient management and infection control. Given the slow growth of most pathogenic mycobacteria, nucleic acid amplification assays are excellent tools for direct identification of mycobacteria in clinical specimens. Recently, a multiplex real-time PCR assay was developed that can directly detect 20 mycobacterial species in clinical specimens. Here, we evaluated the diagnostic performance of the assay for diagnosing mycobacterial disease under routine laboratory conditions.MethodsA total of 3334 specimens collected from 1437 patients suspected of tuberculosis infection were subjected to acid-fast bacilli staining, conventional culture and the multiplex real-time PCR assay. To evaluate the sensitivity and specificity of the assay, the overall diagnosis of tuberculosis was defined by positive culture plus medical history, and the 2007 American Thoracic Society and Infectious Disease Society of America diagnostic criteria for NTM disease were applied.ResultsThe sensitivity, specificity, positive predictive value and negative predictive value were 87.5%, 99.6%, 96.1% and 98.5%, respectively, for the detection of MTBC isolates and 53.3%, 99.9%, 95.2%, and 98.9%, respectively, for detecting NTM isolates.ConclusionsThus, the assay can correctly differentiate between MTBC and NTM isolates in clinical specimens and would be a useful tool for the rapid differentiation of tuberculosis and NTM disease, despite its limited sensitivity for the diagnosis of NTM disease.

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Abstract 411: Sensitive detection of BRAF V600E mutation by bridged nucleic acid (BNA)-mediate real-time PCR assay

10.1158/1538-7445.am2016-411 ◽

2016 ◽

Author(s):

Xiaoyun Liu ◽

Leticia Loredo ◽

Houquan Dai ◽

Aaron Castro ◽

Yuewei Zhao ◽

...

Keyword(s):

Nucleic Acid ◽

Real Time ◽

Real Time Pcr ◽

Braf V600e Mutation ◽

Braf V600e ◽

Sensitive Detection ◽

Pcr Assay

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Rapid Detection of Acquired and Inducible Clarithromycin Resistance in Mycobacterium abscessus Group by a Simple Real-Time PCR Assay

Journal of Clinical Microbiology ◽

10.1128/jcm.00132-15 ◽

2015 ◽

Vol 53 (7) ◽

pp. 2337-2339 ◽

Cited By ~ 9

Author(s):

Robert F. Luo ◽

Cheyenne Curry ◽

Nathan Taylor ◽

Indre Budvytiene ◽

Niaz Banaei

Keyword(s):

Nucleic Acid ◽

Real Time ◽

Real Time Pcr ◽

Rapid Detection ◽

Mycobacterium Abscessus ◽

Nucleic Acid Testing ◽

Pcr Assay ◽

Content Type ◽

Clarithromycin Resistance ◽

Group A

By targeting theerm(41) andrrlgenes in theMycobacterium abscessusgroup, a multiplex real-time PCR assay for clarithromycin resistance showed 95% (38/40) concordance with nucleic acid testing and 95% (37/39) concordance with phenotypic testing. This assay provides a simple and rapid alternative to extended incubation orerm(41) sequencing.

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Evaluating Performance of Multiplex Real Time PCR for the Diagnosis of Malaria at Elimination Targeted Low Transmission Settings of Ethiopia.

10.21203/rs.3.rs-572301/v1 ◽

2021 ◽

Author(s):

Mahlet Belachew ◽

Mistire Wolde ◽

Desalegn Nega ◽

Bokretsion Gidey ◽

Legessie Negash ◽

...

Keyword(s):

Light Microscopy ◽

Real Time ◽

Malaria Elimination ◽

Real Time Pcr ◽

Nucleic Acid Amplification ◽

Molecular Testing ◽

Pcr Assay ◽

Blood Samples ◽

Low Transmission ◽

Highly Sensitive

Abstract Background: Malaria incidence has declined in Ethiopia in the past ten years. Current malaria diagnostic tests, including light microscopy and antigen-detecting rapid tests (RDTs) cannot reliably detect low-density infections. Studies have shown that nucleic acid amplification tests are highly sensitive and specific in detecting malaria infection. Thus, this study took place with the aim of evaluating the performance of multiplex real time PCR for the diagnosis of malaria using patient samples collected from health facilities located at malaria elimination targeted low transmission settings in Ethiopia. Methods: A health facility based cross sectional survey was conducted in selected malaria sentinel sites. Malaria suspected febrile outpatients referred to laboratory for malaria testing between December 2019 and March 2020 were enrolled into this study. Socio demographic information and capillary blood samples were collected from the study participants and tested at spot with RDTs. Additionally, five circles of dry blood sample (DBS) samples on Whatman filter paper and thick and thin smear were prepared for molecular testing and microscopic examination, respectively. Multiplex real time PCR assay was performed at EPHI malaria laboratory. The performance of multiplex real time PCR assay, microscopy and RDT for the diagnosis of malaria was compared and evaluated against each other.Results: Out of 271 blood samples, multiplex real time PCR identified 69 malaria cases as P. falciparum infection, 16 as P. vivax and 3 as mixed infections. Of the total samples, light microscopy detected 33 as Pf, 18 as PV and RDT detected 43 as Pf, 17 as PV, and one mixed infection. Using light microscopy as reference test, the sensitivity and specificity of multiplex real time PCR were 100% (95% CI [93-100]) and 83.2% (95% CI [77.6-87.9]), respectively. Using multiplex real time PCR as a reference, light microscopy and RDT had sensitivity of 58% (95% CI [46.9-68.4] and 67% (95% CI [56.2-76.7]); and 100% (95% CI [98-100] and 98.9 (95% CI (96-99.9), respectively. Substantial level of agreement was reported between microscopy and multiplex real time PCR results with kappa value of 0.65. Conclusions: Multiplex real time PCR had an advanced performance in parasite detection and species identification on febrile patients’ samples than did microscopy and RDT in low malaria transmission settings. It is highly sensitive malaria diagnostic method that can be used in malaria elimination program, particularly for community based epidemiological samples. Although microscopy and RDT had reduced performance when compared to multiplex real time PCR, still had an acceptable performance in diagnosis of malaria cases on patient samples at clinical facilities.

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