scholarly journals Genomic Variations in SARS-CoV-2 Strains at the Target Sequences of Nucleic Acid Amplification Tests

2020 ◽  
Author(s):  
Canhui Cao ◽  
Ruidi Yu ◽  
Shaoqing Zeng ◽  
Dan Liu ◽  
Wenjian Gong ◽  
...  

Abstract Background: Nucleic acid amplification is the main method used to detect infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the false-negative rate of nucleic acid tests cannot be ignored. Methods: Herein, we demonstrated genomic variations at the target sequences for the tests and the geographical distribution of the variations across countries by analyzing the whole-genome sequencing data of SARS-CoV-2 strains from the 2019 Novel Coronavirus Resource (2019nCoVR) database. Results: Among the 21 pairs of primer sequences in regions ORF1ab, S, E, and N, the total length of primer and probe target sequences was 938bp, with 131(13.97%) variant loci in 2415 (38.96%) isolates. Primer targets in the N region contained the most variations that were distributed among the most isolates, and the E region contained the least. Single nucleotide polymorphisms were the most frequent variation, with C to T transitions being detected in the most variant loci. G to A transitions and G to C transversions were the most common and had the highest isolate density. Genomic variations at the three mutation sites N: 28881, N: 28882, and N: 28883 were the most commonly detected, including in 608 SARS-CoV-2 strains from 33 countries, especially in the United Kingdom, Portugal, and Belgium. Conclusions: Our work comprehensively analyzed genomic variations on the target sequences of the nucleic acid amplification tests, offering evidence to optimize primer and probe target sequence selection, thereby improving the performance of the SARS-CoV-2 diagnostic test.

Author(s):  
Canhui Cao ◽  
Ruidi Yu ◽  
Shaoqing Zeng ◽  
Dan Liu ◽  
Wenjian Gong ◽  
...  

IntroductionNucleic acid amplification is the main method used to detect infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the false-negative rate of nucleic acid tests cannot be ignored.Material and methodsHerein, we demonstrated genomic variations at the target sequences for the tests and the geographical distribution of the variations across countries by analyzing the whole-genome sequencing data of SARS-CoV-2 strains from the 2019 Novel Coronavirus Resource (2019nCoVR) database.ResultsAmong the 21 pairs of primer sequences in regions ORF1ab, S, E, and N, the total length of primer and probe target sequences was 938bp, with 131(13.97%) variant loci in 2415 (38.96%) isolates. Primer targets in the N region contained the most variations that were distributed among the most isolates, and the E region contained the least. Single nucleotide polymorphisms were the most frequent variation, with C to T transitions being detected in the most variant loci. G to A transitions and G to C transversions were the most common and had the highest isolate density. Genomic variations at the three mutation sites N: 28881, N: 28882, and N: 28883 were the most commonly detected, including in 608 SARS-CoV-2 strains from 33 countries, especially in the United Kingdom, Portugal, and Belgium.ConclusionsOur work comprehensively analyzed genomic variations on the target sequences of the nucleic acid amplification tests, offering evidence to optimize primer and probe target sequence selection, thereby improving the performance of the SARS-CoV-2 diagnostic test.


2020 ◽  
Author(s):  
Canhui Cao ◽  
Ruidi Yu ◽  
Shaoqing Zeng ◽  
Dan Liu ◽  
Wenjian Gong ◽  
...  

Abstract Background Nucleic acid amplification is the main method used to detect infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the false-negative rate of nucleic acid tests cannot be ignored. Methods Herein, we demonstrated genomic variations at the target sequences for the tests and the geographical distribution of the variations across countries by analyzing the whole-genome sequencing data of SARS-CoV-2 strains from the 2019 Novel Coronavirus Resource (2019nCoVR) database. Results Among the 21 pairs of primer sequences in regions ORF1ab, S, E, and N, the total length of primer and probe target sequences was 938 bp, with 131(13.97%) variant loci in 2415 (38.96%) isolates. Primer targets in the N region contained the most variations that were distributed among the most isolates, and the E region contained the least. Single nucleotide polymorphisms were the most frequent variation, with C to T transitions being detected in the most variant loci. G to A transitions and G to C transversions were the most common and had the highest isolate density. Genomic variations at the three mutation sites N: 28881, N: 28882, and N: 28883 were the most commonly detected, including in 608 SARS-CoV-2 strains from 33 countries, especially in the United Kingdom, Portugal, and Belgium. Conclusions Our work comprehensively analyzed genomic variations on the target sequences of the nucleic acid amplification tests, offering evidence to optimize primer and probe target sequence selection, thereby improving the performance of the SARS-CoV-2 diagnostic test.


2020 ◽  
Vol 7 (11) ◽  
Author(s):  
Gwynngelle A Borillo ◽  
Ron M Kagan ◽  
Russell E Baumann ◽  
Boris M Fainstein ◽  
Lamela Umaru ◽  
...  

Abstract Background Nucleic acid amplification testing is a critical tool for addressing the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Specimen pooling can increase throughput and conserve testing resources but requires validation to ensure that reduced sensitivity does not increase the false-negative rate. We evaluated the performance of a real-time reverse transcription polymerase chain reaction (RT-PCR) test authorized by the US Food and Drug Administration (FDA) for emergency use for pooled testing of upper respiratory specimens. Methods Positive specimens were selected from 3 prevalence groups, 1%–3%, >3%–6%, and >6%–10%. Positive percent agreement (PPA) was assessed by pooling single-positive specimens with 3 negative specimens; performance was assessed using Passing-Bablok regression. Additionally, we assessed the distributions of RT-PCR cycle threshold (Ct) values for 3091 positive specimens. Results PPA was 100% for the 101 pooled specimens. There was a linear relationship between Ct values for pooled and single-tested specimens (r = 0.96–0.99; slope ≈ 1). The mean pooled Ct shifts at 40 cycles were 2.38 and 1.90, respectively, for the N1 and N3 targets. The median Cts for 3091 positive specimens were 25.9 (N1) and 24.7 (N3). The percentage of positive specimens with Cts between 40 and the shifted Ct was 1.42% (N1) and 0.0% (N3). Conclusions Pooled and individual testing of specimens positive for SARS-CoV-2 demonstrated 100% agreement, which demonstrates the viability of pooled specimens for SARS-COV-2 testing using a dual-target RT-PCR system. Pooled specimen testing can help increase testing capacity for SARS-CoV-2 with a low risk of false-negative results.


Sexual Health ◽  
2011 ◽  
Vol 8 (1) ◽  
pp. 9 ◽  
Author(s):  
Christopher K. Fairley ◽  
Marcus Y. Chen ◽  
Catriona S. Bradshaw ◽  
Sepehr N. Tabrizi

The use of nucleic acid amplification tests (NAAT), as well as or in preference to culture for non-genital sites is now recommended both in Australia and overseas because of their greater sensitivity and improved specificity. A survey of 22 Australian sexual health clinics who each year test over 14 500 men who have sex with men (MSM) show that culture remains the predominate method for detecting gonorrhoea at pharyngeal (64%) and rectal (73%) sites. This editorial discusses the potential disadvantages of using culture over NAAT in relation to optimal gonorrhoea control among MSM and advocates that significantly improved control would be achieved by moving to NAAT with the proviso that culture samples are taken wherever possible on NAAT-positive samples and from clients with urethritis to ensure continued surveillance for antimicrobial resistance.


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