A Chlamydia trachomatis Strain With a 377-bp Deletion in the Cryptic Plasmid Causing False-Negative Nucleic Acid Amplification Tests

2007 ◽  
Vol 34 (5) ◽  
pp. 255-256 ◽  
Author(s):  
Torvald Ripa ◽  
Peter A. Nilsson
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.


Sexual Health ◽  
2015 ◽  
Vol 12 (1) ◽  
pp. 48 ◽  
Author(s):  
Basil Donovan ◽  
Wayne Dimech ◽  
Hammad Ali ◽  
Rebecca Guy ◽  
Margaret Hellard

Background Gonorrhoea notifications have been increasing in Australia’s cities, in both men and women. We investigated if this could be, at least in part, a result of a testing artefact. Methods: We surveyed 28 laboratories that were known to test for both Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) to determine their testing and reporting practices, and when these practices were instituted. Results: By 2012, 23 (82%) of the laboratories were routinely performing duplex nucleic acid amplification tests for both CT and NG even if a test for only one organism was requested, up from 9 (32%) laboratories before 2007. Although written reports of negative NG tests were not provided if the test was not requested, positive NG tests were always communicated to the attending clinician. Conclusions: The move towards routine duplex testing for CT and NG has probably resulted in more Australians being tested for NG than ever before. While this change has advantages for case-finding and improved public health outcomes, it also brings an increasing potential for false-positive NG tests. Recent trends in NG notifications should be interpreted with caution.


Sign in / Sign up

Export Citation Format

Share Document