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- Hadad, Ronza, 1984-, et al.
(författare)
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A Chlamydia trachomatis 23S rRNA G1523A variant escaping detection in the Aptima Combo 2 assay (Hologic) was widespread across Denmark in July-September 2019
- 2020
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley-Blackwell Publishing Inc.. - 0903-4641 .- 1600-0463. ; 128:6, s. 440-444
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Tidskriftsartikel (refereegranskat)abstract
- Chlamydia trachomatis infection is the most common bacterial sexually transmitted infection globally, and nucleic acid amplification tests (NAATs) are recommended for highly sensitive and specific diagnosis. In early 2019, the Finnish new variant of Chlamydia trachomatis (FI-nvCT) was identified. The FI-nvCT has a C1515T mutation in the 23S rRNA gene, making it escaping detection in the Aptima Combo 2 (AC2; Hologic) NAAT, and the FI-nvCT has been subsequently reported in Sweden and Norway. In the present study, we investigated the presence of the FI-nvCT and other AC2 diagnostic-escape CT mutants in July-September 2019 in Denmark. The FI-nvCT was present but rare in Denmark. However, another AC2 diagnostic-escape CT mutant (with a 23S rRNA G1523A mutation) was found to be widespread across Denmark, accounting for 95% (76/80) of AC2 diagnostic-escape nvCT samples from five Danish CT-diagnostic laboratories. This nvCT-G1523A has previously only been detected in one single sample in the United Kingdom and Norway, respectively. It is vital to monitor the continued stability of the NAAT targets in local, national and international settings and monitor as well as appropriately analyse incidence, unexplained shifts in diagnostics rates, and/or annual collections of samples diagnosed as negative/equivocal using NAATs with different target(s). Furthermore, diagnostic CT NAATs with dual target sequences are crucial and fortunately, an updated Hologic AC2 assay including one additional target sequence is in advanced development.
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| 3. |
- Unemo, Magnus, 1970-, et al.
(författare)
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Sensitivity, specificity, inclusivity and exclusivity of the updated Aptima Combo 2 assay, which provides detection coverage of the new diagnostic-escape Chlamydia trachomatis variants
- 2020
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Ingår i: BMC Infectious Diseases. - : BioMed Central. - 1471-2334. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Four new variants of Chlamydia trachomatis (nvCTs), detected in several countries, cause false-negative or equivocal results using the Aptima Combo 2 assay (AC2; Hologic). We evaluated the clinical sensitivity and specificity, as well as the analytical inclusivity and exclusivity of the updated AC2 for the detection of CT and Neisseria gonorrhoeae (NG) on the automated Panther system (Hologic).Methods: We examined 1004 clinical AC2 samples and 225 analytical samples spiked with phenotypically and/or genetically diverse NG and CT strains, and other potentially cross-reacting microbial species. The clinical AC2 samples included CT wild type (WT)-positive (n = 488), all four described AC2 diagnostic-escape nvCTs (n = 170), NG-positive (n = 214), and CT/NG-negative (n = 202) specimens.Results: All nvCT-positive samples (100%) and 486 (99.6%) of the CT WT-positive samples were positive in the updated AC2. All NG-positive, CT/NG-negative, Trichomonas vaginalis (TV)-positive, bacterial vaginosis-positive, andCandida-positive AC2 specimens gave correct results. The clinical sensitivity and specificity of the updated AC2 for CT detection was 99.7 and 100%, respectively, and for NG detection was 100% for both. Examining spiked samples, the analytical inclusivity and exclusivity were 100%, i.e., in clinically relevant concentrations of spiked microbe.Conclusions: The updated AC2, including two CT targets and one NG target, showed a high sensitivity, specificity, inclusivity and exclusivity for the detection of CT WT, nvCTs, and NG. The updated AC2 on the fully automated Panther system offers a simple, rapid, high-throughput, sensitive, and specific diagnosis of CT and NG, which can easily be combined with detection of Mycoplasma genitalium and TV.
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