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.

中文翻译：

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2019年7月至9月在丹麦各地广泛开展了Aptima Combo 2分析（Hologic）中的沙眼衣原体23S rRNA G1523A变种逃逸检测。

沙眼衣原体感染是全球最常见的细菌性传播感染，建议使用核酸扩增试验（NAAT）进行高度敏感和特异的诊断。在2019年初，芬兰的沙眼衣原体新变种（FI-nvCT）已确定。FI-nvCT在23S rRNA基因中具有C1515T突变，使其逃避了Aptima Combo 2（AC2； Hologic）NAAT的检测，随后在瑞典和挪威报道了FI-nvCT。在本研究中，我们调查了2019年7月至9月在丹麦存在的FI-nvCT和其他AC2诊断逃逸CT突变体。FI-nvCT存在但在丹麦很少见。但是，发现另一个AC2诊断逃逸CT突变体（具有23S rRNA G1523A突变）在丹麦广泛分布，占来自五个丹麦CT诊断实验室的AC2诊断逃逸nvCT样本的95％（76/80）。以前，仅在英国和挪威的一个样品中才检测到该nvCT-G1523A。监控NAAT目标在当地的持续稳定性至关重要，国家和国际环境，并使用具有不同目标的NAAT对发生率，诊断率的无法解释的变化和/或被诊断为阴性/明确的样本的年度收集进行适当的监控和分析。此外，具有双重靶序列的诊断性CT NAATs至关重要，幸运的是，包括一个额外靶序列的最新Hologic AC2检测方法正在开发中。