Surveillance for Chlamydia trachomatis variants escaping detection with the Aptima Combo 2 assay in Canada from 2019 to 2021

• DOI: 10.1128/spectrum.02062-24
• Publication Date: 2025-01-23T14:00:17Z
• Authors: Felicia Roy; Jennifer Beirnes; Jason J. LeBlanc; Suzanne Gibbons; Aida Sivro; Alberto Severini
• Keywords: 23S ribosomal RNA

ABSTRACT Nucleic acid amplification tests (NAATs) are the method of choice for Chlamydia trachomatis diagnosis, but these strategies susceptible to target site mutations. C. variants escaping detection with Aptima Combo 2 (AC2) assay on Hologic Panther instrument from 23S rRNA mutations have been reported in Nordic countries, England, Japan, and United States. Given potential false negative results, this study investigated whether strains AC2 were present Canada. Surveillance was conducted Canadian laboratories 2019 2021. Specimens suspected included those low-value detections assay, subsequent high-value Trachomatis (ACT) used confirmatory testing. AC2/ACT discrepant results subjected sequencing (i.e., rRNA). Sequencing revealed 15 (4.8%) diagnostic escape which carrying either C1514T, G1523A, or G1526A All specimens a mutation detected reformulated version assay. Overall, while prevalence rare, their presence population supports use new kit formulation need ongoing genetic surveillance NAAT-based assays. IMPORTANCE Molecular commonly sexually transmitted infections (STIs) like . Mutations impacting molecular several raising concerns about results. This showed failures submitted testing A test is now available that can identify harboring impacted by previous formulation. While rare Canada, revealing important ensure accurate existing methods. monitoring sites, as well avoid transmissions.