The 'Finnish new variant of Chlamydia trachomatis' escaping detection in the Aptima Combo 2 assay is widespread across Norway, June to August 2019

Tone Bjordal Johansen; Hilde Kløvstad; Rikard Rykkvin; Einar Bredo Herrfurth-Erichsen; Joakim Sorthe; Gro Njølstad; Marit Helen Ebbesen; Randi Monsen Nygaard; Ellen Kristin Sandmoen; Carina Thilesen; Annette Onken; Inger Liljedal; Ronza Hadad; Magnus Unemo

doi:10.2807/1560-7917.ES.2019.24.42.1900592

The 'Finnish new variant of Chlamydia trachomatis' escaping detection in the Aptima Combo 2 assay is widespread across Norway, June to August 2019

Euro Surveill. 2019 Oct;24(42):1900592. doi: 10.2807/1560-7917.ES.2019.24.42.1900592.

Authors

Affiliations

¹ Norwegian Institute of Public Health, Oslo, Norway.
² European Public Health Microbiology Training Programme (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
³ Fürst Medical Laboratory, Oslo, Norway.
⁴ Haukeland University Hospital, Bergen, Norway.
⁵ Tønsberg Hospital Trust, Department of Medical Microbiology, Tønsberg, Norway.
⁶ Unilabs Laboratory Medicine, Department of Medical Microbiology, Skien, Norway.
⁷ Vestre Viken Hospital Trust, Department of Microbiology, Drammen, Norway.
⁸ Levanger Hospital, Department for Laboratory Medicine, Levanger, Norway.
⁹ WHO Collaborating Centre for Gonorrhoea and other STIs, National Reference Laboratory for STIs, Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.

PMID: 31640843
PMCID: PMC6807255
DOI: 10.2807/1560-7917.ES.2019.24.42.1900592

Abstract

The 'Finnish new variant of Chlamydia trachomatis' (FI-nvCT), escaping detection in the Aptima Combo 2 assay (AC2), is widespread across Norway. From June to August 2019, 84% (81/97) of available AC2/Aptima CT discordant samples from five laboratories were confirmed as FI-nvCT. Two additional CT variants (CT 23S rRNA C1514T and G1523A) also escaped AC2 detection. The high FI-nvCT proportion might indicate a long-term national spread and it cannot be excluded that FI-nvCT emerged in Norway.

Keywords: Aptima Combo 2 assay; Chlamydia trachomatis; FI-nvCT; Norway; diagnostic escape.

MeSH terms

Chlamydia Infections / diagnosis*
Chlamydia Infections / epidemiology
Chlamydia Infections / microbiology
Chlamydia trachomatis / genetics*
Chlamydia trachomatis / isolation & purification
Female
Humans
Male
Norway / epidemiology
Nucleic Acid Amplification Techniques / methods*
RNA, Bacterial / genetics
RNA, Ribosomal, 23S / genetics
Sensitivity and Specificity
Sequence Analysis, RNA / methods*

Substances

RNA, Bacterial
RNA, Ribosomal, 23S