BACKGROUND: The Aptima Combo 2 (AC2) assay manufactured by Hologic, Inc., detects Neisseria gonorrhoeae and/or Chlamydia trachomatis (CT) in urogenital and extragenital specimens by targeting either a 16S rRNA (N. gonorrhoeae) or 23S rRNA (CT) region. In 2019, a mutation (C1515T) in the 23S rRNA region was reported to cause false-negative/equivocal results in specimens collected in Finland. Specimens containing this variant (Fl-nvCT) were also discovered internationally. Working with specimens submitted to a large commercial laboratory, we sought to determine if this variant was also present in the United States. METHODS: A subset (n = 401) of specimens tested with the AC2 assay collected during a 5-week period in late 2019/early 2020 were evaluated using an updated AC2 assay. RESULTS: Although the FI-nvCT variant was not detected within this specimen panel, 2 CT variants containing 23S rRNA mutations (A1518G, G1526A) were identified. The updated AC2 assay targeting an additional region of the 23S rRNA detected both of these variants. A retrospective study of >18 million AC2 results tested between 2018 and 2019 did not display a decrease in CT positivity. CONCLUSIONS: Although we did not detect the Fl-nvCT variant among US specimens, we show evidence that the low occurrence of similar diagnostic-escape mutants can be detected with an updated AC2 assay using multiple 23S rRNA targets.
BACKGROUND: The Aptima Combo 2 (AC2) assay manufactured by Hologic, Inc., detects Neisseria gonorrhoeae and/or Chlamydia trachomatis (CT) in urogenital and extragenital specimens by targeting either a 16S rRNA (N. gonorrhoeae) or 23S rRNA (CT) region. In 2019, a mutation (C1515T) in the 23S rRNA region was reported to cause false-negative/equivocal results in specimens collected in Finland. Specimens containing this variant (Fl-nvCT) were also discovered internationally. Working with specimens submitted to a large commercial laboratory, we sought to determine if this variant was also present in the United States. METHODS: A subset (n = 401) of specimens tested with the AC2 assay collected during a 5-week period in late 2019/early 2020 were evaluated using an updated AC2 assay. RESULTS: Although the FI-nvCT variant was not detected within this specimen panel, 2 CT variants containing 23S rRNA mutations (A1518G, G1526A) were identified. The updated AC2 assay targeting an additional region of the 23S rRNA detected both of these variants. A retrospective study of >18 million AC2 results tested between 2018 and 2019 did not display a decrease in CT positivity. CONCLUSIONS: Although we did not detect the Fl-nvCT variant among US specimens, we show evidence that the low occurrence of similar diagnostic-escape mutants can be detected with an updated AC2 assay using multiple 23S rRNA targets.
Authors: Michelle Jayne Cole; Grahame S Davis; Helen Fifer; John Michael Saunders; Magnus Unemo; Ronza Hadad; David J Roberts; Mohammed Fazal; Michaela Joanne Day; Jack Minshull; Peter Muir; Paddy J Horner; Noel O Gill; Kate Folkard Journal: Sex Transm Infect Date: 2021-09-11 Impact factor: 4.199
Authors: David J Roberts; Grahame S Davis; Michelle J Cole; Dixita Naik; Hitiksha Maru; Neil Woodford; Peter Muir; Paddy Horner; Ian Simms; George Thickett; Paul Crook; Kirsty Foster; Nick Andrews; John Saunders; Helen Fifer; Kate Folkard; O Noel Gill Journal: Euro Surveill Date: 2019-09
Authors: Kaisu Rantakokko-Jalava; Kati Hokynar; Niina Hieta; Anniina Keskitalo; Pia Jokela; Anna Muotiala; T Sakari Jokiranta; Rutta Kuusela; Hannu Sarkkinen; Janne Aittoniemi; Tytti Vuorinen; Antti J Hakanen; Mirja Puolakkainen Journal: Euro Surveill Date: 2019-05
Authors: Kati Hokynar; Kaisu Rantakokko-Jalava; Antti Hakanen; Marika Havana; Laura Mannonen; Pia Jokela; Satu Kurkela; Maija Lappalainen; Magnus Unemo; Mirja Puolakkainen Journal: Microorganisms Date: 2019-07-31