Session Type: 1-hour ePoster Review
Session Title: 1-hour ePoster Review
Authors(s): T. Poncin (1, 2), M. Mainardis (1), J. Guiraud (3, 4), A. Braille (1), M. Mérimèche (1), F. Caméléna (1, 2), H. Jacquier (1, 2), C. Bébéar (3, 4), B. Berçot (1, 2)
Authors Affiliations(s): (1) Bacteriology Unit, Saint Louis-Lariboisière-Fernand Widal Hospital, French National Reference Center for bacterial STI, Associated laboratory for gonococci, APHP, France, (2) University of Paris, INSERM, IAME unit, UMR1137, France, (3) University of Bordeaux, USC EA 3671 Mycoplasmal and Chlamydial Infections in Humans, France, (4) Bordeaux University Hospital, Bacteriology Department, National Reference Center for bacterial sexually transmitted infections, France
Background:
The diagnosis of bacterial Sexually Transmitted Infections (STIs) due to Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG) remains difficult, especially in asymptomatic patients. Hence, numerous multiplex RT-PCR are now developed, and the aim of this study was to determine the performances of the new CE-IVD marked Alinity-m system (STI assay) (Abbott, Rungis, France) for the detection of CT, NG and MG in genital and extragenital sites.
Methods:Between March 2019 and July 2020, 662 clinical samples were collected at the French National Reference Center (NRC) for bacterial STI including 342 rectal samples (100 CT-positive, 100 NG-positive and 42 MG-positive samples), 200 throat samples (100 NG-positive samples), and 120 urine samples (30 CT-positive, 30 NG-positive and 30 MG-positive samples). The performances of the Abbott STI assay for the detection of CT, NG, MG were compared to that of the Cobas CT/NG and TV/MG assay (Roche Diagnostics) performed on the Cobas 6800 system. Overall, positive and negative percentage agreements (OPA, PPA, and NPA; respectively) were calculated. Discrepant tests were investigated at the NRC using in-house reference RT-PCR.
Results:Alinity-m and Cobas6800 showed excellent overall agreement at 98%, 96% and 91% for CT, MG and NG, respectively.
For CT detection, PPA was found at 94% and 89% in urines and rectal swabs, respectively; NPA was≥99% in all samples. Considering NG detection, a good concordance was observed in anorectal samples with PPA, NPA ≥ 90% but PPA remained low in oropharyngeal samples (81.5%).
For MG detection, PPA was <90% (87.9% for urine and 80.9 % for anorectal samples) and NPA values for MG were ≥98% in all samples.
However, Alinity-m and Cobas 6800 gave discrepant results in 14% (93/662) of cases. They are mostly found in extragenital samples [78.5% (73/93)] and in cases of late positivity determined by a cycle threshold superior to 35 cycles of RT-PCR [90.3% (84/93)].
Conclusions:Alinity-m and Cobas 6800 displayed high agreement on genital and extragenital samples for the detection of CT, NG and MG. Nevertheless, discrepant results were observed between both techniques, especially for NG detection from extragenital swabs and for late amplification signals.
Keyword(s): Sexually Transmitted Infections, Molecular diagnostics, extragenital sitesSession Type: 1-hour ePoster Review
Session Title: 1-hour ePoster Review
Authors(s): T. Poncin (1, 2), M. Mainardis (1), J. Guiraud (3, 4), A. Braille (1), M. Mérimèche (1), F. Caméléna (1, 2), H. Jacquier (1, 2), C. Bébéar (3, 4), B. Berçot (1, 2)
Authors Affiliations(s): (1) Bacteriology Unit, Saint Louis-Lariboisière-Fernand Widal Hospital, French National Reference Center for bacterial STI, Associated laboratory for gonococci, APHP, France, (2) University of Paris, INSERM, IAME unit, UMR1137, France, (3) University of Bordeaux, USC EA 3671 Mycoplasmal and Chlamydial Infections in Humans, France, (4) Bordeaux University Hospital, Bacteriology Department, National Reference Center for bacterial sexually transmitted infections, France
Background:
The diagnosis of bacterial Sexually Transmitted Infections (STIs) due to Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG) remains difficult, especially in asymptomatic patients. Hence, numerous multiplex RT-PCR are now developed, and the aim of this study was to determine the performances of the new CE-IVD marked Alinity-m system (STI assay) (Abbott, Rungis, France) for the detection of CT, NG and MG in genital and extragenital sites.
Methods:Between March 2019 and July 2020, 662 clinical samples were collected at the French National Reference Center (NRC) for bacterial STI including 342 rectal samples (100 CT-positive, 100 NG-positive and 42 MG-positive samples), 200 throat samples (100 NG-positive samples), and 120 urine samples (30 CT-positive, 30 NG-positive and 30 MG-positive samples). The performances of the Abbott STI assay for the detection of CT, NG, MG were compared to that of the Cobas CT/NG and TV/MG assay (Roche Diagnostics) performed on the Cobas 6800 system. Overall, positive and negative percentage agreements (OPA, PPA, and NPA; respectively) were calculated. Discrepant tests were investigated at the NRC using in-house reference RT-PCR.
Results:Alinity-m and Cobas6800 showed excellent overall agreement at 98%, 96% and 91% for CT, MG and NG, respectively.
For CT detection, PPA was found at 94% and 89% in urines and rectal swabs, respectively; NPA was≥99% in all samples. Considering NG detection, a good concordance was observed in anorectal samples with PPA, NPA ≥ 90% but PPA remained low in oropharyngeal samples (81.5%).
For MG detection, PPA was <90% (87.9% for urine and 80.9 % for anorectal samples) and NPA values for MG were ≥98% in all samples.
However, Alinity-m and Cobas 6800 gave discrepant results in 14% (93/662) of cases. They are mostly found in extragenital samples [78.5% (73/93)] and in cases of late positivity determined by a cycle threshold superior to 35 cycles of RT-PCR [90.3% (84/93)].
Conclusions:Alinity-m and Cobas 6800 displayed high agreement on genital and extragenital samples for the detection of CT, NG and MG. Nevertheless, discrepant results were observed between both techniques, especially for NG detection from extragenital swabs and for late amplification signals.
Keyword(s): Sexually Transmitted Infections, Molecular diagnostics, extragenital sites