| Autor: |
Derendinger, Brigitta, de Vos, Margaretha, Pillay, Samantha, Venter, Rouxjeane, Metcalfe, John, Ghebrekristos, Yonas, Minnies, Stephanie, Dolby, Tania, Beylis, Natalie, Warren, Robin, Theron, Grant |
| Zdroj: |
The Journal of Molecular Diagnostics; May 2022, Vol. 24 Issue: 5 p494-502, 9p |
| Abstrakt: |
Strengthening second-line drug-resistant tuberculosis (TB) detection is a priority. GenoType MTBDRplusVER 2.0 performance is reduced with non-recommended ramp rate usage (temperature change speed between PCR cycles); however, ramp rate’s effect on GenoType MTBDRslVER 2.0 (MTBDRsl) performance, is unknown. Fifty-two Xpert MTB/RIF Ultra-positive rifampicin-resistant smear-negative sputa and a Mycobacterium tuberculosisdilution series were tested at a manufacturer-recommended (2.2°C/second) or suboptimal (4.0°C/second) ramp rate. M. tuberculosis–complex-DNA positivity, indeterminates, fluoroquinolone- and second-line injectable-resistance accuracy, banding differences, and, separately, inter-reader variability were assessed. Five (39%) of 13 re-surveyed laboratories did not use the manufacturer-recommended ramp rate. On sputum, 2.2°C/second improved indeterminates versus 4.0°C/second (0 of 52 versus 7 of 51; P= 0.006), incorrect drug-class diagnostic calls (0 of 104 versus 6 of 102; P= 0.013), and incorrect banding calls (0 of 1300 versus 54 of 1275; P< 0.001). Similarly, 2.2°C/second improved valid results [(52 of 52 versus 41 of 51; +21% (P= 0.001)] and banding call inter-reader variability [34 of 1300 (3%) versus 52 of 1300 (4%); P= 0.030]. At the suboptimal ramp rate, false-resistance and false-susceptible calls resulted from wild-type band absence rather than mutant band appearance, resulting in misclassification of moxifloxacin resistance level from high-to-low. Suboptimal ramp rate contributes to poor MTBDRslperformance. Laboratories must ensure that the manufacturer-recommended ramp rate is used. |
| Databáze: |
Supplemental Index |
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