P003
Increased sensitivity for Mycobacterium tuberculosis detection with the updated FluoroType MTBDR v2
E Svensson(1) D B Folkvardsen(1) E M Rasmussen(1) A Norman(1) X E, S Iversen(1) T Lillebaek(1,2)
1:Statens Serum Institut; 2:University of Copenhagen
FluoroType MTBDR v2 (FT; Hain LifeScience) is a multiplex, multi-probe real-time PCR for the simultaneous detection of Mycobacterium tuberculosis complex (MTBC) and resistance-conferring mutations for rifampicin (RIF; rpoB) and isoniazid (INH; katG, inhA). The recent kit upgrade (FT-new) improves the MTBC sensitivity by adding the IS6110 element to the existing rpoB in FT-old.
The performance of FT-new to detect MTBC was compared with that of FT-old using MTBC culture as a reference.
In total, 1483 prospective clinical samples of different types were analysed in parallel from the same FluoroLyse DNA extraction. Samples were re-analysed if the FT-old was inhibited or for a first-time PCR-positive patient. PCR results were compared with MTBC culture in MGIT and on Löwenstein-Jensen.
1411 FT-old and 1377 FT-new had results that could be evaluated. The sensitivity and specificity for FT-new were 0.87 and 0.95, respectively; for FT-old, 0.70 and 0.95, respectively. In sputum samples, the sensitivity was 0.92 (FT-new) and 0.81 (FT), respectively. At least one of the three resistance targets was detected in 39 samples tested with FT-new and 34 samples tested with FT-old.
In conclusion, adding the insertion element IS6110 as a target for MTBC detection increases the sensitivity considerably. However, the sensitivity of detecting resistance targets does not increase.