The MTB/MDR Test Kit (Sanity 2.0) (Abbreviation: Sanity-2 MTB/MDR) is a cartridge-based test kit designed for the qualitative detection of Mycobacterium tuberculosis complex (MTBC) and multidrug-resistance mutations, including rifampin-resistant and isoniazid-resistant mutations in Mycobacterium tuberculosis (MTB) from sputum samples. This kit is specifically designed for use with the Sanity 2.0 System, a fully automated, all-in-one instrument that integrates nucleic acid extraction, real-time polymerase chain reaction (RT-PCR), melting curve analysis, and result interpretation.
Principle
The Sanity-2 MTB/MDR uses Taqman probe-based real-time polymerase chain reaction (RT-PCR) to qualitatively detect IS6110 gene that is specific for MTBC as well as a non-human internal control (Arabidopsis thaliana SUC2 gene).
At the same time, the Sanity-2 MTB/MDR employs dually labeled probes to target the excess single-stranded amplicons generated by asymmetric PCR; then uses melting curve analysis to generate the minus derivative of the fluorescence intensity versus temperature, and compares the melting temperature (Tm) to gain mutation information of the sequences. Where, perfect match of target sequence and probe gives the highest Tm; partially mismatch, e.g., point mutation, insertion or deletion, would cause decreased Tm than that of perfect match. The decreased degree is related to the type of point mutation, base number of insertion or deletion as well as the mutation location. The Sanity-2 MTB/MDR covers the mutations of rpoB (codons 507~533) to determine the resistance of rifampin; the mutations of ahpC promoter region (positions -44~-30 and -15~4), inhA promoter region (positions -17~-8), and katG codon 315, to determine the resistance of isoniazid.
Features
Ease of Use: The Sanity-2 MTB/MDR is designed for use with the Sanity 2.0 all-in-one platform. It features pre-loaded lyophilized reagents for easy handling and room-temperature transportation.
Multidrug Resistance Testing: The test allows for the identification of MTBC, as well as rifampin-resistant and isoniazid-resistant strains, in a single reaction.
Reliable: The UNG system and internal control are included to prevent carry-over contamination and ensure the accuracy of experimental results.
Performance
The kit (formerly known as Meltpro® kit, referred to as Meltpro in the publication cited below) employs MMCA® technology, which offers high sensitivity and specificity for the detection of mutations associated with multidrug-resistant Mycobacterium tuberculosis[1].
Table 1 Assay Performance for Detection of Rifampin Resistance
Pilot | Meltpro | DST | Total | Sensitivity(%, 95% CI) | Specificity(%, 95% CI) | PPV(%, 95% CI) | NPV(%, 95% CI) | |
R | S | |||||||
Shandong |
R |
107 |
15 |
122 |
96.4 (91.1–98.2) |
97.6 (96.0–98.2) |
87.7 (80.7–92.4) |
99.2 (98.2-99.7) |
S |
4 |
601 |
605 |
|||||
Total |
111 |
616 |
727 |
|||||
Guangzhou |
R |
155 |
17 |
172 |
92.8 (87.9–95.8) |
97.4 (95.8–98.4) |
90.1 (84.7–93.7) |
98.2 (96.8–99.0) |
S |
12 |
630 |
642 |
|||||
Total |
167 |
647 |
814 |
|||||
Total | R |
262 |
32 |
294 |
94.2 (90.9–96.4) |
97.5 (96.4–98.2) |
89.1 (85.0–92.2) |
98.7 (97.9–99.2) |
S |
16 |
1231 |
1247 |
|||||
Total |
278 |
1263 |
1541 |
Abbreviations: DST = drug susceptibility test, R = resistant, S = sensitive, PPV = positive predictive value, NPV = negative predictive value.
Table 2 Assay Performance for Detection of Isoniazid Resistance
Pilot | Meltpro | DST | Total | Sensitivity(%, 95% CI) | Specificity(%, 95% CI) | PPV(%, 95% CI) | NPV(%, 95% CI) | |
R | S | |||||||
Shandong |
R |
134 |
13 |
147 |
86.4 (80.2–91.0) |
97.7 (96.2–98.7) |
91.2 (85.5–94.8) |
96.4 (94.5–97.6) |
S |
21 |
559 |
580 |
|||||
Total |
155 |
572 |
727 |
|||||
Guangzhou |
R |
197 |
10 |
207 |
83.8 (78.6–88.0) |
98.3 (96.8–99.1) |
95.2 (91.3–97.4) |
93.7 (91.5–95.4) |
S |
38 |
569 |
607 |
|||||
Total |
235 |
579 |
814 |
|||||
Total | R |
331 |
23 |
354 |
84.9 (81.0–88.1) |
98.0 (97.0–98.7) |
93.5 (90.4–95.6) |
95.0 (93.6–96.1) |
S |
59 |
1128 |
1187 |
|||||
Total |
390 |
1151 |
1541 |
Table 3 Assay Performance for Detection of Multi-drug Resistance
Pilot | Meltpro | DST | Total | Sensitivity(%, 95% CI) | Specificity(%, 95% CI) | PPV(%, 95% CI) | NPV(%, 95% CI) | |
R | S | |||||||
Shandong |
R |
85 |
14 |
99 |
87.6 (79.6–92.8) |
97.8 (96.3–98.7) |
85.9 (77.6–91.4) |
98.1 (96.7–98.9) |
S |
12 |
616 |
628 |
|||||
Total |
97 |
630 |
727 |
|||||
Guangzhou |
R |
130 |
16 |
146 |
86.1 (79.7–90.7) |
97.6 (96.1–98.5) |
89.0 (82.9–93.1) |
96.9 (95.2–97.9) |
S |
21 |
647 |
668 |
|||||
Total |
151 |
663 |
814 |
|||||
Total |
R |
215 |
30 |
245 |
86.7 (81.9–90.4) |
97.7 (96.7–98.4) |
87.8 (83.1–91.3) |
97.4 (96.4–98.2) |
S |
33 |
1263 |
1296 |
|||||
Total |
248 |
1293 |
1541 |
Sample type
Cultured cells
Sputum
CE-IVD Marked
[1] Pang Y, Dong H, Tan Y, Deng Y, Cai X, Jing H, Xia H, Li Q, Ou X, Su B, Li X, Zhang Z, Li J, Zhang J, Huan S, Zhao Y. Rapid diagnosis of MDR and XDR tuberculosis with the MeltPro TB assay in China. Sci Rep. 2016 May 6;6:25330. doi: 10.1038/srep25330.
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