Table 3.
Consistency analysis of drug resistance detection between nucleic acid-based MALDI-TOF MS and MGIT 960 culture (n = 34 MTB-positive cases).
| A. First-line drugs | |||
|---|---|---|---|
| 1. Rifampicin (RIF) | |||
| MALDI-TOF MS | MGIT 960 culture | Total | |
| Resistant | Sensitive | ||
| Resistant | 32 | 0 | 32 |
| Sensitive | 1 | 1 | 2 |
| Total | 33 | 1 | 34 |
| Performance metrics: Sensitivity: 96.97% (95% CI: 84.24–99.92%); Specificity: 100% (95% CI: 2.50–100%); PPV: 100% (95% CI: 89.11–100%); NPV: 50.00% (95% CI: 1.26–98.74%); Accuracy: 97.06%, κ = 0.65, χ2 = 16.485, p < 0.001. | |||
| 2. Isoniazid (INH) | |||
|---|---|---|---|
| MALDI-TOF MS | MGIT 960 culture | Total | |
| Resistant | Sensitive | ||
| Resistant | 25 | 0 | 25 |
| Sensitive | 4 | 5 | 9 |
| Total | 29 | 5 | 34 |
| Performance metrics: Sensitivity: 86.21% (95% CI: 68.34–96.11%). Specificity: 100% (95% CI: 47.82–100%). PPV: 100% (95% CI: 86.28–100%). NPV: 55.56% (95% CI: 21.20–86.30%). Accuracy: 88.24%, κ = 0.64, χ2 = 16.284, p < 0.001. | |||
| 3. Ethambutol (EMB) | |||
|---|---|---|---|
| MALDI-TOF MS | MGIT 960 culture | Total | |
| Resistant | Sensitive | ||
| Resistant | 9 | 3 | 12 |
| Sensitive | 1 | 21 | 22 |
| Total | 10 | 24 | 34 |
| Performance metrics: Sensitivity: 90.00% (95% CI: 55.50–99.75%); Specificity: 87.50% (95% CI: 67.64–97.34%); PPV: 75.00% (95% CI: 42.81–94.51%); NPV: 95.45% (95% CI: 77.16–99.88%); Accuracy: 88.24%, κ = 0.73, χ2 = 18.565, p < 0.001. | |||
| 4. Streptomycin (Sm) | |||
|---|---|---|---|
| MALDI-TOF MS | MGIT 960 culture | Total | |
| Resistant | Sensitive | ||
| Resistant | 18 | 0 | 18 |
| Sensitive | 1 | 15 | 16 |
| Total | 19 | 15 | 34 |
| Performance metrics: Sensitivity: 94.74% (95% CI: 73.97–99.87%); Specificity: 100% (95% CI: 78.20–100%); PPV: 100% (95% CI: 81.47–100%); NPV: 93.75% (95% CI: 69.77–99.84%); Accuracy: 97.06%, κ = 0.94, χ2 = 30.197, p < 0.001. | |||
| B. Second-line drugs | |||
|---|---|---|---|
| 1. Levofloxacin (Ofx) | |||
| MALDI-TOF MS | MGIT 960 culture | Total | |
| Resistant | Sensitive | ||
| Resistant | 8 | 0 | 8 |
| Sensitive | 0 | 26 | 26 |
| Total | 8 | 26 | 34 |
| Performance metrics: Sensitivity: 100% (95% CI: 63.06–100%); Specificity: 100% (95% CI: 86.78–100%); PPV: 100% (95% CI: 63.06–100%); NPV: 100% (95% CI: 86.78–100%); Accuracy: 100%, κ = 1.00, χ2 = 34.000, p < 0.001. | |||
| 2. Moxifloxacin (Mfx) | |||
|---|---|---|---|
| MALDI-TOF MS | MGIT 960 culture | Total | |
| Resistant | Sensitive | ||
| Resistant | 8 | 0 | 8 |
| Sensitive | 0 | 26 | 26 |
| Total | 8 | 26 | 34 |
| Performance metrics: Sensitivity: 100% (95% CI: 63.06–100%); Specificity: 100% (95% CI: 86.78–100%); PPV: 100% (95% CI: 63.06–100%); NPV: 100% (95% CI: 86.78–100%); Accuracy: 100%, κ = 1.00, χ2 = 34.000, p < 0.001. | |||
| 3. Amikacin/kanamycin/Capreomycin (am/km/cm) | |||
|---|---|---|---|
| MALDI-TOF MS | MGIT 960 culture | Total | |
| Resistant | Sensitive | ||
| Resistant | 2 | 1 | 3 |
| Sensitive | 0 | 31 | 31 |
| Total | 2 | 32 | 34 |
| Performance metrics: Sensitivity: 100% (95% CI: 15.81–100%); Specificity: 96.88% (95% CI: 83.78–99.92%); PPV: 66.67% (95% CI: 9.43–99.16%); NPV: 100% (95% CI: 88.78–100%); Accuracy: 97.06%, κ = 0.78, χ2 = 21.958, p < 0.001. | |||
PPV, positive predictive value; NPV, negative predictive value; κ, kappa coefficient; CI, confidence interval; RIF, rifampicin; INH, isoniazid; EMB, ethambutol; Sm, streptomycin; Ofx, levofloxacin; Mfx, moxifloxacin; am, amikacin; km, kanamycin; cm, capreomycin.