Table 2. Comparison between spoligotyping and culture results in 350 acid-fast bacilli–positive samples.
| Mycobacteria grown in culture | No. episodes | Results of spoligotyping from clinical samples |
Results of spoligotyping from liquid medium |
Results of spoligotyping from solid medium |
Total |
||||
|---|---|---|---|---|---|---|---|---|---|
| Positive | Negative | Positive | Negative | Positive | Negative | Positive | Negative | ||
| M. tuberculosis | 77 | 54 | 1 | 53 | 5 | 75 | 0 | 182 | 6 |
| M. avium | 28 | 0 | 15 | 0 | 20 | 2 | 31 | 2 | 66 |
| M. gordonae | 15 | 0 | 0 | 0 | 12 | 0 | 14 | 0 | 26 |
| M. xenopi | 8 | 0 | 2 | 1 | 5 | 1 | 6 | 2 | 13 |
| M. kansasii | 2 | 0 | 1 | 0 | 0 | 0 | 2 | 0 | 3 |
| M. chelonae | 2* | 0 | 2 | 0 | 2 | 0 | 2 | 0 | 6 |
| Other | 6† | 1 | 1 | 0 | 4 | 1 | 4 | 2 | 9 |
| No growth | 26 | 9 | 21 | 1 | 2 | 0 | 0 | 10 | 23 |
| Subtotal | 64 | 43 | 55 | 50 | 79 | 59 | 198 | 152 | |
| Total | 164‡ | 107 | 105 | 138 | 350 | ||||
| Sensitivity, %§ | 98.2 (71.1–98.4) | 91.4 (75.7–90) | 100 | 96.8 (86.2–97) | |||||
| Specificity, %§ | 95.5 (67.7–97.7) | 97.7 (95.6–97.8) | 93.6 | 95.3 (88.4–96.1) | |||||
*Automated DNA sequencing rather than culture growth of M. chelonae confirmed one of these cases. †Other, 1 M. fortuitum, 1 M. asiaticum, and 4 nontyped mycobacteria. ‡16 patients had ≥2 episodes of mycobacterial infections. §Sensitivity and specificity were calculated without including the culture-negative specimens. Values in parentheses are ranges that include specimens with no growth.