TABLE 2.
Comparison of the discriminatory power of various genetic markers to type M. tuberculosis strains from Hong Kong
| Strains typed (n) | Typing method | Total no. of type patterns | No. of unique types (%) | No. of clusters | No. of clustered isolates (%) | Maximum no. of isolates in a cluster | Average cluster size | HGI | Ha |
|---|---|---|---|---|---|---|---|---|---|
| All strains (69)c | Spoligo (43 spacers) | 19 | 16 (23) | 3 | 53 (77) | 49 | 17.7 | 0.498 | NAd |
| Spoligo (5 spacers) | 5 | 0 (0) | 5 | 69 (100) | 49 | 13.8 | 0.467 | NA | |
| Spoligo (48 spacers) | 21 | 17 (25) | 4 | 52 (75) | 44 | 13.0 | 0.593 | NA | |
| ETR VNTR (5 loci) | 22 | 13 (19) | 9 | 56 (81) | 35 | 6.2 | 0.738 | 0.285 | |
| MIRU VNTR (5 loci) | 21 | 12 (17) | 9 | 57 (83) | 27 | 6.3 | 0.829 | 0.350 | |
| MIRU VNTR (7 loci) | 30 | 21 (30) | 9 | 48 (70) | 25 | 5.3 | 0.861 | 0.411 | |
| QUB VNTR (4 loci) | 36 | 24 (35) | 12 | 45 (65) | 16 | 3.8 | 0.937 | 0.532 | |
| VNTR of all locib | 57 | 50 (72) | 7 | 19 (28) | 6 | 2.7 | 0.990 | 0.377 | |
| IS6110 RFLP | 65 | 62 (90) | 3 | 7 (10) | 3 | 2.3 | 0.998 | NA | |
| Beijing family strains (51) | Spoligo (43 spacers) | 3 | 2 (4) | 1 | 49 (96) | 49 | 49 | 0.078 | NA |
| Spoligo (5 spacers) | 3 | 0 (0) | 3 | 51 (100) | 45 | 17 | 0.218 | NA | |
| Spoligo (48 spacers) | 5 | 3 (6) | 2 | 48 (94) | 44 | 24 | 0.253 | NA | |
| ETR VNTR (5 loci) | 12 | 8 (16) | 4 | 43 (84) | 35 | 10.8 | 0.528 | 0.117 | |
| MIRU VNTR (5 loci) | 13 | 7 (14) | 6 | 44 (86) | 27 | 7.3 | 0.705 | 0.192 | |
| MIRU VNTR (7 loci) | 21 | 14 (27) | 7 | 37 (73) | 13 | 5.3 | 0.905 | 0.196 | |
| QUB VNTR (4 loci) | 20 | 10 (20) | 10 | 41 (80) | 16 | 4.1 | 0.886 | 0.383 | |
| VNTR of all locib | 39 | 32 (63) | 7 | 19 (37) | 6 | 2.7 | 0.982 | 0.218 | |
| IS6110 RFLP | 48 | 46 (90) | 2 | 5 (10) | 3 | 2.5 | 0.997 | NA |
a
The mean allelic diversity (H) is the average of the allelic diversity values of the according loci.
b
Combined result of ETR, MIRU (5 non-overlapping loci) and QUB.
c
Fifty-one strains belonged to the Beijing family, and 18 strains were non-Beijing family strains.
d
NA, not applicable.