Volume 12, Number 5—May 2006
THEME ISSUE
Tuberculosis Special Section
Research
Tuberculosis Transmission Attributable to Close Contacts and HIV Status, Malawi
Table 1
Comparison of Mycobacterium tuberculosis strains of index cases and putative source contacts (PSCs)
| Comparison of strains, no. (%) |
||||||
|---|---|---|---|---|---|---|
| Identical | 1–4 bands different and first example of new strain | 1–4 bands different and not first example | >4 bands different | Total | ||
| Total | 51 (25.5) | 8 (4.0) | 15 (7.5) | 126 (63.0) | 200 | |
| Source of linking information | ||||||
| Database only | 9 (25.7) | 1 (2.9) | 5 (14.3) | 20 (57.1) | 35 | |
| History only | 14 (16.5) | 4 (4.7) | 6 (7.1) | 61 (71.8) | 85 | |
| Both | 28 (35.0) | 3 (3.8) | 4 (5.0) | 45 (56.3) | 80 | |
| Characteristic of PSC in case-PSC pairs | ||||||
| Smear-positive pulmonary | 48 (28.7) | 7 (4.2) | 15 (9.0) | 97 (58.1) | 167 | |
| Smear-negative pulmonary | 2 (9.1) | 1 (4.6) | 0 (0.0) | 19 (86.4) | 22 | |
| Extrapulmonary | 1 (9.1) | 0 (0.0) | 0 (0.0) | 10 (90.9) | 11 | |
| No. bands in RFLP* of PSC | ||||||
| <5 | 6 (40.0) | 1 (6.7) | 0 (0.0) | 8 (53.3) | 15 | |
| 5–10 | 17 (22.7) | 6 (8.0) | 8 (10.7) | 44 (58.7) | 75 | |
| >10 | 28 (25.5) | 1 (0.9) | 7 (6.4) | 74 (67.3) | 110 | |
*RFLP, restriction fragment length polymorphism.


