Volume 19, Number 5—May 2013
CME ACTIVITY - Research
Transmission of Mycobacterium tuberculosis Beijing Strains, Alberta, Canada, 1991–2007
Deanne Langlois-Klassen, Ambikaipakan Senthilselvan, Linda Chui, Dennis Kunimoto, L. Duncan Saunders, Dick Menzies, and Richard Long
Table 1
Characteristics of persons with pulmonary TB associated with Mycobacterium tuberculosis Beijing and non-Beijing strains, Alberta, Canada, 1991–2007
| Characteristic | Strain |
OR (95% CI)* |
|||
|---|---|---|---|---|---|
| Beijing, no. (%) | Non-Beijing, no. (%) | Unadjusted | Adjusted | ||
| Sex | |||||
| F | 100 (38.8) | 492 (43.9) | 1.0 | 1.0 | |
| M |
158 (61.2) |
629 (56.1) |
1.2 (0.9–1.6) |
1.3 (0.9–1.8) |
|
| Age at diagnosis, y | |||||
| <35 | 72 (27.9) | 319 (28.5) | 1.0 | 1.0 | |
| 35–64 | 69 (26.7) | 421 (37.6) | 0.7 (0.5–1.04) | 0.7 (0.1–1.01) | |
| >64 |
117 (45.3) |
381 (34.0) |
1.4 (0.98–1.9) |
1.1 (0.7–1.6) |
|
| Population group | |||||
| Canadian-born | 19 (7.4) | 520 (46.4) | 1.0 | 1.0 | |
| Foreign-born, other | 26 (10.1) | 346 (30.9) | 2.1 (1.1–3.8) | 2.1 (1.1–4.1) | |
| Foreign-born, Western Pacific |
213 (82.6) |
255 (22.7) |
22.9 (14.0–37.4) |
22.6 (13.1–39.2) |
|
| Sputum smear status† | |||||
| Negative | 132 (54.1) | 517 (49.0) | 1.0 | 1.0 | |
| Positive |
112 (45.9) |
538 (51.0) |
0.8 (0.6–1.1) |
1.2 (0.8–1.7) |
|
| Bacillary loadठ| |||||
| Low | 38 (70.4) | 177 (66.5) | 1.0 | ||
| High |
16 (29.6) |
89 (33.5) |
0.8 (0.4–1.6) |
||
| Results of chest radiography | |||||
| No cavitation | 206 (79.8) | 853 (76.1) | 1.0 | 1.0 | |
| Cavitation |
52 (20.2) |
268 (23.9) |
0.8 (0.6–1.1) |
0.8 (0.5–1.3) |
|
| Drug resistance | |||||
| Pan-susceptible | 202 (78.3) | 1000 (89.2) | 1.0 | 1.0 | |
| Monoresistance | 30 (11.6) | 90 (8.0) | 1.7 (1.1–2.6) | 0.8 (0.5–1.3) | |
| Polyresistance | 20 (7.8) | 25 (2.2) | 4.0 (2.2–7.3) | 1.7 (0.9–3.5) | |
| Multidrug resistance |
6 (2.3) |
6 (0.5) |
5.0 (1.6–15.5) |
3.7 (0.9–14.7) |
|
| Clustering | |||||
| Nonclustered | 203 (78.7) | 703 (62.7) | 1.0 | 1.0 | |
| Clustered |
55 (21.3) |
418 (37.3) |
0.5 (0.3–0.6) |
0.8 (0.6–1.3) |
|
| Total | 258 (100.0) | 1,121 (100.0) | |||
*Boldface indicates significance (p<0.05). TB, tuberculosis; OR, odds ratio.
†Sputum smear microscopy was not completed for all cases.
‡Semiquantitative scores for acid-fast bacilli load on the baseline sputum smear. Positive smears with semiquantitative scores of 3+ or 4+ were categorized as having high bacillary load; all remaining positive smears were labeled as having a low bacillary load.
§Bacillary load was not included in multivariate modeling because of multicollinearity with sputum smear status.
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