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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 LongComments to Author 
Author affiliations: University of Alberta, Edmonton, Alberta, Canada (D. Langlois-Klassen, A. Senthilselvan, L. Chui, D. Kunimoto, L.D. Saunders, R. Long); Provincial Laboratory for Public Health, Edmonton (L. Chui); McGill University Health Centre, Montreal, Quebec, Canada (D. Menzies); McGill University, Montreal (D. Menzies)

Main Article

Table 4

Risk factors for the recent transmission of Mycobacterium tuberculosis among index case-patients born in Alberta, Canada, in the Western Pacific, 1993–2007

Characteristic Index case-patients
Secondary
case-patients Transmission index* Relative transmission index (95% CI)†
Nonclustered Clustered Unadjusted Adjusted
Sex
F 122 9 10 0.08 1.0
M
195
9
10
0.05
0.6 (0.3–1.5)

Age at diagnosis, y
<35 83 5 5 0.06 1.0
35–64 110 4 4 0.04 0.6 (0.2–2.3)
>64
124
9
11
0.08
1.5 (0.5–4.2)

Sputum smear status‡
Negative 174 7 7 0.04 1.0 1.0
Positive
126
9
11
0.08
2.1 (0.8–5.4)
2.1 (0.8–5.5)
Bacillary load§
Low 53 3 5 0.09 1.0
High
17
1
1
0.06
0.6 (0.1–5.3)

Chest radiography
No cavitation 252 14 16 0.06 1.0
Cavitation
65
4
4
0.06
1.0 (0.3–2.9)

Drug resistance
Pan-susceptible 239 13 14 0.06 1.0
Monoresistance 51 2 2 0.04 0.7 (0.2–3.0)
Polyresistance 21 3 4 0.17 3.0 (1.0–9.1)
Multidrug resistance¶
6
0
0
0


M. tuberculosis lineage
Non-Beijing 171 9 11 0.06 1.0 1.0
Beijing
146
9
9
0.06
1.0 (0.4–2.3)
0.9 (0.3–2.2)
Time since arrival in Canada, y
<2 76 3 3 0.04 1.0
3–5 43 1 1 0.02 0.6 (0.1–5.8)
6–10 53 6 6 0.10 2.7 (0.7–10.7)
>10
112
8
10
0.08
2.2 (0.6–8.0)

Total 317 18 20 0.06

*The number of secondary cases divided by the number of index cases.
†Bivariate Poisson regression using an offset of 1 each index case.
‡Sputum smear microscopy was not completed with all cases.
§Bacillary load was not included in multivariate modeling because of multicollinearity with sputum smear status.
¶Multidrug-resistant tuberculosis was excluded from bivariate analyses.

Main Article

Page created: April 25, 2013
Page updated: April 25, 2013
Page reviewed: April 25, 2013
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