Bj. Manns et al., ANTITUBERCULOSIS DRUG-RESISTANCE IN IMMIGRANTS TO ALBERTA, CANADA, WITH TUBERCULOSIS, 1982-1994, The international journal of tuberculosis and lung disease, 1(3), 1997, pp. 225-230
SETTING: Provincial Tuberculosis Service, Alberta, Canada. OBJECTIVE:
To estimate resistance rates of Mycobacterium tuberculosis to antitube
rculosis drugs in relation to previous treatment, country of origin, a
ge and duration of residence in Canada. DESIGN: Retrospective chart re
view of all culture-positive tuberculosis diagnosed between 1982 and 1
994 in immigrants to Alberta. RESULTS: A total of 753 immigrants with
culture-positive tuberculosis were studied; 131 patients (17.4%, 95% C
onfidence Interval [CI] 14.7, 20.1) had strains resistant to one or mo
re of the first-line medications (isoniazid [INH], rifampin [RIF], eth
ambutol [EMB], pyrazinamide [PZA], and streptomycin [SM]). Initial and
secondary resistance rates were 16.4% and 30.3%, respectively (P = 0.
003, Odds ratio [OR] 2.2, 95% CI 1.3, 3.8). Resistance occurred in 22.
2% of patients 40 years of age and under, and in 13.8% of those over 4
0 years of age (P = 0.005, OR 1.8, 95% CI 1.2, 2.6). Resistant M. tube
rculosis was isolated from 20.4% of those who had lived in Canada for
less than 15 years, and in 9.0% of those who had immigrated to Canada
more than 15 years before diagnosis (P < 0.001; OR 2.4, 95% CI 1.3, 4.
2). Resistance rates to individual medications in all immigrants were
as follows: INH 9.9% (95% CI 7.8, 12.0), RIF 0.8% (95% CI 0.2, 1.4), E
MB 1.9% (95% CI 1.0, 2.8), PZA 1.9% (95% CI 0.3, 3.5), and SM 12.9% (9
5% CI 10.4, 15.4). Immigrants from Vietnam, China, and the Philippines
had tuberculosis strains that were resistant to one or more of the fi
rst line medications in 30.2%, 21.8%, and 15.5% of cases, respectively
(P = 0.04). CONCLUSION: In industrialized countries such as Canada wh
ere most cases of tuberculosis are diagnosed among the foreign-born, d
rug resistance surveys continue to be an important part of an effectiv
e tuberculosis control program.