Antituberculosis drug resistance in immigrants to Alberta, Canada, with tuberculosis, 1982-1994.
METHODS
Provincial Tuberculosis Service, Alberta, Canada.


OBJECTIVE
To estimate resistance rates of Mycobacterium tuberculosis to antituberculosis drugs in relation to previous treatment, country of origin, age and duration of residence in Canada.


METHODS
Retrospective chart review of all culture-positive tuberculosis diagnosed between 1982 and 1994 in immigrants to Alberta.


RESULTS
A total of 753 immigrants with culture-positive tuberculosis were studied; 131 patients (17.4%, 95% Confidence Interval [CI] 14.7, 20.1) had strains resistant to one or more of the first-line medications (isoniazid [INH], rifampin [RIF], ethambutol [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 40 years of age (P = 0.005, OR 1.8, 95% CI 1.2, 2.6). Resistant M. tuberculosis 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), EMB 1.9% (95% CI 1.0, 2.8), PZA 1.9% (95% CI 0.3, 3.5), and SM 12.9% (95% CI 10.4, 15.4). Immigrants from Vietnam, China, and the Philippines had tuberculosis strains that were resistant to one or more of the first line medications in 30.2%, 21.8%, and 15.5% of cases, respectively (P = 0.04).


CONCLUSIONS
In industrialized countries such as Canada where most cases of tuberculosis are diagnosed among the foreign-born, drug resistance surveys continue to be an important part of an effective tuberculosis control program.
Manns
B J
BJ
University of Calgary, Foothills Hospital, Alberta, Canada.
Fanning
E A
EA
Cowie
R L
RL
D000293:Adolescent; D000328:Adult; D000416:Alberta / Q000453:epidemiology; D000995:Antitubercular Agents / Q000627:therapeutic use; D001208:Asia / Q000208:ethnology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004641:Emigration and Immigration / Q000706:statistics & numerical data*; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects; D012189:Retrospective Studies; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology / Q000208:ethnology* / Q000517:prevention & control
D000995:Antitubercular Agents