Postsanatorium pattern of antituberculous drug resistance in the Canadian-born population of western Canada: effect of outpatient care and immigration.

Concurrent with the shift in tuberculosis case management from sanatorium to outpatient setting was a shift in the continent of origin (Europe to Asia) of most new immigrants to CANADA: To assess the impact of these two events on antituberculous drug resistance in the Canadian-born population, the authors reviewed the results of six drug resistance surveys conducted in the two westernmost provinces of Canada between 1963 and 1994. Survey data were complemented by new molecular diagnostic and contact tracing data collected over 5 years (1994--1998) in one of the three large urban centers of the region. Over the time spanned by the surveys, there was no increase in the proportion of all Canadian-born tuberculosis cases who relapsed or the proportion of all Canadian-born relapsed cases who were drug resistant (approximately 12--13%). In addition, the prevalence of primary drug resistance among Canadian-born cases did not increase; rates consistently averaged between 2% and 5% despite a doubling of primary resistance rates among foreign-born cases. Molecular diagnostic and contact tracing data strongly supported the survey findings. The authors concluded that outpatient care and immigration have thus far had no measurable impact on the pattern of antituberculous drug resistance in the Canadian-born population of western CANADA: