Epidemiologic differences between United States- and foreign-born tuberculosis patients in Houston, Texas

The proportion of foreign-born tuberculosis patients in the United States i s increasing. To analyze the epidemiology of tuberculosis in foreign-born p eople, culture-positive patients with tuberculosis in Houston, Texas, were interviewed from October 1995 through September 1998, and their isolates we re molecularly characterized. Of the 1131 patients included in the study, 7 95 (70.3%) were US born and 336 (29.7%) were foreign born. The decrease in tuberculosis case rate among US-born people was 3.5 times that of foreign-b orn people. Significantly more US-born than foreign-born patients belonged to strain clusters (71.3% vs. 29.5%; P < .001). Risk factors associated wit h strain clustering were as follows: black ethnicity, low income, and homel essness in US-born patients and homelessness in foreign-born patients. Isol ates from foreign-born patients were more likely to be resistant to <greate r than or equal to>1 drug (15.4% vs. 8.4%;) P = .001 and to be multidrug re sistant (2.4% vs. 0.7%; P = .027) than isolates from US-born patients. Thes e observations warrant increased emphasis on this distinct subpopulation of tuberculosis patients.