Genotyping analyses of tuberculosis cases in U.S.- and foreign-born Massachusetts residents.

Sharon Sharnprapai,Edward Nardell,Robert Suruki,Michael Mcgarry,Edward Corkren,Sue Etkind,Jeffrey Driscoll,Ann C Miller

doi:10.3201/eid0811.020370

Abstract

We used molecular genotyping to further understand the epidemiology and transmission patterns of tuberculosis (TB) in Massachusetts. The study population included 983 TB patients whose cases were verified by the Massachusetts Department of Public Health between July 1, 1996, and December 31, 2000, and for whom genotyping results and information on country of origin were available. Two hundred seventy-two (28%) of TB patients were in genetic clusters, and isolates from U.S-born were twice as likely to cluster as those of foreign-born (odds ratio [OR] 2.29, 95% confidence interval [CI] 1.69, 3.12). Our results suggest that restriction fragment length polymorphism analysis has limited capacity to differentiate TB strains when the isolate contains six or fewer copies of IS6110, even with spoligotyping. Clusters of TB patients with more than six copies of IS6110 were more likely to have epidemiologic connections than were clusters of TB patients with isolates with few copies of IS6110 (OR 8.01, 95%; CI 3.45,18.93).

Highlights

We used molecular genotyping to further understand the epidemiology and transmission patterns of tuberculosis (TB) in Massachusetts
In 2000, 46% of all reported TB cases in the United States occurred among persons not born in the United States, and 20 states reported that >50% of TB cases occurred among the foreign-born [2]
Describe the epidemiology of TB patients in Massachusetts and results of using genotyping to evaluate the extent to which genetic clustering of Mycobacterium tuberculosis differs between foreign-born and U.S.-born TB patients

Summary

Introduction

We used molecular genotyping to further understand the epidemiology and transmission patterns of tuberculosis (TB) in Massachusetts. In Massachusetts, 202 (71%) of 285 cases reported were among foreign-born persons (from 41 different countries). Between 1996 and 2000, the proportion of foreign-born TB patients reported in Massachusetts rose from 61% to72%. This increase was seen primarily among Asians, Africans, and immigrants from Central and South America. We describe the epidemiology of TB patients in Massachusetts and results of using genotyping to evaluate the extent to which genetic clustering of Mycobacterium tuberculosis differs between foreign-born and U.S.-born TB patients

Methods

Results

Conclusion