Transmission of tuberculosis among the urban homeless.

摘要

OBJECTIVE--To determine the relative frequencies of primary and reactivation tuberculosis in the urban homeless. DESIGN--Prospective evaluation of homeless tuberculosis patients. SETTING--Central Los Angeles, Calif. PATIENTS--Thirty-four homeless patients with culture-proven tuberculosis. INTERVENTIONS--IS6110-based restriction fragment length polymorphism (RFLP) analysis was performed on Mycobacterium tuberculosis isolates. If results were inconclusive, pTBN12-based RFLP analysis was performed. MAIN OUTCOME MEASURE--Clustering of M tuberculosis isolates. A cluster consisted of two or more isolates with indistinguishable RFLP patterns. RESULTS--Twenty-four of 34 homeless patients had clustered isolates in six clusters. CONCLUSIONS--The minimum percentage of cases due to primary tuberculosis in the homeless was estimated to be 53%, compared with the traditional estimate of 10% in the general population. The results suggest that primary tuberculosis caused the majority of tuberculosis cases in this population of the urban homeless in central Los Angeles.