Transmission of tuberculosis among the urban homeless.
OBJECTIVE
To determine the relative frequencies of primary and reactivation tuberculosis in the urban homeless.


METHODS
Prospective evaluation of homeless tuberculosis patients.


METHODS
Central Los Angeles, Calif.


METHODS
Thirty-four homeless patients with culture-proven tuberculosis.


METHODS
IS6110-based restriction fragment length polymorphism (RFLP) analysis was performed on Mycobacterium tuberculosis isolates. If results were inconclusive, pTBN12-based RFLP analysis was performed.


METHODS
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.
Department of Medicine, University of Southern California School of Medicine, Los Angeles 90033, USA.
P F
PF
Barnes
H
H
el-Hajj
S
S
Preston-Martin
M D
MD
Cave
B E
BE
Jones
M
M
Otaya
J
J
Pogoda
K D
KD
Eisenach
D000328:Adult; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000453:epidemiology; D006703:Ill-Housed Persons / Q000706:statistics & numerical data; D006801:Humans; D015141:Los Angeles / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D011446:Prospective Studies; D012008:Recurrence; D014376:Tuberculosis / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission; D014505:Urban Population / Q000706:statistics & numerical data