Recurrent tuberculosis in Houston, Texas: a population-based study.
OBJECTIVE
To determine the predictors of recurrence of tuberculosis (TB), the drug resistance pattern of Mycobacterium tuberculosis strains recovered from recurrent TB patients, and the frequency of re-infection with a new M. tuberculosis strain among patients with recurrent disease.


METHODS
A population-based, retrospective case-control study using the Houston Tuberculosis Initiative database.


RESULTS
We found that, among 100 patients with recurrent TB who completed adequate therapy for a first episode of TB, not receiving directly observed therapy, pulmonary disease, HIV/AIDS diagnosis, not having a family physician, being unemployed and using public transportation were predictors of recurrent disease. There was a significant increase in drug-resistant M. tuberculosis strains in the second episode of disease compared to the first episode (21.3% vs. 8.2%, P = 0.04). Exogenous re-infection with a new strain of M. tuberculosis was found to cause 24-31% of recurrent TB.


CONCLUSIONS
Recurrent TB in Houston is associated with a significant increase in drug-resistant M. tuberculosis strains. Re-infection with a new M. tuberculosis strain causes a significant proportion of recurrent TB in an area of low TB incidence. Patients with HIV/AIDS constitute a population at increased risk of disease recurrence.
El Sahly
H M
HM
Department of Pathology, Baylor College of Medicine, Houston, Texas 77030, USA.
Wright
J A
JA
Soini
H
H
Bui
T T
TT
Williams-Bouyer
N
N
Escalante
P
P
Musser
J M
JM
Graviss
E A
EA
D000328:Adult; D002353:Carrier State / Q000453:epidemiology; D016022:Case-Control Studies; D002947:Cities / Q000453:epidemiology; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000235:genetics; D011159:Population Surveillance; D012008:Recurrence; D012307:Risk Factors; D012959:Socioeconomic Factors; D013781:Texas / Q000453:epidemiology; D014376:Tuberculosis / Q000453:epidemiology* / Q000382:microbiology / Q000628:therapy; D014504:Urban Health