Does DOTS work in populations with drug-resistant tuberculosis?
BACKGROUND
Directly observed therapy (DOTS) is the main strategy for prevention and control of tuberculosis worldwide. However, its effect on tuberculosis transmission in populations with moderate rates of drug-resistant disease is not known.


METHODS
This population-based prospective study in southern Mexico between March, 1995, and February, 2000, was based on passive case finding and detection of acid-fast bacilli in sputum samples to diagnose pulmonary tuberculosis. We also used cultures, drug-susceptibility testing, bacterial genotyping, and monitoring of treatment outcomes.


RESULTS
We enrolled 436 patients; the HIV seroprevalence rate was 2%. We used three indicators to monitor continuing tuberculosis transmission: the incidence rate of pulmonary tuberculosis, which decreased by 54.4% between 1995 and 2000, from 42.1 to 19.2 per 10(5) population (p=0.00048); the percentage of clustered pulmonary tuberculosis cases, which decreased by 62.6% from 22% to 8% (p=0.02); and the rate of primary drug resistance, which decreased by 84.0% from 9.4 to 1.5 per 10(5) population (p=0.004). Rates of multidrug-resistant (MDR) tuberculosis also decreased (p<0.0001). The case-fatality ratio was 12% for MDR tuberculosis (five of 41), 7% for strains resistant to at least one drug after exclusion of MDR (four of 55), and 3% for pansusceptible strains (nine of 272). There were 13 treatment failures (11%) in 1995 and one (2%) in 2000 (p=0.012).


CONCLUSIONS
Even in settings with moderate rates of MDR tuberculosis, DOTS can rapidly reduce the transmission and incidence of both drug-susceptible and drug-resistant tuberculosis. However, further interventions, such as drug-susceptibility testing and standardised or individualised treatment regimens, are needed to reduce mortality rates for MDR tuberculosis.
DeRiemer
Kathryn
K
Division of Infectious Diseases and Geographic Medicine, Stanford University Medical Center, Stanford, CA, USA.
García-García
Lourdes
L
Bobadilla-del-Valle
Miriam
M
Palacios-Martínez
Manuel
M
Martínez-Gamboa
Areli
A
Small
Peter M
PM
Sifuentes-Osornio
José
J
Ponce-de-León
Alfredo
A
D023801:Directly Observed Therapy; D006801:Humans; D015994:Incidence; D008800:Mexico / Q000453:epidemiology; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000453:epidemiology / Q000517:prevention & control