Rate and amplification of drug resistance among previously-treated patients with tuberculosis in Kampala, Uganda.
BACKGROUND
Drug-resistant Mycobacterium tuberculosis has emerged as a global threat. In resource-constrained settings, patients with a history of tuberculosis (TB) treatment may have drug-resistant disease and may experience poor outcomes. There is a need to measure the extent of and risk factors for drug resistance in such patients.


METHODS
From July 2003 through November 2006, we enrolled 410 previously treated patients with TB in Kampala, Uganda. We measured the prevalence of resistance to first- and second-line drugs and analyzed risk factors associated with baseline and acquired drug resistance.


RESULTS
The prevalence of multidrug-resistant TB was 12.7% (95% confidence interval [95% CI], 9.6%-16.3%). Resistance to second-line drugs was low. Factors associated with multidrug-resistant TB at enrollment included a history of treatment failure (odds ratio, 23.6; 95% CI, 7.7-72.4), multiple previous TB episodes (odds ratio, 15.6; 95% CI, 5.0-49.1), and cavities present on chest radiograph (odds ratio, 5.9; 95% CI, 1.2-29.5). Among a cohort of 250 patients, 5.2% (95% CI, 2.8%-8.7%) were infected with M. tuberculosis that developed additional drug resistance. Amplification of drug resistance was associated with existing drug resistance at baseline (P < .01) and delayed sputum culture conversion (P < .01).


CONCLUSIONS
The burden of drug resistance in previously treated patients with TB in Uganda is sizeable, and the risk of generating additional drug resistance is significant. There is an urgent need to improve the treatment for such patients in low-income countries.
Temple
Beth
B
Medical Research Council-Uganda Virus Research Institute, Uganda Research Unit on AIDS, Entebbe, Uganda.
Ayakaka
Irene
I
Ogwang
Sam
S
Nabanjja
Helen
H
Kayes
Susan
S
Nakubulwa
Susan
S
Worodria
William
W
Levin
Jonathan
J
Joloba
Moses
M
Okwera
Alphonse
A
Eisenach
Kathleen D
KD
McNerney
Ruth
R
Elliott
Alison M
AM
Smith
Peter G
PG
Mugerwa
Roy D
RD
Ellner
Jerrold J
JJ
Jones-López
Edward C
EC
D000328:Adult; D015331:Cohort Studies; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000302:isolation & purification; D012307:Risk Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy / Q000382:microbiology; D014454:Uganda / Q000453:epidemiology