Risk factors for MDR and XDR-TB in a tertiary referral hospital in India.
BACKGROUND
India has a high burden of drug resistant TB, although there are few data on XDR-TB. Although XDR-TB has existed previously in India, the definition has not been widely applied, and surveillance using second line drug susceptibility testing has not been performed. Our objective was to analyze clinical and demographic risk factors associated with isolation of MDR and XDR TB as compared to susceptible controls, at a tertiary center.


RESULTS
Retrospective chart review based on positive cultures isolated in a high volume mycobacteriology laboratory between 2002 and 2007. 47 XDR, 30 MDR and 117 susceptible controls were examined. Drug resistant cases were less likely to be extrapulmonary, and had received more previous treatment regimens. Significant risk factors for XDR-TB included residence outside the local state (OR 7.43, 3.07-18.0) and care costs subsidized (OR 0.23, 0.097-0.54) in bivariate analysis and previous use of a fluoroquinolone and injectable agent (other than streptomycin) (OR 7.00, 95% C.I. 1.14-43.03) and an initial treatment regimen which did not follow national guidelines (OR 5.68, 1.24-25.96) in multivariate analysis. Cavitation and HIV did not influence drug resistance.


CONCLUSIONS
There is significant selection bias in the sample available. Selection pressure from previous treatment and an inadequate initial regimen increases risk of drug resistance. Local patients and those requiring financial subsidies may be at lower risk of XDR-TB.
Balaji
V
V
Department of Microbiology, Christian Medical College Vellore, Vellore, Tamil Nadu, India.
Daley
Peter
P
Anand
Alok Azad
AA
Sudarsanam
Thambu
T
Michael
Joy Sarojini
JS
Sahni
Rani Diana
RD
Chordia
Poorvi
P
George
Ige Abraham
IA
Thomas
Kurien
K
Ganesh
Alka
A
John
K R
KR
Mathai
Dilip
D
D000293:Adolescent; D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D054908:Extensively Drug-Resistant Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use; D006761:Hospitals; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000378:metabolism; D012189:Retrospective Studies; D012306:Risk; D012307:Risk Factors; D013307:Streptomycin / Q000627:therapeutic use; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000453:epidemiology*
D000995:Antitubercular Agents; D024841:Fluoroquinolones; D013307:Streptomycin