Methods: We enrolled patients with active TB in two health regions of Lima, Peru from September 2009 through August 2012. We obtained sputum smears and cultures at baseline and at two months of therapy, and tested the baseline sample for pyrazinamide resistance using the modified Wayne method (pyrazinamidase assay). We restricted our analysis to patients with MDR-TB who were treated with first-line antituberculous drugs during the first two months of treatment. Using a multivariate logistic regression model, we tested the association between baseline pyrazinamide resistance and two-month smear and culture positivity, adjusting for age, sex, and baseline ethambutol resistance.
Results: Three hundred and eleven MDR-TB patients were eligible for the study, of whom 157 (50.5%) had isolates resistant to pyrazinamide at baseline. Pyrazinamide resistance was associated with higher odds of two-month smear positivity (OR = 2.31; 95% CI, 1.40-3.81) and two-month culture positivity (OR = 4.27; 95% CI, 2.36-7.72) after we adjusted for age, sex, and baseline ethambutol resistance.
Conclusion: Since phenotypic pyrazinamide resistance is associated with treatment response in patients with MDR-TB, we conclude that routine pyrazinamide drug susceptibility testing should be included in baseline investigations for patients with active TB.
G. E. Velásquez,
C. D. Mitnick, None
M. C. Becerra, Janssen Global Public Health: Grant Investigator , Research grant
Z. Zhang, None
C. C. Contreras, None
R. M. Yataco, None
J. T. Galea, None
L. W. Lecca, None
M. B. Murray, None