572. Clinical Relevance of Routine Pyrazinamide Drug Susceptibility Testing in Multidrug-Resistant Tuberculosis
Session: Poster Abstract Session: TB: Multidrug Resistant TB
Thursday, October 8, 2015
Room: Poster Hall
Background: The relevance of phenotypic pyrazinamide drug susceptibility testing on tuberculosis (TB) treatment outcomes is not well understood. Here we evaluate the association between pyrazinamide resistance and sputum smear and culture conversion among multidrug-resistant tuberculosis (MDR-TB) patients.

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.

Gustavo E. Velásquez, M.D., M.P.H.1,2, Roger I. Calderon, Laboratory Director3, Carole D. Mitnick, Sc.D.3,4,5, Mercedes C. Becerra, Sc.D.3,4,5, Zibiao Zhang, Programmer/Analyst5, Carmen C. Contreras, Sub-Director of Research Projects3, Rosa M. Yataco, Data Coordinator3, Jerome T. Galea, Ph.D., M.S.W.3,4, Leonid W. Lecca, M.D.3 and Megan B. Murray, MD, MPH, ScD4,5,6, (1)Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, (2)Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, (3)Partners In Health / Socios En Salud, Lima, Peru, (4)Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, (5)Division of Global Health Equity, Brigham and Women's Hospital, Boston, MA, (6)Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA


G. E. Velásquez, None

R. I. Calderon, None

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

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