Setting: In Latvia, 11% of tuberculosis (TB) patients have multidrug-resistant TB (MDR-TB). The INNO-LiPA Rif.TB ® line-probe assay (LPA) detects rifampin (RMP) resistance and may accelerate the time to effective MDRTB treatment.
Objective: To determine the impact of LPA on time to diagnosis, initiation of treatment, sputum culture conversion and treatment outcome.
Design: From October 2004 to September 2006, we performed LPA and drug susceptibility testing (DST) using BACTEC and Löwenstein-Jensen (LJ) media among all individuals at risk for MDR-TB compared to a 2003 cohort of 48 MDR-TB patients detected by BACTEC.
Results: In a total of 107 sputum smear-positive individuals at risk for MDR-TB, Mycobacterium tuberculosis was isolated from 85; 23 were RMP-resistant on LJ compared to 22 on LPA (96% sensitivity). There was a significant difference in the mean time between specimen collection and LPA result (10.0 days) and BACTEC DST result (17.0 days, P = 0.0005) in the LPA cohort. The LPA cohort achieved culture conversion a median of 105 days after treatment initiation vs. a median of 88.5 days (P = 0.54) in the BACTEC cohort. There was no difference in the proportion achieving culture conversion (P = 0.54) or in treatment outcome ( P = 0.65).
Conclusion: LPA accelerated empiric treatment, but did not reduce the time to culture conversion or improve the rate of culture conversion or treatment outcome.