Evaluation of commercial DNA and rRNA amplification assays for assessment of treatment outcome in pulmonary tuberculosis patients

To evaluate the clinical utility of the DNA and RNA amplification assays in monitoring the efficacy of tuberculosis treatment, 416 sputum specimens co llected from 15 smear-positive tuberculosis patients during and after treat ment were tested for the presence of Mycobacterium tuberculosis by microsco py, culture, polymerase chain reaction (Cobas Amplicor Mycobacterium Tuberc ulosis Test; Roche, Switzerland) and AMTDT 2 (Amplified Mycobacterium Tuber culosis Direct Test; Gen Probe, USA). All patients were cured, and no relap ses were found. Results of both amplification assays remained positive long er than results of either smear or culture. Four of 15 patients were positi ve by polymerase chain reaction and/or AMTDT 2 at the completion of treatme nt. Subsequent sputum specimens from these patients converted to negative w ithin 2.5-12 months. The present data do not support the routine use of qua litative amplification assays for monitoring the treatment response of smea r-positive tuberculosis patients.