Min Jin Kim1, You Sun Nam2, Sun Young Cho3, Tae Sung Park3, Hee Joo Lee4. 1. Department of Laboratory Medicine, Graduate School of Medicine, Kyung Hee University, Seoul, Republic of Korea Seegene Medical Foundation, Graduate School, Kyung Hee University, Seoul, Republic of Korea. 2. Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Republic of Korea. 3. Department of Laboratory Medicine, School of Medicine, Kyung Hee University, Seoul, Republic of Korea. 4. Department of Laboratory Medicine, School of Medicine, Kyung Hee University, Seoul, Republic of Korea leehejo@khmc.or.kr.
Abstract
INTRODUCTION: We compared the Xpert MTB/RIF assay with a real-time PCR assay using samples from culture-positive patients with TB. In addition, drug susceptibility test results were compared to evaluate the usefulness of these methods. MATERIALS AND METHODS: Fifty-two clinical specimens were analyzed by standard smear-microscopy, mycobacterial growth indicator tube (MGIT) culture, solid culture, MGIT drug-susceptibility testing, TB real-time PCR, and the Xpert MTB/RIF assay. RESULTS: Diagnostic sensitivity of AdvanSure TB/NTM real-time PCR was 80.0%. As shown from smear positive and negative specimens, sensitivities were 87.5% and 75.9%, respectively. The diagnostic sensitivity of Xpert MTB/RIF assay was 75.5%, and from smear positive and negative specimens, sensitivities were 93.8% and 65.5%, respectively. There were 10 cases with discrepant results between two methods. 2 cases were found resistant to rifampin, although Xpert MTB/RIF assay was able to detect rifampin resistance in only one specimen. DISCUSSION: Xpert MTB/RIF assay is an easier method to conduct and while its ability to detect rifampin resistance simultaneously is a benefit, its sensitivity from smear negative-culture positive specimens was lower than Advansure TB/NTM real-time PCR. Further investigation to increase the sensitivity and detect other drug resistances by kit-based assays is required for the rapid and accurate diagnosis of tuberculosis.
INTRODUCTION: We compared the Xpert MTB/RIF assay with a real-time PCR assay using samples from culture-positive patients with TB. In addition, drug susceptibility test results were compared to evaluate the usefulness of these methods. MATERIALS AND METHODS: Fifty-two clinical specimens were analyzed by standard smear-microscopy, mycobacterial growth indicator tube (MGIT) culture, solid culture, MGIT drug-susceptibility testing, TB real-time PCR, and the Xpert MTB/RIF assay. RESULTS: Diagnostic sensitivity of AdvanSure TB/NTM real-time PCR was 80.0%. As shown from smear positive and negative specimens, sensitivities were 87.5% and 75.9%, respectively. The diagnostic sensitivity of Xpert MTB/RIF assay was 75.5%, and from smear positive and negative specimens, sensitivities were 93.8% and 65.5%, respectively. There were 10 cases with discrepant results between two methods. 2 cases were found resistant to rifampin, although Xpert MTB/RIF assay was able to detect rifampin resistance in only one specimen. DISCUSSION: Xpert MTB/RIF assay is an easier method to conduct and while its ability to detect rifampin resistance simultaneously is a benefit, its sensitivity from smear negative-culture positive specimens was lower than Advansure TB/NTM real-time PCR. Further investigation to increase the sensitivity and detect other drug resistances by kit-based assays is required for the rapid and accurate diagnosis of tuberculosis.
Authors: David J Horne; Mikashmi Kohli; Jerry S Zifodya; Ian Schiller; Nandini Dendukuri; Deanna Tollefson; Samuel G Schumacher; Eleanor A Ochodo; Madhukar Pai; Karen R Steingart Journal: Cochrane Database Syst Rev Date: 2019-06-07
Authors: Mikashmi Kohli; Ian Schiller; Nandini Dendukuri; Keertan Dheda; Claudia M Denkinger; Samuel G Schumacher; Karen R Steingart Journal: Cochrane Database Syst Rev Date: 2018-08-27