Rapid diagnostics of tuberculosis using the Xpert MTB/Rif Ultra test

The aim of the study was evaluation of the diagnostic efficiency of the Xpert MTB/RIF Ultra test for detection of M. tuberculosis DNA and determination of drug susceptibility to rifampicin in various diagnostic samples of patients examined for disease verification. Materials and methods . We analyzed 427 respiratory and extrapulmonary diagnostic samples obtained from 378 patients (including HIV-infected ones) requiring rapid TB diagnostics. The study was conducted from one portion of the sediment of the diagnostic sample using bacteriological methods (luminescent microscopy, cultivation on Middlebrook 7H9 medium in the Bactec MGIT 960 system and on a Lowenstein-Jensen medium) and Xpert MTB/RIF Ultra test. Results . High efficiency of the Xpert MTB/RIF Ultra test-system was demonstrated in verifying of TB in HIV-positive and HIV-negative patients with suspected disease or relapse. Xpert MTB/RIF Ultra demonstrated high efficiency of M. tuberculosis DNA detection (39.2%, 95%CI 32.6–46.2%) in various diagnostic samples that were smear-negative and had no growth on nutrient media and obtained from TB patients. The use of the WHO-recommended QC of 0.5 μg/ml for M. tuberculosis drug susceptibility testing to rifampicin in the Bactec MGIT 960 system would improve the estimated concordance of 97.4% (95% CI: 86.8 – 99.5) with Xpert MTB/Rif Ultra.