The results of drug susceptibility testing of mycobacterium tuberculosis to rifampicin by Xpert® MTB / Rif, BACTEC MGIT 960 as compared with the method of seeding on solid nutrient media

Abstract

In recent years, marked increase in the number of drug resistance (DR)of M. tuberculosis (MBT) to rifampicin (Rif), which is a marker of MDR. Aim: to study efficacy of definition of susceptibility MBT to Rif accelerated methods: Xpert® MTB/Rif (Meth. 1), BACTEC MGIT 960 (Meth. 2) compared with traditional method of seeding on solid nutrient media . Materials . Study 83 patients with newly diagnosed pulmonary tuberculosis (TB) with high risk DR. Investigated parallel sputum, Meth. 1, Meth. 2 and by seeding on solid nutrient media. Results: DR MBT to Rif discovered by Meth. 1 in 30 (36.2%), by Meth. 2 in 29 (34.9%), of these MDR in 28 (33.7%) and isolated Rif resistance in 1 (1.2%) patients. DR MBT to Rif discovered by method by seeding on solid nutrient media. - in 28 (33.7%), including MDR-25 (30.1%) and isolated Rif resistance in 3 (3.6%) patients. Coincidence between results of research by Meth. 1 and by seeding on solid medium for strains sensitive to Rif was 100% for resistant to Rif 98,9%. Meth. 1 compared with seeding on solid media received 2 false-positive results. Coincidence of results of research on Meth. 2 and culture on a solid medium that are sensitive to Rif was 100%, resistant strains Rif 94.5%. Meth. 2 obtained 1 false-negative and 2 false-positive results. Conclusions: Meth. 1 and 2 showed a high percentage of matches with method of seeding on solid nutrient media for DR to Rif 98,9% and 94,5%, respectively. Sensitivity of Meth. 1 is 100%, specificity - 96.4%, Meth. 2 sensitivity - 98.6%, specificity - 96.4%.