Evaluation of Effectiveness of a New Kit of Reagents for Detection of Mutations Associated with Drug Resistance of Tuberculous Mycobacteria to Rifampicin and Isoniazid, by PCR according to Evidences of Clinical Trials

Abstract

The objective: to evalute effectiveness in clinical trials of the new kit of reagents of AmpliTest® MBT-Resist-I based on real-time PCR (RT-PCR) versus similar kits of reagent registered in Russia, to identify genetic markers of M. tuberculosis complex (MTB) resistance to rifampicin (RIF) and isoniazid (INH) in human biological samples and MTB cultures.Subjects and Methods. 200 DNA samples were studied, they had been obtained from biological specimens (sputum (N=100), bronchoalveolar lavage (N=50), biopsy (surgical material; N=50)) of pulmonary tuberculosis patients and containing MTB DNA at a concentration of at least 1 x 103 GE/ml, and from 100 DNA samples of MTB cultures. Efficiency of detecting mutations associated with MTB resistance to RIF and INH using the new kit of reagent of AmpliTest® MBT-Resist-I was evaluated in comparison with HP Amplitube-MDR-RV (OOO Sintol, Russia). In the case of discordant results, the target MTB DNA loci were sequenced by Sanger.Results. We observed complete agreement of the results and consequently high efficiency rates (positive and negative concordance of results - 100%, respectively) of the new kit of reagents of AmpliTest® MBT-Resist-I in comparison with the kit of reagent of Amplitube-MDR-RV in detection of mutations associated with MTB resistance to both RIF and INH, both for human samples and for MTB cultures. In two DNA samples of MTB cultures, an additional mutation (I572L) in the rpoB gene was detected using the new kit of reagents which was not detected by the comparison kit and was confirmed by Sanger sequencing.Conclusion. Inhalers vary significantly by the patients' ability to use them correctly. Asthma patients master the correct inhalation technique better versus COPD patients. Liquid inhalers were more difficult to be used correctly, and the best results were observed with multi-dose powder inhalers. The patient's training by a healthcare professional is critical to assure the correct use of inhalers.