Drug Sensitivity to Bedaquiline of M. kansasii Strains Isolated in Antituberculous Institutions of the City of Moscow

Relevance. M. kansasii are one of the main nontuberculous bacteria pathogens causing mycobacterial infections in most European countries (including Russia). An important problem in the treatment of mycobacteriosis is the resistance of their pathogens to antibacterial drugs (ABDs). Bedaquiline (Bdq) is one of the new ABDs, the effectiveness of which is shown, in particular, in the most common mycobacteriosis – tuberculosis.Aim. To characterize the features of drug sensitivity of M. kansasii isolated from respiratory material at the Moscow Scientific and Practical Center for Tuberculosis Control (MNPC BT).Materials and methods. A total of 76 M. kansasii cultures have been studied. The MIC spectrum of Bdq was determined for M. kansasii, MIC50, MIC90 (the concentrations of Bdq providing inhibition of the growth of 50% and 90% mycobacterial strains, respectively) and ECOFF (epidemiological cut-off value) – the MIC value characterizing the upper limit for the «wild» population type, which was determined using the ECOFFinder statistical calculator – EUCAST. The drug sensitivity of M. kansasii to the main ABDs used in general practice for the treatment of the corresponding mycobacterioses was also evaluated.Results. It was found that the MIC of Bdq in relation to M. kansasii were distributed in the range of 0.003-2.0 (mcg/ml), the growth of most strains (73.7%) was be inhibited by the concentration of Bdq0.015 mcg/ml. Among all studied strains of M. kansasii, the number of isolates resistant to Bdq were 2 (2.6%). The data obtained are generally consistent with the data of other authors and show that Bdq can currently be an effective drug for the treatment of mycobacterial infections caused by M. kansasii.Conclusion. The results of the study, as well as literature data, indicate that M. kansasii is currently usually sensitive to Bdq. However, in some cases, resistance to this drug is already developing.