Medico-social features of resistance development to new anti-TB drugs in patients with MDR/XDR TB

Background: Research of drug sensibility testing (DST) to new drugs – bedaquiline (BDQ), linezolid (LNZ) and moxifloxacin (Mfx), is necessary step in providing complete treatment MDR/XDR TB cases. Aims and objectives: To determine medico-social features - risk factors of drug resistance development to Mfx and new anti–TB drugs. Methods: Methods of nonparametric statistics were used to analyze the DST results and medico-social features of 84 patients of Ural Research Institute with MDR/XDR TB in 2020. DST was performed for M. tuberculosis isolates to the first, second line anti–TB drugs and LNZ on MGIT960 system with critical concentration as recommended by WHO. There were examined sputum and lung surgical material respectively in 49 (58,3%) and 15 (17,9%) patients with pulmonary TB, surgical bone material in 20 (23,8%) patients with TB spondylitis. Results: MDR was identified in 5 (6,0%) patients, pre-XDR - in 40 (47,6%), XDR - in 39 (46,4%). In pre- and XDR patients were identified the resistance to Mfx in 53 persons (63,1%), in 4 (4,85%) - to BDQ, in 6 (7,2%) - to LNZ. Among them TB duration up to three years or more was observed in 31 (58,5%) patients, contact with MDR/XDR TB in 27 (50,9%), HIV infection in 22 (41,5%), low treatment compliance in 27 (50,95%) and 14 (26,4%) patients interrupted courses, including BDQ, LNZ, Mfx. Measurements and Main Results: TB duration up to three years or more, сontact with MDR/XDR TB, coinfection HIV/TB, low treatment compliance and interrupted courses are combined primarily with the Mfx resistance, may be considered as the risk factors and require DST. Low percentage of BDQ and LNZ resistance make their widespread use in MDR/XDR TB regimen reasonable.