Mycobacterium tuberculosis Beijing genotype strains comprise 50-80% in Russian Federation, which are divided into the main B0/W148, CladeA, and CAO clusters based on VNTR and SNP analysis. It should be noted that such phylogenetically highly close MTB strains belong to the modern Beijing family, generally demonstrating high transmissibility, association with drug resistance, and prevalence among patients with severe forms of the disease. However, studies on MTB genetic cluster strain-related virulence are scarce and contradictory. Here, we investigated virulence of diverse Mycobacterium tuberculosis strains belonging to the B0/W148, CladeA and CAO clusters and nonclustered strain NK of the Beijing family as well as laboratory strain H37Rv in C57BL/6 mice. It was found that mice infected with NK and B0/W148 vs. CladeA strains revealed the peak and the lowest mortality, respectively, while assessing survival rate in various groups (20 mice per MTB strain examined). Analyzing experimental data in mice demonstrated that all MTB strains were able to cause typical tuberculosis-related pathogenic signs. In particular, time-dependent evaluation of pathological changes (on 1, 3, 7, 14, 21, 28, 60 and 120 day post infection) in the lungs and spleen revealed significant differences among various strains. Tuberculosis progression was observed in the mice infected with B0/W148 and NK strains, whereas CladeA, CAO and H37Rv strains resulted in stabilized course and less marked organs damage. Moreover, we found that bacterial load after infection with Beijing family clustering strains was lower compared to that of the reference H37Rv strain, except NK strain demonstrating the peak bacterial load among the Beijing family comparable to H37Rv strain at 120 dpi. Thus, it was found that the level of virulence between most virulent B0/W148 cluster strain vs. NK strain was similar. Overall, the data obtained indicate that Beijing genotype strains are characterized by a diverse range of phenotypic virulence in vivo.

Comparative proteomic profiling of M. tuberculosis H37Rv strains cultured on two different nutrient media, Levenstein-Jensen and Middlebrook 7H11, was performed using a label-free LC-MS/MS approach. It was shown that results obtained from two media possessed high convergence. The only difference was observed in the representation of fumarate reductase FrdB, its abundance was higher in the mycobacterial cells cultured on Levenstein-Jensen medium. The correlation analysis of biological repeats revealed the high convergence of the results obtained from Middlebrook 7H11 medium. Thus, we can conclude that the use of the Middlebrook 7H11 medium is most appropriate in the scientific laboratory.

Transplantaciyu fekal'noj mikrobioty (TFM) naznachayut v kachestve terapii dlya lecheniya razlichnyh patologij zheludochno-kishechnogo trakta. Podbor donora yavlyaetsya odnim iz naibolee vazhnyh i znachimyh etapov dlya TFM. Osoboe vnimanie v poslednee vremya udelyayut probleme nalichiya genov ustojchivosti k raznym gruppam antibiotikov v biomateriale. Cel'yu issledovaniya bylo provesti analiz vstrechaemosti geneticheskih markerov lekarstvennoj ustojchivosti mef i ermB sredi raznyh vozrastnyh grupp naseleniya, vklyuchaya mladencev na grudnom vskarmlivanii, a takzhe opredelit' mikrobiologicheskij sostav distal'noj chasti kishechnika u potencial'no zdorovyh dobrovol'cev donorov TFM. Vsego bylo proanalizirovano 52 obrazca biologicheskogo materala (46 obrazcov kala i shest' — grudnogo moloka) metodom polimeraznoj cepnoj reakcii v rezhime real'nogo vremeni. Gen ustojchivosti k makrolidam (mef) sredi raznyh vozrastnyh grupp byl vyyavlen v 97,8% obrazcah kala, gen ustojchivosti k makrolidam, linkozamidam, streptograminu (ermB) — v 93,5%. V otdel'no vydelennoj gruppe «mat' – ditya» gen mef obnaruzhen vo vsekh obrazcah grudnogo moloka i kala. Gen ermB v etoj gruppe podtverzhden v trekh iz shesti obrazcov grudnogo moloka i chetyrekh iz shesti obrazcov kala mladencev. V rezul'tate detekcii geneticheskih determinat mef i ermB ne tol'ko sredi vzroslogo naseleniya, no i u mladencev, bylo vydvinuto predpolozhenie, chto ispol'zovanie transplantata (kal), soderzhashchego dannye geny dopustimo dlya TFM. Analiz mikrobiologicheskogo sostava kala 23 zdorovyh dobrovol'cev — potencial'nyh donorov TFM, pokazal ochen' nizkij procent sootvetstviya (8,7%) normam mikrobioty distal'noj chasti kishechnika.