Clinical features of pulmonary tuberculosis and nanostructural characteristics of multidrug-resistant Mycobacterium tuberculosis

To analyze clinical and instrumental features of the infectious process course in pulmonary tuberculosis (TB) and to characterize of Mycobacterium tuberculosis with multidrug resistance/resistance to rifampicin (MDR/RR), pre-extensively drug resistance (pre-XDR) architectonics and morphogenesis.

A prospective non-randomized study was conducted at the RSPC for Pulmonology and Phthisiology. 40 MDR/RR-TB, pre-XDR-TB patients (30 men (75.0 %), 10 women (25.0 %)) aged 34 to 61 years were included. The results of diagnostic material microbiological examination, clinical, chest X-ray examination of included patients were analyzed. The architectonics and morphogenesis of M. tuberculosis were studied.

Median (Me) [IQR] time to culture conversion in patients with favorable treatment outcome (FTO) was 54.0 [32.0; 83.0], with unfavorable treatment outcome (UTO) – 101.0 [86.8; 188.3] days (p < 0.0001). Significant differences in mycolic acid layer thickness were found when transferring from mycobacilli (12 [10; 12] nm) to rounded morphovars (30 [30; 37.5] nm, p < 0.0001). Mycobacterium surface stiffness coefficient was significantly higher in patients with UTO than in patients with FTO (Me – 58.3 [48.2; 67.6] pN/µm vs. Me – 7.0 [5.2; 7.4] pN/µm). The surface stiffness coefficient of the M. tuberculosis (H37Rv) strain, susceptible to anti-TB drugs, was 5–7 pN/μm.

Among bacillary mycobacteria morphovars there is a shift of mechanically rigid zones to the middle of the bacterial structure. Changes in the architectonics of mycolic acids, the appearance of forms with a rigid envelope may correlate with the virulence of mycobacteria and the clinical course of the disease.

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