The frequency of single nucleotide polymorphisms of IFNL3 gene (rsl12979860 and rs8099917) and dinucleotide polymorphism of IFNL4 gene (ss469415590) were estimated in healthy inhabitants of Mongolia ...and Irkutsk regions taking into account their races. Population and genetic studies were performed in 1520 conventionally healthy volunteers (blood donors), representatives of Caucasian and Mongoloid races. Significant race-related differences in the incidence of IFNL3 and IFNL4 gene polymorphisms associated with spontaneous clearance of hepatitis C virus were found in healthy volunteers.
The data proving low probability of observing Biofilm Formation (BF) by contemporary clinical strains of M. tuberculosis growing on liquid medium in vitro are discussed. A hypothesis about the role ...of MDR/XDR development hindering BF production was proposed. It was found that strains capable of producing BF grow on Lewenstein–Jensen medium generated R-form specific colonies shaped as a disk with a convex center, “UFO-colonies”. Sixty seven “UFO”- strains were investigated to BF production, resistance to antibiotics and their belonging to the main epidemics clusters of the Beijing genotype (CC1 and CC2-W148). It was shown that MDR/XDR strains were also capable of BF production that, however, was remarkably more frequent in strains of CC1 and CC2-W148 genotypes. Thus, it was hypothesized that BF production might potentially influence an outcome of chronic forms of TB-infection.
The objective:
to assess the stability of circulation of S genotype and S-like strains of M. tuberculosis (MTB) in the Republic of Sakha (Yakutia) over a 12-year period and perform their phylogenetic ...identification relative to the L4.4 Euro-American subline.
Subjects and Methods.
Between 2009 and 2022, 513 MTB strains isolated from pulmonary tuberculosis patients were studied using molecular genetic methods. 92 isolates belonging to S genotype or having an S-like genetic profile were found. Whole-genome sequencing of five strains of S genotype that circulated in the territory of the Republic of Sakha (Yakutia) in 2020-2022 was carried out. A global phylogenetic analysis was performed and evolutionary relationship of the obtained genomes was determined, a RT-PCR test was developed for the rapid detection of S genotype strains.
Results.
In the territory of the Republic of Sakha (Yakutia), there is a stable circulation of S and S-like MTB genotypes belonging to the L4.4 Euro-American subline, the L4.4.1.1 subtype. The evolutionary model has confirmed the previously stated hypothesis that the spread of the S genotype among the indigenous population of Yakutia is associated with mass exposure to the Russian settlers which started from the beginning of the 17th century.
Conclusion.
Spread of MTB strains of the L4.4 Euro-American subline, L4.4.1.1 subtype, among the indigenous populations of New Zealand, Canada and Yakutia in the 17th-19th centuries is very similar.
Introduction.The chronic hepatitis C is essential for health care of the Siberian federal district in the territory of which now the incidence of the specified pathology significantly exceeds similar ...indicators across the Russian Federation. Materials and methods. The retrospective analysis of an epidemiological situation onе the chronic hepatitis C in the Siberian federal district for 2006–2015 included case rate assessment with use of official statistical materials. For integrated assessment of an epidemiological situation indicators of a case rate of the chronic hepatitis C and statistical criteria are used: a standard deviation and rate of a gain of a case rate and also an algorithm of calculation of an integrated indicator in the form of presentation coefficient. A genotypical variety of a virus of hepatitis C (HCV) during 2001‒2017 was studied according to the Irkutsk regional clinical consulting and diagnostic center on the basis of the analysis of 13236 PCR-positive blood samples of the sick. The chronic hepatitis C living in the territory of the Irkutsk region. Results and discussion. Assessment of the movement of a case rate of the chronic hepatitis C for the surveyed long-term period on the federal districts of Russia from the West on the East taped its body height in the designated direction. Complex assessment of indicators of a case rate in the administrative territories which are a part of the Siberian federal district in some cases significantly differs from its standard estimates and the most safe territories the Republic of Buryatia and the Omsk region. The Republic of Tyva moved from the first to the eighth rank place. Integrated approach of studying of the key epidemiological indicators allows to carry out deeper comparative assessment of the situation. In distribution of the main genotypes of HCV significant depression of the first and augmentation of the third of genotypes of the chronic hepatitis C originator is observed in recent years.Conclusions. 1 Siberian federal district is the territory of risk for chronic hepatitis C. 2 The generalized case rate indicator reflects implications of epidemic process more objectively. 3 The offered methodical approach, besides a case rate, can be used for profound assessment and other indicators. 4 Processes of globalization and social conditions promote evolution in distribution of the main genotypes of HCV.
Aim. To estimate the dynamics changes in the population structure of the tuberculosis (ТВ) pathogen in the Irkutsk region by comparison of genotypes of M. tuberculosis from patients of different age ...groups. Materials and methods. 588 epidemiologically unrelated strains of M. tuberculosis isolates from 567 ТВ patients were characterized using 24-locus MIRU-VNTR typing. 160 strains belonged to patients of different age groups. 59 strains were isolated from the «young» people with ТВ who were bom after 1990 and 101 isolates from people who were born before 1955. Results. Two-thirds of the samples (427/567) were genotype Beijing with the dominance of two subtypes belonging to the modem epidemic clonal complexes CC1 and CC2. The high level of clustering profiles of CC1 and CC2 genotype Beijing in «older» and «young» patients in the Irkutsk region indicates the presence and active transmission of epidemic CC1 and CC2 subtypes over the past fifty years.
The formation of biofilms by
M. tuberculosis
on Shkolnikova’s medium (synthetic medium, analogue of Sauton’s medium) has been researched. We studied 150 clinical and 20 laboratory strains of
M. ...tuberculosis
. None of the 150 strains isolated from human beings produced biofilms (pellicle), but all yielded abundant planktonic growth. Twenty reference strains of
M. tuberculosis
produced both biofilms (pellicle) and planktonic growth. The phenomenon of biofilm formation by mixed cultures was observed when inoculating sputum treated with NALC-NaOH from patients with tuberculosis. We obtained 63 mixed biofilms. In 30.2% (19/63) of cases, biofilms contained the DNA of the causative agent of tuberculosis. The RV-PCR method was used to select six samples with the highest concentration of mycobacterial DNA. Molecular cloning and sequencing of a fragment of the
16S rRNA
gene from one of the biofilms was carried out. The nucleotide sequence had 99% homology with the
Bacillus thermoamylovorans
species. From the mixed biofilms obtained, three strains of spore-forming bacilli were isolated. Strains are identified by Sanger’s sequencing of the
16S rRNA
gene, one as Bacillus licheniformis, and the other two as
Brevibacillus
spp. A study of the resistance of isolated strains of spore bacilli against 12 antituberculosis drugs of the first and second series was carried out. All three strains were resistant to maximum concentrations of isoniazid, streptomycin, ethionamide, and ethambutol. Strains of
Brevibacillus
spp. were additionally resistant to para-aminosalicylic acid (PAS) and kanamycin. In a model experiment, the possibility of cogrowth of clinical strains of
M. tuberculosis
and
B. licheniformis
was demonstrated with prolonged co-incubation in Shkolnikova’s medium. In the first few days of growth,
B. licheniformis
produced a biofilm that remained stable for the entire observation period of 45 days. The hypothesis suggesting the possibility of a short-term persistence of some “saprophytic” species of bacilli in the caseous contents of necrosis foci in the late stages of pulmonary tuberculosis has been postulated.
A comparative molecular epidemiological analysis of the population structure of Mycobacterium tuberculosis in Mongolia and the neighboring regions of Russia was conducted. The aim was the determining ...of mutual influence the TB in the studied countries. Selected samples of the Mongolian (309 strains) and Russian (933 strains) cohorts of Mycobacterium tuberculosis were carried out based on the results of genotyping (used deletion analysis for RD 105/207, MIRU-VNTR 24 genotyping and subtyping of the clone CC2/W148 by the specific deletion in the kdpD gene). The results of the study indicate the isolation of transmission of TB infection in Mongolia, despite the activity of the historically formed migration between Mongolia and Russia: in the studied territories, the genotypic spectrum is qualitatively different. The subtypes CC1, CC2 and BL7 of the genotype Beijing predominate in the Russian territories (Buryatia, Zabaykalsky Krai and Irkutsk Region), and the CC4 subtype of the genotype Beijing presents in Mongolia (64.5%). The molecular genetic structure of Mycobacterium tuberculosis has no significant differences in the borderlands with Russia and in the central provinces of Mongolia.
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