Corynebacterium spp.: relationship of pathogenic properties and antimicrobial resistance.

Corynebacterium spp. are part of the human microbiome, but can cause the development of inflammatory diseases of various localization. Purpose - to evaluate the relationship between pathogenic properties and resistance to antimicrobial drugs (AMD) of Corynebacterium spp. from patients with inflammatory diseases of the respiratory tract. Strains of Corynebacterium spp. isolated from patients with inflammatory diseases of the respiratory tract (99 pcs.) and practically healthy individuals (33 pcs.). Isolates were identified by mass spectrometric method (MALDI-ToFMS), their adhesive and invasive activity on Hep-2 cells, cytopathic effect (CPE) in CHO-K1 cell culture, and resistance to antimicrobial drugs (AMD) were determined. Indicators of adhesion (3.65±0.679(CFU±m)x102/ml), invasion (1.72±0.230 (CFU±m)x102/ml), cytotoxicity (69.1±3.8% of dead CHO-K1 cells ) Corynebasterium spp. strains isolated from patients are higher (p≤0.05) than similar indicators in practically healthy people. 90.9% of isolates from patients had resistance to AMD, in most cases (57.6±4.9%) resistance to only one AMP was noted, less often to two (25.2±4.3%), three or more (8.08±2.7%). According to the results of correlation-regression analysis, pathogenic properties (adhesiveness, invasiveness, cytotoxicity) of Corynebacterium spp. strains isolated from patients are in close direct relationship with resistance to AMD. This indicates the importance of identifying strains of non-diphtheria corynebacteria resistant to AMDs, which, under the influence of developing resistance to AMDs, can increase their pathogenic potential, moving from commensalism to parasitism.

[Cypopathic effect of diphtheria pathogen in the composition of biofilm.]

When the nasopharynx is colonized with toxigenic strains of the diphtheria pathogen, toxin is released, which contributes to the death of epithelial cells. But in bacterial carriers, the development of the clinical picture of the disease does not occur. This is due to the peculiarities of the state of their immune system, as well as the peculiarities of the production of diphtheria exotoxin by corynebacteria in the biofilm. Goal. Determining the nature of the cytopathic effect of C. diphtheriae as part of a biofilm in CHO-K1 cell culture. The planktonic and biofilm (120- and 720-hour) cultures of the strains were studied: C. diphtheriae gravis tox+ № 665, C. diphtheriae gravis tox+ № 6765, C. diphtheriae mitis tox+ № 269, C. diphtheriae gravis tox+ isolated from a patient with a diagnosis Localized oropharyngeal diphtheria C. diphtheriae gravis with a silent tox-gene. Biofilm (120- and 720-hour) cultures of diphtheria pathogen strains were obtained according to the Watnik method. The cytopathic effect of corynebacterial strains was studied on a CHO-K1 cell culture, taking into account in an inverted microscope. When studying the cytopathic effect of planktonic cultures of toxigenic strains of corynebacteria, it was found that the number of living CHO-K1 cells after 24 hours was insignificant (25.3±1.2%) and sharply decreased (2.5±0.5%) after 72 hours of cultivation. Under the influence of biofilm and, especially, 720-hour cultures, a different cytopathic effect dynamics was found: the number of living cells after 24 hours remained significant (82.5±2.2%), while at 72-hour it decreased to 25.0±3.0%. In the study of filtrates of planktonic and biofilm cultures of C. diphtheriae strain with a «silent¼ tox-gene, similar patterns were revealed. However, the number of live CHO-K1 cells when exposed to the filtrate of a 720-hour biofilm culture was significantly higher (p≤0.05) than when studying toxigenic strains of corynebacteria. Considering the nature of the cytopathic action, it was found that planktonic cultures of toxigenic strains of corynebacteria are characterized by a change in the cell monolayer, manifested by their thinning and elongation. The study of 720-hour biofilm cultures at 72-hour exposure revealed the appearance of a large number of rounded cells (63-69%). The cytopathic effect, formed under the influence of filtrates of planktonic and biofilm cultures of C. diphtheriae with a «silent¼ tox-gene, as well as strains of non-diphtheria corynebacteria, is characterized by rounding of cells and the formation of symplasts. In the biofilm, the intensity of the cytopathic effect of toxigenic C. diphtheriae strains and C. diphtheriae strain with a silent tox-gene decreased. CPD, manifested by thinning and lengthening of CHO-K1 cells, is associated with the action of diphtheria exotoxin, and rounding is associated with corynebacterial enzymes and, apparently, fragments of surface structures - adhesins. Decreased release of toxin and enzymes beyond the C. bihfilm matrix is a significant cause of the «asymptomatic¼ carriage of diphtheria.

[Factors of pathogenicity of Сorynebacterium non-diphtheria, Isolated from patients with the pathology of the respiratory tract.]

Сorynebacteria non-diphtheria of С. pseudodiphtheriticum strains, despite the absence of the ability to produce toxin, can be associated with the development of inflammatory diseases of the respiratory and urogenital tract, skin, purulent-septic processes of various localization, etc. This indicates the presence of other pathogenicity factors, in addition to toxin, which may be adhesive and invasive activity. Characteristics of pathogenicity factors (adhesiveness and invasiveness) of Corynebacteria non-diphtheria isolated from patients with pathology of the respiratory tract. The strains of Corynebacteria non-diphtheria (38) isolated from the upper respiratory tract from patients with chronic tonsillitis (C. pseudodiphtheriticum - 9) and angina (C. pseudodiphtheriticum - 14 pcs.), As well as practically healthy subjects (C. pseudodiphtheriticum - 15 pcs.). The ability for adhesion and invasion of corynebacteria was studied on the culture of the cells of the pharyngeal epithelium Hep-2 carcinoma. The number of corynebacteria, adherent and invaded on Hep-2 cells, was determined by sowing the flush with 20% serum agar, followed by counting the average number of colony forming units (CFU) per 1 ml. Electron microscopic investigation of adhesion and invasion of corynebacteria on the culture of Hep-2 cells was carried out by transmission electron microscopy. The adhesiveness of strains of C. pseudodiphtheriticum isolated from practically healthy individuals was lower (p≤0,05) than that of all the investigated strains of Corynebacteria non-diphtheria isolated from patients with pathology of the respiratory tract. The most pronounced adhesive properties (238.3±6.5 CFU/ml) were found in C. pseudodiphtheriticum strains isolated from patients with angina compared with those isolated from patients with chronic tonsillitis. Adhesiveness and invasiveness in all strains studied had a positive correlation. Electron microscopic examination shows corynebacteria, both adherent to the surface of Hep-2 cells and accumulated contrast medium, and invasive, electron-transparent. Corynebacteria non-diphtheria of C. pseudodiphtheriticum strains isolated from patients with respiratory tract pathology (angina, chronic tonsillitis) had a higher ability to adhere and invade than C. dodiphtheriticum strains isolated from practically healthy individuals. The pronounced ability for adhesion and invasion, considered as pathogenicity factors of C. pseudodiphtheriticum, allows them to realize their pathogenic potential, protecting against the action of the host's immune system and antibacterial drugs.

[The enzyme activity of neutrophils of blood in patients with chronic viral hepatitis C depending on gender characteristics].

The study was carried out to analyze dynamics of diaphorase and esterase activity ofneutrophils of blood in patients with chronic viral hepatitis C of lower degree of activity depending on gender characteristics in dynamics of treatment. The examination and treatment were organized concerning sampling of 113 patients with chronic viral hepatitis C of lower degree of activity. The diaphorase and esterase activity of neutrophils in dynamics of treatment was detected The analysis of diaphorases was carried out according R.P. Nartsissov technique. The content of esterase was estimated by V.M. Wachstein-FG. Wolf technique. The count of results was implemented using Kaplow semiquantitative technique. In patients with chronic viral hepatitis C of lower degree of activity prior to treatment the activity of NAD-diaphorase was lowered both in males and females. The activity of NADF-diaphorase prior to treatment significantly exceeded standard in males and matched standard in females. The application of basic therapy resulted in qualitative redistribution of cellular composition of reacting cells. All of them reacted following medium degree of activity (b). At that, average cytochemical indicator of reaction was normal in males and in females increasing of activity was observed. The activity og both diaphorases after application of complex therapy (basic therapy and cycloferon) totally returned to normality both in males and females. The esterase activity prior to treatment was decreased in males and increased in females (alpha-naphthylacetate esterase) and vice versa (alpha-naphthylbutyrate esterase) was increased in males and decreased infemales. After application of basic therapy in males increasing of esterase activity was registered and total redistribution of qualitative composition of reacting neutrophils (from degree "a" to degree "b"). In females after treatment the activity of alpha-naphthylacetate esterase was decreased and alpha-naphthylbutyrate esterase was increased. The redistribution of qualitative composition of cells was absent. The application of cycloferon brings to normality the activity of alpha-naphthylbutyrate esterase in males and activity of diaforaselpha- naphthylacetate esterase in females. In patients with chronic viral hepatitis C of lower degree of activity the differences in diaphorase and esterase activity ofneutrophils depending on gender characteristics in dynamics of treatment are observed.

[Adhesion of corynebacterium diphtheriae: the role of surface structures and formation mechanism].

The paper is devoted to the study of surface structures including pili (fimbriae) 67-72p surface protein, DIP 1281 surface protein, lipoarabinomannan CdiLAM and their role in the adhesion and colonization of the mucous membrane of the throat by Corynebacterium diphtheriae. A description is offered for the main stages in the adhesion process of diphtheria causative agent and the ability of its adhesins to stimulate the effect of innate and acquired immunity factors. The paper stresses prospectiveness of the development of vaccines forming immunoprotection of the organism against adhesive activity of C. diphtheriae and also preventing their colonization and reproduction. That would facilitate a solution for the problem of diphtheria carrier state, which cannot be solved using the existing means of preventive vaccination.

[Indicator strains of cholera vibrions for detection and primary identification of cholera phages]. / Indikatornye shtammy kholernykh vibrionov dlia obnaruzheniia i pervichnoi identifikatsii kholernykh fagov.

A set of test-strains is suggested; it comprises V. eltor P-13169 and V. cholerae 163-0139 designed for the primary identification of unknown previously choleraic bacteriophages.