Etiological significance of Corynebacterium spp. in the development of diseases of the respiratory tract.

Corynebacterium spp. It is associated with inflammatory diseases of the respiratory tract (tracheitis, pharyngitis, rhinosinusitis, bronchitis, pneumonia, etc.). C. pseudodiphtheriticum can be the causative agent of bacterial coinfection in patients with a new coronavirus infection (COVID-19). The aim is to determine the pathogenic properties and resistance to antimicrobial drugs of Corynebacterium spp. strains to establish their etiological significance in the development of inflammatory diseases of the respiratory tract. Strains of Corynebacterium spp. isolated from patients with inflammatory diseases of the respiratory tract (43 pcs.) and practically healthy individuals (29 pcs.). Isolates were identified by mass spectrometric method (MALDI-TOF MS), their cytopathic effect in CHO-K1 cell culture, hemolytic, urease activity, antimicrobial drug resistance were determined. Strains of Corynebacterium spp. isolated from patients in the amount of 105 CFU/ml or more, practically healthy - 104 CFU/ml or less. Isolates of Corynebacterium spp. patients had a more pronounced cytopathic effect (83.7±11.1%) and were more often resistant to antimicrobial drugs than those isolated from practically healthy. To establish the etiological significance of Corynebacterium spp. isolates. in the development of inflammatory diseases of the respiratory tract, it is advisable to determine their amount in biological material (105 CFU/ml or more), the cytopathic effect on CHO-K1 cell culture, as well as the presence of multiple resistance to antimicrobial drugs. Differences in the characteristics of Corynebacterium spp. isolates. from patients with respiratory tract pathology and practically healthy individuals are associated with the strain, not the species, of corynebacteria.

Corynebacterium spp. - problematic pathogens of the human respiratory tract (review of literature).

Corynebacterium spp. - representatives of the normal microflora of the human body, but their role in the development of diseases in both immunocompromised and immunocompetent patients is known. Corynebacterim spp. (C. pseudodiphtheriticum, C. striatum, C. amycolatum, C. accolens, C. argentoratense, etc.) is associated with diseases of the respiratory tract: tracheitis, pharyngitis, rhinosinusitis, bronchitis, etc. They can be transmitted by airborne droplets, household contact, and possibly by hematogenic pathways. Corynebacterim spp. toxins do not produce, but are capable of adhesion and invasion, biofilm formation, production of neuraminidase, hyaluronidase, and hemolysin. It is necessary to take into account not so much the species, but the strain affiliation of isolates of Corynebacterium spp., since among the representatives of one species of non-diphtheria corynebacteria (for example, C. pseudodiphtheriticum), colonizing the respiratory tract, there may be strains that can exhibit not only pathogenic properties, but also probiotic activity. Microbiological diagnostics is based on their quantitative determination in biological material, phenotypic (culture study, test systems for biochemical identification, Vitek 2 automated systems) and genotypic (16SpRNA gene sequencing and rpoB) methods. It is possible to use mass spectrometric analysis (MALDI-ToF-MS). The greatest activity against Corynebacterium spp. in vitro studies preserve vancomycin, teicoplanin, and linezolid. Successful therapy with at least two of the following antimicrobial agents (AMP) has been reported: vancomycin, rifampicin, linezolid, and daptomycin. The sensitivity of isolates of Corynebacterium spp. to AMP is not related to the species, but is due to strain differences, and therefore it is necessary to test each isolated strain. Continuous monitoring of the sensitivity of Corynebacterium spp. strains to AMP is necessary due to the observed variability of these traits. Of particular importance is the identification of multidrug-resistant isolates that are currently considered highly pathogenic. When compiling the review, the databases Scopus, Web of Science, The Cochrane Library, CyberLeninka, RSCI were used.

[Analysis of the frequency of allocation of Corynebacteria non-diphtheria from patients with inflammatory diseases of the respiratory tract.]

Corynebacteria non-diphtheria and, in particular, C. pseudodiphtheriticum species that are closely related to C. propinquum and C. striatum form a group of new respiratory pathogens leading to the development of bronchitis, tracheitis, exacerbation of chronic obstructive pulmonary diseases, nosocomial pneumonia and other pathology. The goal is to analyze the frequency of the release of Сorynebacteria non-diphtheria from the upper respiratory tract of patients with various inflammatory diseases of the respiratory tract. Strains of Сorynebacteria non-diphtheria (C. pseudodiphtheriticum, C. propinquum, C. accolens, et al.), isolated from patients with inflammatory diseases of the respiratory tract (60 pcs.) and practically healthy individuals (31 pcs.) were studied. Identification of Сorynebacteria was performed using the method of mass spectrometry (MALDI-ToFMS). Сorynebacteria nondiphtheria in the amount of 105 and higher were more frequently detected with the development of chronic tonsillitis (60.0%) and nasopharyngitis (30%). The strains of C. pseudodiphtheriticum (40.0±6.4%) and the closely related species C. propinquum (21.7±5.3%) were mainly found; much less often - C. accolens (8.3±3.6%), C. afermentans (6.7±3.3%), et al. In 86.7% of cases, Corynebacteria non-diphtheria were isolated from children. In chronic tonsillitis, C. pseudodiphtheriticum and the closely related species of C. propinquum were isolated more often; in nasopharyngitis and bronchitis - С. pseudodiphtheriticum. Isolation of Corynebacteria non-diphtheria and, especially, C. pseudodiphtheriticum, C. propinquum, C. accolens species from patients with inflammatory diseases of the respiratory tract in the amount of 105 and above, if there are no other pathogenic microorganisms in the role of microbial associates, of clinical importance.

[Sensitivity and resistance to antimicrobial agents ESBL-producing and not producing ESBL strains of E. coli in patients with urinary tract infection.]

As a result of the conducted researches it is shown that 44.1% of urinary tract infections (UTIS) caused by E. coli are accounted for by producers of beta-lactamase of the extended spectrum of action (ESBL). Associated resistance to fluoroquinolones and co-trimoxazole was found in 93.3% of BLRS-producing E. coli strains. All studied strains regardless of ESBL production were sensitive to imipenem, the majority showed sensitivity to ertapenem, gentamicin and resistance to doxycycline. Not producing ESBL strains of E. coli were sensitive to fosfomycin. Comparison of data obtained during testing of isolated cultures on ESBL, study of their sensitivity and resistance to beta-lactams (amoxicillin/clavulanate, ceftazidime, ceftriaxone, cefotaxime, imipenem) indicates the need to test isolates for AmpC products. To this end, during the screening test for ESBL and the method of «double disks¼, along with cephalosporins of III generation, it is necessary to use a phenotypic test for sensitivity to cefepime. The use of test results of E. coli isolates isolated from patients with UTIS for the production of ESBL, ampC enzymes, carbapenemase and sensitivity to AMP will improve the effectiveness of antimicrobial therapy and will help to curb the formation and spread of antimicrobial-resistan strains.

[Corynebacterium riegelii as an unusual species separated from female patient with tuberculosis.]

The article describes a clinical case of tuberculosis of of urinary tracts of a female patient with massive discharge of strain Corynebacterium riegelii from urogenital tract. The data of clinical laboratory examination of female patient are analyzed. The characteristics of isolated strain C. riegelii (high degree of isolation rate (106 and higher) expressed urease activity (decomposition of urease during 5 min), presence of hemolytic activity) with consideration for estimation of its antibiotics sensitivity. The etiologic significance of isolated species C. riegelii in development of infection process in urogenital tract is demonstrated.

[THE IMMUNOLOGIC INDICATORS IN PATIENTS WITH CARIES OF CONTACT SURFACES OF LATERAL TEETH].

The samplings of patients aged 18-45 years with caries of contact surfaces of lateral teeth (n=18) and healthy adults aged 18-20 years with intact teeth (n=18) were examined The saliva taken in rotary vial on empty stomach in amount of 3-4 mi served as assay for analysis. To identify secretory immunoglobulin A, interleukin lß, interleukin-4 and interferon y saliva was centrifuged during 15 min under 1500 rpm. The supernatant fluid was analyzed using enzymoimmunoassay (test-systems "Vector-Best", Novosibirsk). The registration of reaction was implemented using multiscan Labsystem under wavelength 450 nm. The content of secretory immunoglobulin A was expressed in mg/l, cytokines - in pg/ml. It is demonstrated that in patients with caries average level of interleukin lß was almost two times higher (p<0.05) than analogous indicator in healthy examined patients. In healthy patients average level of interferon γ significantly (more than in 10 times) exceeded upper limit of allowable standard and was higher (p<0.05) in comparison with such in patients with caries of contact surfaces. The analysis of content of secretory immunoglobulin A in saliva established that in healthy patients average values of the given indicator were higher (p<0.05) than in patients with caries of contact surfaces of lateral teeth. The lower content of secretory immunoglobulin A and interferon y against the background of increased level of interleukin lß was detected in saliva of patients with caries of contact surfaces of lateral teeth. This occurrence can be considered as factor predisposing to development of caries process.

[THE COMPARATIVE ANALYSIS OF TECHNIQUES OF IDENTIFICATION OF CORYNEBACTERIUM NON DIPHTHERIAE].

The comparative analysis was carried out concerning effectiveness of three techniques of identification of Corynebacterium non diphtheriae: bacteriological, molecular genetic (sequenation on 16SpRNA) andmass-spectrometric (MALDI-ToFMS). The analysis covered 49 strains of Corynebacterium non diphtheriae (C.pseudodiphheriticum, C.amycolatum, C.propinquum, C.falsenii) and 2 strains of Corynebacterium diphtheriae isolated under various pathology form urogenital tract and upper respiratory ways. The corinbacteria were identified using bacteriologic technique, sequenation on 16SpRNA and mass-spectrometric technique (MALDIToF MS). The full concordance of results of species' identification was marked in 26 (51%) of strains of Corynebacterium non diphtheriae at using three analysis techniques; in 43 (84.3%) strains--at comparison of bacteriologic technique with sequenation on 16S pRNA and in 29 (57%)--at mass-spectrometric analysis and sequenation on 16S pRNA. The bacteriologic technique is effective for identification of Corynebacterium diphtheriae. The precise establishment of species belonging of corynebacteria with variable biochemical characteristics the molecular genetic technique of analysis is to be applied. The mass-spectrometric technique (MALDI-ToF MS) requires further renewal of data bases for identifying larger spectrum of representatives of genus Corynebacterium.

[Apoptogenic activity of microbes-associants during Epstein-Barr virus infection].

AIM: Study apoptogenic activity of-microbes-associants during Epstein-Barr virus infection (EBVI) on the model of mice peritoneal macrophages in vitro. MATERIALS AND METHODS: Evaluation of apoptosis induced by bacteria isolated from EBVI patients was carried out by characteristic morphological changes of macrophages in smears stained by May-Grunwald with additional staining by Romanowsky-Giemsa. RESULTS: All the EBVI microbes-associants were established to have apoptogenic activity, however, the highest pathogenic potential was noted in Streptococcus pyogenes. CONCLUSION: The presence of apoptogenic activity in bacterial microflora accompanying EBVI against immune system cells could serve as means of their survival and be the pathogenetic basis for prolonged persistence in the organism.

[Macrophage apoptosis as a mechanism of pathogenic effect of diphtheria infectious agent].

AIM: Study of the apoptogenic effect of Corynebacterium diphtheriae toxigenic strains on mice peritoneal macrophages in vitro. MATERIALS AND METHODS: Evaluation ofapoptosis induced by Corynebacterium diphtheriae, Corynebacterium pseudodiphtheriticum, Staphylococcus aureus, Streptococcus pyogenes strains was performed by characteristic morphological changes in macrophages in smears stained by azure eosin by Romanovsky-Giemsa. RESULTS: Apoptogenic activity of diphtheria infectious agent was established to be determined by diphtheria exotoxin at early (after 1 hour) and surface structures and pathogenicity enzymes at later (3 hours) stages of effect. CONCLUSION: The ability of diphtheria infectious agent to cause macrophage apoptosis is one of the mechanisms of realization of its pathogenic properties determined by the effect of diphtheria exotoxin, as well as its surface structures and pathogenicity enzymes. The increase of apoptogenic activity of toxigenic strains of C. diphtheriae in association with S. pyogenes may be a pathogenetic base of formation of prolonged forms of bacteria carriage against the background of chronic ENT pathology.

[State of immunity to diphtheria and tetanus in women in early postpartum period].

AIM: Study of anti-diphtheria and anti-tetanus immunity in women in early postpartum period depending on age. MATERIALS AND METHODS: Women in early postpartum period (n =139) with unknown vaccine anamnesis aged 17 to 44 years and under the supervision of Rostov-on-Don maternity hospital No. 2 were examined for the evaluation of the anti-diphtheria and anti-tetanus immunity state. RESULTS: All the women had high level of protection form these infections. The level of anti-tetanus immunity intensity in the examined was higher than anti-diphtheria. CONCLUSION: Monitoring of anti-diphtheria and anti-tetanus immunity in women of childbearing age is necessary to resolve the issue of vaccine administration in this group. High level of maternal immunity intensity will allow to form a sufficient protection from infectious agents in neonates.

[Influence of polyoxydonium on adhesive properties of Corynebacterium diphtheriae].

AIM: To study the ability of polyoxydonium (PO) to influence on adhesive properties of C. diphtheriae. MATERIALS AND METHODS: Ability of PO to influence on adhesive properties of toxigenic and nontoxigenic strains of C. diphtheriae isolated from patients, carriers, contact persons as well as from healthy persons during prophylactic examinations of population in Rostov-on-Don and Rostov region was studied. RESULTS: It was established that addition of PO in cultivation medium always suppressed adhesive activity of C. diphtheriae. In experiments on breaking of adhesion the blocking effect of PO on adhesive characteristics of bacteria had dose-dependent pattern and was pronounced when PO was used in concentration of 1200 mcg/ml. CONCLUSION: Obtained data prove that PO has marked antiadhesive activity against both toxigenic and nontoxigenic strains of C. diphtheriae, which could be used for the treatment of diphtheria infection.

[Immunity to diphtheria in population of Rostov-on-Don city and Rostov region in recent years].

AIM: To study the magnitute of antitoxic immunity against diphtheria in different age groups of Rostov-on-Don city and Rostov region population. MATERIALS AND METHODS: Antitoxic immunity against diphtheriawas studied in children 3 - 15 years old (661 persons) and adults 16 - 59 y.o. (893 persons), which were tested during 2003 - 2007 using direct hemagglutination assay manufactured by Mechnikov Scientific Production Association "Biomed" (Moscow). RESULTS: Proportion of children 3 - 15 y.o. seropositive to diphtheria was 98.6 +/- 0.5%. Children aged 3 years and 4 - 6 years were identified as a risk group for diphtheria as they had highest proportions of non-immune persons. Proportion of immune to diphtheria in adults was 94.4 +/- 0.8%. Maximal level of protection was observed in personsaged 16 - 17and 18 - 19 years, in which the proportion of seropositive persons was 99.1 - 100%. Persons > or = 50 years old formed group of risk because persons with low or moderate titers of antitoxin were identified in this age group mostly. CONCLUSION: Obtained results provide evidence on enough high level of protection of Rostov-on-Don cityand Rostov region population against diphtheria. Group of increased risk comprised of persons aged 3 - 6 years and > or = 50 years.