Correlation of marker periodontopathogenic bacteria with the immune component sCD14 secretion level in inflammatory periodontal diseases.

Lipopolysaccharide of the cell wall of gram-negative bacteria is a highly active biological substance: its interaction with toll-like receptors-4 (TLR-4) of myeloid cells leads to the activation of a cascade of inflammatory reactions, which is accompanied by the release of the soluble CD14 receptor (sCD14), which can be considered not only as a marker of cell activation by endotoxin, but also as a marker of microbial translocation. The aim of the work was to assess the prognostic significance of the sCD14 level in the samples of the periodontal pocket in inflammatory periodontal diseases and the relationship of its secretion with marker periodontopathogens. For the study, washes were obtained from the periodontal pocket (88 samples in total) from patients with chronic periodontitis and intact periodontium. The sCD14 content was determined by ELISA; during real-time PCR, the marker periodontopathogens Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, Porphyromonas gingivalis, Prevotella intermedia, and Candida albicans were isolated. The study revealed differences in the level of sCD14 secretion by groups: in chronic periodontitis, its content was 8,5 times higher than in the control group and amounted to 17,2±4,06 ng/ml (p=0,006). The frequency of detecting genes of periodontal pathogenic bacteria was 89,3% in patients with periodontitis and 31,25% in the group with intact periodontium. An interesting dependence of the detection of periodontal pathogenic bacteria in the group of patients with chronic periodontitis was established depending on the content of sCD14. Thus, at high concentrations of soluble coreceptor, a greater number of periodontopathogenic bacteria of the I and II orders were released. Thus, in inflammatory periodontal diseases, the processes of sCD14 synthesis change, which is probably due to the colonization of periodontal pathogenic bacteria and the action of their toxins and aggression factors. The relationship of marker periodontopathogens with the level of secretion of the immune component sCD14 and its effect on the structure of the periodontal index reflect shifts in the processes of reparative regeneration of the oral mucosa and the regulation of local immunity in response to microbial invasion.

Role of antimicrobial peptides system in inflammatory periodontal diseases non-specific oral cavity protection.

The system of antimicrobial peptides (AMP) is one of the most ancient mechanisms of the macroorganism resistance to infectious pathogens invasion. The aim of the study was to determine the role of the antimicrobial peptides system and periodontal pathogenic markers in the development and progression of inflammatory periodontal diseases. Gingival pocket washes (91 samples in total) for the research were received from patients with inflammatory periodontal diseases (chronic periodontitis and gingivitis) and intact periodontium. Using ELISA, the content of antimicrobial peptides was determined: human alpha-defensin (HNP 1-3), beta-defensin (HBD 1-3) and cathelicidin (LL-37). Periodontal pathogenic markers were isolated during RT-PCR. The study revealed differences in AMP concentrations by groups: level of HBD 2 in patients with chronic periodontitis was 1,36 times higher than those in the group of patients with chronic gingivitis (p=0,023) and 2,39 times higher than those in the control group (p<0,001), the content of HNP 1-3 in the group of patients with chronic periodontitis was reduced by 1,23 times compared with the indicators of the group of patients with gingivitis (p=0,045) and by 1,97 times compared with the indicators of the control group (p<0,001). The frequency of detection of periodontal pathogenic bacteria genes was 88,0% in patients with periodontitis, 76,92% in patients with gingivitis and 33,3% in the group with intact periodontium. HBD 2 content moderately correlated with the definition of P. gingivalis (r=0,612; p=0,022), T. forsythensis (r= 0,434; p=0,015), A. actinomycetemcomitans (r=0,483; p=0,006), a moderate negative correlation was detected between the content of HNP 1-3 and the release of periodontal pathogens in associations (P. gingivalis with T. forsythensis and T. denticola) (r=-0,388; p=0,031) in the group of patients with chronic periodontitis. Thus, the revealed relationships and correlations indicate shifts in the processes of reparative regeneration of the oral cavity and the regulation of local immunity in response to microbial invasion.

Spectrum and resistance determinants of oral streptococci clinical isolates.

The profiles of oral streptococci sensitivity to antibacterial drugs may reflect information about the presence of macroorganism resistance determinants. The aim of the work was to isolate the spectrum of oral streptococci from the microbiota of the oral cavity of patients and to determine their sensitivity to a wide range of antibiotics. A total of 342 microbial streptococcal isolates were isolated from saliva samples and a periodontal pocket and tested for antibiotic sensitivity. Species identification of streptococci was carried out using biochemical API test systems. Evaluation of antibiotic resistance was performed using E-tests. Real-time PCR was used to identify the presence of tetracycline and macrolide resistance genes. The study identified six types of oral streptococci: S. oralis, S. salivarius, S. mitis, S. sanguinis, S. anginosus and S. mutans. All streptococci were sensitive to linezolid and meropenem. The proportion of penicillin-resistant streptococci in the subgroup S. oralis / mitis / mutans was 47,8% versus 23,5% in the subgroup S. salivarius / sanguinis / anginosus (p = 0.020). Significant levels of resistance were revealed to macrolides (erythromycin) - 47,9%, tetracyclines (tetracycline) - 44,4% and quinolones (ofloxacin) - 41%. Multiple drug resistance (MDR) was detected in 31,9% of oral streptococcal isolates, a combination of erythromycin, tetracycline and ofloxacin resistance was prevalent in 79 isolates (23,1%). The most common genotypes of macrolides and tetracycline resistant oral streptococci (in 127 streptococcal isolates with combined resistance) were ermB-mefE + and tetM + tetQ-, respectively. Thus, S. oralis / mitis / mutans group streptococci predominated in the structure of antibiotic-resistant oral streptococci, including MDR. So, being in one of the most densely populated biotopes of a macroorganism, oral streptococci can mediate the transfer of resistance determinants to more pathogenic and clinically significant microorganisms, which requires careful monitoring of their level of susceptibility to antimicrobial agents.