The present study shows that, from 300 Lactobacillus strains isolated from the oral cavity and large intestine of 600 healthy people, only 9 had high antagonistic activity against pathogens and opportunistic pathogens. All antagonistic strains of lactobacilli have been identified by 16S rRNA sequencing and assigned to four species: Lactobacillus fermentum, Lactobacillus rhamnosus, Lactobacillus plantarum, and Lactobacillus casei. In addition, these lactobacilli appeared to be nonpathogenic and had some probiotic potential: the strains produced lactic acid and bacteriocins, showed high sensitivity to broad-spectrum antibiotics, and were capable of forming biofilms in vitro. With the help of PCR and specific primers, the presence of genes for prebacteriocins in L. plantarum (plnEF, plnJ, plnN) and L. rhamnosus (LGG_02380 and LGG_02400) has been revealed. It was found that intestinal strains of lactobacilli were resistant to hydrochloric acid and bile. Lactobacilli isolated from the oral cavity were characterized by a high degree of adhesion, whereas intestinal strains were characterized by average adhesion. Both types of lactobacilli had medium to high rates of auto-aggregation and hydrophobicity and could coaggregate with pathogens and opportunistic pathogens. Additionally, the ability of the lactobacilli strains to produce gasotransmitters, CH, CO, CH, CO, and NH, has been revealed.

Post-resection wound healing, oral microbiota composition and saliva lysozyme activity were assessed in 36 patients with tongue carcinoma before and after surgery with the local application of 2% solution of acid-diluted chitosan in the postoperative period. The microbiocenosis of the oral cavity before treatment in cancer patients was represented by conditionally pathogenic and pathogenic bacteria, whose number is more than 4 lg CFU/cm, indicating dysbiosis; the lysozyme level was reduced, accounting for 25.4±8.5 µg/ml. After the radical hemi-glossectomy the reduction in the frequency and quantity of conditionally pathogenic and pathogenic microorganisms was statistically determined, as well as an increase in the level of lysozyme of saliva on the 10 day of treatment. Patients receiving local treatment with chitosan showed an increasing number of normal microbiota in 1,5-2 times, and the level of lysozyme in 8 times (amounted to 202.87±56.85 µg/ml).

Тверской государственный медицинский университетЦель. Оценить метаболическую активность высокоантагонистических штаммов лактобацилл, выделенных из полости рта и кишечника здоровых людей. Материалы и методы. В исследование включены 9 высокоантагонистически активных штамма лактобацилл, выделенных из зубного налета и кишечника здоровых людей разных возрастных групп от 8 до 35 лет. У лактобацилл были изучены ферменты патогенности, кислотообразование, газовые сигнальные молекулы (CH 4, CO 2, C 2 H 6, CO и NH 3 ), а также степень чувствительности к соляной кислоте, желчи. Результаты. Все исследуемые штаммы лактобацилл были генетически идентифицированы по гену 16S РНК и отнесены к 4 видам: L.fermentum, L.rhamnosus, L.plantarum и L.casei. Они оказались апатогенными, вырабатывали широкий спектр метаболитов разной степени выраженности: молочную кислоту и простые газовые сигнальные молекулы, CH 4, CO 2, C 2 H 6, CO и NH 3 . Кишечные