An experimental model for correction of the vaginal microbiota during the inflammatory process

Currently, the development of inflammatory processes in the female urogenital tract is already clearly associated with a decline in the number of lactobacilli that are dominant in the vaginal microbiota in health. Lactic acid (LA) is the main metabolite of lactobacilli, which regulates their anti-inflammatory functions. Objective. To determine the antimicrobial activity of LA in combination with glycogen against various test cultures of opportunistic pathogenic microorganisms. To investigate morphofunctional changes in the cells of the opportunistic pathogenic bacteria S. aureus and E. coli and the microscopic fungus C. albicans in the presence of LA with glycogen in vitro. To develop an experimental model to study the effect of various pH values that mimic the inflammatory process on the growth of test cultures of probiotic lactobacilli, the main representatives of the vaginal microbiota in the presence of LA with glycogen. Materials and methods. The investigation was concerned with the associations of lactobacilli, the main representatives of the vaginal microbiota, Complex No. 1 (L. crispatus, L. rhamnosus, L. gasseri, L. jensenii), Complex No. 2 (L. gasseri, L. fermentum, L. plantarum), Complex No. 3 (L. crispatus, L. brevis, and L. acidophilus), and L. casei. The museum strains of S. aureus 65 and E. coli M17, as well as the museum strain of microscopic C. albicans 8 fungi from the collection of the N.F. Gamaleya Research Institute of Epidemiology and Microbiology were selected as opportunistic pathogenic bacteria. Lactagel, a vaginal gel containing LA 225 mg and glycogen, was used as a source of LA. The growth of the cultures and the morphological properties of the cells when exposed to LA were analyzed by microbiological and electron microscopic assays using transmission electron microscopy. Results. A model for carrying out experiments was developed to determine the ability of LA in combination with glycogen to stimulate the growth and development of probiotic lactobacilli at high pH values characteristic of inflammation. The effect of LA with glycogen on opportunistic pathogenic bacteria and microscopic fungi was manifested by inhibition of the growth of these microorganisms. An electron microscopic study of ultrathin sections of opportunistic pathogenic bacteria and fungi made it possible to establish destructive changes in their morphofunctional properties when exposed to LA in combination with glycogen. At the same time, LA did not adversely affect the morphological properties of lactobacilli and stimulated their growth. LA in combination with glycogen showed an average of 1.5-3.5-fold greater antimicrobial activity than probiotic lactobacillus strains against opportunistic pathogenic bacteria and fungi. Conclusion. An experimental model for conducting a fundamental study of the effect of LA in combination with glycogen on the growth and development of probiotic lactobacilli in vitro, by taking into account the pH value of a medium, was first described. The investigation established that LA in combination with glycogen might be used as the main factor regulating the natural composition of the vaginal microbiota.

lactic acid, glycogen, Lactagel, lactobacilli, opportunistic microorganisms, pH