The vaginal microbiome of healthy women contains nondiphtheria corynebacteria. The role and functions of nondiphtheria corynebacteria in the vaginal biotope are still under study. We sequenced and analysed the genomes of three vaginal C. amycolatum strains isolated from healthy women. Previous studies have shown that these strains produced metabolites that significantly increased the antagonistic activity of peroxide-producing lactic acid bacteria against pathogenic and opportunistic microorganisms and had strong antimicrobial activity against opportunistic pathogens. Analysis of the C. amycolatum genomes revealed the genes responsible for adaptation and survival in the vaginal environment, including acid and oxidative stress resistance genes. The genes responsible for the production of H₂O₂ and the synthesis of secondary metabolites, essential amino acids and vitamins were identified. A cluster of genes encoding the synthesis of bacteriocin was revealed in one of the annotated genomes. The obtained results allow us to consider the studied strains as potential probiotics that are capable of preventing the growth of pathogenic microorganisms and supporting colonisation resistance in the vaginal biotope.

The genus Corynebacterium contains more than 100 species, the vast majority of which have been isolated from human. The usual approach to consider this group of microorganisms alone as the causative agents of infection in humans has recently lost its relevance. The attention of researchers has been shifted to non-diphtheriae or non-pathogenic corynebacteria, whose major components are the normal flora of human skin and mucous membranes. In this review, we summarized the literature data and the results of our own research on the biological properties of the corynebacteria isolated from the female genital tract. We believe, that the non-diphtheriae corynebacterium present in the female genital tract has a high adaptive potential. Due to the unique biological properties, these microorganisms interact with the host organism and other representatives of the vaginal microbiota, which allow them to exist both in women with vaginal eubiosis and in women with nonspecific infectious diseases of the vagina. The ability of non-diphtheriae corynebacterium to produce organic acids, thereby reducing pH, stimulate the production of antiinflammatory cytokines, enhance the antagonistic activity of lactobacilli producing hydrogen peroxide against opportunistic microorganisms, as well as the ability to destroy biofilms of pathogenic microorganisms points to the important role of these microorganisms in the formation of eubiosis and, probably, determines the key role of non-diphtheriae corynebacteria in protecting the vaginal biotope from infection in those women who do not have lactobacilli. The data opens prospects for future fundamental medical research to study individual strains of non-diphtheriae corynebacterium as promising probiotic microorganisms.

The genus Corynebacterium spp., also known as "diphtheroids" or "coryneform" includes diverse group of microorganisms inhabiting different biotopes of the human body. In this work we have studied the influence of metabolites from Corynebacterium spp. strains isolated from the reproductive tract of a healthy woman on growth, biofilm formation and on developed biofilms (24h grown) K. pneumoniae, E. coli, P. aeruginosa and S. aureus. We found that all human bacterial pathogens showed slower growth in the presence of metabolites of Corynebacterium. All the isolated Corynebacterium strains to inhibit biofilm formation and destroy developed biofilms (24h grown) K. pneumoniae, E. coli, P. aeruginosa and S. aureus. The obtained data reveals the important role of Corynebacteria in protecting the vaginal biotope from infection in those women who do not have Lactobacilli and suggest a probiotic potential of these Corynebacterium strains as an anti-bacterial agent in the vagina.