Effect of <i>Enterococcus faecium</i> strain 18 on fungi of the genus <i>Candida</i>

Introduction. Enterococcus spp. which are representatives of the intestinal normal microbiota, play an important role in ensuring colonization resistance of mucous membranes, producing antimicrobial compounds, and therefore are widely used as the basis of probiotic drugs. In the last decade, infections caused by Candida fungi have become a serious clinical problem. In this regard, it is relevant to evaluate the probiotic characteristics of the E. faecium strain 18 and study its antifungal activity. The aim is to investigate the effect of the E. faecium strain 18 on the growth and mature biofilm of Candida spp., as well as to characterize its agregation and coagregation abilities. Materials and methods. The effect on fungal growth was determined by the dynamics of the optical density of broth cultures; the effect of enterococcus supernatant on formed biofilms was studied in sterile polystyrene 96-well plates. The probiotic potential of E. faecium strain 18 was assessed by its ability to autoagregate and coagregate interaction with 20 strains of Candida of different species — C. albicans, C. krusei, C. kefir, C. glabrata. The scanning electron microscopy was used to obtain images. Results. The inhibitory effect of the supernatant of E. faecium strain 18 has been shown to affect the growth of Candida of all studied species, as well as their mature biofilms. The level of inhibition of the growth of formed biofilms in non-albicans species was 58.6–72.9% and 51.4% for C. albicans. The autoagregation rates of E. faecium strain 18 were 57.6% after 2 hours of incubation and 60.4% after 5 hours. E. faecium strain 18 demonstrated different levels of coagregation with the studied species of Candida, with the index values observed after 5 hours of cultivation being higher in non-albicans species, and the maximum value recorded for C. glabrata (85.6%). Conclusion. The experimental data obtained allow us to consider the studied strain as the basis for a probiotic that has an anti-candidiasis effect.