In vitro analysis of postbiotic antimicrobial activity against Candida Species in a minimal synthetic model simulating the gut mycobiota in obesity.

Gut fungal imbalances, particularly increased Candida spp., are linked to obesity. This study explored the potential of Lactiplantibacillus plantarum cell-free extracts (postbiotics) to modulate the growth of Candida albicans and Candida kefyr, key members of the gut mycobiota. A minimal synthetic gut model was employed to evaluate the effects of Lactiplantibacillus plantarum postbiotics on fungal growth in mono- and mixed cultures. Microreactors were employed for culturing, fungal growth was quantified using CFU counting, and regression analysis was used to evaluate the effects of postbiotics on fungal growth. Postbiotics at a concentration of 12.5% significantly reduced the growth of both Candida species. At 24 h, both C. albicans and C. kefyr in monocultures exhibited a decrease in growth of 0.11 log CFU/mL. In contrast, mixed cultures showed a more pronounced antifungal effect, with C. albicans and C. kefyr reductions of 0.62 log CFU/mL and 0.64 log CFU/mL, respectively. Regression analysis using the Gompertz model supported the antifungal activity of postbiotics and revealed species-specific differences in growth parameters. These findings suggest that L. plantarum postbiotics have the potential to modulate the gut mycobiota by reducing Candida growth, potentially offering a therapeutic approach for combating fungal overgrowth associated with obesity.

The intestinal mycobiota and its relationship with overweight, obesity and nutritional aspects.

BACKGROUND: The fungal community of the gastrointestinal tract has recently become of interest, and knowledge of its relationship with the development of obesity is scarce. The present study aimed to evaluate the cultivable fungal fraction from the microbiota and to analyze its relationship with obesity. METHODS: Samples were taken from 99 participants with normal weight, overweight and obesity (n = 31, 34 and 34, respectively) and were cultivated in selective medium, and the cultivable yeasts were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Anthropometric and biochemical measures were also evaluated. RESULTS: Eutrophic, overweight and obese groups presented concentrations of 1.6, 2.16 and 2.19 log10  colony-forming units g-1 yeast, respectively. Ascomycota and Basidiomycota were the two identified phyla. At the genus level, Candida spp. showed a relatively high prevalence, and 10 different species were detected: Candida glabrata, Candida orthopsilosis, Candida lambica, Candida kefyr, Candida albicans, Candida krusei, Candida valida, Candida parapsilosis, Candida utilis and Candida humilis (with relative abundances of 71.72%, 5.05%, 21.21%, 6.06%, 29.29%, 27.27%, 8.08%, 16.16%, 1.01% and 2.02%, respectively). CONCLUSIONS: The obese group presented a higher prevalence of Candida albicans. Furthermore, Candida albicans, Candida kefyr and Rhodotorula mucilaginosa showed a high positive correlation with obesity, weight gain and fat mass and showed a negative correlation with high-density lipoprotein and lean mass, parameters related to weight loss.