Screening delle potenzialità probiotico-terapeutiche di microrganismi isolati da latte umano

The symbiotic relationship between humans and microorganisms has evolved over millions of years, resulting in the formation of a superorganism known as a "holobiont." The microbial communities, collectively referred to as microbiota, residing within the human body play a crucial role in maintaining health. Dysbiosis, an imbalance in the microbiota, has been associated with various disorders, including vaginal dysbiosis characterized by infections and gynecological complications. Probiotics, live microorganisms with health benefits, have been utilized since ancient times to restore microbial equilibrium and promote disease management. Lactic acid bacteria, specifically the genera Lactobacillus and Bifidobacterium, have demonstrated efficacy in treating gastrointestinal diseases, lactose intolerance, colon cancer, obesity, atherosclerosis, diabetes prevention, oral health, and skin disorders. However, to ensure safety and functionality, probiotics must meet specific criteria. Human breast milk, considered a novel source of probiotics and bioactive compounds, plays a crucial role in promoting infant health. Although the exact origin of milk bacteria remains unclear, it is hypothesized that they may translocate from the maternal gut through an entero-mammary pathway. Various factors, such as maternal diet, delivery mode, and antibiotic usage, influence the composition of milk microbiota, emphasizing the importance of establishing beneficial microorganism colonization within the infant's gut after birth. This study aims to isolate bacterial strains from breast milk and to assess their probiotic potential in relation to human health, particularly focusing on pathogens associated with vaginal dysbiosis. Microorganism selection was based on their ability to grow in specific media and exhibit biochemical and phenotypical characteristics aligned with Lactic Acid Bacteria. The isolated strains were subjected to an accurate validation of antibiotic susceptibility, followed by phenotypic and genetic identification. Further evaluation involved the assessment of functionality criteria, including physicochemical properties of cell surfaces and viability within the gastrointestinal tract for oral administration. Ultimately, probiotic activity was analyzed through in vitro assays on vaginal cell lines, examining the strains' antagonistic potential against pathogens, their ability to disrupt biofilm, and their capacity to facilitate healing of vaginal epithelium lesions. Four bacterial strains have been chosen for their exceptional antimicrobial activity against pathogens associated with intestinal, skin, and vaginal infections. These strains have demonstrated ability in inhibiting pathogen growth and biofilm formation, adhering to vaginal cell surfaces, and stimulating cell proliferation. These findings indicate the therapeutic potential of breast milk-derived strains as probiotics. Future investigations should focus on assessing the antimicrobial activity of these strains on specific cell lines involved in polymicrobial infections. Additionally, exploring the mechanisms of action and safety profiles of these probiotics through animal model studies and clinical trials is warranted.