Human breast milk isolated Lactic Acid Bacteria: antimicrobial and immunomodulatory activity on the Galleria mellonella burn wound model

Infection of burn injuries represents a challenge to health care. Due to the alarming increase of antibiotic resistance, bacteria's role in preventing or treating infection compliance is held in ever greater consideration. In the last few years, Lactic Acid Bacteria have gained attention thanks to their antimicrobial and immunomodulatory properties. However, the conceivable risk associated to the use of live bacteria on such complex wounds like those from burn injuries make essential in vivo models to assess this new therapeutic approaches. This study evaluates the safety profile and antimicrobial activity of human breast milk Lactic Acid Bacteria isolated by the Galleria mellonella preclinical animal model. This study's starting point is their in vitro inhibition activity against Pseudomonas aeruginosa ATCC 27853 compared to a conventional antibiotic commonly prescribed in burn infection management. Survivability rate monitoring, molecular analysis on mRNA expression levels of Gallerymicin and Relish/NF-κB, and analysis on their correlation and implication, corroborated by statistical analysis, revealed fascinating results. The protective and immunomodulatory activity of Lactic Acid Bacteria in G. mellonella burn wound model also suggests a negative feedback already mechanism observed in Drosophila melanogaster. Overall, this study opens promising avenues for further explorations and clinical translation of Lactic Acid Bacteria for the burn wound care, and validating the potential G. mellonella larvae as a burn wound model.