Neonatal sepsis is a global health concern with particularly grim consequences in low- and middle-income countries that do not succeed in reducing the mortality rate, urging for new and affordable modalities to prevent and treat sepsis among neonates. Klebsiella pneumoniae is the most prevalent cause of neonatal sepsis and is associated with significant resistance rates. A key virulence factor of K. pneumoniae is its capsule used for adhesion and protection against different immune factors such as phagocytosis. Bacteriophage depolymerases remove the capsule of pathogenic bacteria, eliminating their virulence and resulting in their clearance. They are rapidly acting and highly stable enzymes, and only low doses are required. Their specificity explains the microbiome-friendly nature of their mode-of-action, resulting in long-lasting positive health effects on the neonates.
In this project we select for the best depolymerases in terms of efficacy, yield and stability, fulfilling criteria for their affordability, and we broaden their specificity by cocktail design and protein engineering using ancestral sequence reconstruction. The eventual lead depolymerases and a cocktail thereof will be subjected to an in vitro and in vivo analysis using cell lines (impact on cell adhesion and phagocytosis), a Galleria mellonella larvae infection model (efficacy as therapeutic and prophylactic agent) and a neonate mouse model (prevention of neonatal sepsis by mother gut decolonization and treatment of infected neonates) to collect the necessary data to support their further development as a novel modality.