Antibiotic-resistant Staphylococcus aureus (S. aureus) infections pose a major health challenge, with biofilm-associated infections being complicated to treat. Biofilms protect bacterial cells from antibiotics and immune responses. Traditional antibiotic treatments are often ineffective, necessitating the search for new therapeutic strategies. One alternative is phage therapy, but its clinical application remains limited due to an incomplete understanding of how phages interact with biofilms and replicate in bacterial cells. Project BioPhage aims to fill this knowledge gap by visualizing the infection dynamics of Herelleviridae phage phi812 in S. aureus biofilms and determining the molecular mechanisms of phage replication in bacterial cells. Using a unique combination of light-sheet fluorescence microscopy (LSFM), correlative light-electron microscopy, and cryo-electron tomography (cryo-ET), we will: (i) Characterize phage infection dynamics in biofilms, identifying how biofilm structure, extracellular matrix, and metabolically dormant cells contribute to phage resistance and herd immunity. (ii) Determine molecular mechanisms of phage replication in individual bacterial cells, revealing key steps in phage genome ejection, assembly, and maturation.
This research will advance our fundamental understanding of phage-biofilm interactions and may provide insights for improving phage therapy. By identifying biofilm vulnerabilities and mechanisms that limit phage efficacy, our findings could inform strategies to enhance phage penetration and replication, increasing the therapeutic potential of phage-based treatments against antibiotic-resistant infections. Ultimately, this work contributes to the broader goal of developing novel, effective alternatives to antibiotics, addressing a critical public health need.
