Phage-steering permits antibody-mediated clearance of E. coli K1 from the gut.

Summary

In mice, K1-specific phages select capsule-deficient E. coli mutants that expose O-antigen, rendering them vulnerable to vaccine-induced intestinal IgA and enabling competitive exclusion by E. coli Nissle. Maternal vaccination plus phage therapy protected 77% of pups from E. coli K1 transmission, outperforming either modality alone.

Key Findings

• K1-specific phages drove rapid selection of capsule-less E. coli mutants with exposed O-antigens.
• Vaccine-induced intestinal IgA targeted O-antigen, enabling competitive exclusion by E. coli Nissle.
• Maternal vaccination plus phages protected 77% of pups from E. coli K1 transmission; either alone was inferior.

Clinical Implications

If translated to humans, maternal vaccination plus phage-steering could reduce E. coli K1 gut colonization and vertical transmission, potentially preventing neonatal sepsis and meningitis without broad-spectrum antibiotics.

Limitations

• Preclinical murine study; human efficacy and safety are untested.
• High E. coli diversity may limit generalizability across strains and hosts.

Future Directions

Evaluate safety, dosing, and efficacy of combined maternal vaccination and phage therapy in translational models and early-phase human studies; define strain coverage and resistance dynamics.