STEC infections are caused by food contamination and are very dangerous, especially to children, leading to bloody diarrhea and potentially life-threatening kidney damage. Antibiotics are typically avoided because they can trigger toxin production.
We developed EB003, a non-replicative CRISPR-based antimicrobial that selectively targets and eliminates O157 STEC clinical isolates while preventing toxin release.
EB003 uses a Cas12 nuclease to cleave >99% of all Shiga toxin (stx) variants found in O157 strains, leading to bacterial killing and suppression of toxin production.
To ensure targeted delivery, we engineered a capsid derived from bacteriophage λ. The tail tip, gpJ, was modified to ensure recognition of a primary receptor, OmpC, that is consistently expressed by E. coli in the gut environment.
The side tail fibers were modified to recognize the O157 antigen, ensuring efficient delivery into the vast majority of clinical isolates of O157 E. coli. High-throughput screening of tail fiber chimeras was used to identify the best candidate.
When checking the stability of our delivery vehicle during passage through the mouse GI tract, we however had the bad surprise that the side tail fibers were degraded.
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