ABS 100: A Bacterial Therapeutic Delivery Mechanism for Drug Resistant Tuberculosis

Hayoung Jin ¹ , Yu-Yu Chen ¹ , Tetsuhiro Harimoto ¹ , Hannah Kim ¹ , Dennis Jing ¹ , Tal Danino ¹

¹ Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA

Van Wickle (2025) Volume 1, ABS0 100

Introduction: The rise of antimicrobial resistance (AMR) bacteria, such as Mycobacterium tuberculosis, presents an alarming public health threat. Additionally, instead of being cleared from the body, M. tuberculosis can remain dormant in the form of granulomas, which are structures composed of bacteria surrounded by a cluster of immune cells, isolated from the body. This stasis could eventually be broken, resulting in the patient falling ill again.
To tackle both granulomas and AMR, we engineered the bacteria Escherichia coli Nissle 1917 (EcN) as a direct delivery mechanism of therapeutic proteins that can lyse the Mycobacterium family’s waxy envelope. By using hypoxia-dependent bacteria (Chien et al, 2022, Nature Biomedical Engineering), we programmed them to sense and populate this environmental condition found in granulomas. We cloned a library of plasmids with varying replication origin and promoter strength to produce proteins documented to be able to break the different layers of the Mycobacterium cell wall and quantified their production through both Western Blots and ELISAs.
After optimizing therapeutic production, we tested efficacy in vitro by culturing the luminescent Mycobacterium marinum and antibiotic-resistant M. marinum with supernatant from our EcN cultures. Different concentrations of supernatant of the array of strains were tested for a week, measuring optical density and luminescence to track bacterial growth and inhibition. Our results show that our strains are effective at killing the Mycobacterium at concentrations as low as 5% of supernatant in the culture, even against the drug-resistant strain. Given this, we believe engineered bacteria presents a new category of treatments to be explored to combat AMR.