UMMS Affiliation

Program in Molecular Medicine

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Immunology and Infectious Disease | Microbiology | Parasitic Diseases


Gastrointestinal nematodes (GINs) of humans, e.g., hookworms, negatively impact childhood growth, cognition, nutrition, educational attainment, income, productivity, and pregnancy. Hundreds of millions of people are targeted with mass drug administration (MDA) of donated benzimidazole anthelmintics. However, benzimidazole efficacy against GINs is suboptimal, and reduced/low efficacy has been seen. Developing an anthelmintic for human MDA is daunting: it must be safe, effective, inexpensive, stable without a cold chain, and massively scalable. Bacillus thuringiensis crystal protein 5B (Cry5B) has anthelmintic properties that could fill this void. Here, we developed an active pharmaceutical ingredient (API) containing B. thuringiensis Cry5B compatible with MDA. We expressed Cry5B in asporogenous B. thuringiensis during vegetative phase, forming cytosolic crystals. These bacteria with cytosolic crystals (BaCC) were rendered inviable (inactivated BaCC [IBaCC]) with food-grade essential oils. IBaCC potency was validated in vitro against nematodes. IBaCC was also potent in vivo against human hookworm infections in hamsters. IBaCC production was successfully scaled to 350 liters at a contract manufacturing facility. A simple fit-for-purpose formulation to protect against stomach digestion and powdered IBaCC were successfully made and used against GINs in hamsters and mice. A pilot histopathology study and blood chemistry workup showed that five daily consecutive doses of 200 mg/kg body weight Cry5B IBaCC (the curative single dose is 40 mg/kg) was nontoxic to hamsters and completely safe. IBaCC is a safe, inexpensive, highly effective, easy-to-manufacture, and scalable anthelmintic that is practical for MDA and represents a new paradigm for treating human GINs.


Bacillus thuringiensis; anthelmintic, crystal protein, gastrointestinal nematodes, helminths, hookworms, paraprobiotic, soil-transmitted helminths

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Copyright © 2021 Li et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.

DOI of Published Version



Li H, Abraham A, Gazzola D, Hu Y, Beamer G, Flanagan K, Soto E, Rus F, Mirza Z, Draper A, Vakalapudi S, Stockman C, Bain P, Urban JF Jr, Ostroff GR, Aroian RV. Recombinant Paraprobiotics as a New Paradigm for Treating Gastrointestinal Nematode Parasites of Humans. Antimicrob Agents Chemother. 2021 Feb 17;65(3):e01469-20. doi: 10.1128/AAC.01469-20. PMID: 33318013; PMCID: PMC8092541. Link to article on publisher's site

Journal/Book/Conference Title

Antimicrobial agents and chemotherapy


Full author list omitted for brevity. For the full list of authors, see article.

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Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.