In situ treatment of H. pylori infection in mice stomach with bioengineered probiotic bacteria releasing guided Antimicrobial peptides

Objectives Targeted therapies seek to selectively eliminate a pathogen without disrupting the resident microbial community. This is even more important when a pathogen like H. pylori resides in stomach, a sensitive microbial ecosystem. Using a probiotic like Lactococcus lactis and bioengineering it to release a guided Antimicrobial Peptide (AMP) targeted towards the pathogen offers a pathway to specifically knock-out the deleterious species and not disturbing the stomach microbiome. Results Three AMPs, Alyteserin, CRAMP and Laterosporulin, were genetically fused to a guiding peptide MM1, which selectively binds to Vacuolating Toxin A (VacA) of H. pylori and cloned into an excretory vector pTKR inside L. lactis . The probiotics were then fed to mice infected with H. pylori , both as a therapeutic and prophylactic measure, and the samples were collected using a novel gavage method and analyzed using qPCR and Illumina sequencing of the extracted stomach samples over a 10-day period. Microbiome analysis with Next-Gen sequencing also revealed a dysbiosis created by H. pylori , determined by creating a Correlation network model with the relative abundances of taxa across the samples, and this dysbiosis was palliated by the bioengineered probiotics which preserved and boosted key microbiome species and reducing the load of deleterious ones. The bioengineered probiotic also significantly improved the OTU diversity compared to antibiotics and L. lactis cloned with empty vector, with gAMP- L. lactis faring the best. Conclusions Probiotics bioengineered to excrete guided AMPs can be a novel and useful approach for combating pathogens without endangering the natural microbial flora. Given the wealth of AMPs and guiding ligands, both natural and synthetic, this approach can be adapted to develop a diverse array of chimeric guided AMPs and can be cloned into probiotics to create a safe and effective alternative to conventional chemical antibiotics.