How BactiFeed Works

Bacteriocins modified to target specific bacteria

Farm to Fork:

Food security within the agricultural environment is what we are targeting, in particular focusing on bacterial infections within livestock and drug resistance. Food security begins right at the beginning of the production line: at the farm. The industrialization of animal production was made possible by the availability of antibiotics for livestock and poultry. The live-stock must be kept healthy in order to reach food security standards, not only is this important to the agricultural environment but it also means a healthy economy for the farming industry. Antibiotics are currently used in feed to protect livestock from infections as well as to generally boost their growth, however drug resistance is causing large problems and the more antimicrobials are abused the worse the situation gets.

Discovery of new antibiotics is at an all-time low; it has been 30 years since a new class of antibiotics was last introduced. Only 3 of the 41 antibiotics in development have the potential to act against the majority of the most resistant bacteria.

Our mission is to use synthetic biology in order to solve this problem and to create an array of novel toxins by modularising the structure and function of Bacteriocins.

Colicins are the bacteriocins produced by E. coli and are proteins produced and excreted by bacteria in order to eliminate closely related competitor strains. Not only this would be a benefit but also the ability to design selective toxic domains targeting only pathogenic strains is a plus point over antibiotics, which are often rather non-selective. The livestock produce can now pass the food security standards without impacting global antimicrobial resistance and land safely on the consumer’s fork.

Beak to Bum:

Our idea was to create a feed for livestock (in this case we focused on chickens), which is coated in colicin producing bacteria. This is BactiFeed. The concept is simple; the chickens eat BactiFeed, as the bacteria travel through the GI tract of the chicken they begin to produce colicins. The colicins are not active when contained in the host cell, which contains a corresponding immunity to the colicin. The cells must lyse to release colicins.

Starting from the beak lets follow the journey of our BactiFeed bacteria. After ingestion the bacteria reach the chickens stomach, in a chickens case there are two called the proventriculus and the gizzard. These have a low pH environment so we decided to begin our plasmid construct with a pH sensitive promoter to induce production of colicins. Throughout the following 20 minutes (or less depending on the individual chickens digestion speed) the bacteria begin to synthesise colicins that build up within the cell. The next stop for our bacteria is the intestine, at which point they encounter bile salts produced by the chicken’s liver. Naturally the next part of our plasmid design included a bile salt induced promoter with a lysis cassette downstream of it. This lyses the cells releasing the colicins to travel to their targets and kill them. The journey has now come to an end and the chicken’s faeces contain no live genetically modified bacteria.

This project addressed the problem of antibiotic over use in livestock by replacing antibiotics with genetically modified bacteria. To protect from further drug resistant bacterial strains the colicins contain a multiple cloning site allowing for easy interchanging of toxins at the cytotoxic domain. In order to combat the lack of selectivity of current treatment for bacterial infections (antibiotics) the toxins that may be added to the colicins have the advantage of being more specific towards strains of bacterial species. Another great benefit of this is that the natural biome within the chicken’s gastro-intestinal tract is not damaged as much as it would be by non-selective broad range antibiotics, which often wipe out healthy as well as pathogenic bacteria.