Principal Investigator (PI)
The Foundation is providing £244,687 in support.
Rayén Ignacia León-Quezada
1. We will use GSK contacts to obtain a diverse Salmonella strain collection for testing the antibacterial activity of endolysins/Innolysins.
2. We will use GSK expertise and cell lines for testing antibacterial activity of endolysins/Innolysins in tissue culture infection experiments.
3. We will also benefit from GSK experience working with Salmonella persisters and biofilms.
4. We will follow approaches and protocols developed by GSK and benefit from GSK expertise in confocal fluorescence microscopy.
5. We will use GSK expertise and technical assistance for testing the antibacterial activity of enzymes in a in vivo mouse model.
Salmonella is a major cause of foodborne bacterial disease worldwide, usually leading to gastroenteritis. However, severe complications and high mortality rates are seen particularly in developing countries. In addition, increasing antibiotic resistance and ability of Salmonella to persist, call for novel treatment solutions of Salmonella infections.
Here, we aim to target Salmonella by using and engineering endolysins, which are phage-encoded enzymes degrading the peptidoglycan of the cell wall, thus killing bacteria. Endolysins appear promising antibacterials due to the low probability of bacterial resistance, however, only few endolysins can kill Gram-negative bacteria due to their outer membrane blocking access to the peptidoglycan.
Here, we will identify novel endolysins with intrinsic antibacterial activity against Salmonella and further expand the use of endolysins as antibacterials by engineering to Innolysins. Innolysins are endolysins fused with phage receptor-binding proteins (RBP), used by phages to specifically bind to bacterial surface. We previously developed the concept of Innolysins and were able to kill Escherichia and Campylobacter.
Here, we aim to develop novel endolysin-based antibacterials against S. Typhimurium causing systemic infections in Africa. We will develop Innolysins by using Salmonella phage RBPs to target specific bacterial structures on Salmonella, allowing the fused endolysin to degrade the peptidoglycan. We will use a VersaTile approach for a rapid construction of hundreds of Innolysins targeting diverse bacterial receptors. The most potent Innolysins will be identified and Innolysin cocktails will be tested for increasing antibacterial activity and putatively interfering with bacterial virulence.
To identify whether endolysins/Innolysins can target persister cells, we will test their antibacterial activity against intracellular Salmonella in cell lines or against biofilms in vitro. Also, the synergistic effect of combining antibiotics and Innolysins will be determined.
Finally, we aim to evaluate whether endolysins/Innolysins can access and efficiently kill S. Typhimurium in vivo in a mouse model with special focus on persister cells. Since endolysins works through different molecular mechanisms than antibiotics they can kill multidrug resistant bacteria.
The proposed project will thus provide the foundation for how Innolysins can be used as novel antibacterials against Salmonella and other enteric pathogens including antibitiotic resistant strains.