The discovery and testing of novel antimicrobials for swine health

Project 16-008 - Lead Researcher: Chris Gray

OP Project 16-008
Lead Researcher: Chris Gray
Project funded 2016 and is currently active
Graduate students: Mostafa Nategholeslam, a post-doctorate fellow in biophysics with Chris Gray.

Many strains of infectious bacteria have now developed resistance against traditional antibiotics.  Antimicrobial peptides (AMPs) are an attractive alternative for traditional antibiotics. AMPs have a different mechanism of action compared to traditional antibiotics in that they directly attack the bacterial cell membranes and hence bacteria are less likely to develop resistance to them.   However, resistance could develop in the some strains of bacteria against weaker types of AMPs. Naturally occurring AMPs generally act at the front line of an organisms’ immune systems by inhibiting the proliferation of the microbes. This happens much earlier than the adaptive response to infection, and can prevent the advancement of the infection to more serious stages. 

There is currently widespread research to determine possible new AMPs.  New AMPs, whether discovered or designed, need to be tested for their various chemical and biological properties before they are suited for animal trials. For a given AMP, this involves studies such as identification of the structure of the molecule and characterization of its interaction with various cell membranes through both experimental and simulation methods, as well as biological studies that characterize the peptide’s minimum inhibitory concentration (MIC) and quantify its hostility against red blood cells.  University of Guelph researchers have commenced the characterization studies of their selected antimicrobial peptide, HHC-36.  This peptide was previously identified as an excellent new antimicrobial peptide through laboratory experiments, MIC tests, and mice trials.  The final phase of the trial will be to determine optimum dosages of peptide antimicrobials for both prevention and treatment of infections in pigs.

With stricter regulatory restrictions being imposed on using traditional antibiotics in animal production systems, farmers will need new alternatives that are potent, nontoxic and multi-target. The antimicrobial peptides discovered and/or tested in this project will respond to that need in the coming years. Furthermore, it may be possible to produce these peptides using biological methods, thus significantly reducing both the cost of production and the difficulty of administering these antimicrobial peptides.