Staphylococcus aureus is a commensal bacterial species which usually resides in the nasal cavity. However, problems can arise once it is present in circulation. In this project, we are investigating two known genes that S. aureus uses when undergoing active infection. In particular, tcaA and mspA. tcaA was shown to be involved with the retention of wall teichoic acids (WTAs) in S. aureus. WTAs are an appendage which bacteria use for adhesion on host tissues. Prof. Mc Loughlin and colleagues showed that mutant tcaA had decreased expression of the WTAs, this allowed the bacterium to circumvent host defence and launch a successful infection.
The second gene of interest is mspA. This gene is involved with membrane integrity and immune evasion. Studies in which Prof. Mc Loughlin was also involved, showed that wild-type mspA strains had resistance to innate immune defences. However, mutant mspA strains showed increased susceptibility to host immune defences, allowing successful killing of the pathogen.
S. aureus and many other pathogens have the potential to survive intracellularly. Therefore, our hypothesis is to determine whether or not two known virulence factors, tcaA and mspA genes play a role in the intracellular survival of S. aureus within human phagocytes.
We aim to look at host factors such as PCR, ELISA and the SeaHorse test to analyze our results. We hope our results will determine whether or not these genes are involved in the intracellular of S. aureus in human phagocytes. Identification of such genes is important for the intervention of therapeutics against such infections.