Electronic Thesis and Dissertation Repository


Master of Science


Microbiology and Immunology


McGavin, Martin J.


The RND superfamily of efflux pumps plays vital roles in the intrinsic defence mechanisms of bacterial pathogens. The staphylococci have two genes encoding RND transporters; farE, which promotes efflux of antimicrobial fatty acids, and an uncharacterized gene we have named femT. Although RND pumps are known to contribute to maintenance of cellular homeostasis and antimicrobial resistance, the function of FemT, and the relationship between FemT and FarE in staphylococci have not been identified. Using established assays, we have tested the phenotype of a femT deletion mutant. Here, we show that this mutant is more susceptible to lysostaphin, vancomycin and oxacillin, and grows faster in Mueller-Hinton broth. Most notably, when evaluating the relationship between these transporters, inducible expression of FarE in fatty acids was abolished in FemT-deficient mutants. These findings suggest an interplay between the two transporters, and cumulatively, represent the first description of both systems operating together in S. aureus.