Mark T. Anderson

Ph.D. (University of Minnesota)

Postdoctoral Fellow (Northwestern University)

My research focuses on the physiology and pathogenesis of Serratia marcescens. Specifically, I am interested in understanding the means by which this opportunistic pathogen causes life-threatening bloodstream infections. Using high-throughput “omics” approaches we have identified a set of fitness genes required for bacterial survival in an experimental model of bacteremia. One fitness pathway of interest is the polysaccharide capsule biosynthesis system of S. marcescens. Our goal with this work is to characterize the mechanisms by which capsule contributes to bacterial survival during infection and determine how capsule polysaccharide variability affects pathogen fitness.

Another area of research aims to characterize the transcriptional response of S. marcescens to the essential element sulfur. We have established that sulfate availability modulates gene expression in S. marcescens, including several genes with no known function in sulfate assimilation. Examples of non-assimilatory sulfur-responsive genes include those encoding phospholipase, hemolysin and the flagellar apparatus. Our objective is to characterize the mechanism of transcriptional regulation for non-assimilatory genes in response to sulfate availability and understand how sulfate acquisition in the infection environment contributes to bacterial fitness.