Dr. James Folsom
General Info

© 2010 - 2019
James Folsom

Dr. James Folsom|Sr. Reseach Microbiologist LONZA

Research Experience

Before arriving at LONZA I was a post-doctoral research microbiologist working with Dr. Ross Carlson at Montana State University. In this position I provided proteomic and microbiology expertise for a systems biology project with the aim of improving interpretability of metabolic networks.

During my postdoctoral study at the University of Georgia, I secured the opportunity to further my study of biofilms at the Center For Biofilm Engineering (CBE). Under the direction of Dr. Phillip Stewart I led two research projects. In the first year I completed a transcriptomic study of Pseudomonas aeruginosa drip flow biofilms exposed to tobramycin or ciprofloxacin. This work produced one paper and continues to generate research hypotheses for additional future papers.

My second year at the CBE was made possible by funding I received for a grant proposal that I wrote to study the efficacy of bismuth thiols against pre-formed biofilms. Bismuth is an anti-microbial heavy metal, with low water solubility. The antimicrobial nature of bismuth can be improved by binding it with thiol compounds which results in improved solubility and reduced human toxicity. There are many thiol compounds, and the mode of action isn't known, so I utilized colony biofilm and drip flow biofilm models to screen a variety of bismuth thiol compounds for the ability to destroy biofilms. Several compounds were identified that have the ability to kill biofilms and described in a peer reviewed paper.

My doctoral research project examined L. monocytogenes biofilms and the strain variation in this trait. There has been some debate about the ability of this organism to form biofilms and also whether certain groups of closely related strains make more biofilm. In order to gain a better understanding of Listeria biofilms I utilized repPCR genotyping, biofilm assays, sanitizer resistance assays, and proteomics. I found that chlorinated water could select for hypochlorous acid resistant strains that produce prodigious amounts of biofilm, and that both the type of growth media and serotype affect the amount of biofilm formed.

The research for My master's focused on the effect of chlorinated water on the thermo- tolerance of Escherichia coli O157:H7. This is important because the E. coli literature had shown that exposure to hypochlorous acid resulted in the induction of a heat shock response. Additionally, an outbreak traced to apple cider had resulted in a proposal to require pasteurization of apple juice. Since hypochlorous acid is the active agent in the chlorinated water used to wash apples, there was the possibility that this would adversely affect heat pasteurization protocols. To resolve this issue, I overcame the difficulty of exposing bacterial cells to three sequential stresses: chlorinated water, exposure to apple juice (a low pH stress), and heating with successful enumeration of the survivors. Because the stresses of the apple juice and chlorine were greater than the benefit of the heat shock response, concern was not warranted.