Investigating Clostridioides difficile Genes Important during Zinc Limitation in the Presence of the Intestinal Microbiota
Sciences and Mathematics, College of
BURS Faculty Advisor
Clostridioides difficile is an intestinal bacterial pathogen that causes severe diarrhea, pseudomembranous colitis, toxic megacolon, and even death. This bacterium currently putting increased financial strain on the healthcare system as incidence of C. difficile infection (CDI) and death rates have been on the rise. The intestinal microbiota plays a role in preventing CDI as the microbiota is thought regulate the immune system response and compete with the C. difficile for nutrients, but specific mechanisms of competition have not be fully defined. Zinc is a vital nutrient for C. difficile growth and therefore its ability to cause disease. The immune system exploits the necessity for zinc by producing the metal-chelating protein calprotectin (CP). CP binds zinc from the intestinal environment to starve C. difficile and other bacterial pathogens. It is also hypothesized that members of the microbiota compete with C. difficile for zinc. Considering the host-induced zinc limitation and the importance of the microbiota for colonization resistance, we hypothesized that there are specific genes within the C. difficile genome that are important to maintain zinc homeostasis during limitation conditions when the microbiota members, Bacteroides, are present. To test this hypothesis, we used the next-generation sequencing technique, Transposon Sequencing (Tn-Seq) by competing a C. difficile transposon mutant library with Bacteroides thetaiotaomicron and Bacteroides fragilis in zinc deplete and replete conditions. We discovered that a mutation in feoB, a putative ferrous iron transporter, was selected against during zinc limitation, and we aim to investigate the specific role of this gene during zinc limitation like that which would be experienced in the intestines. Taken together, Tn-Seq can further been used to determine genes important for colonization and infection. This improved understanding of mechanisms for colonization and infection in C. difficile could lead to a new generation therapeutics that specifically inhibit these mechanisms.
McNeely, Tess; Munneke, Matthew; Green, Erin PhD; and Skaar, Eric PhD, MPH, "Investigating Clostridioides difficile Genes Important during Zinc Limitation in the Presence of the Intestinal Microbiota" (2022). Belmont University Research Symposium (BURS). 116.