Date of Award

Fall 2021

Document Type

Open Access Thesis


Biomedical Science

First Advisor

Bob Price


Antibiotics have been our most effective weapon against bacterial infections since their discovery in the early 1900s. Their use has been critical in reducing mortality rate from infectious diseases. However, in the last few decades, the overuse of antibiotics, beginning at an early age and into adulthood, has become a growing concern globally. Penicillin is one of many extensively used antibiotics in early childhood that has been used to treat childhood infections. Recent studies showed that exposure to low dose penicillin can have adverse effects leading to chronic illness such as diabetes, allergies, inflammation, and susceptibility to obesity, with the latter two having links to colorectal cancer. In this study, our goal was to determine if exposure to low dose penicillin has an impact on the intestinal microbiota composition and inflammation and determine the impact on development in tumors of the intestine of the mice, a genetic model of intestinal tumor development. Mice were administered low dose penicillin in their drinking water, fecal samples were collected at four-week intervals to analyze changes in microbiome composition, and tumor burden was analyzed when mice were 18 weeks of age. Although other studies showed a correlation between antibiotic exposure and microbiota disruption and inflammation in the intestine, we found no significant differences in microbiota composition between exposed and control ApcMin/+ mice. However, we found a significant increase in tumor burden specifically in female mice but not in male mice.


© 2021, Kinsey Ann Sierra Meggett