Graduation Year

2023

Document Type

Campus Only Senior Thesis

Degree Name

Bachelor of Arts

Department

Molecular Biology

Reader 1

Dr. Pete Chandrangsu

Reader 2

Dr. Aditi Vyas

Abstract

Antibiotic resistance is currently a big threat to global health, with bacteria constantly developing new resistance mechanisms and putting medical advances at risk. The antibiotic resistance of Staphylococcus epidermidis is significant, as it is an opportunistic pathogen that becomes virulent upon entering the human body, mainly through medical and prosthetic devices. Metals have long been used as antibiotics, but their mechanisms to combat bacteria are still being studied. This study aimed to look into defense mechanisms used by Staphylococcus epidermidis when it is treated with copper. A growth assay was performed, in order to determine the concentration of copper used to treat the bacteria. Then, RNA extractions were performed on copper-treated and untreated bacteria, in order to analyze which genes were upregulated and downregulated, based on RNA-sequencing data. Among many processes, upregulated genes were involved in replication and DNA repair, processes necessary to the survival of the bacteria, such as metal homeostasis and iron storage, and processes to excrete metals out of the cell membrane. Downregulated genes were involved in resistance against cadmium and production of phenol-soluble modulins. The RNA-sequencing data uncovers more of the genetic defense of Staphylococcus epidermidis, as the results show how the bacteria defends itself against copper, using mechanisms to transport copper out of cells, replicate plasmids, in order to increase resistance against copper, and upregulate biochemical pathways necessary for its survival against harsh conditions. Future directions may include creating knockdown mutants of these genes, in order to find specific genes to target in the creation of antibiotics.

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This thesis is restricted to the Claremont Colleges current faculty, students, and staff.

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