Date of Award

Fall 12-8-2023

Embargo Period

12-7-2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biochemistry and Molecular Biology

Additional Department

Molecular and Cellular Biology and Pathology

College

College of Graduate Studies

First Advisor

Jessica Hartman

Abstract

Acinetobacter is a genus of gram-negative bacteria that have been appearing frequently in hospitals contributing to infections in the blood, lungs, urinary tract, and other parts of the body. It infects patients with weakened immune systems that are placed on ventilators, after the use of catheters, or have any other open wounds produced by prolonged hospital stays. This genus of bacteria is problematic due to its high probability of becoming resistant to multiple classes of antibiotics. Thus, we are determining the pathogenicity of clinical isolates of Acinetobacter calcoaceticus using the organism Caenorhabditis elegans as a model.

We are testing this using the following methods, a plate survival assay using eight strains of bacteria, including two laboratory-adapted strains and four clinical isolates of Acinetobacter calcoaceticus, Acinetobacter baumannii as a negative control, and Escherichia coli OP50 as a positive control, the second method being a worm microtracker assay using the same strains cultured in brain-heart infusion or ZMB1, and methods pertaining to identifying what is causing virulence such as methanol extraction, proteinase K treatment, and centrifuge filtering. Our hypotheses for each are: On the plates and in liquid, wild type, N2 strain worms will expire faster on/in the clinical isolates of Acinetobacter.

Our hypothesis for the microtracker analyses states that Acinetobacter calcoaceticus is pathogenic due to the decreased motility in the wells over time. Pertaining to what causes virulence in the nematodes, we hypothesize that it’s a protein.

Our results on plates indicate that after ingesting Acinetobacter, nematodes live for the same amount of time and in some cases longer than the nematodes plated on OP50. However, when placed in the liquid culture the nematodes in the BHI solution expire within twenty-four hours. When treated with proteinase K or filtered we observed protection from lethality. In future experiments we plan to send samples off to partner labs to perform proteomics to search for possible virulence proteins. The findings of this project will help lead us to a better understanding of the pathogenicity of this strain of Acinetobacter and its effects on the innate immune system.

Rights

Copyright is held by the author. All rights reserved.

Download

Share

COinS