Date of Award

2019

Degree Type

Thesis

Degree Name

Master of Science in Biomedical Sciences

First Advisor

Valerie Cadet, PhD

Second Advisor

Shafik Habal, MD

Third Advisor

Francis Jenney, PhD

Abstract

Since the discovery of the first antibiotics, they have been a cornerstone of medical treatment for bacterial infections. With the evolution of resistance to these existing agents, it is becoming increasingly important to find novel antibiotics to maintain the level of care of modern medicine.

The Small World Initiative created at Yale University aims to tackle this problem by crowdsourcing the study of antibiotics that may be present in soil and sediment in different environments. According to the Small World Initiative, over two thirds of antibiotics originate from soil bacteria or fungi.

We aim to characterize the bacteria in soil obtained from Radium Springs, GA and analyze their metabolic products for antibiotic activity against Staphylococcus aureus and Acinetobacter baumannii under various conditions of environmental stress. This site was chosen because we hypothesized that the presence of trace amounts of radium in the natural water supply may give the local biome unique characteristics. We isolated bacteria from soil samples collected from several locations with differing levels of moisture. The isolates were co-cultured with S. aureus and A. baumannii (our “tester” strains). We also exposed our tester strains to the metabolites from the soil bacteria to determine if antibiotic activity was inherent to the soil bacteria even without the presence of the target bacteria.

Our research did not find any significant antibiotic activity from the metabolites of our soil bacteria against S. aureus or A. baumannii. Further tests should be conducted on these samples with different methodologies that may induce the production of other metabolites or varying levels of the same metabolites.

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