Honors Theses

Date of Award


Document Type

Undergraduate Thesis



First Advisor

Colin Jackson

Relational Format



The bacteria on and within an organism make up that organism’s microbiome. Given interest in the use of antibiotics in agriculture and the effect of microbes on human health, more studies are needed on the microbial community composition of different organisms and how it responds to antibiotic use. This study investigated changes in the amount of antibiotic resistant bacteria present in dragonfly nymphs exposed to differing concentrations of amoxicillin. Next generation sequencing of the 16S rRNA gene was used to identify cultures of these antibiotic resistant bacteria. Increasing the concentration of antibiotics the dragonfly nymphs were exposed to resulted in greater numbers of antibiotic resistant bacteria. From both amoxicillin + TSA and TSA-only plates, Proteobacteria was the most abundant phyla detected. Bacteroidetes was the major phyla detected in nymphs raised in 0% amoxicillin and plated on amoxicillin + TSA plates. There was a high relative proportion of members of the phylum Firmicutes in all samples plated on TSA plates. In the nymphs raised in 0% amoxicillin plated on TSA plates, members of Firmicutes made up the majority of their microbiome. This study demonstrates that the bacterial communities associated with dragonfly nymphs are affected by changes in the environment, and that exposure to antibiotic pollution likely increases the number of antibiotic resistant bacteria within aquatic insects.

Included in

Biology Commons



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