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Characterizing Bacterial Antibiotic Resistance, Prevalence, and Persistence in the Marine Environment

Megan May, Ph.D., 2019
Rebecca Gast, Advisor

Antibiotics are naturally occurring chemicals in bacteria that were recently discovered and utilized by humans. While resistance is often thought of in hospitals, antibiotics and antibiotic resistance genes from human activity are disposed of into nature where they are able to interact with naturally occurring antibiotics and resistance.  In this dissertation, I examine the ocean as an understudied environment for antibiotic resistance. In Chapter 2, I explore policies that have contributed to the antibiotic resistance crisis. In Chapters 3 and 4, I collected individual bacterial cultures from Cape Cod, MA beaches and show that antibiotic resistance is prevalent and persistent over both spatial and temporal scales. In Chapter 5, I used metagenomics to assess the abundance and types of resistance genes at coastal impacted Massachusetts sites. I found that, even in sites that seem distinct in terms of anthropogenic impact, prevalence of resistance remained the same. Finally, in Appendix A, I examined some TARA Ocean dataset samples for prevalence of antibiotic resistance genes and found that there are distinctions between different ocean biomes based upon antibiotic, metal, and mobile genetic elements. This dissertation has increased understanding of temporal and spatial dynamics of antibiotic resistance in the coastal and open ocean.