Date of Award

2020

Document Type

Open Access Master's Report

Degree Name

Master of Science in Biological Sciences (MS)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Stephen Techtmann

Committee Member 1

Paul Goetsch

Committee Member 2

Rupali Datta

Abstract

Microbial resistance to antimicrobials is an important topic to investigate not only for our health but for the environment. There is a growing concern about expanding microbial resistance to both antibiotics and other antimicrobials such as biocides. We wanted to know how bacteria previously exposed to hydraulic fracturing fluids, including biocides, would react to biocide exposure and what the mechanism of resistance looked like. In order to test this hypothesis bacterial isolates were obtained from water and sediment from a stream that had been previously exposed to a spill of hydraulic fracturing water. Thirty bacterial isolates were obtained from these samples that could withstand a moderate dose of two biocides (Glutaraldehyde and 2,2-dibromo-3-nitrilopropionamide (DBNPA)). These isolates then had their DNA extracted and taxonomy identified using 16S rRNA sequencing. We also tested minimum inhibitory concentrations (MIC) for each isolate against each biocide. This data however was not conclusive. Attempts were made to perform whole genome sequencing on these isolates to better understand resistance mechanisms. Sequencing was also attempted but due to complications was not completed. To increase our understanding of the mechanism of resistance a comparative genomic study was undertaken to compare between hydraulic fracturing associate Bacillus spp. and non-hydraulic fracturing associated relatives. Overall, isolates resistant to glutaraldehyde, DBNPA or both were obtained and identified. More isolates were found resistant to either glutaraldehyde or DBNPA not both. Meaning that the mechanisms of resistance may be different for the two biocides.

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