Term of Award

Fall 2022

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Biology

Committee Chair

Risa Cohen

Committee Member 1

Asli Aslan

Committee Member 2

Christine Hladik

Abstract

Due to extensive worldwide use and rapid acquisition of bacterial resistance, antibiotics are now considered emerging contaminants in the aquatic environment. Antimicrobial resistance (AMR) disrupts microbial communities and increases the transmission of resistant pathogens among animals and humans. In aquatic environments, AMR introduced from land-based sources eventually settles from the water onto sediment. However, bacterial resuspension in the water as a result of sediment disturbance may increase exposure to AMR. Understanding how sediment disturbance during recreational activity impacts AMR resuspension is important for identifying and preventing ecological and public health risks associated with antimicrobial resistance.

Chapter one describes two experiments designed to test the hypothesis that sediment disturbance affects the amount and duration of antimicrobial resistance (AMR) resuspension in the water, thereby increasing the potential for AMR to contaminate coastal waters. Aquatic sediment from a site with known AMR exposure was manipulated to determine the effect that different levels of disturbance have on total bacteria, total E. coli, and tetracycline resistant E. coli concentrations in artificial stream microcosms in a greenhouse. Disturbance treatments were control (no disturbance), low intensity disturbance, and high intensity disturbance. Water samples were collected at pre-disturbance and post-disturbance intervals of 0, 6, 24, 48, and 72 hours. A field experiment was also conducted at Kings Ferry public beach, Chatham County, GA, USA where one level of sediment disturbance was administered to simulate recreational activity within the beach. A transect parallel to the public beach consisted of three sites where water samples were collected at pre-disturbance and post-disturbance intervals of: 0, 15, and 30 min. Increases in total E. coli and patterns of increase in tetracycline resistant E. coli were observed within the study. Thus, results from this study improve understanding of how antibiotic resistant bacteria are resuspended and transported within various aquatic environments, particularly within areas of high recreational activity and high potential for human exposure.

Chapter two describes a survey used in combination with remote sensing land use data to test the hypothesis that 1) land use influences the abundance of tetracycline resistant E. coli within the Ogeechee River; 2) abundance of tetracycline resistant E. coli is seasonal. Water samples were collected from 6 (summer) and 7 (winter) sites along the Ogeechee River upstream and downstream of Kings Ferry County Park, Chatham County, GA, USA. Survey samples collected were used to relate total bacteria, total E. coli, and tetracycline resistant E. coli concentrations within the river to surrounding land use and between winter and summer seasons. A land use classification was conducted using Sentinel-2A satellite imagery data of the study site to determine potential sources of AMR runoff from the area surrounding Kings Ferry to the Ogeechee River.

OCLC Number

1361806689

Research Data and Supplementary Material

No

Download

Share

COinS