A Longitudinal Analysis of Antibiotic Resistance in the Sediment Samples of the Delaware River Watershed and in the Clinical Infections in the Reading Hospital

Open Access
- Author:
- Sindhar, Safitaj
- Area of Honors:
- Biology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Tami H Mysliwiec, Thesis Supervisor
Sandy Feinstein, Thesis Honors Advisor - Keywords:
- Antibiotic Resistance
Delaware River Watershed
Tetracycline
Ampicillin
Enterococcus
Escherichia coli
Polymerase Chain Reaction
DNA
Berks County
tet(A)
tet(R)
ctx
oxa
blaP - Abstract:
- Healthy waterways are essential for maintaining a safe water supply. Recreational activities, agricultural use of pesticides, and industrial discharge contaminate the waterways and promote bacterial resistance to various antibiotics. To understand the impact of emerging contaminants on antibiotic resistance, a two-part study was conducted. The first part of the study focused on monitoring changes in the health, microbial concentration, and prevalence of antibiotic-resistance genes in sediment samples over time within the Delaware River Watershed in Southeastern Pennsylvania. This watershed serves as an important drinking water source for more than two million people. Three sampling locations were chosen throughout the watershed, and every month water and sediment samples were collected for chemical and microbiological testing. The second part of the study aimed to link the rise in resistant pathogens in the environment to clinical infections caused by antibiotic-resistant bacteria in the local community. Antibiogram data provided by the Reading Hospital were used to determine changes in tetracycline- and ampicillin-resistance patterns in E. coli and Enterococci. In the environmental portion of the study, seasonal variability especially elevated nitrate, and phosphate levels for all sites in fall and spring were found through chemical analyses. The sites were found to have E. coli and Enterococci counts higher than the EPA-recommended criteria. Additionally, a vast majority of the bacteria samples were resistant to at least one antibiotic. PCR analysis revealed that the genome of the microorganisms in the upstream and downstream sample sites contain tetracycline-resistant genes, tet(A) and tet(R), as well as ampicillin-resistant genes, ctx, oxa and blaP. qPCR, which was employed to quantitate antibiotic-resistance genes in the microbiome of the sediment samples, showed a rise in the relative number of resistant genes from one year to the next. The results suggest that human activities may influence the frequency and genetic profile of pathogenic microbial communities within the Delaware River Watershed. Nevertheless, the analysis of the clinical data revealed stable resistance patterns over the past five years, suggesting that there is not a direct link between increased antibiotic-resistant bacteria in the environment and more clinical infections caused by resistant bacteria.