Date of Award

2008

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Charles C. Somerville

Second Advisor

Ron Gain

Third Advisor

Thomas G. Jones

Abstract

Background: Prior studies of the Ohio and Mud Rivers have shown that fecal contamination alone does not explain the distribution of antibiotic resistant bacteria (ARB) in surface waters. The objectives of this study were to determine effects on the distribution of ARB in the Mud.

Methods: Water samples and physical parameters were collected twice per season in spring through fall at 12 sites on the Mud River. Aliquots were plated on R2A agar and R2A agar plus individual antibiotics for the enumeration of total cultivable bacteria, and cultivable bacteria resistant to ciprofloxacin, virginiamycin, or tetracycline respectively. The IDEXX Quanti-Tray/2000™ method was used to enumerate total coliforms, E. coli, and antibiotic resistant E. coli (AREc). Atomic absorption spectrometry was used for heavy metals analysis. Watershed land use parameters were observed and mapped using ARC Map 9.2. Raster analysis and CANOCO 4.5 were used for statistical analyses.

Results: Storm water runoff significantly increased the load of E. coli and ARB in surface waters. E. coli and AREc counts were always far below ARB counts which increased each season and were higher under conditions of lower dissolved oxygen/temperature and higher conductivity with strong associations between ARB and urban/paved areas and cattle pastures.

Conclusions: These data represent an early step in understanding both the natural and anthropogenic characteristics that impact the distribution of ARB in surface waters. If surface water ARB represents a human health risk, studies such as this will be important in modeling the relationships between water resources and public health.

Subject(s)

Water quality - Mud River.

Water quality - Ohio River.

Bacteria - Ecology.

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