Masters Theses

Abstract

"There has been little research looking at the degree of antibiotic resistance and the disinfection of the bacteria associated with animal wastes generated at concentrated animal feeding operations (CAFOs). To address this concern, the diversity of tetracycline resistance was evaluated by screening tetracycline resistant isolates for the presence of 18 different genes that confer tetracycline resistance. Forty-eight of 85 isolates were found to not contain targeted tet efflux genes. None of the isolates possessed any of the targeted ribosomal protection proteins. The disinfection potential of chlorine and ultraviolet (UV) light against aerobic lagoon bacteria was examined. Furthermore, the role of solids in the lagoon was investigated as a potential barrier to disinfection. It was found that 30 mg/L of chlorine achieved a 2-4 log removal of bacteria in all lagoon samples. Increasing the amount of chlorine provided little additional disinfection activity. Chlorine was equally or more effective against bacteria resistant to either chlorotetracycline, lincomycin, sulfamethazine, or tetracycline. The inability to achieve complete disinfection could be due to the presence of two potentially chlorine resistant bacterial isolates, which most closely related to Bacillus subtilis and }Jacillus lichenifonnis. A UV dose of 3240 mJ/cm2 effectively dropped the number of bacteria in all samples to approximately 1000 cfu/ml. The highest UV dosage of 9720 mJ/cm2 essentially drove the number of bacteria to zero. Our results clearly show there are still unknown genes that confer tetracycline resistance and that most facultative bacteria in swine waste lagoons can be effectively treated using chlorine or UV light. Thus, it is critical to understand gene-mediated resistance as well as the antibiotic resistant organisms and their potential control through disinfection"-- Abstract, p. iii

Advisor(s)

Mormile, Melanie R.
Adams, Craig D.

Committee Member(s)

Westenberg, David J.

Department(s)

Biological Sciences

Degree Name

M.S. in Applied and Environmental Biology

Publisher

University of Missouri--Rolla

Publication Date

Spring 2005

Pagination

viii, 57 pages

Note about bibliography

Includes bibliographical references (pages 53-56)

Geographic Coverage

United States

Rights

© 2005 John J. Macauley, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Swine farrowing facilities -- Environmental aspects -- United States
Disinfection and disinfectants
Chlorine
Antibiotics
Tetracycline

Thesis Number

T 8774

Print OCLC #

62675810

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