Abstract

Historically, focal areas of infection have been linked to a number of systemic ailments. During the early part of the 20th century, patients who were suffering from inexplicable diseases and who were suspected of having infected teeth were referred to the dentist for multiple extraction of their dentition. The discovery of antibiotics provided a false sense of security that the war against microorganisms is no longer a concern for mankind. However, more recently, it has become common belief that increasing numbers of systemic diseases are linked to chronic infections. Recovery of bacteria from representative tissues has led investigators to believe that microorganisms and the host reaction resulting in an inflammatory response responsible for clinical manifestations of disease processes such as cardiovascular diseases, respiratory diseases, diabetes and even cancers. Although these conclusions may be accurate, the isolated microorganisms may not be the cause of the secondary disease processes. Modem science has not yet dismissed the possibility that the diseased sites may provide a susceptible site for colonization by microorganisms.

The purpose of this investigation was to develop a model, which can be used to monitor bacterial dissemination in animals. Infective endocarditis was used as the model to evaluate the potential colonization of catheterized or injured rat hearts by light-emitting bacteria that were introduced intravenously or through the root canal system of a tooth. Based on the results of this study, injured hearts were consistently colonized by Enterococcus faecalis when the bacteria were intravenously injected. Furthermore, our data demonstrated that bacteria introduced into a rat molar could cause sufficient bacteremia to allow colonization of a catheterized heart in 4 of 10 animals tested. Noncatheterized hearts did not become infected after introduction of the light-emitting bacteria into the rat teeth. The differences between the groups were statistically significant (p < 0.001). Based on the results of this study, while normal rat hearts are able to clear circulating bacteria, catheterized hearts are susceptible to colonization following a bacteremia induced by the intravenous injection of 1 x 108 bacterial cells. In addition, E. faecalis is capable of entering the bloodstream from the root canal system of a tooth to colonize catheterized rat hearts.

LLU Discipline

Microbiology and Molecular Genetics

Department

Microbiology

School

Graduate School

First Advisor

James D. Kettering

Second Advisor

Hansel Fletcher

Third Advisor

Larry Sowers

Fourth Advisor

Aladar A. Szalay

Fifth Advisor

Mahmound Torabinejad

Degree Name

Doctor of Philosophy (PhD)

Degree Level

Ph.D.

Year Degree Awarded

2001

Date (Title Page)

12-2001

Language

English

Library of Congress/MESH Subject Headings

Bacteremia -- physiopathology; Endocarditis, Bacterial -- physiology; Chronic Disease; Focal Infection, Dental; Enterococcus Faecalis; Disease Models, Animal; Platelet Aggregation -- physiology; Risk Factors

Type

Dissertation

Page Count

xi; 87

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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