Graduation Year

2006

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Public Health

Major Professor

Boo Kwa, Ph.D.

Keywords

Nosocomial infection, Antibiotic resistance, Bacterial pathogens, Alternative therapies, Bacterial viruses

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is among the most important pathogens affecting the human race in our time. In spite of recent medical advances, our therapeutic choices for MRSA infections remain limited due to the propensity of this organism to develop resistance to antimicrobials. Therefore, there is a continuing need to develop newer methods of treating MRSA infections. This dissertation examines the effects of bacteriophages 88 and 92 on ten clinical isolates of MRSA from the central Florida area. . For the majority of the MRSA isolates, bacteriophages 88 and 92 were unable to induce lysis. However, bacteriophage 88 was found to lyse MRSA Sample 94. Reduced cytotoxicity and apoptosis due to MRSA Sample 94 was also observed. This protective effect was most notable in the 1:10-6 concentration of MRSA 94 and bacteriophage 88. In addition, this effect was observable with both immediate inoculation of the cell culture with the MRSA concurrent with the bacteriophage and with bacteriophage applied one hour after initial inoculation of the MRSA.

This effect was likely due to the increased replication of the bacteriophage in the actively growing bacteria found in the 1:10-6 samples. The bacteria in the 1:10-6 concentration were likely more able to replicate in comparison to the higher bacterial concentrations because of less competition between the bacteria for the limited nutrients in the 1:10-6 concentration. The long-term goal of this study is the development of a bacteriophage-containing ointment for the control of MRSA nasal carriage. In addition, the concept of bacteriophage therapy may open a new horizon in controlling infections such as those caused by MRSA. Finally, as for future studies, it would be informative to be able compare these results with other MRSA isolates and bacteriophages samples to examine the effects across a wider sample of bacteria and bacteriophages.

In addition, it would be interesting to examine the possibility of being able to modify the bacteriophage in order to allow lysis of the previously resistant bacterial strains.

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