Document Type

Dissertation

Date of Degree

Fall 2015

Degree Name

PhD (Doctor of Philosophy)

Degree In

Microbiology

First Advisor

Patrick Schlievert

Abstract

Staphylococcus aureus is a gram-positive opportunistic pathogen responsible for more deaths every year than HIV/AIDS. Its formidable repertoire of virulence factors, ubiquitous nature, and ability to acquire antibiotic resistance quickly allow S. aureus to colonize and persist in nearly any body site if given the opportunity. S. aureus is the leading cause of many common and severe skin diseases, i.e. atopic dermatitis and surgical site infections, which can result in significant morbidity and mortality due to lack of available treatments and chronic non-healing nature of each infection. The human body is capable of producing many antimicrobial factors, such as defensins in the epidermis, in conjunction with providing a seamless barrier to many environmental threats, i.e. the skin, yet when given the opportunity, S. aureus can overtake these innate defenses, colonize, and cause disease. Despite S. aureus being a prominent organism in skin infections, little has been done to identify critical factors of S. aureus to cause skin infections. This document demonstrates the capacity of specific S. aureus virulence factors, superantigens and cytotoxins, to alter re-epithelialization and wound healing, as indicated by altered keratinocyte migration and proliferation. In an attempt to harness natural occurring host defenses, we have also identified and generated novel antimicrobial peptides capable of ablating toxin production independent of bacterial growth inhibition. Evidence presented should convince the reader that S. aureus exotoxin production is critical in perpetuating chronic wounds through local keratinocyte interaction. This suggests targeting production of these toxins to prevent cell toxicity and inflammatory responses, could allow the host to repair damaged tissue effectively.

Public Abstract

Staphylococcus aureus is a gram-positive opportunistic pathogen responsible for more deaths every year than HIV/AIDS. Its formidable repertoire of virulence factors, ubiquitous nature, and ability to acquire antibiotic resistance quickly allow S. aureus to colonize and persist in nearly any body site if given the opportunity. S. aureus is the leading cause of many common and severe skin diseases, i.e. atopic dermatitis and surgical site infections, which can result in significant morbidity and mortality due to lack of available treatments and chronic non-healing nature of each infection. The human body is capable of producing many antimicrobial factors, such as defensins in the epidermis, in conjunction with providing a seamless barrier to many environmental threats, i.e. the skin, yet when given the opportunity, S. aureus can overtake these innate defenses, colonize, and cause disease. Despite S. aureus being a prominent organism in skin infections, little has been done to identify critical factors of S. aureus to cause skin infections. This document demonstrates the capacity of specific S. aureus virulence factors, superantigens and cytotoxins, to alter re-epithelialization and wound healing, as indicated by altered keratinocyte migration and proliferation. In an attempt to harness natural occurring host defenses, we have also identified and generated novel antimicrobial peptides capable of ablating toxin production independent of bacterial growth inhibition. Evidence presented should convince the reader that S. aureus exotoxin production is critical in perpetuating chronic wounds through local keratinocyte interaction. This suggests targeting production of these toxins to prevent cell toxicity and inflammatory responses, could allow the host to repair damaged tissue effectively.

Keywords

publicabstract, atopic dermatitis, S. aureus, secreted factors, surgical site infection, therapeutic

Pages

xii, 112 pages

Bibliography

Includes bibliographical references (pages 96-112).

Copyright

Copyright 2015 Joseph Alan Merriman

Included in

Microbiology Commons

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