Walden University ScholarWorks Walden Dissertations and Doctoral Studies Walden Dissertations and Doctoral Studies Collection 2018 The mpI act of Lemongrass, Oregano, and Thyme Essential Oils on Candida albicans' Virulence Factors Jennifer Marie Eddins Walden University Follow this and additional works at: https://scholarworks.waldenu.edu/dissertations Part of the Alternative and Complementary Medicine Commons, Microbiology Commons, and the Public Health Education and Promotion Commons This Dissertation is brought to you for free and open access by the Walden Dissertations and Doctoral Studies Collection at ScholarWorks. It has been accepted for inclusion in Walden Dissertations and Doctoral Studies by an authorized administrator of ScholarWorks. For more information, please contact [email protected]. Walden University College of Health Sciences This is to certify that the doctoral dissertation by Jennifer M. Eddins has been found to be complete and satisfactory in all respects, and that any and all revisions required by the review committee have been made. Review Committee Dr. Aimee Ferraro, Committee Chairperson, Public Health Faculty Dr. Angela Prehn, Committee Member, Public Health Faculty Dr. Jagdish Khubchandani, University Reviewer, Public Health Faculty Chief Academic Officer Eric Riedel, Ph.D. Walden University 2018 Abstract The Impact of Lemongrass, Oregano, and Thyme Essential Oils on Candida albicans’ Virulence Factors by Jennifer M. Eddins BS, Colorado State University, 1989 Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Public Health Walden University May 2018 Abstract Increased systemic infections and growing resistance of Candida species in immunosuppressed people have prompted research for additional treatment options. The purpose of this quantitative study was to investigate the potential of lemongrass, oregano, and thyme essential oils tested individually, combined, and combined with the antifungal agents fluconazole and caspofungin to kill Candida albicans isolates in a controlled laboratory setting. This study was grounded on the theoretical concepts of the epidemiologic triangle model. The experimental data collected were used to investigate risk factors related to age, gender, race, and comorbidities. Kill rates of lemongrass, oregano, and thyme essential oils individually and combined, kill rates of fluconazole, caspofungin, and the kill rates when the antifungals were each combined with the 3 essential oils were compared using 117 isolates recovered from bloodstream infections between January 2009 through August 1, 2017. The data collected were analyzed using 2-way repeated ANOVAS. According to study results, there were statistically significant increases in kill rates when the isolates were exposed to any of the combinations of essential oils tested. Using binomial and multinomial regression to analyze age, gender, race, and comorbidities resulted in the age group 25-34, kidney failure, and solid organ tumor cancer all being statistically significantly associated with an increased risk for Candida albicans bloodstream infections, and multiple organ failure negatively associated with the risk. Health care practitioners can use the results of this study to reduce the number of patients becoming infected with life-threatening yeast infections, which could reduce the costs associated with infections. The Impact of Lemongrass, Oregano, and Thyme Essential Oils on Candida albicans’ Virulence Factors by Jennifer M. Eddins BS, Colorado State University, 1989 Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Public Health Walden University May 2018 Acknowledgments I would like to first and foremost thank God who I leaned on during much of this time. In addition, a big thank you to my family and friends who have supported and encouraged me throughout this process. I would also like to thank Dr. Aimee Ferraro and Dr. Angela Prehn for your support and guidance while creating, writing, and revising. Table of Contents List of Tables……………………………………………………………………………...v List of Figures…………………………………………………………………………....vii Chapter 1: Introduction to the Study ...................................................................................1 Introduction ....................................................................................................................1 Background ....................................................................................................................2 Problem Statement .........................................................................................................4 Purpose of the Study ......................................................................................................5 Research Questions and Hypotheses .............................................................................6 Theoretical Framework ..................................................................................................9 Nature of the Study ......................................................................................................11 Definitions....................................................................................................................12 Assumptions .................................................................................................................13 Scope and Delimitations ..............................................................................................14 Limitations ...................................................................................................................15 Significance of the Study .............................................................................................15 Summary and Transition ..............................................................................................16 Chapter 2: Literature Review .............................................................................................18 Introduction ..................................................................................................................18 Literature Search Strategy............................................................................................19 Theoretical Framework ................................................................................................20 Risk Factors Associated with Bloodstream Infections ................................................24 i Immunocompromised Patients, Infections, and Prophylactic Treatments ...................27 Virulence and Resistance .............................................................................................28 Alternative Treatment Options and Host Defenses .....................................................33 Essential Oil Treatments for Fungus and Yeast ...........................................................37 Chemical Composition and Mechanisms of Action of Lemongrass, Oregano, and Thyme Essential Oils ................................................................................38 Activity of Essential Oils Against Yeast and Fungus ..................................................40 Effects of Combining Antimicrobials and Essential Oils ............................................44 Evaluation of Host Cell Toxicity from Essential Oils .................................................47 Methodology Review ...................................................................................................49 Conclusion ...................................................................................................................51 Chapter 3: Research Method ..............................................................................................55 Introduction ..................................................................................................................55 Research Design and Rationale ...................................................................................56 Methodology ................................................................................................................58 Population ..............................................................................................................58 Sampling and Sampling Procedures ......................................................................59 Data Collection Procedure ...........................................................................................62 Instrumentation and Scale ............................................................................................62 Establishing Reliability for the Measurement and Scale .............................................65 Establishing Validity ....................................................................................................66 Addressing Potential Weaknesses and Threats to Validity..........................................68 ii Analysis........................................................................................................................69 Ethical Concerns ..........................................................................................................71 Summary ......................................................................................................................71 Chapter 4: Results ..............................................................................................................73 Introduction ..................................................................................................................73