Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2020 Chelation-based enhancement of novel and commercially available antimicrobials against foodborne pathogens Allison Brost Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Recommended Citation Brost, Allison, "Chelation-based enhancement of novel and commercially available antimicrobials against foodborne pathogens" (2020). Graduate Theses and Dissertations. 18052. https://lib.dr.iastate.edu/etd/18052 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Chelation-based enhancement of novel and commercially available antimicrobials against foodborne pathogens by Allison Brost A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Microbiology Program of Study Committee: Byron Brehm-Stecher, Co-major Professor Gregory Phillips, Co-major Professor Ajay Nair The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this thesis. Graduate College will ensure this thesis is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2020 Copyright © Allison Brost, 2020. All rights reserved. ii DEDICATION This work is dedicated in its entirety to my loving parents who have given me sound guidance, and unwavering love and support. To my friends and teammates who have enabled me to persist throughout this trying experience. You all have celebrated my victories and stood by to help shift my perspective when my motivation faltered. I will always strive to make you all proud. iii TABLE OF CONTENTS Page LIST OF FIGURES .........................................................................................................................v LIST OF TABLES ........................................................................................................................ vii NOMENCLATURE .................................................................................................................... viii ACKNOWLEDGMENTS ............................................................................................................. ix ABSTRACT .....................................................................................................................................x CHAPTER 1. GENERAL INTRODUCTION ................................................................................1 Foodborne Disease..................................................................................................................... 1 Model Organisms....................................................................................................................... 2 Escherichia coli .................................................................................................................... 2 Salmonella Typhimurium ..................................................................................................... 3 Staphylococcus aureus ......................................................................................................... 3 Listeria monocytogenes ........................................................................................................ 4 Antimicrobials and Antimicrobial Resistance ........................................................................... 5 Select Antimicrobials ........................................................................................................... 8 Impacts of Chelation ................................................................................................................ 11 References................................................................................................................................ 13 CHAPTER 2. ENHANCEMENT OF COMMERCIALLY AVAILABLE SANITIZERS AND DISINFECTANTS BY ACTIVE FOOD INGREDIENTS ...........................................................15 Abstract .................................................................................................................................... 15 Introduction.............................................................................................................................. 16 Materials and Methods ............................................................................................................ 18 Chelator Selection .............................................................................................................. 18 Chrome Azurol S test ......................................................................................................... 18 Full-Spectrum Absorbance Analysis .................................................................................. 19 Model Organisms and Culture Conditions ......................................................................... 19 Minimum Inhibitory Concentrations .................................................................................. 20 Fractional Inhibitory Concentrations.................................................................................. 20 Agar Overlay Protocol........................................................................................................ 21 Results...................................................................................................................................... 22 Discussion ................................................................................................................................ 31 References................................................................................................................................ 32 CHAPTER 3. ANTIBACTERIAL SPECTRUM AND ENHANCEMENT OF SYNTHETIC PYRONE COMPOUNDS .............................................................................................................33 Abstract .................................................................................................................................... 33 Introduction.............................................................................................................................. 34 Materials and Methods ............................................................................................................ 34 iv Model Organisms and Culture Conditions ......................................................................... 34 Antimicrobial Screening via Agar Overlay ........................................................................ 35 Results...................................................................................................................................... 37 Discussion ................................................................................................................................ 39 References................................................................................................................................ 40 CHAPTER 4. GENERAL CONCLUSIONS .................................................................................41 References................................................................................................................................ 42 v LIST OF FIGURES Page Figure 1. Summary of antibiotic resistance mechanisms................................................................ 7 Figure 2. Structure and chemical formula of the cyclic compound benzalkonium chloride .......... 8 Figure 3. Structure of two cyclic antimicrobial phenolic compounds .......................................... 10 Figure 4. Schematic depicting the research plan of the study ....................................................... 18 Figure 5. Demonstration of CAS Assay by serial 1:2 dilutions from right to left, top row being 50mg/mL phytic acid, bottom row 0.M EDTA .............................................. 22 Figure 6. Demonstration of the full spectrum absorbance of EDTA at a range of concentrations (0.1M to 0.001M), and a blank negative control .............................. 24 Figure 7. Demonstration of the full spectrum absorbance of phytic acid at a range of concentrations (0.15M to 0.00015M), and a blank negative control ........................ 25 Figure 8. Full spectrum absorbance of a range of phytic acid concentrations (.15M to 0.0015M) is shown and compared to the model chelator EDTA (0.1M to 0.001M) .................................................................................................................... 26 Figure 9. The two graphs above demonstrate the minimum inhibitory concentration (MIC) of Ceptylprydinium Chloride (CPC) to have bactericidal effects on E. coli (16 µM CPC) and Salmonella Typhimurium (2.5 µM CPC). ........................................ 27 Figure 10. The two graphs above demonstrate the minimum inhibitory concentration (MIC) of FS Amine, a QAC-based sanitizer, to have bactericidal effects on E. coli (75ppm FS Amine) and Salmonella Typhimurium (150 ppm FS Amine). .............. 27 Figure 11. Demonstration of antimicrobial enhancement capabilities of BekaPlus FS Polyphosphate..........................................................................................................