Doctor of Philosophy (PhD)
Bacteria can thrive in diverse environments and are often harmless or beneficial. Bacteria in digestive tracts is one example of beneficial bacteria; however, bacteria can be harmful and when this type proliferates, it can cause infections within hosts. Bacterial infections are easily treated with antibiotics in most cases. However, bacteria are also capable of developing mutations which could cause them to become multi-drug resistant and eventually, “superbugs.” Therefore, the development of novel antimicrobial agents and materials capable of combating drug-resistant bacteria is necessary. Research presented in this dissertation focuses on different strategies for minimizing and preventing topical bacterial infections using Groups of Uniform Materials Based on Organic Salts (GUMBOS) and biopolymers.
The first part of this dissertation focuses on the synthesis and antibacterial activity of GUMBOS created from antiseptics and β-lactam antibiotics to combat Neisseria gonorrhoeae. Firstly, using ion-exchange reactions, antimicrobial GUMBOS from an outmoded antibiotic were synthesized and characterized using proton and carbon NMR, mass spectrometry, and FT-infrared spectroscopy. Improvement or bioequivalence in in vitro antibacterial activity was obtained on isolates of N. gonorrhoeae. In the second project, GUMBOS were synthesized using a currently prescribed antibiotic. GUMBOS not only showed improvement for killing N. gonorrhoeae, but also demonstrated increased efficacy against isolates of Escherichia coli, Klebsiella pneumoniae, and Enterobacter cloacae. Overall, these studies present an alternative to current antibiotic drug therapy by using a novel group of ionic antimicrobial materials that have improved bio availabilities, multi-modal properties, and potent antimicrobial activity as a viable alternative to combating N. gonorrhoeae in the oropharynx. Finally, acute cytotoxicity against cervical cellular lines in addition to an assessment of intestinal permeability and bioavailability were completed.
The next part of this dissertation focuses on developing materials from biopolymers for providing potential improvements to wound care and topical infection prevention applications. In the third project, composite materials using biopolymer blends are presented. These composites were synthesized using a simple ionic liquid and were incorporated with antimicrobial GUMBOS. Composites showed great potential for combating topical Staphylococcus aureus infections. Moreover, composites presented high swelling capabilities, which could be translated to exudation capacity. The fourth project focuses on polyelectrolyte complexes synthesized using metathesis reactions from a biopolymer and antiseptics. These complexes were then evaluated for use as oral and topical patches for combating bacterial infections. These materials were characterized using several analytical techniques. Further, these complexes were heat pressed into films which showed steady antiseptic release over several hours.
Lopez, Kelsey Marie, "Antimicrobial Strategies for Topical Applications" (2020). LSU Doctoral Dissertations. 5304.