Date of Graduation
8-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Cell & Molecular Biology (PhD)
Degree Level
Graduate
Department
Cell & Molecular Biology
Advisor/Mentor
Kwon, Young Min
Committee Member
Sun, Xiaolun
Second Committee Member
Lessner, Daniel J.
Third Committee Member
Gibson, Kristen E.
Keywords
Salmonella Typhimurium; Reactive oxygen species; Sodium hypochlorite; Drug resistance
Abstract
Salmonella Typhimurium (S.T) is a foodborne pathogenic bacterium which causes salmonellosis in human beings. Chicken is the most common source of S.T contamination. In chapter I, I discuss the growth of the poultry industry, the role chickens play as Salmonella reservoirs, the spread of drug-resistant strains caused by chicken husbandry and antibiotic use, and how eugenol can be used in poultry feed to decrease Salmonella infections and improve intestinal health. In chapter Ⅱ, I summarize the role of reactive oxygen species (ROS) in bactericidal activity. In chapter Ⅲ, I describe the killing mechanism of sodium hypochlorite (NaOCl) and identify the genetic response to ROS production by showing the effects on predicted mutants that increased or decreased ROS levels. Thus, these results suggests that NaOCl killing mechanism is based on ROS production. In addition, In chapter Ⅳ, I describe the development of drug resistance after exposing Salmonella to sublethal concentrations of NaOCl. The experiment evaluated the mutation rate after NaOCl exposure by testing drug resistance to ampicillin, chloramphenicol, and kanamycin. The results suggested that sublethal concentrations of NaOCl leads to ROS production resulting in an increase in the bacterial mutation rate. In conclusion, in this dissertation, I studied the killing mechanisms of eugenol oil and NaOCl. In addition, I investigated S.T. genes which may play important roles in the ROS killing mechanism. Lastly, I tested the possibility of developing drug resistance by inducing ROS production. The finding suggests the killing mechanism of eugenol and NaOCl is ROS dependent. Lastly, I found that sublethal concentrations of NaOCl increased ROS production leading to an increase in the mutation rate and drug resistance.
Citation
Aljuwayd, M. (2024). The Impact of Reactive Oxygen Species on Bactericidal Activity and Drug Resistance in Salmonella Typhimurium upon Chlorine and Eugenol Exposure. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5405
