Advisory Committee Chair
Advisory Committee Members
Date of Award
Degree Name by School
Master of Science (MS) College of Arts and Sciences
Vibrio vulnificus is an environmentally encountered pathogen that humans may be exposed to through open wound contact with brackish waters or by ingestion of contaminated shellfish. In susceptible individuals, a V. vulnificus infection can spread rapidly, resulting in hospitalization, amputation, or even death. This bacterial species can cause aggressive infection, so treatment must often be aggressive as well. A typical treatment regimen includes combination therapy with a third-generation cephalosporin along with either a tetracycline or a fluoroquinolone. Although this method can work for now, antibiotic resistance is a looming threat that has emerged in many bacterial pathogens, including V. vulnificus. In this project, the effect which four common environmental temperatures might have on the invasion of resistance alleles among a culture exposed to tetracycline is observed. When unexposed cultures were tested for initial resistance at different temperatures, V. vulnificus grown at 22°C and 40°C demonstrated significantly less ability to grow in the presence of the antibiotic stressor than the 30°C and 37°C cultures. Six replicates at each temperature were evolved in serial batch culture in the presence of tetracycline for approximately 500 generations, and during this time, all replicates displayed a general upward trend in their half-maximal effective concentration (EC50) values, implying that each population was continually subject to selection for members with more effective resistance alleles. After 500 generations of selection, the 22°C and 40°C cultures displayed the greatest increase in their EC50 values for tetracycline. Post-evolution, there was also no longer a significant difference in EC50 between temperatures. Interestingly, cultures evolved at all temperatures developed substantial multiple drug resistance against other antibiotics, but cultures evolved at 30°C and 37°C had developed the best multiple drug resistances. Based on the results of these experiments, temperature does play a role in the rate at which a population of V. vulnificus evolves resistance to several classes of antibiotics when exposed to just one class over an extended period of time.
Richardson, Amber Marie, "The Effect of Temperature on the Rate of Antibiotic Resistance Development in Vibrio Vulnificus" (2023). All ETDs from UAB. 63.