Date of Award

Summer 8-1-2023

Document Type




First Advisor

Dr. Andrei L. Barkovskii

Second Advisor

Dr. Dave Bachoon

Third Advisor

Dr. Christopher Burt


In the face of global warming, waterborne pathogens are evolving rapidly and expanding geographically. The Vibrio Harveyi clade encompasses a number of human and aquatic organism pathogens, and due to their physiology, they may benefit from ongoing changes in the temperature, pH, and salinity of the global Ocean. With this, the Southeastern United States might become an accommodating environment for Harveyi clade species, and it is imperative to monitor for their abundance and distribution in the environment. A qPCR assay was developed for the detection and quantification of clade-specific virulence genes toxRvh, hly, toxR, luxR, srp, vhha, vhh, and vhp. These genes were detected in waters and sediments at all three study sites in Georgia (USA). This study showed а usual temporal trend with higher gene concentrations in summer months while also revealing a heterogeneity in Harveyi clade virulence genes. These results evidence that the Harveyi clade Vibrio are split into two distinct groups in Georgia waters; one group represented by toxR and srp were less adapted to elevated temperatures, alkali pH, and low salinity compared to the group harboring luxR, vhp, vhha, and vhh. Moreover, lack of detection of V. harveyi and V. campbellii, the most known pathogens of the clade, suggests that these Vibrios are not the carriers for the aforementioned virulence genes. The positive response to elevated temperature and low pH exhibited by Vibrio pathogens in this research demands their future study as prospective agents of future Vibrio disease outbreaks.

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