College of Science

Brett Froelich, PhD

Assistant Professor, Department of Biology

PhD, Biology, University of North Carolina

Key Interests
Microbiology | Microbial Ecology | Microbial Physiology | Type VI Secretion | Aquaculture | Shellfish | Oysters | Microbial Competition | Bacterial Genetics
Phone: 703-993-7186 | Email:

Research Focus

I study the ecology and physiology of human pathogens, specifically Vibrio vulnificus and V. parahaemolyticus. These bacteria typically gain access to the human host when eating raw shellfish, especially oysters. A better understanding of the ecological and physiological interactions between Vibrio and shellfish can ultimately lead to fewer infections.

Current Projects

■ We are examining the variations of toxins produced by Vibrio vulnificus bacteria, secreted by the Type VI secretion system, and the role in bacterial competition for surface space. When the bacteria are on a surface and make contact, they inject each other with a toxin, causing cell death. Different strains produce different toxins, and we have currently uncovered 16 different types. Some strains produce an antitoxin for the toxins that other strains possess. We are creating a susceptibility matrix to better understand these microbial interactions in vivo.

■ We are developing a probiotic treatment for oysters grown in aquaculture. Combining research in techniques to remove competing bacteria, increase bacterial uptake efficiency in oysters, we will treat oysters with a probiotic bacterium to reduce human infections.

Select Publications

B. A. Froelich et al., In hot water: effects of climate change on Vibrio‐human interactions. Environ Microbiol 10.1111/1462-2920.14967 (2020).

B. A. Froelich et al., Decadal monitoring reveals an increase in Vibrio spp. concentrations in the Neuse River Estuary, North Carolina, USA. PLOS ONE 14 (4) (2019).

B. A. Froelich et al., Development of a matrix tool for the prediction of Vibrio species in oysters harvested from North Carolina. Appl Environ Microbiol 81 (3) 1111-9 (2015).

B. A. Froelich et al., Integration of Vibrio vulnificus into marine aggregates and its subsequent uptake by Crassostrea virginica oysters. Appl Environ Microbiol 79 (5) 1454-1458 (2013).


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