Development of a Controlled Laboratory-scale Inoculation System to Study Vibrio parahaemolyticus-oyster Interactions

Area of Science:

• Marine microbiology
• Food safety
• Pathogen-host interactions

Background:

• Seafood-borne gastroenteritis from Vibrio parahaemolyticus (V. parahaemolyticus) is increasing globally.
• V. parahaemolyticus is a reportable emerging human pathogen in the US.
• Eastern oysters (Crassostrea virginica) harbor V. parahaemolyticus, but interactions are poorly understood.

Purpose of the Study:

• To develop a laboratory system for studying V. parahaemolyticus-oyster interactions.
• To investigate the influence of oyster harvest season on V. parahaemolyticus colonization.

Main Methods:

• A Biosafety Level-2 (BSL2) inoculation system was created for oysters.
• Oysters harvested in summer and winter were exposed to a marked V. parahaemolyticus strain (VP RIMDmC).
• Bacterial levels were quantified using selective agar medium after chloramphenicol treatment.

Main Results:

• Chloramphenicol treatment reduced endogenous Vibrio spp., enhancing VP RIMDmC detection.
• Winter-harvested oysters showed higher VP RIMDmC levels post-inoculation.
• Summer-harvested oysters had higher native Vibrio levels and lower VP RIMDmC colonization.
• The oyster's native microbiome may confer protection against V. parahaemolyticus.

Conclusions:

• The developed BSL2 system allows controlled study of V. parahaemolyticus-oyster interactions.
• Oyster microbiome composition, influenced by season, impacts V. parahaemolyticus susceptibility.
• This system can be used to test environmental variables and mitigation strategies for V. parahaemolyticus control.