Projects

Validation of fieldā€applicable detection kits for total and pathogenic Vibrio parahaemolyticus in oysters

End Date: 08/31/16
The proposed project will address the FY2014 Topical Priority “Research to informpending, regulatory decisions on the local, state, or federal level leading to an information product-- such as a tool, technology, template, or model-- needed to make final decisions on aspecific question regarding impacts of aquaculture”. Some commonly used aquaculture practices, such as desiccation for anti-biofouling, allow pathogenic Vibrio spp. to proliferate inshellfish. Due to the potential public health risk of this anti-biofouling practice, the regulatory authorities required Alabama farmers to re-submerge oysters for 30 days prior to final harvest in 2013. The minimum amount of time the oysters need to be re-submerged after desiccation to allow Vibrio levels to return to background levels is currently being investigated. Validation ofrapid tests kits for enumeration of total and pathogenic V. parahaemolyticus in oysters will provide investigators a rapid and cost-effective tool to evaluate not only the practice of resubmersion following anti-biofouling, but also other aquaculture practices that state and federal regulators may find likely to increase the risk of vibrio illness.

Objectives

Despite V. parahaemolyticus management plans and industry efforts, illness rates continue to go up indicating that industry and regulators have been unable to manage the problem. Rapid and easy-to-use tests kits for enumeration of total and pathogenic V. parahaemolyticus in oysters will provide investigators a rapid and cost-effective tool to evaluate not only the practice of re-submersion following anti-biofouling, but also other aquaculture practices that state and federal regulators may find likely to increase the risk of vibrio illness. 
 
The objectives of this project are (1) to validate the current Vp kits for the detection of total and pathogenic V. parahaemolyticus in oysters against reference methods; (2) to develop pectin and gelatin-based alternatives for the current agar-based test kits to allow production without heating, and (3) totransfer technology to laboratories involved in regulatory testing for state shellfish control authorities and the oyster industry. The key features of Vp test kits is a novel two phase culture approach that allows simultaneous enrichment, separation and confirmation of V. parahaemolyticus which requires multiple steps and several days to complete using currently accepted regulatory methods. The liquid phase enhances recovery of stressed cells during enrichment while the solid phase provides selectivity by chemical suppression of background microflora and differentiation through two biomarkers, arabinose fermentation (total V. Parahaemolyticus) and urease expression (pathogenic V. Parahaemolyticus).