Analyzing the metabolic capabilities of a Vibrio parahaemolyticus strain that causes Early Mortality Syndrome in shrimp

Abstract

Shrimp disease results in significant annual economic loss to the global aquaculture industry. Since 2009, the primary causative agent of shrimp disease has been Vibrio parahaemolyticus (VP) strains that cause Early Mortality Syndrome (EMS) or acute hepatopancreatic necrosis disease (AHPND). EMS strains have acquired a plasmid via horizontal gene transfer that encodes an insect toxin, which is responsible for the rapid death of infected shrimp. Based on previous experiments, it was hypothesized that an EMS strain of VP has unique growth properties compared to other VP strains, which may give it an interspecific competitive advantage in the environment. Accordingly, three strains of VP underwent testing; EMS 13-028/A3 that causes EMS disease in shrimp, RIMD2210633 that is a human clinical isolate, and LM5312 that is an environmental isolate. The ability of these three different strains of VP to grow on 71 different carbon sources/substrates was measured using Biolog GEN III MicroPlates. The EMS strain was able to utilize a variety of nutrient sources (23 out of 71) more efficiently than the other two strains as ascertained by significantly greater growth. A comparative bioinformatics analysis of the EMS genome identified a unique set of genes associated with fucose metabolism. This study demonstrates that Biolog plates can be used to ascertain distinctive metabolic properties of pathogenic bacterial strains such as VP EMS that may help guide development of new disease mitigation strategies for production of shrimp in aquaculture environments.