Plasmid mediated tetracycline resistance of Vibrio parahaemolyticus associated with acute hepatopancreatic necrosis disease (AHPND) in shrimps

• We found two pathogenic tetracycline resistant strains (Vibrio parahaemolyticus) associated with acute hepatopancreatic necrosis disease (AHPND, also known as early mortality syndrome, EMS) from shrimp.
• In the tested strains, the tetracycline resistance was related with the distribution of the tetracycline resistance (tetB) gene.
• In the strain 13-511/A1, the tetB gene was harbored in the mobile element (plasmid) comprising 5162-bp with 40% G + C.
• This is the first report of plasmid mediated tetracycline resistance in V. parahaemolyticus strains causing AHPND.

Antimicrobial resistance is one of the most important problems in public health, veterinary medicine and aquaculture. Importantly, plasmid mediated antibiotic resistance of pathogenic Vibrio parahaemolyticus from shrimp can potentially be transferred through transposition, conjugation and plasmid uptake to different bacterial species in aquaculture systems. In this study, we evaluated the antibiotic resistance pattern in V. parahaemolyticus strains associated with acute hepatopancreatic necrosis disease (AHPND) from penaeid shrimp and identified AHPND strains from Mexico showed a high level of resistance to tetracycline (≥5 μg/mL) and have the tetB gene coding tetracycline resistance. In particular, the tetB gene was carried in a single copy plasmid (named as pTetB-VA1) comprising 5162-bp with 40% G + C content from the strain (13-511/A1). The plasmid pTetB-VA1 consists of 9 ORFs encoding tetracycline resistant and repressor proteins, transcriptional regulatory proteins and transposases and showed a 99% sequence identity to other tet gene plasmids (pIS04_68 and pAQU2).