pirABvp -Bearing Vibrio parahaemolyticus and Vibrio campbellii Pathogens Isolated from the Same AHPND-Affected Pond Possess Highly Similar Pathogenic Plasmids

Xuan Dong; Dexi Bi; Hailiang Wang; Peizhuo Zou; Guosi Xie; Xiaoyuan Wan; Qian Yang; Yanping Zhu; Mengmeng Chen; Chengcheng Guo; Zhen Liu; Wenchao Wang; Jie Huang

doi:10.3389/fmicb.2017.01859

pirAB^vp -Bearing Vibrio parahaemolyticus and Vibrio campbellii Pathogens Isolated from the Same AHPND-Affected Pond Possess Highly Similar Pathogenic Plasmids

Front Microbiol. 2017 Oct 5:8:1859. doi: 10.3389/fmicb.2017.01859. eCollection 2017.

Authors

Xuan Dong¹, Dexi Bi², Hailiang Wang¹, Peizhuo Zou^{1

3}, Guosi Xie¹, Xiaoyuan Wan¹, Qian Yang¹, Yanping Zhu¹, Mengmeng Chen^{1

3}, Chengcheng Guo¹, Zhen Liu⁴, Wenchao Wang¹, Jie Huang¹

Affiliations

¹ Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China.
² Department of Pathology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
³ College of fisheries and life science, Shanghai Ocean University, Shanghai, China.
⁴ Shanghai Majorbio Bio-pharm Biotechnology, Shanghai, China.

Abstract

Acute hepatopancreatic necrosis disease (AHPND) is a severe shrimp disease originally shown to be caused by virulent strains of Vibrio parahaemolyticus (VP_AHPND). Rare cases of AHPND caused by Vibrio species other than V. parahaemolyticus were reported. We compared an AHPND-causing V. campbellii (VC_AHPND) and a VP_AHPND isolate from the same AHPND-affected pond. Both strains are positive for the virulence genes pirAB^vp . Immersion challenge test with Litopenaeus vannamei indicated the two strains possessed similar pathogenicity. Complete genome comparison showed that the pirAB^vp -bearing plasmids in the two strains were highly homologous, and they both shared high homologies with plasmid pVA1, the reported pirAB^vp -bearing plasmid. Conjugation and DNA-uptake genes were found on the pVA1-type plasmids and the host chromosomes, respectively, which may facilitate the dissemination of pirAB^vp . Novel variations likely driven by ISVal1 in the genetic contexts of the pirAB^vp genes were found in the two strains. Moreover, the VC_AHPND isolate additionally contains multiple antibiotic resistance genes, which may bring difficulties to control its future outbreak. The dissemination of the pirAB^vp in non-parahaemolyticus Vibrio also rises the concern of missing detection in industrial settings since the isolation method currently used mainly targeting V. parahaemolyticus. This study provides timely information for better understanding of the causes of AHPND and molecular epidemiology of pirAB^vp and also appeals for precautions to encounter the dissemination of the hazardous genes.

Keywords: Vibrio campbellii; Vibrio parahaemolyticus; acute hepatopancreatic necrosis disease; comparative genomics; plasmid.