Phenotypic and genomic characterization of a Vibrio parahaemolyticus strain causing disease in Penaeus vannamei provides insights into its niche adaptation and pathogenic mechanism

Abstract

The virulence of Vibrio parahaemolyticus is variable depending on its virulence determinants. A V. parahaemolyticus strain, in which the virulence is governed by the pirA and pirB genes, can cause acute hepatopancreatic necrosis disease (AHPND) in shrimps. Some V. parahaemolyticus that are non-AHPND strains also cause shrimp diseases and result in huge economic losses, while their pathogenicity and pathogenesis remain unclear. In this study, a non-AHPND V. parahaemolyticus , TJA114, was isolated from diseased Penaeus vannamei associated with a high mortality. To understand its virulence and adaptation to the external environment, whole-genome sequencing of this isolate was conducted, and its phenotypic profiles including pathogenicity, growth characteristics and nutritional requirements were investigated. Shrimps following artificial infection with this isolate presented similar clinical symptoms to the naturally diseased ones and generated obvious pathological lesions. The growth characteristics indicated that the isolate TJA114 could grow well under different salinity (10–55 p.p.t.), temperature (23–37 °C) and pH (6–10) conditions. Phenotype MicroArray results showed that this isolate could utilize a variety of carbon sources, amino acids and a range of substrates to help itself adapt to the high hyperosmotic and alkaline environments. Antimicrobial-susceptibility test showed that it was a multidrug-resistant bacterium. The whole-genomic analysis showed that this V. parahaemolyticus possessed many important functional genes associated with multidrug resistance, stress response, adhesions, haemolysis, putative secreted proteases, dedicated protein secretion systems and a variety of nutritional metabolic mechanisms. These annotated functional genes were confirmed by the phenotypic profiles. The results in this study indicated that this V. parahaemolyticus isolate possesses a high pathogenicity and strong environmental adaptability.

Comparative genome analyses of five Vibrio penaeicida strains provide insights into their virulence-related factors

“…Moreover, The V. penaeicida genomes harboured the pilA , B , C and D genes encoding the components of the type IV pilus, which mediates bacterial motility on solid surfaces, host–cell adhesion, bacteriophage adsorption, microcolony formation and transformation [ 70 ]. This result is in accordance with that of a recent study, which identified a type IV pilus in the genome of V. parahaemolyticus causing disease in Penaeus vannamei [ 71 ]. QS gives bacteria the ability to control several critical processes, including virulence factor secretion, antibiotic production, biofilm formation, motility, bioluminescence, development of genetic competence and sporulation [ 72 ].…”

“…This result is in accordance with that of a recent study, which identified a type IV pilus in the genome of V. parahaemolyticus causing disease in Penaeus vannamei [71]. QS gives bacteria the ability to control several critical processes, including virulence factor secretion, antibiotic production, biofilm formation, motility, bioluminescence, development of genetic competence and sporulation [72].…”

Phenotypic and genomic insights into the pathogenicity and antimicrobial resistance of an Enterobacter roggenkampii strain isolated from diseased silver arowana (Osteoglossum bicirrhosum)

“…The presence of multiple fimbriae genes associated with type I fimbriae and type IV pili indicated that EOBSR_19 was likely able to adhere to and colonize a rather wide range of hosts or environments. Similar genes are also reported earlier in other strains, including E. roggenkampii ED5 (Guo et al, 2020), E. cloacae ATCC13047 (Liu et al, 2013), Vibrio parahaemolyticus TJA114 (Zhang et al, 2021),…”

Signaling events induced by lipopolysaccharide-activated Toll in response to bacterial infection in shrimp

“…The habitats of aquatic invertebrates are typically characterized by bacteria and viruses. V. parahaemolyticus, a gram-negative bacterium, is a dominant autochthonous microflora found in estuarine and coastal marine environments and is linked to aquatic animal diseases (47). Interestingly, in mice, only one of the 12 TLR members, TLR4, recognizes LPS (48) whereas in shrimp, five of the nine Tolls have such a function.…”