Vibrio Diabolicus Research Articles

Pan-Genome Provides Insights into Vibrio Evolution and Adaptation to Deep-Sea Hydrothermal Vents.

This study delves into the genomic features of 10 Vibrio strains collected from deep-sea hydrothermal vents in the Pacific Ocean, providing insights into their evolutionary history and ecological adaptations. Through sequencing and pan-genome analysis involving 141 Vibrio species, we found that deep-sea strains exhibit larger genomes with unique gene distributions, suggesting adaptation to the vent environment. The phylogenomic reconstruction of the investigated isolates revealed the presence of 2 main clades: The first is monophyletic, consisting exclusively of Vibrio alginolyticus, while the second forms a monophyletic clade comprising both Vibrio antiquarius and Vibrio diabolicus species, which were previously isolated from deep-sea vents. All strains carry virulence and antibiotic resistance genes related to those found in human pathogenic Vibrio species which may play a wider ecological role other than host infection in these environments. In addition, functional genomic analysis identified genes potentially related to deep-sea survival and stress response, alongside candidate genes encoding for novel antimicrobial agents. Ultimately, the pan-genome we generated represents a valuable resource for future studies investigating the taxonomy, evolution, and ecology of Vibrio species.

Genome sequences of Vibrio diabolicus and Algoriphagus sp. isolated from the San Elijo coastal lagoons in San Diego.

We report two draft genome sequences related to the genera Vibrio and Algoriphagus, isolated from water samples at the San Elijo Lagoon Ecological Reserve, which is one of the largest remaining coastal wetlands in San Diego, California. The initial whole genome-based comparison illustrates the uniqueness of these species.

Novel indigenous probiotic isolated from the healthy Pacific white shrimp Litopenaeus vannamei intestine in differing stages based on metagenomic and screening approaches

The healthy intestinal microbiota of shrimp can be used as an indicator sustainable shrimp production. In this study, the integrated of metagenomic and screening probiotic approach from healthy Litopenaeus vannamei intestines in differing stages was studied to find novel indigenous probiotics. The microbiota from intestine of naupli, post larva (PL-10), juvenile (40 days), and adult (80 days) of Pacific white shrimp were characterized using a high-quality sequence of V3–V4 of 16S rRNA gene as the hypervariable region. The classifiable sequence number was detected in 54 phyla. Several core intestine bacteria, 35 of these 557 genera, have a prevalence >10 sequences across all samples. We found microbiota were different taxa in the difference stages, such as Proteobacteria, Firmicutes, and Bacteriodetes. The top 10 most abundant genera were Vibrio, Pseudoalteromonas, Spingomonas, Marinibacterium, Klebsiella, Alteromonas, Aestuaribacter, Shimia, Stenotrophomonas, and Ruegeria. Microbiota profiling based on a metagenomic approach was integrated with screening assessment for pathogenicity, antagonistic activity with Vibrio parahaemolyticus Vp5, antibiotic resistance, and digestive enzyme activities. As their assessment activity, several screened culturable bacteria were 19 of these 84 isolates. Three isolates with high activities (P < 0.05) found as novel indigenous probiotics were Shewanella algae A1, Shewanella algae A3, and Vibrio diabolicus UB3. Integrating metagenomic and screening methods was a new signature for the isolating novel indigenous probiotics in Pacific white shrimp.

Multi-step semi-synthesis, structural characterization and growth factor interaction study of regiochemically sulfated diabolican polysaccharides

Diabolican is an exopolysaccharide (EPS) produced by Vibrio diabolicus HE800, a mesophilic bacterium firstly isolated from a deep-sea hydrothermal field. Its glycosaminoglycan (GAG)-like structure, consisting of a tetrasaccharide repeating unit composed of two aminosugars (N-acetyl-glucosamine and N-acetyl-galactosamine) and two glucuronic acid units, suggested to subject it to regioselective sulfation processes, in order to obtain some sulfated derivatives potentially acting as GAG mimics. To this aim, a multi-step semi-synthetic approach, relying upon tailored sequence of regioselective protection, sulfation and deprotection steps, was employed in this work. The chemical structure of the obtained sulfated diabolican derivatives was characterized by a multi-technique analytic approach, in order to define both degree of sulfation (DS) and sulfation pattern within the polysaccharide repeating unit, above all. Finally, binding affinity for some growth factors relevant for biomedical applications was measured for both starting diabolican and sulfated derivatives thereof. Collected data suggested that sulfation pattern could be a key structural element for the selective interaction with signaling proteins not only in the case of native GAGs, as already known, but also for GAG-like structures obtained by regioselective sulfation of naturally unsulfated polysaccharides.

Use of Trehalose as an Additive to Bacteriophage Vb_Pd_PDCC-1: Long-Term Preservation Analysis and Its Biocontrol Against Vibrio diabolicus Infection.

Phage therapy is a promising alternative to control bacterial diseases and the increasing problem of antibiotic resistance. In this sense, this research evaluates the viability of lyophilized vibrio phage vB_Pd_PDCC-1 using trehalose as a preservative excipient at different concentrations (4, 2, 1, and 0.5% w/v) and its potential for phage therapy application against a pathogenic bacteria Vibrio diabolicus in brine shrimp nauplii (Artemia franciscana). The lyophilized phages were stored at 4 and 23°C and rehydrated using biological sterile saline solution to test their viability at days 1, 15, and 60 post-lyophilization. The results showed that trehalose is beneficial in maintaining the viability of post-lyophilization phages (without titer losses) at 4°C and even at room temperature (23°C). When lyophilized phages with 4% w/v trehalose concentration were stored at 23°C, they had not titer losses among the trials; viability and titer concentration were maintained up to 60days at log 7. The use of lyophilized phage PDCC-1 increased brine shrimp survival and reduced Vibrio concentrations. The present study has identified trehalose as a promising lyophilization excipient to effectively preserve lyophilized bacteriophages for biotechnological applications and long-term storage.

Sulfamethoxazole degradation by Aeromonas caviae and co-metabolism by the mixed bacteria

Sulfamethoxazole (SMX) is a frequently detected antibiotic in the environment and has attracted much attention. Aeromonas caviae strain GLB-10 was isolated, which could degrade SMX to Aniline and 3-Amino-5-methylisoxazole. Compared to the single bacteria, the mixed bacteria including stain GLB-10, Vibrio diabolicus strain L2-2, Zobellella taiwanensis, Microbacterium testaceum, Methylobacterium, etc, had an ultrahigh degradation efficiency to SMX, with 250 mg/L SMX being degraded in 3 days. In addition to bioproducts of single bacteria, SMX bioproducts by the mixed bacteria also included acetanilide and hydroquinone which were not detected in the single bacteria. The SMX degradation mechanism of the mixed bacteria was more complicated including acetylation, sulfur reduction 4S pathway, and ipso-hydrolysis. The molecular mechanism of the mixed bacteria degrading SMX was also investigated, revealing that the resistance mechanism related to protein outer membrane protein and catalase peroxidase were overexpressed, meanwhile, 6-hydroxynicotinate 3-monooxygenase and ammonia monooxygenase might be the key proteins in SMX degradation. The mixed bacteria could efficiently degrade SMX in different real environments including tap water, river water, artificial lake water, estuary, and, marine water, and have very great research value in bacterial co-metabolism and biodegradation of sulfonamides antibiotics in the environment.

Investigating of the microbial communities in a red circle disease of sea cucumber based on metagenomic sequencing

Diseases in aquaculture restrict the survival and development of Apostichopus japonicus, one of the most important Chinese marine culture species. A novel disease, named "red circle" disease, is frequently observed in sea cucumber seedling ponds and results in the death of sea cucumbers. No information about this disease in A. japonicus is available. In this study, we investigated the whole microbial community structure and predicted microbial functional profiles in "red circle" disease affecting sea cucumbers through metagenomics. Metataxonomic analysis of "red circle" samples showed different domains, namely, bacteria (71.39%), virus (5.11%), archaea (0.15%), eukaryotes (0.06%), and some unclassified microbiota (23.29%). Proteobacteria was the most abundant phylum (42.88%), followed by Bacteroidetes (3.30%), Viruses_noname (3.12%), Verrucomicrobia (2.99%), Planctomycetes (2.67%), and Viruses_unclassified (1.99%). The species belong to genus Vibrio, which accounted for 4.51% of the microbiota. Vibrio alginolyticus was the most abundant species of genus Vibrio in the "red circle" samples, followed by Vibrio diabolicus, Vibrio parahaemolyticus, Vibrio cholerae, and Vibrio tubiashii. Functional analysis of "red circle" samples metagenome revealed the genes for the metabolism and environmental information processing of a wide range of bioactive compounds, including amino acids and carbohydrates. Results of our study provides insight into the "red circle" disease and microbial community in A. japonicus seedling ponds and widens our understanding of this new disease.

NMR Analyses of the Enzymatic Degradation End-Products of Diabolican: The Secreted EPS of Vibrio diabolicus CNCM I-1629.

Diabolican, or HE800, is an exopolysaccharide secreted by the non-pathogenic Gram-negative marine bacterium Vibrio diabolicus (CNCM I-1629). This polysaccharide was enzymatically degraded by the Bacteroides cellulosilyticus WH2 hyaluronan lyase. The end products were purified by size-exclusion chromatography and their structures were analyzed in depth by nuclear magnetic resonance (NMR). The oligosaccharide structures confirmed the possible site of cleavage of the enzyme showing plasticity in the substrate recognitions. The production of glycosaminoglycan-mimetic oligosaccharides of defined molecular weight and structure opens new perspectives in the valorization of the marine polysaccharide diabolican.

Prevalence, Genomic Characterization, and Risk Assessment of Human Pathogenic Vibrio Species in Seafood

Pathogenic Vibrio species are largely responsible for human diseases associated with consumption of contaminated seafood. The aim of this study was to determine the prevalence, population densities, species diversity, and molecular characteristics of pathogenic Vibrio in various seafood commodities and the health risks associated with consumption of these contaminated commodities. Samples of finfish and shellfish (oysters and sea urchins) were collected from various regions and analyzed for Vibrio with the most-probable-number (MPN) technique. Genomic DNA of putative Vibrio isolates was analyzed by whole genome sequencing for taxonomic identification and identification of virulence and antimicrobial resistance genes. The risk of Vibrio-related illnesses due to the consumption of contaminated seafood was assessed with Risk Ranger. Populations of presumptive Vibrio were 2.6 to 4.4 log MPN/g and correlated with season; Vibrio levels were significantly higher (P < 0.05) in the summer. Fifteen Vibrio isolates were identified as Vibrio alginolyticus (five isolates), Vibrio parahaemolyticus (six isolates), Vibrio harveyi (two isolates), and Vibrio diabolicus (two isolates). Two of the six V. parahaemolyticus isolates (ST 2504 and ST 2505) from oysters harbored either the tdh gene for thermostable direct hemolysin or the trh gene for thermostable direct hemolysin-related hemolysin. In addition to virulence genes, the shellfish isolates also harbored genes encoding resistance to multiple antibiotics, including tetracycline, penicillin, quinolone, and β-lactams, thus arousing concern. The risk assessment predicted that an estimated 21 cases of V. parahaemolyticus-associated gastroenteritis could occur in the general population annually due to consumption of contaminated oysters. This study highlights both the wide prevalence and diversity of Vibrio in seafood and the potential for certain strains to threaten public health.

Influence of the Carbon and Nitrogen Sources on Diabolican Production by the Marine Vibrio diabolicus Strain CNCM I-1629.

Recent advances in glycobiotechnology show that bacterial exopolysaccharides (EPS) presenting glycosaminoglycan (GAG)-like properties can provide a valuable source of bio-active macromolecules for industrial applications. The HE800 EPS, named diabolican, is a marine-derived anionic high-molecular-weight polysaccharide produced by Vibrio diabolicus CNCM I-1629 which displays original structural features close to those of hyaluronic acid. We investigated the impact of carbon and nitrogen substrates on both Vibrio diabolicus growth and diabolican production. Both substrates were screened by a one-factor-at-a-time method, and experimental designs were used to study the effect of glucose, mannitol, and ammonium acetate various concentrations. Results showed that the medium composition affected not only the bacterium growth and EPS yield, but also the EPS molecular weight (MW). EPS yields of 563 and 330 mg L−1 were obtained in the presence of 69.3 g L−1 glucose and 24.6 g L−1 mannitol, respectively, both for 116.6 mM ammonium acetate. MW was the highest, with 69.3 g L−1 glucose and 101.9 mM ammonium acetate (2.3 × 106 g mol−1). In parallel, the bacterial maximum specific growth rate was higher when both carbon and nitrogen substrate concentrations were low. This work paves the way for the optimization of marine exopolysaccharide production of great interest in the fields of human health and cosmetics.

16S rRNA sequences of Exiguobacterium spp. bacteria dominant in a biofloc pond cultured with whiteleg shrimp, Penaeus vannamei

Biofloc technology is being applied increasingly in shrimp aquaculture. Many countries have adopted this technology to increase shrimp aquaculture production. Owing to its major importance, this study was conducted to identify the bacterial population from biofloc aquaculture shrimp pond water of Singkir Laut, Kedah, Malaysia. Samples of mature biofloc were collected from the biofloc pond water at different shrimp ages (day of culture [DOC]): DOC30, DOC60 and DOC90. Overall, 43 sequences of bacterial species were blasted, which were identified as Exiguobacterium spp., Bacillus spp., Vibrio spp., Acinetobacter junii, Cobetia marina, Rheinheimera aquimaris and Pseudoalteromonas spp. These bacterial species were identified mostly from heterotrophic plate count agar. The bacterial species of Exiguobacterium aestuarii, Exiguobacterium profundum and Exiguobacterium aurantiacum were identified with 16S rRNA gene sequence similarities of 98.45–99.44%. Bacterial species of Bacillus pumilus, Bacillus velezensis, Bacillus cereus, Bacillus safensis and Bacillus subtilis were identified with 16S rRNA gene sequence similarities of 98.81–99.21%. Bacterial species of Vibrio diazotrophicus, Vibrio diabolicus, Vibrio natriegens and Vibrio harveyi were identified with 16S rRNA gene sequence similarities of 98.03–99.19%. Bacteria from Rheinheimera aquimaris were also identified with 16S rRNA gene sequence similarities of 98.69–99.26%; this bacterium is a novel bacterium identified from biofloc samples of the present study and has not been reported from biofloc samples in any previous study. Exiguobacterium spp. from the novel strains of E. aestuarii and E. profundum were identified as dominant, with 23 of 43 samples isolated from a shrimp pond at time points DOC30, DOC60 and DOC90; these bacteria are Gram-variable rod-shaped organisms that are capable of producing extracellular enzyme activity to break down chemical structures, thereby helping to remove organic compounds from aquaculture waste. Exiguobacterium spp. are usually identified in tidal flat sediments and on muddy sea coasts. This discovery is consistent with the site of the shrimp pond near to a muddy beach area, which might be the source of seawater leading to the predominance of this type of bacteria in the biofloc samples in the studied pond.

Glycosaminoglycan-like sulfated polysaccharides from Vibrio diabolicus bacterium: Semi-synthesis and characterization

Sulfated glycosaminoglycan (GAG) analogues derived from plant, algae or microbial sourced polysaccharides are highly interesting in order to gain bioactivities similar to sulfated GAGs but without risks and concerns derived from their typical animal sources. Since the exopolysaccharide (EPS) produced by the bacterium Vibrio diabolicus HE800 strain from deep-sea hydrothermal vents is known to have a GAG-like structure with a linear backbone composed of unsulfated aminosugar and uronic acid monomers, its structural modification through four different semi-synthetic sulfation strategies has been performed. A detailed structural characterization of the six obtained polysaccharides revealed that three different sulfation patterns (per-O-sulfation, a single N-sulfation and a selective primary hydroxyls sulfation) were achieved, with molecular weights ranging from 5 to 40 kDa. A Surface Plasmonic Resonance (SPR) investigation of the affinity between such polysaccharides and a set of growth factors revealed that binding strength is primarily depending on polysaccharide sulfation degree.

The probiotics Vibrio diabolicus (Ili), Vibrio hepatarius (P62), and Bacillus cereus sensu stricto (P64) colonize internal and external surfaces of Penaeus vannamei shrimp larvae and protect it against Vibrio parahaemolyticus

The vibrios carrying the pirA and pirB toxin genes cause acute hepatopancreatic necrosis disease (AHPND) in cultivated shrimp, significantly affecting the yield. The use of probiotic strains is a promising strategy to prevent vibriosis in shrimp cultures. The microbial consortium formulated with three strains, Vibrio diabolicus (Ili strain), Vibrio hepatarius (P62 strain), and Bacillus cereus sensu stricto (P64 strain), is used to control vibriosis. Despite the effectiveness of these probiotics, until now there is not a description of the cellular structures necessary to help shrimp colonization, an important process to exclude pathogenic vibrios. Initially, the three probiotic strains were characterized by scanning electron microscopy, which allowed us to observe that Ili has numerous flagella and P62 has numerous fimbriae, while P64 has both flagella and fimbriae. Next, the colonization capacity of the three probiotic strains in P. vannamei shrimp larvae was determined by direct exposure of the shrimp larvae to probiotics previously stained with fluorochrome dyes, orange acridine, Evans blue, and DAPI. The larvae were observed using epifluorescence and confocal microscopy, which showed the three probiotics adhered to the body cuticle and internal gut lining. Larvae exposed to AHPND-causing V. parahaemolyticus stained with acridine orange were quickly and completely colonized, however, the previous treatment of larvae with probiotic consortium limited the colonization of the pathogenic Vibrio. The ability of probiotic strains to exclude pathogenic vibrio from shrimp surfaces could be explained by the cell surface appendages observed in probiotic strains, thus limiting the free spaces for pathogenic vibrios. Finally, the probiotic consortium in P. vannamei larvae was evaluated in a larviculture (Nauplii 5 to postlarvae 8), where the three probiotics were applied daily. The trial included a control group without the application of the probiotic. After 16 days of culture, the larvae treated with the microbial consortium and the control group were challenged with a pathogenic, the AHPND-causing V. parahaemolyticus strain. We registered a significant (P < 0.05) higher survival in the larvae treated with the microbial consortium 75.33 ± 12.62% compared to the control group 32.27 ± 9.57%. These results indicate that the preventive use of probiotic strains with colonization capacity increase larvae protection. This may be a good strategy for the control of AHPND in shrimp larvae hatcheries.

Draft genome sequence of first Vibrio diabolicus in Mexico strain InDRE-D1-M1, an emergent threat.

The complete genome of the marine environmental bacterium Vibrio diabolicus isolated from raw shrimp in the city of Guadalajara in the state of Jalisco in Mexico is reported here. Vibrio spp. it was isolated and identified using standard microbiological and molecular techniques. Whole genome sequencing was performed using the Miseq system (Illumina, USA). The Multi Locus Sequence Typing profile of the isolated Vibrio bacteria coincided only with 4 specific loci (atpA, gyrB, pyrH and recA) and with a total coverage of the species belonging to Vibrio spp. Analysis of the complete genome of the Vibrio isolate and other closely related species, using the genomic fingerprints of the Virtual Analysis Method for PHylogenomic fingerprint estimation (VAMPHyRe) software, revealed the clustering of this species among the clade Vibrio diabolicus. The antibiogram revealed that this strain of Vibrio diabolicus is resistant to ampicillin, which is consistent with the bioinformatic finding of the β-lactamase enzyme that hydrolyzes carbenicillin class A. This study demonstrated that the environmental marine bacterium Vibrio diabolicus contains carrier genes associated with pathogenicity and ecological function, which could represent a threat to public health.

Emergence of the cfr Gene in Vibrio diabolicus of Seafood Origin.

The emergence and transmission of multidrug resistance (MDR) gene cfr have incurred great public health concerns worldwide. Recently, Gram-negative pathogens were found to carry cfr by various mobile elements. Here, we investigated a cfr-positive Vibrio diabolicus isolate by phenotyping and genomic analysis and found cfr in a translocatable structure (IS26-hp-cfr-IS26) among the MDR region in pNV27-cfr-208K, an emerging MDR plasmid in Vibrio species. This study highlights the necessity of surveillance of cfr in bacteria of diverse origins.

Microbial community characterization of shrimp survivors to AHPND challenge test treated with an effective shrimp probiotic (Vibrio diabolicus)

BackgroundAcute hepatopancreatic necrosis disease (AHPND) is an important shrimp bacterial disease caused by some Vibrio species. The severity of the impact of this disease on aquaculture worldwide has made it necessary to develop alternatives to prophylactic antibiotics use, such as the application of probiotics. To assess the potential to use probiotics in order to limit the detrimental effects of AHNPD, we evaluated the effect of the ILI strain, a Vibrio sp. bacterium and efficient shrimp probiotic, using metabarcoding (16S rRNA gene) on the gastrointestinal microbiota of shrimp after being challenged with AHPND-causing V. parahaemolyticus.ResultsWe showed how the gastrointestinal microbiome of shrimp varied between healthy and infected organisms. Nevertheless, a challenge of working with AHPND-causing Vibrio pathogens and Vibrio-related bacteria as probiotics is the potential risk of the probiotic strain becoming pathogenic. Consequently, we evaluated whether ILI strain can acquire the plasmid pV-AHPND via horizontal transfer and further cause the disease in shrimp. Conjugation assays were performed resulting in a high frequency (70%) of colonies harboring the pv-AHPND. However, no shrimp mortality was observed when transconjugant colonies of the ILI strain were used in a challenge test using healthy shrimp. We sequenced the genome of the ILI strain and performed comparative genomics analyses using AHPND and non-AHPND Vibrio isolates. Using available phylogenetic and phylogenomics analyses, we reclassified the ILI strain as Vibrio diabolicus. In summary, this work represents an effort to study the role that probiotics play in the normal gastrointestinal shrimp microbiome and in AHPND-infected shrimp, showing that the ILI probiotic was able to control pathogenic bacterial populations in the host's gastrointestinal tract and stimulate the shrimp’s survival. The identification of probiotic bacterial species that are effective in the host’s colonization is important to promote animal health and prevent disease.ConclusionsThis study describes probiotic bacteria capable of controlling pathogenic populations of bacteria in the shrimp gastrointestinal tract. Our work provides new insights into the complex dynamics between shrimp and the changes in the microbiota. It also addresses the practical application of probiotics to solve problems with pathogens that cause high mortality-rate in shrimp farming around the world.5HokUSghi4XQ9JWVrk_iScVideo

Associated Vibrio Species in Shrimp Vibriosis from Traditional Brackish Water Pond in the North Coastal of Central Java, Indonesia

Indonesian shrimp cultures are threatened by vibriosis. Some traditional brackish water ponds remained along the north coast of Central Java after the disease outbreaks destroyed the shrimp culture. This study aimed to discover the Vibrio diversity associated with shrimp vibriosis in traditional brackish water ponds. An exploratory method with purposive sampling was used in this study. Twenty-four shrimps presumably infected with vibriosis were collected from two district regions on the north coast of Central Java in July–September 2018. The bacteria associated in shrimp vibriosis were isolated from the telson and inner part of the hepatopancreas with TCBS medium. Forty-one bacteria associated with shrimp vibriosis were obtained, and then repetitive-polymerase chain reaction (rep-PCR) was performed to obtain Vibrio strains. On the basis of rep-PCR results, five respresentative strains were selected for further study. The results of 16S rDNA sequence analysis showed that the JKP03, JKP05, JKP19, JKM01, and JKM06 isolates were closely related to Vibrio rotiferianus, Vibrio diabolicus, Vibrio parahaemolyticus, Vibrio alginolyticus, and Shewanella algae, respectively. Vibrio biodiversity in shrimp vibriosis was high. These results confirmed that traditional shrimp farming was susceptible to vibriosis. Therefore, control methods such as vaccines, probiotics, and immunostimulant formulas must be developed to prevent and control the outbreak of shrimp vibriosis in traditional brackish water pond.

Isolation and characterization of a marine bacterium Vibrio diabolicus strain L2-2 capable of biotransforming sulfonamides

Sulfonamides (SAs) have attracted much attention because of their high detection rates in natural water. In this study, a marine bacterium Vibrio diabolicus strain L2-2 was isolated which could metabolize 9 SAs to a different extent. Compared with SAs and their analogs, SAs with N-oxides of heterocyclic structure were easier to be transformed to their N4-acetylated metabolites or their isoxazole ring rearrangement isomers by strain L2-2. And, gene vdnatA and vdnatG were likely to be the key genes in SAs acetylation process, which might code Arylamine N-acetyltransferase. The biotransformation rates of sulfathiazole(STZ), sulfamonomethoxine(SMT), sulfadiazine(SDZ), sulfamethoxazole(SMX) and sulfisoxazole(SIX) could reach 29.39 ± 5.63, 24.97 ± 4.45, 79.41 ± 4.05, 64.64 ± 1.71, 32.82 ± 4.46% in 6 days, respectively. Besides, the overall optimal conditions for SAs biotransformation were less than 100 mg/L for total SAs in neutral or weakly alkaline medium with the salinity of 10–20‰ and additional nutrients like glucose, sucrose or glycerine. Furthermore, toxicity was demonstrated to be significantly reduced after biotransformation. Together, this study introduced a strategy to use V. diabolicus strain L2-2 to realize simultaneous removal and detoxification of multiple SAs in freshwater and seawater, and revealed SAs removal pathways and relevant molecular mechanism.

Draft Genome Sequences of Vibrio alginolyticus Strain S6-61 and Vibrio diabolicus Strain S7-71, Isolated from Corals in the Andaman Sea.

We report the draft genome sequences of Vibrio alginolyticus strain S6-61 and Vibrio diabolicus strain S7-71, isolated from the corals Pocillopora verrucosa and Fungia danai, respectively. The genomes of strains S6-61 and S7-71 contain 4,880 and 4,641 protein coding genes, respectively, and harbor genes associated with the ectoine biosynthesis pathway.

Manila clam (Ruditapes philippinarum) marketed in Korea as a source of vibrios harbouring virulence and β-lactam resistance genes.

The present study assessed the occurrence, virulence determinants and antimicrobial susceptibility patterns of Vibrio spp. isolated from live Manila clam (Ruditapes philippinarum). A total of 31 Vibrio spp. including 27 V. diabolicus, two V. fluvialis, one V. alginolyticus and one V. antiquarius were isolated and identified. Phenotypic detection of DNase, lipase, phospholipase, amylase and caseinase activities was 100%; and 87% gelatinase, 45% slime production and 6% haemolysin activities were also observed. The prevalence of toxin-related virulence genes for collagenase (94%), toxR (100%), tlh (68%), and VPI (71%) was detected by PCR. Additionally, two V. fluvialis isolates carried F-toxR and hupo genes. Moreover, 61% of the isolates showed multiple antimicrobial resistance indices >0·2. The resistance rates of ampicillin, piperacillin, colistin sulfate, rifampicin, and cephalothin were 100, 81, 71, 77 and 68% respectively. The prevalence of blaCTX-M (87%), blaTEM (55%) and Int1 (90%) genes was observed, whereas blaSHV, strA-strB, tetA, tetB, and aadA2 gene cassette were reported in varying combinations. However, armA, aac(3)-IIa and quinolone resistance genes (qnrA, qnrB, qnrS) were not amplified. Thus, the virulence along with extended-spectrum β-lactamases (ESBLs) and other antimicrobial resistance genes in multidrug-resistant Manila clam-borne vibrios may pose a public health threat for consumers. SIGNIFICANCE AND IMPACT OF THE STUDY: In Korea, eating raw seafood is considered a great delicacy. This has negatively affected the public by increasing health issues over the years due to the ingestion of vibrios. For the first time, we could identify Vibrio diabolicus and Vibrio antiquarius in marketed Manila clams in Korea. The prevalent Vibrio diabolicus isolates demonstrated the Vibrio parahaemolyticus and Vibrio cholerae homologous virulence genes (toxR, tlh, and VPI). Additionally, the abundance of extended-spectrum β-lactamases (ESBLs) and integron (IntI1) harboured by Manila clam-borne vibrios elucidate the potential health risk for consumers and may complicate health treatments in the case of infection.