We analyzed the usefulness of rpoA, recA, and pyrH gene sequences for the identification of vibrios. We sequenced fragments of these loci from a collection of 208 representative strains, including 192 well-documented Vibrionaceae strains and 16 presumptive Vibrio isolates associated with coral bleaching. In order to determine the intraspecies variation among the three loci, we included several representative strains per species. The phylogenetic trees constructed with the different genetic loci were roughly in agreement with former polyphasic taxonomic studies, including the 16S rRNA-based phylogeny of vibrios. The families Vibrionaceae, Photobacteriaceae, Enterovibrionaceae, and Salinivibrionaceae were all differentiated on the basis of each genetic locus. Each species clearly formed separated clusters with at least 98, 94, and 94% rpoA, recA, and pyrH gene sequence similarity, respectively. The genus Vibrio was heterogeneous and polyphyletic, with Vibrio fischeri, V. logei, and V. wodanis grouping closer to the Photobacterium genus. V. halioticoli-, V. harveyi-, V. splendidus-, and V. tubiashii-related species formed groups within the genus Vibrio. Overall, the three genetic loci were more discriminatory among species than were 16S rRNA sequences. In some cases, e.g., within the V. splendidus and V. tubiashii group, rpoA gene sequences were slightly less discriminatory than recA and pyrH sequences. In these cases, the combination of several loci will yield the most robust identification. We can conclude that strains of the same species will have at least 98, 94, and 94% rpoA, recA, and pyrH gene sequence similarity, respectively.Vibrios are gram-negative, usually motile rods, are mesophilic and chemoorganotrophic, and have a facultatively fermentative metabolism (5). They are generally able to grow on marine agar and on the selective medium thiosulfate-citratebile salt-sucrose agar and are mostly oxidase positive. Vibrios belong to the Gammaproteobacteria according to 16S rRNA gene sequence analysis. These bacteria are found abundantly in aquatic habitats and in association with eukaryotes. Associations established by vibrios range from mutualistic, e.g., Vibrio fischeri-bobtail squid (26), to pathogenic, e.g., V. cholerae-humans (45). Probiotic Vibrio strains for fish and shellfish have also been documented (44).The current family Vibrionaceae comprises the genera Enterovibrio (2 species), Grimontia (1 species), Photobacterium (7 species), Salinivibrio (1 species), and Vibrio (64 species). The novel species Photobacterium rosenbergii and Enterovibrio coralii have recently been proposed to encompass isolates associated with coral bleaching (41). Several new Vibrio species, mainly in the phylogenetic neighborhood of V. harveyi, V. halioticoli, V. splendidus, V. tubiashii, and V. fluvialis, have been described in the last few years, with V. neonatus, V. ezurae (28), and V. ponticus (22) being the most recent ones. V. harveyi, V. splendidus, and V. tubiashii are frequently associated with disease in different spe...

Vibrio sp. YB1T (=ATCC BAA-450 T =LMG 20984 T ), the aetiological agent of tissue lysis of the coral Pocillopora damicornis, was characterized as a novel Vibrio species on the basis of 16S rDNA sequence, DNA-DNA hybridization data (G+C content is 45?6 mol%), AFLP and GTG 5 -PCR genomic fingerprinting patterns and phenotypic properties, including the cellular fatty acid profile. The predominant fatty acids were 16 : 0 and 18 : 1w7c. The name Vibrio coralliilyticus sp. nov. is proposed for the novel coral-pathogenic species. In addition to strain YB1 T , which was isolated from the Indian Ocean, five additional strains of V. coralliilyticus have been isolated, three from diseased P. damicornis in the Red Sea, one from diseased oyster larvae (Kent, UK) and one from bivalve larvae (Brazil). The six V. coralliilyticus strains showed high genotypic and phenotypic similarities and all were pathogenic to P. damicornis. The closest phylogenetic neighbours to V. coralliilyticus are Vibrio tubiashii, Vibrio nereis and Vibrio shilonii.

Background: Vibrio taxonomy has been based on a polyphasic approach. In this study, we retrieve useful taxonomic information (i.e. data that can be used to distinguish different taxonomic levels, such as species and genera) from 32 genome sequences of different vibrio species. We use a variety of tools to explore the taxonomic relationship between the sequenced genomes, including Multilocus Sequence Analysis (MLSA), supertrees, Average Amino Acid Identity (AAI), genomic signatures, and Genome BLAST atlases. Our aim is to analyse the usefulness of these tools for species identification in vibrios.

Aims:  To determine the relationship between yellow band disease (YBD)‐associated pathogenic bacteria found in both Caribbean and Indo‐Pacific reefs, and the virulence of these pathogens. YBD is one of the most significant coral diseases of the tropics. Materials and Results:  The consortium of four Vibrio species was isolated from YBD tissue on Indo‐Pacific corals: Vibrio rotiferianus, Vibrio harveyi, Vibrio alginolyticus and Vibrio proteolyticus. This consortium affects Symbiodinium (zooxanthellae) in hospite causing symbiotic algal cell dysfunction and disorganization of algal thylakoid membrane‐bound compartment from corals in both field and laboratory. Infected corals have decreased zooxanthella cell division compared with the healthy corals. Vibrios isolated from diseased Diploastrea heliopora, Fungia spp. and Herpolitha spp. of reef‐building corals display pale yellow lesions, which are similar to those found on Caribbean Montastraea spp. with YBD. Conclusions:  The Vibrio consortium found in YBD‐infected corals in the Caribbean are close genetic relatives to those in the Indo‐Pacific. The consortium directly attacks Symbiodinium spp. (zooxanthellae) within gastrodermal tissues, causing degenerated and deformed organelles, and depleted photosynthetic pigments in vitro and in situ. Infected Fungia spp. have decreased cell division compared with the healthy zooxanthellae: 4·9%vs 1·9%, (P ≥ 0·0024), and in D. heliopora from 4·7% to 0·7% (P ≥ 0·002). Significance and Impact of the Study:  Pathogen virulence has major impacts on the survival of these important reef‐building corals around the tropics.

This study analysed the usefulness of recA gene sequences as an alternative phylogenetic and/or identification marker for vibrios. The recA sequences suggest that the genus Vibrio is polyphyletic. The high heterogeneity observed within vibrios was congruent with former polyphasic taxonomic studies on this group. Photobacterium species clustered together and apparently nested within vibrios, while Grimontia hollisae was apart from other vibrios. Within the vibrios, Vibrio cholerae and Vibrio mimicus clustered apart from the other genus members. Vibrio harveyiand Vibrio splendidus-related species formed compact separated groups. On the other hand, species related to Vibrio tubiashii appeared scattered in the phylogenetic tree. The pairs Vibrio coralliilyticus and Vibrio neptunius, Vibrio nereis and Vibrio xuii and V. tubiashii and Vibrio brasiliensis clustered completely apart from each other. There was a correlation of 0?58 between recA and 16S rDNA pairwise similarities. Strains of the same species have at least 94 % recA sequence similarity. recA gene sequences are much more discriminatory than 16S rDNA. For 16S rDNA similarity values above 98 % there was a wide range of recA similarities, from 83 to 99 %.Cultivation-dependent and -independent studies have shown that vibrios are abundant worldwide in aquatic environments, including estuaries, marine coastal waters and sediments, and aquaculture settings (Heidelberg et al., 2002a, b;Suantika et al., 2001;Urakawa et al., 2000). Vibrios are particularly abundant in and/or on marine organisms (Gomez-Gil et al., 1998;Nishiguchi, 2000;Rosenberg & Ben-Haim, 2002). Several Vibrio species are serious pathogens of aquatic animals (Austin & Austin, 1999; Lightner & Redman, 1998). Vibrio anguillarum, Vibrio salmonicida and Vibrio vulnificus are important bacterial pathogens of several fish species, while Vibrio splendidus-related species represent a threat to bivalves, and Vibrio harveyi and Vibrio campbellii to shrimps (Austin & Austin, 1999;Le Roux et al., 2002). Vibrio cholerae, Vibrio parahaemolyticus and V. vulnificus are pathogens of man (Farmer & Hickman-Brenner, 1992;Wachsmuth et al., 1994). V. cholerae, the causative agent of cholera, has killed thousands of people worldwide in the last decade (WHO, 2001(WHO, , 2002; http://www.who.int/en/). In the last 3 years alone, about 10 000 people have died of cholera, mainly in developing countries (WHO, 2001(WHO, , 2002.According to Bergey's Manual of Systematic Bacteriology (2002) (see http://dx.doi.org/10.1007/bergeysoutline200210), there are six genera within the current family Vibrionaceae: Allomonas (one species), Enhydrobacter (one species), Listonella (two species), Photobacterium (six species), Salinivibrio (one species) and Vibrio (44 species). The genera Allomonas (Kalina et al., 1984) and Enhydrobacter (Staley et al., 1987) were tentatively allocated to the family Vibrionaceae based on phenotypic characteristics, but it is now known that Allomonas belongs to Vibrio and Enhydrobacter to Moraxella . Several...