Diversity and Dynamics of a North Atlantic Coastal Vibrio Community

Vibrios are ubiquitous marine bacteria that have long served as models for heterotrophic processes and have received renewed attention because of the discovery of increasing numbers of facultatively pathogenic strains. Because the occurrence of specific vibrios has frequently been linked to the temperature, salinity, and nutrient status of water, we hypothesized that seasonal changes in coastal water bodies lead to distinct vibrio communities and sought to characterize their level of differentiation. A novel technique was used to quantify shifts in 16S rRNA gene abundance in samples from Barnegat Bay, N.J., collected over a 15-month period. Quantitative PCR (QPCR) with primers specific for the genus Vibrio was combined with separation and quantification of amplicons by constant denaturant capillary electrophoresis (CDCE). Vibrio populations identified by QPCR-CDCE varied between summer and winter samples, suggesting distinct warm-water and year-round populations. Identification of the CDCE populations by cloning and sequencing of 16S rRNA genes from two summer and two winter samples confirmed this distinction. It further showed that CDCE populations corresponded in most cases to ~98% rRNA similarity groups and suggested that the abundance of these follows temperature trends. Phylogenetic comparison yielded closely related cultured and often pathogenic representatives for most sequences, and the temperature ranges of these isolates confirmed the trends seen in the environmental samples. Overall, this suggests that temperature is a good predictor of the occurrence of closely related vibrios but that considerable microdiversity of unknown significance coexists within this trend.     

Isolation and molecular characterization of genetically diverse antagonistic, diazotrophic red-pigmented vibrios from different mangrove rhizospheres

Genetic diversity of red-pigmented vibrios from different mangrove rhizospheres ( Porteresia coarctata, Avicennia marina and Rhizophora mucronata ) collected from Pichavaram mangrove, India was investigated. Twenty red–pink pigmented strains were isolated, 16S rRNA gene analyses indicted that these isolates belong to the genus Vibrio and were phylogenetically closely related to the type strains of Vibrio rhizosphaerae and Vibrio ruber . The rep-PCR analysis using GTG₅ and BOX primers had similar groupings, and segregated these pigmented Vibrio isolates including two type strains into seven unique genotypic groups (REP groups A1–A7). The rhizosphere of P. coarctata harbors highly genetically diverse groups of red-pigmented vibrios compared to other plants. Multilocus sequence analysis using four genetic loci ( pyrH, recA, rpoA , 16S rRNA) clearly supported the hypothesis that strains MSSRF38 (REP group A5) and MSSRF39 (REP group A6) could represent new Vibrio species. Biological functions of these vibrios were also determined and it was found that all these isolates have antagonistic activity against phytopathogens, and isolates belonging to REP groups A5 and A6 were positive for nifH gene by PCR. In conclusion, this study for the first time demonstrates the occurrence of genetically diverse groups of antagonistic, diazotrophic red-pigmented vibrios from different mangrove plants and suggests a new ecological role for vibrios as heterotrophic plant associated rhizobacteria.     

两株对虾幼体弧菌病病原的分离和鉴定

从患弧菌病的凡纳滨对虾（Litopenaeus vannamei）幼体中分离到两株病原菌zouA和zouB,常规形态和生理生化试验表明均为弧菌属菌种,弧菌编码鉴定系统分别鉴定为溶藻弧菌（Vibrioatginolyticus）和副溶血弧菌（V.parahaemolyticus）。副溶血弧菌R72H序列检测结果进一步证实菌株zouB为副溶血弧菌。对菌株zouA的16S rRNA基因序列分析表明该菌株与溶藻弧菌、副溶血弧菌等弧菌的相似性均高于98％,相互间不能区分;HSP60基因序列分析表明该菌株与溶藻弧菌相似性达98％以上,而与所有其它弧菌的相似性不到92％。结合表型和分子特征的鉴定结果,菌株zouA和zouB分别被鉴定为溶藻弧菌和副溶血弧菌。     

Occurrence and potential pathogenesis of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus on the South Coast of Sweden

During the summer of 2006, several wound infections - of which three were fatal - caused by Vibrio cholerae were reported from patients who had been exposed to water from the Baltic Sea. Before these reports, we initiated a sampling project investigating the occurrence of potential human pathogenic V. cholerae, Vibrio vulnificus and Vibrio parahaemolyticus in The Sound between Sweden and Denmark. The Blue mussel (Mytilus edulis) was used as an indicator to follow the occurrence of vibrios over time. Molecular analyses showed high frequencies of the most potent human pathogenic Vibrio spp.; 53% of mussel samples were positive for V. cholerae (although none were positive for the cholera toxin gene), 63% for V. vulnificus and 79% for V. parahaemolyticus (of which 47% were tdh(+) and/or trh(+)). Viable vibrios were also isolated from the mussel meat and screened for virulence by PCR. The mortality of eukaryotic cells when exposed to bacteria was tested in vivo, with results showing that the Vibrio strains, independent of species and origin, were harmful to the cells. Despite severe infections and several deaths, no report on potential human pathogenic vibrios in this area had been published before this study.     

Phylogenetic study and identification of human pathogenic Vibrio species based on partial hsp60 gene sequences

The use of hsp60 gene sequences for phylogenetic study and identification of pathogenic marine vibrios was investigated. A 600-bp partial hsp60 gene was amplified by PCR and sequenced from 29 strains representing 15 Vibrio species within the family Vibrionaceae. Sequence comparison of the amplified partial hsp60 gene revealed 71-82% sequence identity among different Vibrio species and 96-100% sequence identity among epidemiologically distinct strains with the same species designation. This degree of discrimination allows unambiguous differentiation of all Vibrio species included in the current study from each other, as well as from Aeromonas hydrophila and Plesiomonas shigelloides, which are often misidentified as Vibrio species by conventional biochemical methods. Based on the hsp60 gene sequences, two previously unidentified shrimp isolates were found to be more closely related to Vibrio alginolyticus (93-94% sequence identity) than to Vibrio parahaemolyticus (89% sequence identity), whereas 16S rRNA gene analysis was unable to differentiate among these closely related species (95-97% sequence identity). Our results indicate that the hsp60 gene may be a useful alternative target for phylogenetic analysis and species identification of marine Vibrios to complement more conventional identification systems.     

Microbial Communities Can Be Described by Metabolic Structure: A General Framework and Application to a Seasonally Variable,Depth-Stratified Microbial Community from the Coastal West Antarctic Peninsula

Taxonomic marker gene studies, such as the 16S rRNA gene, have been used to successfully explore microbial diversity in a variety of marine, terrestrial, and host environments. For some of these environments long term sampling programs are beginning to build a historical record of microbial community structure. Although these 16S rRNA gene datasets do not intrinsically provide information on microbial metabolism or ecosystem function, this information can be developed by identifying metabolisms associated with related, phenotyped strains. Here we introduce the concept of metabolic inference; the systematic prediction of metabolism from phylogeny, and describe a complete pipeline for predicting the metabolic pathways likely to be found in a collection of 16S rRNA gene phylotypes. This framework includes a mechanism for assigning confidence to each metabolic inference that is based on a novel method for evaluating genomic plasticity. We applied this framework to 16S rRNA gene libraries from the West Antarctic Peninsula marine environment, including surface and deep summer samples and surface winter samples. Using statistical methods commonly applied to community ecology data we found that metabolic structure differed between summer surface and winter and deep samples, comparable to an analysis of community structure by 16S rRNA gene phylotypes. While taxonomic variance between samples was primarily driven by low abundance taxa, metabolic variance was attributable to both high and low abundance pathways. This suggests that clades with a high degree of functional redundancy can occupy distinct adjacent niches. Overall our findings demonstrate that inferred metabolism can be used in place of taxonomy to describe the structure of microbial communities. Coupling metabolic inference with targeted metagenomics and an improved collection of completed genomes could be a powerful way to analyze microbial communities in a high-throughput manner that provides direct access to metabolic and ecosystem function.     

Bacteria associated with mucus and tissues of the coral Oculina patagonica in summer and winter

The relative abundance of bacteria in the mucus and crushed tissue of the Mediterranean coral Oculina patagonica was determined by analyses of the 16S rRNA genes of isolated colonies and from a 16S rRNA clone library of extracted DNA. By SYBR gold staining, the numbers of bacteria in mucus and tissue samples were 6.2 x 10(7) and 8.3 x 10(8)/cm2 of coral surface, respectively, 99.8% of which failed to produce colonies on Marine Agar. From analysis of mucus DNA, the most-abundant bacterium was Vibrio splendidus, representing 68% and 50% of the clones from the winter and summer, respectively. After removal of mucus from coral by centrifugation, analyses of DNA from the crushed tissue revealed a large diversity of bacteria, with Vibrio species representing less than 5% of the clones. The most-abundant culturable bacteria were a Pseudomonas sp. (8 to 14%) and two different alpha-proteobacteria (6 to 18%). Out of a total 1,088 16S rRNA genes sequenced, 400 different operational taxonomic units were identified (> 99.5% identity). Of these, 295 were novel (< 99% identical to any sequences in the GenBank database). This study provides a comprehensive database for future examinations of changes in the bacterial community during bleaching events.     

两株对虾幼体弧菌病病原的分离和鉴定

从患弧菌病的凡纳滨对虾(Litopenaeus vannamei)幼体中分离到两株病原菌zouA和zouB, 常规形态和生理生化试验表明均为弧菌属菌种, 弧菌编码鉴定系统分别鉴定为溶藻弧菌(Vibrio alginolyticus)和副溶血弧菌(V. parahaemolyticus)。副溶血弧菌R72H序列检测结果进一步证实菌株zouB为副溶血弧菌。对菌株zouA的16S rRNA基因序列分析表明该菌株与溶藻弧菌、副溶血弧菌等弧菌的相似性均高于98%, 相互间不能区分; HSP60基因序列分析表明该菌株与溶藻弧菌相似性达98%以上, 而与所有其它弧菌的相似性不到92%。结合表型和分子特征的鉴定结果, 菌株zouA和zouB分别被鉴定为溶藻弧菌和副溶血弧菌。     

Occurrence of pathogenic vibrios in coastal areas of France

AIMS: This study was carried out to investigate the occurrence of potentially pathogenic species of Vibrio in French marine and estuarine environments. METHODS AND RESULTS: Samples of coastal waters and mussels collected between July and September 1999 were analysed by culture, using selective media including thiosulphate-citrate-bile salts-sucrose and modified cellobiose-polymixin B-colistin agar. Presumptive Vibrio colonies were isolated and identified using selected biochemical tests. Specific primers based on flanking sequences of the cytolysin, vvhA gene, pR72H DNA fragment and 16S-23S rRNA intergenic spacer region (ISR) were used in a polymerase chain reaction (PCR) to confirm the identification of Vibrio vulnificus, V. parahaemolyticus and V. cholerae, respectively. In this study, V. alginolyticus (99 of 189) was the predominant species, followed by V. parahaemolyticus (41 of 189), V. vulnificus (20 of 189) and non-O1/non-O139 V. cholerae (three of 189). All 20 V. vulnificus isolates showed PCR amplification of the vvhA gene, 16 of which had been isolated from estuarine water. The PCR amplification of the pR72H DNA fragment in 41 V. parahaemolyticus isolates generated two unique amplicons of 387 and 320 bp. The latter, present in 24.4% of these isolates, had not previously been found in V. parahaemolyticus strains examined to date. Amplification of the trh gene in two of the isolates suggested these to be virulent strains. Three strains identified as V. cholerae by amplification of the 16S-23S rRNA ISR were confirmed to be non-cholera (non-O1/non-O139) strains. CONCLUSIONS: The results of this study demonstrated the presence of pathogenic Vibrio species in French coastal waters. Furthermore, the PCR approach proved useful for the rapid and reliable confirmation of species identification. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings indicate the potential sanitary risk associated with the presence of pathogenic Vibrio spp. in cultivated mussels and in the aquatic environment. The PCR can be used to detect pathogenic vibrios directly in environmental samples.     

Phylogenetic differentiation of two closely related Nitrosomonas spp. That inhabit different sediment environments in an oligotrophic freshwater lake.

The population of ammonia-oxidizing bacteria in a temperate oligotrophic freshwater lake was analyzed by recovering 16S ribosomal DNA (rDNA) from lakewater and sediment samples taken throughout a seasonal cycle. Nitrosospira and Nitrosomonas 16S rRNA genes were amplified in a nested PCR, and the identity of the products was confirmed by oligonucleotide hybridization. Nitrosospira DNA was readily identified in all samples, and nitrosomonad DNA of the Nitrosomonas europaea-Nitrosomonas eutropha lineage was also directly detected, but during the summer months only. Phylogenetic delineation with partial (345 bp) 16S rRNA gene sequences of clones obtained from sediments confirmed the fidelity of the amplified nitrosomonad DNA and identified two sequence clusters closely related to either N. europaea or N. eutropha that were equated with the littoral and profundal sediment sites, respectively. Determination of 701-bp sequences for 16S rDNA clones representing each cluster confirmed this delineation. A PCR-restriction fragment length polymorphism (RFLP) system was developed that enabled identification of clones containing N. europaea and N. eutropha 16S rDNA sequences, including subclasses therein. It proved possible to analyze 16S rDNA amplified directly from sediment samples to determine the relative abundance of each species compared with that of the other. N. europaea and N. eutropha are very closely related, and direct evidence for their presence in lake systems is limited. The correlation of each species with a distinct spatial location in sediment is an unusual example of niche adaptation by two genotypically similar bacteria. Their occurrence and relative distribution can now be routinely monitored in relation to environmental variation by the application of PCR-RFLP analysis.     

Ecology of Vibrio parahaemolyticus in Chesapeake Bay

A study of the ecology of Vibrio parahaemolyticus and related vibrios in the Rhode River area of Chesapeake Bay was carried out over the period December 1970 through August 1971. The incidence of V. parahaemolyticus and related vibrios was found to be correlated with water temperature. The vibrios could not be detected in the water column during the winter months, although they were present in sediment. From late spring to early summer, when water temperatures were 14 +/- 1 C, vibrios over-wintering in sediment were released from the bottom communities and attached to zooplankton, proliferating as the temperature rose. The number of vibrios in and on plankton was reflected in the water column bacterial population densities at water temperatures of ca. 19 C. Thus, temperature of the water column in the range of 14 to 19 C was found to be critical in the annual cycle of the vibrios. Interaction between sediment, water, and zooplankton was found to be essential in the natural estuarine ecosystem. Bacterial counts of zooplankton were found to be temperature dependent. The bacterial population associated with zooplankton was found to be predominantly on external surfaces and was specific, differing from that of the sediment. Vibrio spp. and related organisms comprised the total bacterial population associated with zooplankton in summer months. The ecological role of Vibrio spp., including V. parahaemolyticus, was found to be significant, with respect to their property of chitin digestion and in relation to the population dynamics of zooplankton in Chesapeake Bay.     

Low incidence of Vibrio vulnificus among Vibrio isolates from sea water and shellfish of the western Mediterranean coast

A specific search for Vibrio vulnificus in natural marine samples from the Spanish Mediterranean Sea was carried out by nested PCR and cultural approaches using thiosulphate-citrate-bile salts-sucrose agar (TCBS) and cellobiose-polymixin B-colistin agar (CPC), incubated at 40 degrees C, as selective media. Presumptive colonies were identified by PCR using specific primers against 23S rRNA sequences. This species was isolated from sea water and edible bivalves, mainly after preenrichment in alkaline peptone water (APW) at 40 degrees C followed by CPC agar. None of the V. vulnificus isolates identified corresponded to serovar E. Dominant Vibrio species on directly inoculated TCBS plates incubated at 25 degrees C were V. splendidus below 20 degrees C and V. harveyi and V. mediterranei above that temperature. Low percentages of several pathogenic vibrios were recorded but V. vulnificus was never recovered at this incubation temperature. The incidence of this species in the samples studied was lower than that described for other geographical areas, probably due to the high salinity values of the Mediterranean Sea.     

Recurring seasonal dynamics of microbial communities in stream habitats

Recurring seasonal patterns of microbial distribution and abundance in three third-order temperate streams within the southeast Pennsylvania Piedmont were observed over 4 years. Populations associated with streambed sediments and rocks (epilithon) were identified using terminal restriction length polymorphism (tRFLP) and sequencing of 16S rRNA genes selectively amplified with primers for the bacterial domain. Analyses of the relative magnitudes of tRFLP peak areas by using nonmetric multidimensional scaling resolved clear seasonal trends in epilithic and sediment populations. Oscillations between two dominant groups of epilithic genotypes, explaining 86% of the seasonal variation in the data set, were correlated with temperature and dissolved organic carbon. Sequences affiliated with epilithic phototrophs (cyanobacteria and diatom chloroplasts), a Rhodoferax sp., and a Bacillus species clustered in the summer, whereas sequences most closely related to "Betaproteobacteria" (putative Burkholderia sp.), and a putative cyanobacterium clustered in the fall/spring. The sediment genotypes also clustered into two groups, and these explained 85% of seasonal variation but correlated only with temperature. A summer tRFLP pattern was characterized by prevalence of "Betaproteobacteria," "Gammaproteobacteria," and a Bacillus sp., whereas the winter/spring pattern was characterized by phylotypes most closely related to "Firmicutes," "Gammaproteobacteria," and "Nitrospirae." A close association between these headwater streams and their watersheds was suggested by the recovery of sequences related to microbial populations provisionally attributed to not only freshwaters but also terrestrial habitats.     

Occurrence and distribution of halophilic vibrios in subtropical coastal waters of Hong Kong.

The summer occurrence and distribution of halophilic vibrios in the subtropical coastal waters of Hong Kong were investigated. The density of vibrios in six sample sites ranged from 90 to 6,700 per ml, which made up 0.41 to 40% of the total bacterial populations of these sample sites. The sucrose-positive vibrios were found to be much more common (88% of total vibrios) than the sucrose-negative ones. A total of 48 strains belonging to six Vibrio species were fully characterized. Among these, Vibrio alginolyticus was the most frequently isolated, followed by V. parahaemolyticus, V. harveyi, V. vulnificus, V. campbellii, and V. fluvialis. The finding that eight of the nine strains of V. harveyi showed a positive Kanagawa reaction warrants further study.     

Occurrence and distribution of halophilic vibrios in subtropical coastal waters of Hong Kong

The summer occurrence and distribution of halophilic vibrios in the subtropical coastal waters of Hong Kong were investigated. The density of vibrios in six sample sites ranged from 90 to 6,700 per ml, which made up 0.41 to 40% of the total bacterial populations of these sample sites. The sucrose-positive vibrios were found to be much more common (88% of total vibrios) than the sucrose-negative ones. A total of 48 strains belonging to six Vibrio species were fully characterized. Among these, Vibrio alginolyticus was the most frequently isolated, followed by V. parahaemolyticus, V. harveyi, V. vulnificus, V. campbellii, and V. fluvialis. The finding that eight of the nine strains of V. harveyi showed a positive Kanagawa reaction warrants further study.     

16S rDNA restriction fragment length polymorphism analysis of psychrotrophic vibrios from Japanese coastal water

Restriction fragment length polymorphism (RFLP) analysis was carried out for 136 natural isolates belonging to the family Vibrionaceae. These were collected from inshore areas of Japan, mainly in winter. Twenty-eight 16S rDNA genotypes were obtained by digestion with four restriction endonucleases (HhaI, DdeI, RsaI, and Sau3AI). To estimate the genetic relationships, 53 informative fragments were scored by their presence or absence. A dendrogram was constructed using the unweighted pair group method with the arithmetic averages algorithm. Five RFLP groups (groups I to V) were obtained. Group I corresponded to Vibrio splendidus-like strains. It was confirmed that this group was not only found in Otsuchi Bay, but also in broad coastal areas of Japan. Group II strains were not identified as previously known Vibrio species. Group III strains were regarded as members of the Vibrio main group, which is a major phylogenetic group deduced from 16S rRNA gene analysis in the family Vibrionaceae. The RFLP profile indicated that Group IV strains were closely related to V. hollisae. Group V strains showed RFLP patterns which have not been observed previously. From the clustering analysis, it was concluded that group V strains were not Vibrio species. Most of the isolates studied were not identified as previously described species. It suggests that many psychrotrophic vibrios in cold marine environments remain as unknown species.     

Occurrence of potentially pathogenic vibrios and related environmental factors in Songkhla Lake, Thailand

Vibrios are halophilic bacteria that are ubiquitous in marine environments. Their occurrence in tropical lakes has rarely been investigated. In this study, the predominance and diversity of Vibrio spp. was investigated over a 12-month period in a coastal lagoon, Songkhla Lake, in southern Thailand. Water samples were collected at 2 stations in the estuary near Yor Island in Songkhla Lake. The predominant vibrios were detected by a culture-based method, using thiosulfate-citrate-bile salt-sucrose agar and CHROMagar Vibrio. The diversity of Vibrio spp. was evaluated using denaturant density gradient electrophoresis (DGGE). The highest numbers of total vibrios and Vibrio parahaemolyticus in both areas were observed during the summer. There was no significant correlation between the numbers of vibrios, including V. parahaemolyticus, and either the water temperature or plankton density. Variations in Vibrio species were observed with changes in salinity. Vibrio parahaemolyticus and V. cholerae non-O1/non-O139 were detected during the rainy season when the salinity dropped to nearly 0 parts per thousand. In both areas, V. alginolyticus was the most prominent species detected by the culture method, whereas Vibrio parahaemolyticus was detected by DGGE, every month. Other Vibrio spp. of potential public health concern were also detected by the culture method; they included V. vulnificus , V. fluvialis , and V. mimicus .     

Diversity of Vibrios associated with reared clams in Galicia (NW Spain)

The aim of the present study was to characterize and identify vibrios isolated from cultured clams in Galicia (NW Spain). A total of 759 isolates were obtained, phenotypically characterized, grouped and assigned to the genus Vibrio. Subsequently, the genomic diversity of 145 representative strains was analyzed by means of amplified fragment length polymorphism (AFLP), which revealed a high genetic diversity amongst these isolates. Only 57 out of 145 strains could be identified to the species level, and they were distributed in 13 AFLP clusters. V. cyclitrophicus, V. splendidus and V. alginolyticus were the most abundantly represented species. Eighty-eight isolates remained unidentified, 59 were distributed over 16 clusters, while 29 were unclustered. Sequencing of the 16S rRNA and two house-keeping genes (rpoA and recA) from representative strains belonging to eight unidentified clusters with the highest number of isolates confirmed their assignation to the Vibrionaceae family, and some of these probably represent new species within the genus. The present study confirmed that the phenotypic characterization of vibrios is not sufficient to identify them at the species level. A wide diversity of vibrios was found in cultured clams from all four geographic locations analyzed. In total, more than 12 Vibrio species and at least three potential new species in this genus were identified.     

Temporal variability of coastal Planctomycetes clades at Kabeltonne station, North Sea

Members of the bacterial phylum Planctomycetes are reported in marine water samples worldwide, but quantitative information is scarce. Here we investigated the phylogenetic diversity, abundance, and distribution of Planctomycetes in surface waters off the German North Sea island Helgoland during different seasons by 16S rRNA gene analysis and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). Generally Planctomycetes are more abundant in samples collected in summer and autumn than in samples collected in winter and spring. Statistical analysis revealed that Planctomycetes abundance was correlated to the Centrales diatom bloom in spring 2007. The analysis of size-fractionated seawater samples and of macroaggregates showed that ~90% of the Planctomycetes reside in the >3-μm size fraction. Comparative sequence analysis of 184 almost full-length 16S rRNA genes revealed three dominant clades. The clades, named Planctomyces-related group A, uncultured Planctomycetes group B, and Pirellula-related group D, were monitored by CARD-FISH using newly developed oligonucleotide probes. All three clades showed recurrent abundance patterns during two annual sampling campaigns. Uncultured Planctomycetes group B was most abundant in autumn samples, while Planctomyces-related group A was present in high numbers only during late autumn and winter. The levels of Pirellula-related group D were more constant throughout the year, with elevated counts in summer. Our analyses suggest that the seasonal succession of the Planctomycetes is correlated with algal blooms. We hypothesize that the niche partitioning of the different clades might be caused by their algal substrates.     

Characterization and Relatedness of Marine Vibrios Pathogenic to Fish: Physiology, Serology, and Epidemiology

Cultural characteristics and serological relationships of pathogenic marine vibrios isolated from fish in the Pacific Northwest were studied. These organisms were compared with cultures of Vibrio anguillarum, a known fish pathogen. On the basis of morphological and cultural characteristics, the Pacific Northwest strains of Vibrio were found to be closely related to V. anguillarum. Serological analyses of thermostable antigens served to distinguish three serotypes among the vibrios. Serotype 1 was composed of organisms isolated from Northwest salmonids; serotype 2 of strains of V. anguillarum from European waters; and serotype 3 of organisms isolated from Pacific herring. The epidemiology of vibrio disease among populations of fish in the Pacific Northwest is discussed.