Indole-positive Vibrio vulnificus isolated from disease outbreaks on a Danish eel farm

Dalsgaard, Inger; Høi, Lise; Siebeling, R. J.; Dalsgaard, Anders

doi:10.3354/dao035187

Cited by 73 publications

(44 citation statements)

References 9 publications

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“…1. At eel farm E2 (Table 1), both biotypes of Vibrio vulnificus were found in the time period of the study, similar to Danish brackish-water eel farms (Høi et al 1998, Dalsgaard et al 1999. Until now, biotype 1 has been considered non-pathogenic to eels .…”

Section: Discussionsupporting

confidence: 54%

Vibrio vulnificus outbreaks in Dutch eel farms since 1996: strain diversity and impact

Haenen

Zanten²,

Jansen³

et al. 2014

Dis. Aquat. Org.

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Vibrio vulnificus is a potentially zoonotic bacterial pathogen of fish, which can infect humans (causing necrotic fasciitis). We analysed 24 V. vulnificus isolates (from 23 severe eel disease outbreaks in 8 Dutch eel farms during 1996 to 2009, and 1 clinical strain from an eel farmer) for genetic correlation and zoonotic potential. Strains were typed using biotyping and molecular typing by high-throughput multilocus sequence typing (hiMLST) and REP-PCR (Diversilab ® ). We identified 19 strains of biotype 1 and 5 of biotype 2 (4 from eels, 1 from the eel farmer), that were subdivided into 8 MLST types (ST) according to the international standard method. This is the first report of V. vulnificus biotype 1 outbreaks in Dutch eel farms. Seven of the 8 STs, of unknown zoonotic potential, were newly identified and were deposited in the MLST database. The REP-PCR and the MLST were highly concordant, indicating that the REP-PCR is a useful alternative for MLST. The strains isolated from the farmer and his eels were ST 112, a known potential zoonotic strain. Antimicrobial resistance to cefoxitin was found in most of the V. vulnificus strains, and an increasing resistance to quinolones, trimethoprim + sulphonamide and tetracycline was found over time in strain ST 140. Virulence testing of isolates from diseased eels is recommended, and medical practitioners should be informed about the potential risk of zoonotic infections by V. vulnificus from eels for the prevention of infection especially among high-risk individuals. Additional use of molecular typing methods such as hiMLST and Diversilab ® is recommended for epidemiological purposes during V. vulnificus outbreaks.

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Section: Discussionsupporting

confidence: 54%

Vibrio vulnificus outbreaks in Dutch eel farms since 1996: strain diversity and impact

Haenen

Zanten²,

Jansen³

et al. 2014

Dis. Aquat. Org.

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“…The first cases in Europe were recorded in 1989 in Spanish eel farms (Biosca et al, 1991). Later, the disease spread to other countries such as Sweden, The Netherlands and Denmark (Høi et al, 1998;Dalsgaard et al, 1999), always affecting eels cultured in brackish water.…”

Section: Introductionmentioning

confidence: 99%

Phenotypic and genotypic characterization of a new fish-virulent Vibrio vulnificus serovar that lacks potential to infect humans

2007

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Vibrio vulnificus is a bacterial species that is virulent for humans and fish. Human isolates are classified into biotypes 1 and 3 (BT1 and BT3) and fish isolates into biotype 2 (BT2). However, a few human infections caused by BT2 isolates have been reported worldwide (zoonosis). These BT2 human isolates belong to serovar E (SerE), which is also present in diseased fish. The aim of the present work was to characterize a new BT2 serovar [serovar A (SerA)], which emerged in the European fish-farming industry in 2000, by means of phenotypic, serological and genetic [plasmid profiling, ribotyping and random amplified polymorphic DNA (RAPD)] methodologies. The results confirmed that SerA constitutes a homogeneous O-serogroup within the species that shares plasmidic information with SerE. Like SerE, this new serogroup was resistant to fresh fish serum, as well as being highly virulent for fish. In contrast, it was sensitive to human serum and avirulent for mice, even after pretreatment with iron. The two serovars presented different biochemical profiles as well as specific patterns by ribotyping and RAPD analysis. In conclusion, SerA seems to constitute a different clonal group that has recently emerged within the species V. vulnificus, with pathogenic potential for fish but not for humans.

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“…The lesions on the body of a V. vulnificus-infected eel, similar to those caused by Vibrio anguillarum, include external skin ulcer, hemorrhagic fins, protrusion of the rectum, and hemorrhages and inflammation of the internal organs (4). The BT2 strains are further subdivided into several serovars (6,16,22), among which serovar E is not only the most virulent and prevalent but also the only one isolated from sporadic human infections associated with handling of contaminated fish (1).The virulence mechanism of BT2 V. vulnificus strains in eels remains unclear, although some virulence factors have been proposed. The extracellular products of BT2 strains exhibit hydrolytic/toxic activities and lethality for the eel similar to those produced by the BT1 strains (3), suggesting that they may not be the sole virulence determinants.…”

mentioning

confidence: 99%

A Common Virulence Plasmid in Biotype 2 Vibrio vulnificus and Its Dissemination Aided by a Conjugal Plasmid

Lee

Amaro

et al. 2008

J Bacteriol

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Strains of Vibrio vulnificus, a marine bacterial species pathogenic for humans and eels, are divided into three biotypes, and those virulent for eels are classified as biotype 2. All biotype 2 strains possess one or more plasmids, which have been shown to harbor the biotype 2-specific DNA sequences. In this study we determined the DNA sequences of three biotype 2 plasmids: pR99 (68.4 kbp) in strain CECT4999 and pC4602-1 (56.6 kb) and pC4602-2 (66.9 kb) in strain CECT4602. Plasmid pC4602-2 showed 92% sequence identity with pR99. Curing of pR99 from strain CECT4999 resulted in loss of resistance to eel serum and virulence for eels but had no effect on the virulence for mice, an animal model, and resistance to human serum. Plasmids pC4602-2 and pR99 could be transferred to the plasmid-cured strain by conjugation in the presence of pC4602-1, which was self-transmissible, and acquisition of pC4602-2 restored the virulence of the cured strain for eels. Therefore, both pR99 and pC4602-2 were virulence plasmids for eels but not mice. A gene in pR99, which encoded a novel protein and had an equivalent in pC4602-2, was further shown to be essential, but not sufficient, for the resistance to eel serum and virulence for eels. There was evidence showing that pC4602-2 may form a cointegrate with pC4602-1. An investigation of six other biotype 2 strains for the presence of various plasmid markers revealed that they all harbored the virulence plasmid and four of them possessed the conjugal plasmid in addition.Vibrio vulnificus is a gram-negative bacterial species that is ubiquitous in marine environments. This organism causes infections that are characterized by severe wound infection and primary septicemia with high mortality in humans, particularly those with underlying diseases such as liver cirrhosis and hemochromatosis (33,40). It also causes systemic infections, called vibriosis, with high mortality in brackish-water-cultured eels (4, 16). This organism is considered an emerging pathogen, since cases in fish and human were first reported in 1976 and 1979, respectively (8, 34).Strains of V. vulnificus are divided into three biotypes, biotype 1 (BT1), BT2, and BT3, based on their differences in phenotypic traits, serological type, and host range (6, 7, 42). All three biotypes can cause sporadic cases of human diseases and have been shown to be virulent for the mouse, an animal model; however, only the BT2 strains produce epizootic or outbreaks of vibriosis, mainly in eels (4, 34). The lesions on the body of a V. vulnificus-infected eel, similar to those caused by Vibrio anguillarum, include external skin ulcer, hemorrhagic fins, protrusion of the rectum, and hemorrhages and inflammation of the internal organs (4). The BT2 strains are further subdivided into several serovars (6,16,22), among which serovar E is not only the most virulent and prevalent but also the only one isolated from sporadic human infections associated with handling of contaminated fish (1).The virulence mechanism of BT2 V. vulnificus strains in eels rem...

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Indole-positive Vibrio vulnificus isolated from disease outbreaks on a Danish eel farm

Cited by 73 publications

References 9 publications

Vibrio vulnificus outbreaks in Dutch eel farms since 1996: strain diversity and impact

Vibrio vulnificus outbreaks in Dutch eel farms since 1996: strain diversity and impact

Phenotypic and genotypic characterization of a new fish-virulent Vibrio vulnificus serovar that lacks potential to infect humans

A Common Virulence Plasmid in Biotype 2 Vibrio vulnificus and Its Dissemination Aided by a Conjugal Plasmid

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