The widespread presence of a family of fish virulence plasmids in Vibrio vulnificus stresses its relevance as a zoonotic pathogen linked to fish farms

ABSTRACT 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.

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Plasmid diversity in Vibrio vulnificus biotypes

Microbiology ◽

10.1099/mic.0.023424-0 ◽

2009 ◽

Vol 155 (2) ◽

pp. 489-497 ◽

Cited By ~ 17

Author(s):

Francisco J. Roig ◽

Carmen Amaro

Keyword(s):

Molecular Mass ◽

Vibrio Vulnificus ◽

Bacterial Species ◽

Virulence Gene ◽

Molecular Size ◽

Conjugative Plasmid ◽

Virulence Plasmid ◽

Gene Markers ◽

Virulence Plasmids ◽

Cryptic Plasmids

Vibrio vulnificus is a heterogeneous bacterial species that can be virulent for humans and fish. Virulence in fish seems to rely on a recently described plasmid that can be transmitted between strains, aided by a conjugative plasmid. The main objective of this work was to analyse the plasmid content of a wide collection of strains from the three biotypes of the species, as well as to identify putative conjugative and virulence plasmids by means of Southern hybridization with specific probes and sequence analysis of selected gene markers. We found 28 different plasmid profiles in a total of 112 strains, which were relatively biotype- or serovar-specific. Biotype 1 lacked high-molecular-mass plasmids, with the exception of a putative conjugative plasmid of 48 kb that was present in 42.8 % of clinical and environmental strains isolated worldwide. All biotype 2 strains possessed the virulence plasmid, whose molecular mass ranged between 68 and 70 kb, and 89.65 % of these strains also had a putative conjugative plasmid with a molecular size of 52–56 kb. Finally, a 48 kb putative conjugative plasmid was present in all biotype 3 strains. Data from partial sequencing of traD, traI and the whole vep07 (a recently described plasmid-borne virulence gene) from a selection of strains suggest that the plasmids of 48–56 kb probably belong to the same family of F-plasmids as pYJ016 and that the gene vep07 is absolutely essential for fish virulence. Additional cryptic plasmids of low molecular mass were present in the three biotypes. In conclusion, plasmids are widespread among V. vulnificus species and could contribute substantially to genetic plasticity of the species.

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Pathological, bacteriological and seasonal prevalence of Aeromonas hydrophila, vibrio vulnificus, Proteus vulgaris and Pseudomonas aeruginosa; infecting Oreochromis niloticus in some Egyptian fish farms

Egyptian Journal of Aquatic Biology and Fisheries ◽

10.21608/ejabf.2020.108585 ◽

2020 ◽

Vol 24 (5) ◽

pp. 467-482 ◽

Cited By ~ 1

Author(s):

Islam Elgohary ◽

Jehan I. Abd Elatief ◽

Nasser G. Fadel ◽

Alaa E. Eissa ◽

Mahmoud A. Mahmoud

Keyword(s):

Pseudomonas Aeruginosa ◽

Aeromonas Hydrophila ◽

Oreochromis Niloticus ◽

Vibrio Vulnificus ◽

Seasonal Prevalence ◽

Proteus Vulgaris ◽

Fish Farms

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Method for the specific identification of the emerging zoonotic pathogen Vibrio vulnificus Lineage 3 (formerly Biotype 3)

Journal of Clinical Microbiology ◽

10.1128/jcm.01763-20 ◽

2020 ◽

Author(s):

Hector Carmona-Salido ◽

Naiel Bisharat ◽

Carmen Amaro

Keyword(s):

Vibrio Vulnificus ◽

Genomic Analysis ◽

Epidemiological Studies ◽

Rapid Identification ◽

Comparative Genomic ◽

Zoonotic Pathogen ◽

Genomic Study ◽

Comparative Genomic Study ◽

Pcr Method ◽

Unique Ability

Vibrio vulnificus is a zoonotic pathogen that is spreading worldwide due to global warming. Lineage 3 (L3; formerly biotype 3) includes the strains of the species with the unique ability to cause fish farm-linked outbreaks of septicaemia. The L3-strains emerged recently and are particularly virulent and difficult to identify. Here we describe a new developed PCR method based on a comparative genomic study useful for both rapid identification and epidemiological studies of this interesting emerging group. The comparative genomic analysis also revealed the presence of a genetic duplication in the L3 strains that could be related to the unique ability of this lineage to produce septicemia outbreaks.

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