Phenotypic and genotypic characterization of Vibrio vulnificus: proposal for the substitution of the subspecific taxon biotype for serovar

Abstract

The classification of Vibrio vulnificus strains into two biotypes has been maintained on the basis of phenotypic properties and eel virulence. Biotype 2 is virulent for eels, negative for the indole reaction, and serologically homogeneous (serogroup E), whereas strains of biotype 1 are avirulent, indole positive, and serologically heterogeneous. In the present study, we phenotypically and genotypically characterized 21 V. vulnificus isolates, recovered mainly from northern Europe, by comparing them with reference strains of both biotypes to look for new isolates of biotype 2. The results of this work revealed that the majority of isolates virulent for eels presented phenotypic traits previously considered characteristics of biotype 2 and specific ribotypes with HindIII. However, among the new isolates we found (i) a serogroup E strain virulent for eels but indole positive and (ii) one isolate not belonging to serogroup E but pathogenic for eels. Since no biochemical test or specific serogroup can with certainty be associated with eel virulence, we propose to classify V. vulnificus strains into serovars instead of biotypes. Thus, we suggest serovar E as the denomination of those strains previously classified as biotype 2. Finally, the occurrence of serogroup E in eels cultured in Norway and Sweden, as well as from human infections and shrimp, has been demonstrated.

Ribotyping and plasmid profiling of Yersinia ruckeri

“…Vibrio anguillarum (Pedersen etal. 1996) and Vihio uulnijicus (Biosca et al 1997), plasmids belonging to the same homology group seem to be restricted to the same O-serogroup. The relationship between serotype and plasmid content of Y. ruckeri needs further clarification, but from the present results it seems that the 75 MDa and 12.7 (or 15.5) MDa plasmids are only present in serotype 0 1 strains.…”

Prevalence, characteristics and ecology of Vibrio vulnificus found in New Zealand shellfish

“…Strips were incubated at 37°C and examined after 24 and 48 h. API profile results were analysed by the licensed API-WEB TM software (https://apiweb.biomerieux.com). To define the biotypes of V. vulnificus strains we used the system adopted by Tison et al (1982), Biosca et al (1997) and Sanjuan et al (2009).…”

Vibrio vulnificus produces quorum sensing signals of the AHL-class

“…Vibrio vulnificus is a heterogeneous species and has been divided into three biotypes. Biotype 2 includes fish-virulent strains grouped in different serovars (Biosca et al, , 1997Hoi et al, 1998;Fouz & Amaro, 2003), of which serovar E is the most virulent (Biosca et al, 1997;Hoi et al, 1998). This serovar is termed zoonotic because it can also sporadically infect humans .…”