Phenotypic characterization of Vibrio vulnificus biotype 2, a lipopolysaccharide-based homogeneous O serogroup within Vibrio vulnificus

Abstract

In this study, we have reevaluated the taxonomic position of biotype 2 of Vibrio vulnificus. For this purpose, we have biochemically and serologically characterized 83 biotype 2 strains from diseased eels, comparing them with 17 biotype 1 strains from different sources. Selected strains were also molecularly analyzed and tested for eel and mouse pathogenicity. Results have shown that biotype 2 (i) is biochemically homogeneous, indole production being the main trait that distinguishes it from biotype 1, (ii) presents small variations in DNA restriction profiles and outer membrane protein patterns, some proteins being immunologically related to outer membrane proteins from biotype 1, (iii) expresses a common lipopolysaccharide (LPS) profile, which is immunologically identical among strains and distinct from that of LPS of tested biotype 1 strains, and (iv) contains at least two high-M r plasmids. Regarding host range, we have confirmed that both biotypes are pathogenic for mice but only biotype 2 is pathogenic for eels. On the basis of these data, we propose that biotype 2 of V. vulnificus constitutes an LPS-based O serogroup which is phenotypically homogeneous and pathogenic for eels. In this article, the serogroup is designated serogroup E (for eels).

Characterization of Vibrio vulnificus isolated from cockles (Anadara granosa): antimicrobial resistance, plasmid profiles and random amplification of polymorphic DNA analysis

“…The antimicrobial resistance patterns did not correlate with biotype. The plasmid pro¢les of the 36 V. vulni¢cus strains are in general agreement with previous reports on the plasmid carriage in V. vulni¢cus [16,17]. Approximately 21 biotype 1 and two biotype 2 strains contained plasmid bands ranging in sizes from 1.4 to 9.7 MDa (Table 1).…”

Role of capsular polysaccharide (CPS) in biofilm formation and regulation of CPS production by quorum‐sensing in Vibrio vulnificus

“…They include CPS and LPS, which are tightly attached to the outer membrane, and EPS, which is relatively loosely associated with the cell envelope (Whitfield, 2006). Although LPS and CPS are involved in the pathogenicity of V. vulnificus and other pathogens (Biosca et al, 1996;Powell et al, 1997), all three kinds of extracellular polysaccharides have been found to be differentially involved in biofilm formation of V. vulnificus. EPSdeficient mutants (ΔEPS-I, ΔEPS-II and ΔEPS-III) and an LPS-deficient mutant (ΔgmhD) exhibited significantly decreased ability to form biofilms (Kim et al, 2007;2009), but a CPS-deficient mutant (wbpP; Fig.…”

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

“…Thus, we focused on the characterization of the Spanish biotype 2 isolates, using reference strains of both biotypes for comparison. Our investigations have revealed that biotypes 1 and 2 of V. vulnificus exhibit a high level of phenotypic homology, sharing many biochemical traits, immunologically related outer membrane proteins (OMPs), the expression of several virulence factors, and virulence for mice (2,5,9,(13)(14)(15)(16). Further, we have demonstrated the survival of the eel pathogen in seawater as a free-living microorganism, as well as its water-borne transmissibility (3,11).…”

“…No reports were published in other countries until 1989, when we reported its isolation from diseased eels in Spain (10). Since then, biotype 2 was recovered during different outbreaks that occurred in the same farm (2,16). Thus, we focused on the characterization of the Spanish biotype 2 isolates, using reference strains of both biotypes for comparison.…”