Evaluation of genotypic and phenotypic methods to distinguish clinical from environmental Vibrio vulnificus strains.

V. vulnificus is a heterogeneous bacterial species that comprises virulent and avirulent strains from environmental and clinical sources that have been grouped into three biotypes. To validate the typing methods proposed to distinguish clinical from environmental isolates, we performed phenotypic (API 20E, API20NE and BIOLOG tests) and genetic (ribotyping and DNA polymorphisms at several loci) studies with a large strain collection representing different biotypes, origins and host range. No phenotypic method was useful for biotyping or grouping strains with regard to origin of the isolate and only BIOLOG system was reliable to identify the strains at species level. The DNA polymorphisms divided the population into three major profiles: profile 1 were vcg type C, 16S rRNA type B and vvh type 1 and included most of biotype 1 human septicemic isolates; profile 2 were vcg type E, 16S rRNA type A and vvh type 2 and included all biotype 2 isolates together with biotype 1 isolates from fish, water and some human isolates; and the last one, profile 3, were vcg type E, 16S rRNA type AB and vvh type 2 and composed by biotype 3 strains. Ribotyping divided the species into two groups, one that included profile 1 isolates of biotype 1, and the other including isolates of all three biotypes belonging to the three profiles described. In conclusion, no genotyping system was able to distinguish neither clinical from environmental strains nor biogroups within V. vulnificus species, which suggests that new typing methodologies useful for Public Health have to be developed for this species

A multiplex PCR for the detection of Vibrio vulnificus hazardous to human and/or animal health from seafood

Vibrio vulnificus is a zoonotic pathogen linked to aquaculture that is spreading due to climate change. The pathogen can be transmitted to humans and animals by ingestion of raw shellfish or seafood feed, respectively. The aim of this work was to design and test a new procedure to detect V. vulnificus hazardous to human and/or animal health in food/feed samples. For this purpose, we combined a pre-enrichment step with multiplex PCR using primers for the species and for human and animal virulence markers. In vitro assays with mixed DNA from different Vibrio species and Vibrio cultures showed that the new protocol was 100 % specific with a detection limit of 10 cfu/mL. The protocol was successfully validated in seafood using artificially contaminated live shrimp and proved useful also in pathogen isolation from animals and their ecosystem. In conclusion, this novel protocol could be applied in health risk studies associated with food/feed consumption, as well as in the routine identification and subtyping of V. vulnificus from environmental or clinical samples

Micromón València (Universitat de València)

En Julio de 2017 se creó la red SWI@Spain, auspiciada por el grupo de Docencia y Difusión de la Microbiología (DDM) de la Sociedad Española de Microbiología (SEM), para desarrollar la iniciativa internacional Small World Initiative (SWI) en la península ibérica. En la Universitat de València (UV) se constituyó entonces el grupo de Innovación Docente en Microbiología (IDM) para implementar el proyecto a nivel local. Avalados por el Servei de Formació Permanent i Innovació Educativa (SFPIE) de la UV, el grupo ha llevado a cabo diferentes iniciativas relacionadas con el objetivo fundamental del proyecto: divulgar la problemática actual relacionada con el uso inadecuado de antibióticos, el incremento de bacterias resistentes a éstos y la necesidad de encontrar nuevas moléculas con actividad antibacteriana para combatir las infecciones que provocan

Effectiveness of different vaccine formulations against vibriosis caused by Vibrio vulnificus serovar E (biotype 2) in European eels Anguilla anguilla

Vibriosis due to Vibrio vulnificus serovar E (biotype 2) is one of the main causes of mortality in European eels cultured in Europe. The main objective of this study was to develop a vaccine and a vaccination procedure against this pathogen. With this aim, we tested several vaccine formulations (inactivated whole-cells with and without toxoids‹inactivated extracellular products‹from capsulated and uncapsulated strains, attenuated live vaccines and purified lipopolysaccharide [LPS]) on eels maintained under controlled laboratory conditions using different delivery routes (injection and immersion). To study the immune response we estimated antibody titers and bactericidal/bacteriostatic activity in mucus and serum. To evaluate protection, we calculated the relative percent survival (RPS) after intraperitoneal (i.p.) injection and bath challenge of the pathogen. The overall results indicate that: (1) capsular antigens seem to be essential for protective immunization; (2) vaccines confer the highest protection when administered by i.p. injection; (3) booster is needed to achieve good protection by immersion; (4) enriching the vaccine with toxoids enhances protection to optimal levels (RPS values around 70 to 100%, depending on the delivery route); and (5) the protective effect in serum and mucus depends on the route of administration and seems to be related to the production of specific antibodies.Fouz Rodriguez, Belen, [email protected] ; Sanjuan Caro, Eva, [email protected] ; Amaro Gonzalez, Carmen, [email protected]