0000000001096243
AUTHOR
David Pajuelo Gámez
Novel host-specific iron acquisition system in the zoonotic pathogen Vibrio vulnificus
Vibrio vulnificus is a marine bacterium associated with human and fish (mainly farmed eels) diseases globally known as vibriosis. The ability to infect and overcome eel innate immunity relies on a virulence plasmid (pVvbt2) specific for biotype 2 (Bt2) strains. In the present study, we demonstrated that pVvbt2 encodes a host-specific iron acquisition system that depends on an outer membrane receptor for eel transferrin called Vep20. The inactivation of vep20 did not affect either bacterial growth in human plasma or virulence for mice, while bacterial growth in eel blood/plasma was abolished and virulence for eels was sig-nificantly impaired. Furthermore, vep20 is an iron-regulated gene overexpre…
Iron and virulence in the zoonotic pathogen Vibrio vulnificus
Vibrio vulnificus es un patógeno humano emergente que es autóctono de ecosistemas acuáticos salobres de climas templados, tropicales y subtropicales. La especie se subdivide en 3 biotipos (Bt), de los cuales el Bt2 contiene un grupo de cepas que, además de poder infectar al hombre, pueden causar infecciones en peces. Este grupo es un complejo clonal serológicamente homogéneo que denominamos serovar E o serovar zoonótica (VvBt2SerE). Como patógeno humano, VvBt2SerE causa casos esporádicos de infecciones graves en heridas que pueden derivar en septicemia secundaria en pacientes inmunocomprometidos y como patógeno de peces, brotes o epizootias de una septicemia hemorrágica conocida como vibrio…
MARTX of Vibrio vulnificus biotype 2 is a virulence and survival factor
Vibrio vulnificus biotype 2 is a polyphyletic group whose virulence for fish relies on a plasmid. This plasmid contains an rtxA gene duplicated in the small chromosome that encodes a MARTX (Multifunctional, Autoprocessing Repeats-in-Toxin) unique within the species in domain structure (MARTX type III). To discover the role of this toxin in the fitness of this biotype in the fish-farming environment, single- and double-knockout mutants were isolated from a zoonotic strain and analysed in a series of in vivo and in vitro experiments with eel, fish cell lines and amoebae isolated from gills. Mice, murine and human cell lines were also assayed for comparative purposes. The results suggest that …
Host-Nonspecific Iron Acquisition Systems and Virulence in the Zoonotic Serovar of Vibrio vulnificus
The zoonotic serovar of Vibrio vulnificus (known as biotype 2 serovar E) is the etiological agent of human and fish vibriosis. The aim of the present work was to discover the role of the vulnibactin- and hemin-dependent iron acquisition systems in the pathogenicity of this zoonotic serovar under the hypothesis that both are host-nonspecific virulence factors. To this end, we selected three genes for three outer membrane receptors (vuuA, a receptor for ferric vulnibactin, and hupA and hutR, two hemin receptors), obtained single and multiple mutants as well as complemented strains, and tested them in a series of in vitro and in vivo assays, using eels and mice as animal models. The overall re…