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Host-like carbohydrates promote bloodstream survival of Vibrio vulnificus in vivo.

Lubin JB, Lewis WG, Gilbert NM, Weimer CM, Almagro-Moreno S, Boyd EF, Lewis AL - Infect. Immun. (2015)

Bottom Line: Sialic acids are found on all vertebrate cell surfaces and are part of a larger class of molecules known as nonulosonic acids.In fact, levels of bacterial persistence in the blood corresponded to the overall levels of these molecules expressed by V. vulnificus isolates.Taken together, these results suggest that molecules similar to sialic acids evolved to facilitate the aquatic lifestyle of V. vulnificus but that their emergence also resulted in a gain of function with life-threatening potential in the human host.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware, USA.

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Related in: MedlinePlus

Elaboration of NulO as a virulence factor during V. vulnificus bloodstream infection. (A to C) Animals were infected with approximately 107 bacteria via the tail vein, using a 1:1 mixture of the strain pair shown in each panel (a spontaneously streptomycin-resistant isolate of the Δnab2 strain was utilized). Blood was drawn from the submandibular vein 90 min after infection, and serial dilutions were plated on selective media containing streptomycin or chloramphenicol to distinguish between competing strains, as described in Materials and Methods. (D) The competitive index was calculated as described in Materials and Methods and takes into account both the inoculum dose and 90-min blood titers for both strains. Data shown are for two independent experiments comparing the stated strain competitions in parallel, using 4 mice per group. The Mann-Whitney U test was used to examine statistical significance; *, P < 0.03, ***, P < 0.001; ns, not statistically significant.
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Figure 4: Elaboration of NulO as a virulence factor during V. vulnificus bloodstream infection. (A to C) Animals were infected with approximately 107 bacteria via the tail vein, using a 1:1 mixture of the strain pair shown in each panel (a spontaneously streptomycin-resistant isolate of the Δnab2 strain was utilized). Blood was drawn from the submandibular vein 90 min after infection, and serial dilutions were plated on selective media containing streptomycin or chloramphenicol to distinguish between competing strains, as described in Materials and Methods. (D) The competitive index was calculated as described in Materials and Methods and takes into account both the inoculum dose and 90-min blood titers for both strains. Data shown are for two independent experiments comparing the stated strain competitions in parallel, using 4 mice per group. The Mann-Whitney U test was used to examine statistical significance; *, P < 0.03, ***, P < 0.001; ns, not statistically significant.

Mentions: To determine whether NulO molecules play a role in V. vulnificus systemic virulence, a tail vein injection model was used to directly administer bacteria to the bloodstream in CD1 mice. A spontaneously streptomycin-resistant isolate of the CMCP6 Δnab2 strain (Δnab2 Smr) was generated specifically for use in these experiments to distinguish mutant from WT bacteria during competition in vivo. This strain retained the phenotypes observed for the Δnab2 strain and did not vary from the parental strain in its growth characteristics in vitro (not shown). Strains were set up to compete against each other in a pairwise fashion, using a 1:1 mixed inoculum, to examine relative fitness levels. Blood was drawn at early time points postinfection, and the numbers of CFU of the strains were determined based on differential resistance to streptomycin. These experiments revealed that the nab2 gene confers a strong survival advantage to the WT strain in the bloodstream in vivo. The WT strain was present at approximately 5,000 CFU/ml of blood at 90 min postinfection, whereas the Δnab2 Smr strain was completely cleared by most animals at this time point (Fig. 4A).


Host-like carbohydrates promote bloodstream survival of Vibrio vulnificus in vivo.

Lubin JB, Lewis WG, Gilbert NM, Weimer CM, Almagro-Moreno S, Boyd EF, Lewis AL - Infect. Immun. (2015)

Elaboration of NulO as a virulence factor during V. vulnificus bloodstream infection. (A to C) Animals were infected with approximately 107 bacteria via the tail vein, using a 1:1 mixture of the strain pair shown in each panel (a spontaneously streptomycin-resistant isolate of the Δnab2 strain was utilized). Blood was drawn from the submandibular vein 90 min after infection, and serial dilutions were plated on selective media containing streptomycin or chloramphenicol to distinguish between competing strains, as described in Materials and Methods. (D) The competitive index was calculated as described in Materials and Methods and takes into account both the inoculum dose and 90-min blood titers for both strains. Data shown are for two independent experiments comparing the stated strain competitions in parallel, using 4 mice per group. The Mann-Whitney U test was used to examine statistical significance; *, P < 0.03, ***, P < 0.001; ns, not statistically significant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496609&req=5

Figure 4: Elaboration of NulO as a virulence factor during V. vulnificus bloodstream infection. (A to C) Animals were infected with approximately 107 bacteria via the tail vein, using a 1:1 mixture of the strain pair shown in each panel (a spontaneously streptomycin-resistant isolate of the Δnab2 strain was utilized). Blood was drawn from the submandibular vein 90 min after infection, and serial dilutions were plated on selective media containing streptomycin or chloramphenicol to distinguish between competing strains, as described in Materials and Methods. (D) The competitive index was calculated as described in Materials and Methods and takes into account both the inoculum dose and 90-min blood titers for both strains. Data shown are for two independent experiments comparing the stated strain competitions in parallel, using 4 mice per group. The Mann-Whitney U test was used to examine statistical significance; *, P < 0.03, ***, P < 0.001; ns, not statistically significant.
Mentions: To determine whether NulO molecules play a role in V. vulnificus systemic virulence, a tail vein injection model was used to directly administer bacteria to the bloodstream in CD1 mice. A spontaneously streptomycin-resistant isolate of the CMCP6 Δnab2 strain (Δnab2 Smr) was generated specifically for use in these experiments to distinguish mutant from WT bacteria during competition in vivo. This strain retained the phenotypes observed for the Δnab2 strain and did not vary from the parental strain in its growth characteristics in vitro (not shown). Strains were set up to compete against each other in a pairwise fashion, using a 1:1 mixed inoculum, to examine relative fitness levels. Blood was drawn at early time points postinfection, and the numbers of CFU of the strains were determined based on differential resistance to streptomycin. These experiments revealed that the nab2 gene confers a strong survival advantage to the WT strain in the bloodstream in vivo. The WT strain was present at approximately 5,000 CFU/ml of blood at 90 min postinfection, whereas the Δnab2 Smr strain was completely cleared by most animals at this time point (Fig. 4A).

Bottom Line: Sialic acids are found on all vertebrate cell surfaces and are part of a larger class of molecules known as nonulosonic acids.In fact, levels of bacterial persistence in the blood corresponded to the overall levels of these molecules expressed by V. vulnificus isolates.Taken together, these results suggest that molecules similar to sialic acids evolved to facilitate the aquatic lifestyle of V. vulnificus but that their emergence also resulted in a gain of function with life-threatening potential in the human host.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware, USA.

Show MeSH
Related in: MedlinePlus