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Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City

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ABSTRACT

Shiga-like toxins (Stx) represent a group of bacterial toxins involved in human and animal diseases. Stx is produced by enterohemorrhagic Escherichia coli, Shigella dysenteriae type 1, Citrobacter freundii, and Aeromonas spp.; Stx is an important cause of bloody diarrhea and hemolytic uremic syndrome (HUS). The aim of this study was to identify the stx1/stx2 genes in clinical strains and outer membrane vesicles (OMVs) of Aeromonas spp., 66 strains were isolated from children who live in Mexico City, and Stx effects were evaluated in Vero cell cultures. The capacity to express active Stx1 and Stx2 toxins was determined in Vero cell cultures and the concentration of Stx was evaluated by 50% lethal dose (LD50) assays, observing inhibition of damaged cells by specific monoclonal antibodies. The results obtained in this study support the hypothesis that the stx gene is another putative virulence factor of Aeromonas, and since this gene can be transferred horizontally through OMVs this genus should be included as a possible causal agents of gastroenteritis and it should be reported as part of standard health surveillance procedures. Furthermore, these results indicate that the Aeromonas genus might be a potential causative agent of HUS.

No MeSH data available.


Inhibition of cytotoxic effect induced in Vero cells culture by cell-free bacterial preparations of Aeromonas spp. strains bearing the stx1 or stx2 gene.
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Figure 2: Inhibition of cytotoxic effect induced in Vero cells culture by cell-free bacterial preparations of Aeromonas spp. strains bearing the stx1 or stx2 gene.

Mentions: The application of anti-STX1 Ab in 11/17 (64.7%) strains the damage to cells in the supernatant was completely inhibited at 39.1 μg/μL Ab concentration; in 4/17 (23.5%) cell-free bacterial preparations, reduced cell damage was observed at the same concentration; and in 2/17 (11.7%) cell-free bacterial preparations, cell damage was completely inhibited at a concentration 78.2 μg/μL. Using the Ab anti-STX2 showed that in 9/17 (52.9%) cell-free bacterial preparations, cell damage was totally inhibited at 37.4 μg/μL, and 6/17 (35.2%) cell-free bacterial preparations showed reduced cell damage at the same concentration; and in 2/17 (11.7%) cell-free bacterial preparations, cell damage was completely inhibited with an Ab concentration of 74.8 μg/μL (Figures 2 and 3).


Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City
Inhibition of cytotoxic effect induced in Vero cells culture by cell-free bacterial preparations of Aeromonas spp. strains bearing the stx1 or stx2 gene.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036386&req=5

Figure 2: Inhibition of cytotoxic effect induced in Vero cells culture by cell-free bacterial preparations of Aeromonas spp. strains bearing the stx1 or stx2 gene.
Mentions: The application of anti-STX1 Ab in 11/17 (64.7%) strains the damage to cells in the supernatant was completely inhibited at 39.1 μg/μL Ab concentration; in 4/17 (23.5%) cell-free bacterial preparations, reduced cell damage was observed at the same concentration; and in 2/17 (11.7%) cell-free bacterial preparations, cell damage was completely inhibited at a concentration 78.2 μg/μL. Using the Ab anti-STX2 showed that in 9/17 (52.9%) cell-free bacterial preparations, cell damage was totally inhibited at 37.4 μg/μL, and 6/17 (35.2%) cell-free bacterial preparations showed reduced cell damage at the same concentration; and in 2/17 (11.7%) cell-free bacterial preparations, cell damage was completely inhibited with an Ab concentration of 74.8 μg/μL (Figures 2 and 3).

View Article: PubMed Central - PubMed

ABSTRACT

Shiga-like toxins (Stx) represent a group of bacterial toxins involved in human and animal diseases. Stx is produced by enterohemorrhagic Escherichia coli, Shigella dysenteriae type 1, Citrobacter freundii, and Aeromonas spp.; Stx is an important cause of bloody diarrhea and hemolytic uremic syndrome (HUS). The aim of this study was to identify the stx1/stx2 genes in clinical strains and outer membrane vesicles (OMVs) of Aeromonas spp., 66 strains were isolated from children who live in Mexico City, and Stx effects were evaluated in Vero cell cultures. The capacity to express active Stx1 and Stx2 toxins was determined in Vero cell cultures and the concentration of Stx was evaluated by 50% lethal dose (LD50) assays, observing inhibition of damaged cells by specific monoclonal antibodies. The results obtained in this study support the hypothesis that the stx gene is another putative virulence factor of Aeromonas, and since this gene can be transferred horizontally through OMVs this genus should be included as a possible causal agents of gastroenteritis and it should be reported as part of standard health surveillance procedures. Furthermore, these results indicate that the Aeromonas genus might be a potential causative agent of HUS.

No MeSH data available.