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

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.


Related in: MedlinePlus

Cytotoxicity assay and LD50 determination performed in Vero cell cultures. (A) Vero cell culture with Minimal Essential Medium (Viability test). (B) Vero cell culture with Craig Medium (Viability test). (C) Negative control with E. coli K12. (D) Positive control with E. coli O157: H7, Cytotoxic damage is shown (arrows) by destruction of the cell monolayer and “old lace” effect. (E) Cytotoxic damage of A. hydrophila F-0050 strain. (F) Cytotoxic damage of A. caviae 421423 strain. (G) Graphical representation of the LD50 titer of all strains.
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Figure 1: Cytotoxicity assay and LD50 determination performed in Vero cell cultures. (A) Vero cell culture with Minimal Essential Medium (Viability test). (B) Vero cell culture with Craig Medium (Viability test). (C) Negative control with E. coli K12. (D) Positive control with E. coli O157: H7, Cytotoxic damage is shown (arrows) by destruction of the cell monolayer and “old lace” effect. (E) Cytotoxic damage of A. hydrophila F-0050 strain. (F) Cytotoxic damage of A. caviae 421423 strain. (G) Graphical representation of the LD50 titer of all strains.

Mentions: The cytotoxicity test performed in Vero cell cultures showed that 17/66 (25.7%) cell-free bacterial preparations caused cytotoxic damage, suggesting production of an active Stx (Figure 1), revealed by the characteristic damage caused by Stx.


Active Shiga-Like Toxin Produced by Some Aeromonas spp., Isolated in Mexico City
Cytotoxicity assay and LD50 determination performed in Vero cell cultures. (A) Vero cell culture with Minimal Essential Medium (Viability test). (B) Vero cell culture with Craig Medium (Viability test). (C) Negative control with E. coli K12. (D) Positive control with E. coli O157: H7, Cytotoxic damage is shown (arrows) by destruction of the cell monolayer and “old lace” effect. (E) Cytotoxic damage of A. hydrophila F-0050 strain. (F) Cytotoxic damage of A. caviae 421423 strain. (G) Graphical representation of the LD50 titer of all strains.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 1: Cytotoxicity assay and LD50 determination performed in Vero cell cultures. (A) Vero cell culture with Minimal Essential Medium (Viability test). (B) Vero cell culture with Craig Medium (Viability test). (C) Negative control with E. coli K12. (D) Positive control with E. coli O157: H7, Cytotoxic damage is shown (arrows) by destruction of the cell monolayer and “old lace” effect. (E) Cytotoxic damage of A. hydrophila F-0050 strain. (F) Cytotoxic damage of A. caviae 421423 strain. (G) Graphical representation of the LD50 titer of all strains.
Mentions: The cytotoxicity test performed in Vero cell cultures showed that 17/66 (25.7%) cell-free bacterial preparations caused cytotoxic damage, suggesting production of an active Stx (Figure 1), revealed by the characteristic damage caused by Stx.

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.


Related in: MedlinePlus