Characterization of Aeromonas virulence using an immunocompromised mouse model

Area of Science:

• Microbiology
• Immunology
• Infectious Diseases

Background:

• Aeromonas species are increasingly recognized as opportunistic pathogens.
• Understanding the factors contributing to Aeromonas extraintestinal infections is crucial for public health.

Purpose of the Study:

• To characterize the ability of various Aeromonas strains to cause persistent extraintestinal infections in an immunocompromised mouse model.
• To investigate the correlation between in vitro virulence factors and in vivo persistence.

Main Methods:

• An immunocompromised mouse model was established using cyclophosphamide.
• Thirty-four Aeromonas isolates from seven species were administered via intraperitoneal injection.
• Bacterial persistence in liver and spleen tissues was assessed at 24 hours post-infection.
• In vitro assays were performed to detect cytotoxicity, lipase, elastase, and hemolytic activity.

Main Results:

• Aeromonas hydrophila and Aeromonas veronii biotype sobria strains demonstrated significant persistence in mouse liver and spleen tissues.
• Isolates of other Aeromonas species did not exhibit persistent colonization.
• No correlation was found between the presence of tested virulence factors (cytotoxicity, lipase, elastase, hemolysis) and bacterial persistence in vivo.

Conclusions:

• Aeromonas hydrophila and A. veronii biotype sobria are key species capable of causing persistent extraintestinal infections in immunocompromised hosts.
• Standard in vitro virulence factor assays are insufficient to predict the in vivo persistence and pathogenicity of Aeromonas strains.