Invasive ability of Plesiomonas shigelloides

Area of Science:

• Microbiology
• Infectious Diseases
• Bacterial Pathogenesis

Background:

• Plesiomonas shigelloides is an emerging pathogen causing gastroenteritis in humans.
• Shigella sonnei is a well-characterized invasive bacterial pathogen causing bacillary dysentery.
• Understanding the pathogenic mechanisms of P. shigelloides is crucial for disease management.

Purpose of the Study:

• To investigate the invasive potential of Plesiomonas shigelloides strains isolated from children with acute diarrhea.
• To compare the invasiveness of these strains with Shigella sonnei.
• To explore the correlation between antigen sharing, Sereny test results, and toxin production in invasive P. shigelloides.

Main Methods:

• Isolation of Plesiomonas shigelloides strains from pediatric patients with acute diarrhea.
• In vitro invasiveness assay using HeLa cells.
• Sereny test for bacterial invasiveness.
• Antigenic characterization of bacterial strains.
• Detection and characterization of bacterial toxins affecting HeLa cells.

Main Results:

• Five out of 16 P. shigelloides strains demonstrated HeLa cell invasiveness comparable to Shigella sonnei.
• None of the invasive P. shigelloides strains were positive in the Sereny test.
• Three invasive strains shared antigens with Shigella, but no correlation with invasiveness was found.
• Only one invasive strain produced a toxin causing HeLa cell rounding; others produced a protein synthesis inhibitor without significant morphological changes.

Conclusions:

• Certain P. shigelloides strains possess invasive properties for host cells, independent of the Sereny test.
• Antigenic similarities with Shigella do not necessarily confer invasiveness.
• P. shigelloides exhibits diverse mechanisms of virulence, including cell invasion and toxin production, contributing to diarrheal disease.