Critical role of bacterial dissemination in an infant rabbit model of bacillary dysentery

Area of Science:

• Microbiology
• Pathogenesis
• Animal Models

Background:

• Shigella flexneri causes millions of bacillary dysentery cases and deaths globally.
• Existing small-animal models fail to replicate key human symptoms like bloody diarrhea.

Purpose of the Study:

• To establish and validate a novel small-animal model for Shigella flexneri infection.
• To investigate the pathogenic mechanisms of S. flexneri in a human-relevant model.

Main Methods:

• Infection of infant rabbits with S. flexneri.
• Histopathological analysis of colonic tissue.
• Assessment of bacterial dissemination and host immune response.

Main Results:

• Infant rabbits infected with S. flexneri developed severe inflammation, colonic ulceration, and bloody diarrhea.
• Type III secretion system (T3SS)-dependent invasion is essential for initial inflammation and vascular damage.
• Bacterial cell-to-cell spread is critical for severe ulceration, bloody diarrhea, and weight loss.

Conclusions:

• The infant rabbit model accurately recapitulates human Shigella flexneri infection symptoms.
• Bacterial dissemination is a key factor in S. flexneri pathogenesis.
• This model offers a valuable platform for therapeutic development against bacillary dysentery.