An Oral Inoculation Infant Rabbit Model for Shigella Infection (Kuehl et. al 2020)

What is the primary characteristic of Shigellosis?

Bloody stools and colitis with mucosal damage.

Which species of bacteria causes Shigellosis?

Shigella species.

What is the role of the type III secretion system (T3SS) in Shigella?

It facilitates the invasion and replication of Shigella within the colonic epithelium.

What was the purpose of the oral inoculation infant rabbit model in this study?

To study the pathogenesis of Shigella infection.

What effect did fasting have on infant rabbits before S. flexneri inoculation?

Increased the frequency of disease.

What proinflammatory chemokine was found elevated in infected rabbits?

Interleukin 8 (IL-8).

What bacteria strain was used for the inoculation in the infant rabbit model?

Shigella flexneri strain 2457T.

What result was observed in infant rabbits subjected to orogastric inoculation with S. flexneri?

They developed diarrhea and colonic pathology similar to human shigellosis.

What feature of the colonic pathology did this study document post-infection?

Epithelial sloughing and edema.

Which mutant strains of S. flexneri did not cause disease or diarrhea in the infant rabbits?

AicsA and AmxiM mutant strains.

What does IL-8 expression in the context of Shigella infection indicate?

It promotes recruitment of neutrophils and is linked to the inflammatory response.

How did the presence of the bacterium in the colonic epithelium affect IL-8 expression?

Epithelial invasion was necessary for the upregulation of IL-8.

What major role does IcsA play in Shigella pathogenesis?

Required for bacterial spreading and adhesion to host cells.

What was unique about the infant rabbit model compared to other small animal models for studying Shigella?

It closely mimicked human shigellosis and allowed oral infection.

Which animal model usually does not develop Shigella infection following oral inoculation?

Adult mice.

What was a key finding regarding Shigella infection and heterophil recruitment?

Heterophil recruitment was less pronounced in infections with the WT strain.

What did the transposon insertion sequencing reveal about S. flexneri colonization?

There is a narrow bottleneck in S. flexneri infection leading to loss of genetic diversity.

Which type of microscopy was used to assess the presence of S. flexneri in intestinal tissue?

Immunofluorescence microscopy.

How did fasting infants prior to S. flexneri inoculation affect their health outcomes?

Higher rates of diarrhea and increased bacterial colonization were observed.

What conclusion can be drawn about the role of T3SS in the infant rabbit model of shigellosis?

T3SS is essential for the pathogenicity of S. flexneri in this model.