Related Experiment Video
Updated: May 25, 2026
Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice
Published on: March 17, 2014
Analysis of the pathological lesions of the lung in a mouse model of cutaneous infection with Streptococcus pyogenes
Masaaki Minami1, Sayaka Sobue, Masatoshi Ichihara
1Department of Bacteriology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Abstract:
Invasive diseases such as toxic shock syndrome caused by Streptococcus pyogenes (S. pyogenes) are re-emerging infectious diseases. The mechanism of pathogenesis is not completely understood although the virulence of this organism has been analyzed using animal model systems, particularly using mice. The analysis of the progression of infection, however, is difficult. Computed tomography (CT) scanning is an extremely powerful technique that we applied to the mouse model of cutaneous infection with S. pyogenes. Two or three days after subcutaneous administration of bacteria, high density reticular areas were detected in the lung by CT. Histopathological examination of the lung was performed to examine the results of CT. Increased numbers of cytokeratin-positive epithelial cells, probably alveolar type II epithelial cells, were detected but no remarkable increase of inflammatory cell infiltrates was observed. Our results show that the pathological lesions of the lung in this model, wherein relatively few numbers of neutrophils were in the alveoli, are well correlated with the lung of a part of streptococcal toxic shock syndrome patients. Therefore, CT may be useful in assessing the progression of S. pyogenes infection, particularly in the pathological lesions of the lung in this model.
Insights
Computed tomography (CT) scanning effectively visualizes lung pathology in a mouse model of Streptococcus pyogenes infection. This technique aids in understanding invasive bacterial disease progression, correlating with human streptococcal toxic shock syndrome cases.
Area of Science:
- Microbiology
- Infectious Diseases
- Medical Imaging
Background:
- Streptococcus pyogenes (S. pyogenes) causes re-emerging invasive diseases like toxic shock syndrome.
- The precise mechanisms of S. pyogenes pathogenesis remain incompletely understood.
- Analyzing infection progression in animal models, particularly mice, presents challenges.
Purpose of the Study:
- To evaluate the utility of computed tomography (CT) scanning in assessing S. pyogenes infection progression in a mouse model.
- To correlate CT findings with histopathological changes in the lung.
Main Methods:
- A mouse model of cutaneous S. pyogenes infection was established.
- Subcutaneous bacterial administration was followed by CT scanning of the lungs.
- Histopathological examination of lung tissues was performed for correlation.
Main Results:
- CT scans detected high-density reticular areas in the lungs 2-3 days post-infection.
- Histopathology revealed increased cytokeratin-positive epithelial cells, likely alveolar type II cells.
- Minimal inflammatory cell infiltrates, specifically neutrophils, were observed in the alveoli.
Conclusions:
- CT scanning is a powerful tool for assessing lung pathological lesions in S. pyogenes infection models.
- The observed lung pathology in the mouse model closely resembles that seen in some streptococcal toxic shock syndrome patients.
- CT imaging can aid in understanding the progression of S. pyogenes infections.
