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Role of fibronectin in the pathogenesis of gram-negative bacillary pneumonia
1Department of Microbiology and Infectious Diseases, University of Calgary Health Sciences Center, Alberta, Canada.
Abstract:
Because the pharyngeal flora may be an important determinant of the etiology of pneumonia, the presence of gram-negative bacilli in the oropharynx might be expected to be a prelude to pneumonia due to these organisms. Colonization of the upper respiratory tract by gram-negative bacilli is correlated with adherence of gram-negative bacilli to epithelial cells. Increased adherence is associated with a loss of fibronectin from the surface of oral epithelial cells, which presumably occurs as a result of the action of secretory proteases that denude cells of fibronectin. Thus, fibronectin may be described as a modulator of the composition of the oral flora. It seems more likely that the level of protease activity or the determinants that control the level of protease activity are the true modulators of the composition of the oral flora. The delineation of these determinants should lead to a greater understanding of the pathogenesis of gram-negative bacillary pneumonia.
Insights
Gram-negative bacilli in the throat can lead to pneumonia. Loss of fibronectin on oral cells, likely due to proteases, increases bacterial adherence and colonization, impacting pneumonia risk.
Area of Science:
- Microbiology
- Infectious Diseases
- Pulmonary Medicine
Background:
- The pharyngeal flora plays a role in pneumonia etiology.
- Gram-negative bacilli in the oropharynx may precede pneumonia caused by these organisms.
Purpose of the Study:
- To investigate the role of fibronectin and protease activity in gram-negative bacilli colonization of the oropharynx.
- To understand the determinants modulating oral flora composition and its link to pneumonia pathogenesis.
Main Methods:
- The study focuses on the correlation between gram-negative bacilli colonization and adherence to epithelial cells.
- It examines the association between increased adherence and fibronectin loss from oral epithelial cells.
Main Results:
- Increased adherence of gram-negative bacilli to oral epithelial cells is linked to fibronectin loss.
- This fibronectin loss is presumed to be caused by secretory proteases.
Conclusions:
- Fibronectin is a potential modulator of oral flora, but protease activity is likely the primary determinant.
- Identifying determinants of protease activity is crucial for understanding gram-negative bacillary pneumonia pathogenesis.