Abstract
Aspiration pneumonia is a type of pneumonia to which compromised hosts, such as elderly people, are particularly susceptible. A wide range of indigenous microorganisms found in the oral cavity may be involved in the emergence of aspiration pneumonia. Based on the high concentrations of C. albicans found in the oral cavity of elderly people, the present study investigated the pathogenicity of C. albicans in cases of aspiration pneumonia using a mouse model. C. albicans was inoculated into ICR mice administered with prednisolone. At one day after inoculation, the lungs were removed fromthe mice to prepare tissue sections. These sections showed marked neutrophil infiltration and congestion in the alveoli, as well as bronchiolar epithelial cell detachment.
These inflammatory changes persisted even five days after inoculation. Periodic acid-Schiff staining specific to C. albicans confirmed numerous C. albicans hyphae in the alveoli. Measurements of tumor necrosis factora production in infected murine pulmonary tissue showed marked production, peaking three days after infection. These findings suggest that indigenous C. albicans in the oral cavity may lead to aspiration pneumonia in immuno-compromised hosts, including the elderly.
