Prospective observational study of infection in patients with pneumonia.

, an oral commensal parasite commonly found in the human mouth, is associated with periodontitis and poor oral hygiene. However, it has also been identified in the bronchoalveolar lavage fluid (BALF) of individuals with lung diseases. Notably, significant quantities of have been isolated following bronchoscopy in cases of empyema and acute respiratory distress syndrome (ARDS). Furthermore, research has demonstrated its ability to induce inflammation in pulmonary epithelial cells. To comprehend the potential role of in pneumonia, it is crucial to elucidate the relationship between the parasite and the disease. We investigated the clinical factors associated with infection in patients with pneumonia. Employing nested polymerase chain reactions, we amplified nucleic acids from BALF and analyzed the relationships between and various clinical factors. Our data revealed a significant association between and bacterial infections, high pneumonia severity index (PSI) scores, nasogastric tube feeding, and pulmonary complications. Logistic regression analyses also showed strong associations between and these clinical factors in pneumonia patients. These findings suggest that infection in pneumonia is accompanied by bacterial infection and severe clinical manifestations.