Clinical Significance of Bacteria Isolated from Bronchial Lavage Fluid in Patients with Lung Cancer

In patients with lung cancer, pneumonia has a high mortality rate, but the common pathogens are unclear because oral bacteria contaminate the sputum. This study attempted to identify bacteria in lower respiratory tract secretions obtained by bronchoscopy. The subjects were 437 patients, including 210 with adenocarcinoma, 119 with squamous cell carcinoma, 17 with large cell carcinoma, 73 with small cell carcinoma, and 18 with other cancers. Bronchial lavage was performed with 20 mL of saline followed by transbronchial biopsy. Culture of bronchial lavage fluid was negative in 112 patients, whereas it revealed a- and/or no-hemolytic streptococci in 236 patients, Staphylococcus. aureus in 14, Streptococcus pneumoniae in 14, Pseudomonas aeruginosa in 12, and other organisms in 42. In 16 patients, the same bacteria were identified in sputum and bronchial lavage fluid. When group A patients (negative, α- and/or nonhemolytic streptococci, Neisseria, or Candida) were compared with group B patients (other pathogens), fever after bronchoscopy was significantly more common in group B. Bacteria could colonize the lungs of some patients with lung cancer. These bacteria could be related to febrile episodes after bronchoscopy and could also cause problems during chemotherapy.