Bacterial colonization of the upper respiratory tract of patients with primary lung cancer and nonmalignant lung disease

We examined the bacterial colonization of the upper respiratory tract of 110 patients with primary lung cancer (PLC), 75 patients with nonmalignant lung diseases (NMLD) and 45 healthy volunteers (HV), comparing the sensitivity of expectorated sputum, and throat and nasal swabs. The frequency of bacterial colonization of the upper respiratory tract was significantly higher in the PLC patients (59.1%) than in NMLD patients (37.3%, p < 0.01) and HV (37.8%, p < 0.01). The frequency of gram-negative colonization was significantly higher in PLC patients than in the other subjects (p < 0.01). Expectorated sputum and nasal swab were the most sensitive for detection of whole bacteria and methicillin-resistant Staphylococcus aureus in the patients with PLC. Our results showed that PLC patients are significantly more frequently colonized by bacteria in their upper respiratory tracts and that a combination culture of expectorated sputum and nasal swab is suitable to estimate the bacterial colonization of the upper respiratory tract in the patients.