Protected Transbronchial Needle Aspiration and Protected Specimen Brush in the Diagnosis of Pneumonia

Protected transbronchial needle aspiration (PTBNA) of pneumonic lung theoretically could bypass dislodged upper respiratory tract flora, a potential source of contamination of protected specimen brush (PSB) cultures. To evaluate the usefulness of PSB end PTBNA in establishing the etiology of pneumonia, we prospectively studied 20 patients with acute bacterial pneumonia not receiving antibiotics. After informed consent, patients had fiberoptic bronchoscopy under fluoroscopy to localize the pneumonia, and specimens were obtained by the PSB. The protective plug of a specially devised needle for PTBNA wee pneumatically dislodged end aspiration wee performed within the infiltrate under fluoroscopy. Quantitative cultures were plated immediately for aerobes, anaerobes, and Legionella. Greater than 4 × 102 organisms/brush or 1 × 104 organisms/ml needle aspirate were considered to be consistent with infection. The results using PSB end PTBNA were compared in 15 of 20 patients in whom a definitive diagnosis (positive blood or pleural fluid culture) or presumptive diagnosis (expectorated sputum culture, clinical characteristics, end response to specific therapy) was established. The PSB and PTBNA cultures on uninfected control subjects (n = 5) being bronchoscoped for other reasons were negative. The PSB and PTBNA were each diagnostic in 2 of the 5 patients with definitive diagnosed. In the group with a presumptive diagnosis (n = 10), PSB wee diagnostic in 7 of 10 and PTBNA in 9 of 10. The overall (definitive plus presumptive) diagnostic yield was 60% for PSB and 73% for PTBNA. Multiple organisms were isolated in high concentrations in 53% of the patients. The most common organisms recovered in addition to the primary pathogen was alpha hemolytic streptococci. We conclude that there appears to be no advantage of PTBNA over PSB In the etiologic of bacterial pneumonia, and a substantial number of bacterial pneumonias may be polymicrobial; the role of alpha hemolytic streptococci in bacterial pneumonias deserves further study. Bronchoscopy using either the PSB or PTBNA to obtain quantitative cultures may be superior to nonqualitative methods in high risk patients with bacterial pneumonia.