Bacterial sputum cultures. A clinician's viewpoint.

The expectorated sputum and transtracheal aspiration bacterial culture data presented by Murray and Washington were reanalyzed after removing several species unlikely to cause pneumonia in adults. After these exclusions, mean numbers of species isolated per specimen were not excessive. Those specimens with more than 25 leukocytes per field (groups 3, 4, and 5) has similar numbers of isolates per specimen (1.04, 1.05, and 1.05) compared with those with fewer than 25 leukocytes per field (groups 1, 0.57, and 2, 0.59). For this reason and others, it is recommended that expectorated sputum samples be accepted for bacterial culture if they contain more than 25 leukocytes per field.