The etiologic diagnosis of community-acquired pneumonia (CAP) is still a common medical problem. Streptococcus pneumoniae remains the most frequent cause of CAP, accounting for at least half of the cases. Increasing numbers of other organisms have been reported to be involved in the pathogenesis of this disease. Unfortunately, predicting the bacteria responsible for CAP based solely on clinical features has proved to be successful in only about half of the cases. Since proper treatment is critical in the severe cases, a number of invasive diagnostic procedures have been tested in order to find a more reliable method to certify the bacteriology of the pneumonia.
Culture of bronchial secretions obtained through fiberoptic bronchoscopy has proved to be unreliable in most of the cases due to contamination of the sample with colonizing organisms located in the upper airways. However, by using a telescoping plugged catheter (TPC), this upper airway contamination can be avoided, and quantitative cultures of these specimens can provide an accurate method to determine the etiology of the pneumonia. Broncho-alveolar lavage (BAL) has also been suggested as a useful tool in determining the bacterial etiology of pneumonia. BAL has some advantages over TPC since it does not require sophisticated equipment and allows us to obtain samples from a larger area than TPC. Both techniques have been compared only in mechanically ventilated patients with suspected pneumonia, and in such a setting they are equally reliable and accurate.
The present study was designed to examine the diagnostic value of quantitative BAL fluid cultures and TPC cultures in determining the bacterial etiology of CAP. We hypothesized that BAL cultures may replace TPC cultures in this setting.