Rapid diagnosis of Legionnaires' disease by bronchoalveolar lavage

Legionella pneumophila has, in recent years, emerged as a common pulmonary pathogen in the normal and immunocompromised patient (ICP). Making a specific etiologic diagnosis of pneumonia in the latter group is a common clinical dilemma often complicated by poor specimen availability and risks of invasive procedures. Improved staining and isolation techniques for L pneumophila would suggest that early diagnosis could be possible if adequate specimens were available. This report summarizes our experience with bronchoalveolar lavage (BAL) with which we have diagnosed L pneumophila in eight immunocompromised patients, well in advance of more traditional methods. On the basis of this experience, we would advocate early BAL in the ICP as a rapid, safe, moderately sensitive and specific diagnostic test to aid in the identification of L pneumophila.