Branhamella catarrhalis pneumonia: report of two cases and review of the literature.

Branhamella (Neisseria) catarrhalis is a saprophytic inhabitant of the human oropharynx with the capacity to cause infection, particularly in immunodeficient hosts. There have been 2 cases of Branhamella catarrhalis pneumonia reported in the literature. Two additional cases are described and the subject reviewed. An 80-yr-old woman with chronic lymphocytic leukemia presented with left lower lobe pneumonia. Gram stain of transtracheal aspirate revealed intraleukocytic and extraleukocytic gram-negative diplococci, and a beta-lactamase producing strain of Branhamella catarrhalis was cultured. Therapy with erythromycin resulted in resolution of symptoms and eradication of the organism. A 64-ye-old alcoholic man presented with fever and multiple seizures. Chest roentgenogram revealed left lower lobe pneumonia. Cultures of endotracheal aspirate and blood grew a strain of Branhamella catarrhalis sensitive to penicillin. Penicillin treatment resulted in resolution of pulmonary infiltrate and eradication of the organism. The potential for Branhamella catarrhalis to produce pneumonia and the choice of antimicrobial therapy is discussed. It is emphasized that this organism should not be assumed to be a "normal" isolate and that penicillin may be ineffective in the treatment of Branhamella catarrhalis infections.