Legionella longbeachae pneumonia: report of two cases.

Legionella longbeachae serogroup 1 was isolated from the respiratory secretions of two patients with community-acquired pneumonia. One patient had a mild infection without evidence of the involvement of other organs and recovered, in spite of inappropriate antibiotic therapy. The other patient was severely-ill on presentation with multisystem failure and died soon after admission to hospital. The organisms were identified by the immunofluorescence technique and by quantitative DNA-hybridization studies. The sources of the infection in these patients are unknown as the organism has never been isolated from the SA environment.