Polymerase chain reaction for detection of legionellae DNA in urine samples from patients with community-acquired pneumonia

Polymerase chain reaction (PCR) was used for detectingLegionella DNA in water, sputum, tracheal aspirate and bronchoalveolar lavage fluid. There is paucity of data on the use of PCR for detection ofLegionella in serum and urine samples. In 82 patients admitted with community-acquired pneumonia, urinary PCR was used in addition to urinary antigen assay forLegionella pneumophila serogroup 1 and serological tests (indirect immunofluorescence and ELISA) in paired sera. PCR was positive in urine samples from 21 patients (26 %): in six of seven patients with acute legionellosis by CDC criteria, and 15 patients with negative urine antigen showing no fourfold rise in antibody titers in immunofluorescence test.