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

Polymerase chain reaction (PCR) was used for detecting Legionella DNA in wa ter, sputum, tracheal aspirate and bronchoalveolar lavage fluid. There is p aucity of data on the use of PCR for detection of Legionella in serum and u rine samples. In 82 patients admitted with community-acquired pneumonia, ur inary PCR was used in addition to urinary antigen assay for Legionella pneu mophila 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, a nd 15 patients with negative urine antigen showing no fourfold rise in anti body titers in immunofluorescence test.