Enzyme-linked immunoassay for detection of PCR-amplified DNA of legionellae in bronchoalveolar fluid.

A nonradioactive method is described that detects 10 to 100 legionellae in 1 ml of bronchoalveolar lavage fluid. DNA is purified by a proteinase K-phenol protocol or with a commercial DNA preparation kit and amplified by PCR with amplimers specific for the 16S rRNA gene of Legionella pneumophila. The upstream primer is 5' biotinylated. The amplification product is immobilized on streptavidin-coated microtiter plates. Because of the high binding capacity, no removal of nonincorporated biotin from the PCR product is required. After alkaline denaturation, the single-stranded PCR product is hybridized with a 5' digoxigenin-labeled probing oligomer. The amplification product is then detected by …