Legionella species are slow growing fastidious gram-negative organisms that are ubiquitous in the environment. Most exposures which lead to human disease are waterborne, primarily due to inhalation of water droplets from contaminated potable water. Inhalation of water droplets containing Legionella can lead to severe lower respiratory infection (pneumonia) known as Legionnaire's disease. While Legionella is a cause of community acquired pneumonia, it can also be acquired from hospital water systems. Certain populations are at particularly high risk of developing this disease, including those with underlying chronic illness with a high mortality rate among immunocompromised patients. Early diagnosis is key to preventing Legionella-associated mortality.
Rapid urinary assays used to detect Legionella are specific only for L. pneumophila serotype 1, while culture methods require special media and Legionella species is often slow to grow. The LEGDNA (Legionella PCR) is a real-time PCR assay targeting 16S rRNA gene followed by sequence analysis which detects and identifies Legionella pneumophila and other Legionella spp.
