Legionella micdadei prosthetic valve endocarditis.

Legionella usually causes pneumonia, but occasionally is in the differential diagnosis of "culture negative endocarditis" which sometimes involves prosthetic heart valves. Legionella prosthetic valve endocarditis is nearly always due to Legionella pneumophila and its clinical presentation is indistinguishable from other causes of prosthetic valve endocarditis. Diagnosis of Legionella prosthetic valve endocarditis is by recovery of the organism from the blood, demonstration or isolation of the organism from the prosthetic heart valve, or by persistently high Legionella titers which are extremely elevated in prosthetic valve endocarditis compared to Legionella pneumonia. We believe this is the first case reported of prosthetic valve endocarditis caused by Legionella micdadei, and the first case of Legionella prosthetic valve endocarditis with microscopic hematuria.