Legionella Prosthetic-Valve Endocarditis

Abstract

Since 1982 seven patients at Stanford University Medical Center have been shown to have prosthetic-valve endocarditis caused by Legionella pneumophila or L dumoffii. We studied the clinical features of legionella endocarditis at the time of diagnosis and performed a case-control study to analyze risk factors for the infection. All patients with endocarditis had a chronic course (3 to 19 months after surgery) of fever, night sweats, weight loss, and anemia, but no embolic events or immune-complex deposition disease. Five patients required surgical replacement of their infected prosthetic valves. The case-control study revealed that during the early postoperative period, patients who later contracted legionella endocarditis were more likely to have had symptoms and signs attributable to postcardiomyotomy syndrome than were patients who did not contract endocarditis (PL pneumophila isolates were genotypically identical to isolates from the hospital drinking water. L dumoffii isolates from patients with endocarditis were derived from a single strain apparently unique to this medical center.