Prosthetic valve endocarditis caused by Legionella pneumophila

Area of Science:

• Infectious Diseases
• Cardiology
• Microbiology

Background:

• Prosthetic valve endocarditis (PVE) is a serious complication following cardiac valve replacement surgery.
• Early and accurate diagnosis is crucial for effective treatment and improved patient outcomes.

Observation:

• A case of prosthetic valve endocarditis in a patient with aortic and mitral valve replacements using porcine xenografts.
• The patient presented with persistent fever and aortic regurgitation, suggestive of endocarditis.
• Surgical intervention revealed vegetations on both valve prostheses and an aortic annulus abscess.

Findings:

• Diagnostic investigations including valve tissue cultures, Dieterle stain, direct fluorescent antibody staining, and serum antibody testing confirmed Legionella pneumophila as the causative agent.
• Notably, the infection occurred in the absence of clinical or radiological evidence of pneumonia.
• This highlights a non-respiratory presentation of Legionella pneumophila infection.

Implications:

• Legionella pneumophila should be considered in the differential diagnosis of culture-negative prosthetic valve endocarditis.
• Clinicians should maintain a high index of suspicion for Legionella in patients with PVE, particularly when typical pneumonia symptoms are absent.
• This case underscores the importance of comprehensive microbiological investigations in complex cardiovascular infections.