Infective Endocarditis Related to Unusual Microorganisms: A Prospective Population-Based Study

Area of Science:

• Infectious Diseases
• Cardiology
• Microbiology

Background:

• Advances in cardiac surgery and microbiology have shifted the landscape of infective endocarditis (IE).
• There is an increasing proportion of IE cases associated with less common or unusual microorganisms.

Purpose of the Study:

• To investigate the incidence and characteristics of IE caused by unusual microorganisms.
• To compare the clinical features and risk factors of unusual-microorganism IE with those caused by common pathogens.

Main Methods:

• An ancillary study of a large prospective population-based survey on IE was conducted.
• Unusual-microorganism IE was defined as definite IE (Duke-Li criteria) caused by pathogens other than streptococci, staphylococci, or enterococci.
• Data on patient demographics, clinical presentation, diagnostic methods, and outcomes were analyzed.

Main Results:

• Of 471 documented IE cases, 9.8% were attributed to unusual microorganisms.
• Common unusual pathogens included Candida albicans, Cutibacterium acnes, and Pseudomonas aeruginosa.
• IE due to unusual microorganisms was significantly associated with prior heart disease (69.0% vs 44.3%), prosthetic valves (40.5% vs 18.1%), longer fever duration, and nosocomial acquisition (38.1% vs 20.2%).

Conclusions:

• Unusual microorganisms account for a notable proportion of IE cases, predominantly anaerobes, yeast, and gram-negative bacilli.
• IE caused by unusual pathogens presents with distinct epidemiological and clinical characteristics compared to IE from common bacteria.
• These findings highlight the importance of considering unusual organisms in the diagnosis and management of IE, particularly in high-risk patients.