“Not much room for mushrooms” in the heart: knowns and unknowns of fungal infective endocarditis

Fungal infective endocarditis is a rare but highly lethal condition. Its diagnosis is often delayed due to nonspecific symptoms, inconclusive medical imaging, and negative blood cultures. Recent reviews of cases and series over the last 5 years indicate that the condition remains rare and lethal. If fungi are identified as the causative agents in more than 5% of patient cases with infective endocarditis, it is likely that risk factors such as immune suppression or cardiac implants are probably involved. A series derived from recent case reports indicates that Candida and Aspergillus are still the main causative infectious agents, with. C parapsilosis on the rise. From these cases, diagnostic clues (frequent embolisms, ophthalmic involvement, large, mobile and friable vegetation, non-valvular cardiac manifestations) are pointing towards fungal IE. These reports, however, are not standardized and a publication bias towards rare microorganisms or towards a favorable outcome might exist. Complications might be underreported, and important data such as diagnostic delay are absent or difficult to retrieve. Pharmacologic treatment is not fully standardized. Knowledge of resistant strains in this respect is important. Statistical analysis for the effect of complications and treatment modalities on outcome shows that any result should be treated cautiously. The current series is by no means a valid substitute for a well-designed series of fungal endocarditis. However, the better outcome with Candida and patients treated with surgery confirm earlier results. An international multicentric standardized registry of cases with fungal endocarditis in order to improve the outcome of this disease is highly needed. The effect of diagnostic delay on outcome remains elusive and should be resolved.