Infective endocarditis (IE) is a severe condition characterized by infection of the endocardial surface of the heart, most commonly resulting from bacterial invasion. Fungal etiologies are less common, and can pose a significant challenge due to their specific therapies.

A 42-year-old man with a history of smoking and alcohol addiction was transferred to the Department of Intensive Cardiac Therapy (DICT) with a diagnosis of aortic stenosis and suspected IE treated with vancomycin. His initial hospitalization was prompted by stroke symptoms, including left-side paresis, 6 weeks before.

Upon admission to the DICT, the patient was conscious and presented with hypotonia necessitating continuous infusion of dobutamine. Transthoracic echocardiography (TTE) (Figure 1A) showed a stenotic aortic valve with maximal and mean gradients of 100 mm Hg and 60 mm Hg, respectively, an aortic valve area of 1 cm2, and left ventricular ejection fraction (LVEF) of 45%. Microbiology specimens were collected, and empiric antibiotic therapy was initiated. Transesophageal echocardiography (TEE) showed a bicuspid aortic valve, with fusion of the right and left coronary leaflets, significant degenerative changes, and calcification of the commissure between the coronary and noncoronary leaflets. The absence of noticeable vegetations or paravalvular abscesses suggested no overt signs of IE on the aortic valve. Cardiac computed tomography (CT) angiography confirmed the presence of a bicuspid aortic valve (Figure 1B). A CT scan of the head (Figure 1C) revealed hypodense foci in the right parietal-frontal and occipital regions, consistent with prior findings.

Figure 1. A – transthoracic echocardiography showing a stenotic aortic valve (arrow); B – cardiac computed tomography (CT) angiography, multiplanar reconstruction, transverse projection parallel to the aortic valve, showing bicuspid aortic valve (right and left coronary leaflet fusion) with raphe (arrow) and thickened valve leaflets with calcifications; C – CT image showing hypodense foci in the right parietal-frontal and occipital regions (arrow); D – laboratory parameters of infection monitored during the patient’s hospitalization along with the results of microbiological cultures and antibiotic treatment; red circles indicate blood cultures positive for Trichosporon spp., blue circle, blood cultures positive for metycilline-sensitive Staphylococcus pettenkoferi, black circles, blood cultures positive for methicillin-resistant coagulase-negative Staphylococcus epidermidis, and the green circle indicates negative blood culture results. E – transesophageal echocardiography (TEE) showing the aortic valve, paravalvular abscess (red arrow), and the fused right and left coronary leaflets (white arrow); F – TEE showing a paravalvular leak (arrow)

Abbreviations: AmB, liposomal amphotericin B; CRP, C-reactive protein; IE, infective endocarditis; iv, intravenous 

After a few days, Trichosporon spp. was identified in blood cultures. Preferred treatment for this type of infection is voriconazole; however, due to its extensive side effects and anticipation of a long-term treatment course, we opted to begin therapy with liposomal amphotericin B (AmB), which is an acceptable alternative. The minimum inhibitory concentration for both AmB and voriconazole is 0.032 mg/l. Moreover, blood cultures were positive for metycilline-sensitive Staphylococcus pettenkoferi and therapy with cloxacillin was started (Figure 1D). Despite administration of an appropriate dose of AmB, blood cultures taken 10 days later remained positive, and methicillin-resistant coagulase-negative Staphylococcus epidermidis was additionally detected. Consequently, we initiated treatment with vancomycin and switched AmB to voriconazole (Figure 1D). Repeated TEE showed a large, partially drained paravalvular abscess sized 3.8 cm × 2.4 cm extending from the posterior to the lateral part of the aortic ring. A second abscess was detected along the posterolateral wall of the aorta (Figure 1E), accompanied by small vegetations (<⁠1 cm). Moreover, a paravalvular leak was present (Figure 1F).

The patient underwent cardiac surgery. The aortic valve was replaced with a biological 23-mm On-X valve (On-X Life Technologies Inc., Austin, Texas, United States), and pseudoaneurysm was closed using pericardial tissue. Microbiological culture from the infected valve tested positive for Trichosporon spp.

Postoperatively, the patient’s LVEF decreased to 30%; however, he experienced no complications, and the dobutamine infusion was successfully stopped. Voriconazole therapy was continued for 3 to 4 months postsurgery.

IE remains a diagnostic challenge because of its variable clinical presentation. Symptoms of IE include fever, cardiac murmur, congestive heart failure, embolic complications (as in our patient), and cardiac conduction abnormalities. Echocardiographic imaging and blood cultures should be performed as soon as IE is suspected. Moreover, echocardiography should be repeated 5 to 7 days after initial normal or inconclusive findings, if the suspicion of IE remains high. Bicuspid aortic valve is one of the cardiac risk factors for IE, along with previous IE, prosthetic heart valve, transvenous cardiac implantable electronic device, and congenital heart disease. Noncardiac risk factors include the presence of central venous catheters, drug abuse, immunosuppression, recent dental or surgical procedures, and hemodialysis. Empiric intravenous antibiotic therapy should be started as soon as possible, with subsequent correction as per the results of blood cultures.1 The most frequent microorganism causing IE is Staphylococcus aureus. Fungal etiologies are much less common, and thus more difficult to diagnose and manage.

Trichosporon spp. are responsible for a range of infections, from skin conditions (eg, white piedra), through allergic pneumonia, to severe invasive infections, including fungemia, urinary tract infections, peritonitis, endocarditis, arthritis, esophagitis, meningitis, brain abscess, splenic abscess, and uterine infections.2,3 Mortality rate in Trichosporon spp. infections ranges between 30% and 90%, and is particularly high in immunocompromised patients, especially those with hematologic malignancies.4

Voriconazole is typically the first-line therapy for invasive infections, including those occurring in patients with acute leukemia and myelodysplastic syndrome.3 The ineffective antifungal action of AmB in our patient might be due to the fact that vancomycin has been shown to stimulate planktonic growth of Trichosporon spp. and increase tolerance to AmB.5

Duration of the treatment after the surgery was a matter of debate. Decision regarding prolonged antifungal treatment was based on our experience with patients after heart transplant.

In conclusion, it is particularly important to consider IE in differential diagnosis of patients with embolism and fever. Very often, such patients are referred to physicians specializing in treatment of a specific organ affected by the embolism. In the case of peripheral embolisms or organ abscesses, and especially in patients with fever or positive blood cultures, TTE should always be performed in search of IE signs. In addition, TTE is recommended in individuals with sepsis or those whose blood cultures tested positive for staphylococci.