COVID-19-associated brain abscess caused by Trichosporon dohaense: A case report and review of literature

Abstract

We report the first case of Coronavirus Disease 2019 (COVID-19)-associated brain abscess caused by a rare Trichosporon species, T. dohaense. The patient was a known diabetic and had received systemic corticosteroids for the treatment of COVID-19. He underwent craniotomy and evacuation of abscess. The pus aspirate grew a basidiomycetous yeast, morphologically resembling Trichosporon species. The isolate was initially misidentified by VITEK® MS due to lack of mass spectral database of T. dohaense. Accurate identification was achieved by internal transcribed spacer-directed panfungal polymerase chain reaction. The patient had a favorable outcome following surgical intervention and antifungal therapy.

Keywords: Brain abscess; COVID-19; Internal transcribed spacer; MALDI-TOF MS; MALDI-TOF MS, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; Trichosporon dohaense.

Fig. 1

Axial non-contrast (A) and contrast (B) CT brain at basifrontal level showing non-enhancing hypodensity (blue arrows) in right medial frontal lobe extending till the margins of right frontal horn. Contrast CT brain axial section (C) showing enhancing soft tissue mass (circled) in ethmoidal air cells. MRI Brain T2w coronal section (D) showing mixed signal intensity lesion involving ethmoidal air cells, extending across the cribriform plate (circled) to involve right basifrontal lobe with associated edema in the involved parenchyma. Diffusion weighted axial section (E) showing foci of diffusion restriction within gyrus rectus and pars orbitalis. Axial T1 postcontrast sections (F, G) showing peripheral ring-enhancing lesion in right frontal lobe (arrow head) with thick enhancing soft tissue mass involving paransal sinuses (curved arrow), infiltrating posteriorly to involve cavernous sinuses and anterior part of the carotid canal encasing bilateral internal carotid arteries. Right ICA shows loss of flow void suggestive of thrombosis (blue arrow), thus representing angioinvasive nature of the lesion. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

Microscopic examination of pus. (A) Gram positive oval to ellipsoidal broad-based budding yeast cells (black arrows; x1000) (B) Numerous broad-based budding yeast cells (orange arrow) with pseudohyphae and arthroconidia (black arrows; x400) [A: Gram stain; B: 10% KOH mount]. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 3

Histopathological examination showing suppurative granulomatous lesion with fungal elements. A (x100) Zonation in the abscess wall with central necrotic area (N) surrounded by granulation tissue (G). B (x200) Foamy macrophages (yellow arrow) and polymorphs (blue arrows) in the necrotic area (N) with surrounding granulation tissue (G) containing inflammatory cells, newly formed blood vessels and fibroblastic proliferation. Cell block prepared from abscess fluid reveals numerous budding yeast cells (C, D inset; x400) and occasional hyphae (C, red arrows; x200). [A, B: Hematoxylin & Eosin, C: Grocott Gomori Methanamine Silver, D: Periodic acid Schiff (Scale bars- 50 μm)]. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 4

Colony characteristics and microscopic morphology of T. dohaense. (A) Slow-growing, smooth, creamy, mucoid colonies of T. dohaense on SDA, after 72 h of incubation at 37 °C. (B) LPCB mount showing globose to ellipsoidal yeast cells with polar budding on a broad base (red arrow; x1000) and cylindrical variable sized arthroconidia (black arrow; x1000). (C) Dalmau culture on cornmeal agar showing extensive hyphae and cylindrical arthroconidia of variable size (x400). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)