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Subcutaneous phaeohyphomycosis due to Phaeoacremonium parasiticum in a patient with Chronic Granulomatous Disease
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Advisor(s)
Abstract(s)
Objectives: Phaeoacremonium parasiticum is a ubiquitous dematiaceous mold that
rarely causes infection in humans. Its spectrum of disease ranges from subcutaneous
infections to disseminated disease. The majority of those reported few cases involve
immunocompromised patients. Chronic granulomatous disease (CGD) is an inherited disorder affecting nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex.
CGD patients are susceptible to a broad spectrum of opportunistic infections, being fungal
infections a major determinant of survival. We report a case of Subcutaneous phaeohyphomycosis due to P. parasiticum in a young adult with CGD.
Material and methods: A 28-year-old male patient with autossomic recessive CGD,
due to mutations in CYBA, is followed in Primary Immunodeficiency Center since childhood. He has been under prophylaxis with itraconazole, cotrimoxazole and IFNg and
tapering oral steroids, started for granulomatous colitits 2 years earlier.
In a regular visit to the clinical center, he complained of persistent pain on his left leg
with no history of recent injury in the affected area and without external inflammatory
signs. An ultrasound was performed after 2 weeks revealing a heterogeneous liquid of
slightly irregular contour in the sinus of the left anterior tibial muscle with heterogeneity of
the adjacent muscle. This piomiositis collection was punctured, under ultrasound control,
with drainage of about 7cm3 of hemato-purulent exsudate that was promptly processed
for bacteriology (aerobic and anaerobic) and mycology studies.
Results: Cultures for bacteria were sterile. Culture on Sabouraud was positive after
5 days of incubation, showing slow growing and initially white colonies. Microscopic
examination showed hyaline, septate mycelium with long, thin conidiophores and curved,
aseptate conidia.The fungus was initially identified as an Acremonium sp. and was sent to
the Mycology Reference Laboratory for molecular identification and antifungal susceptibility testing. Its identification was performed by sequencing the internal transcribed spacer
(ITS) region of ribosomal DNA, being the isolate identified as Phaeoacremonium parasiticum
(100% homology).
After 3 weeks incubation, coloration of the colonies emerged, becoming greyish black
upon subculture, with velvety texture and black reverse. Microscopically, pigmented
hyphae with tapering, funnel-shaped phialides were observed, and conidia were hyaline
and oblong, forming clusters at the tip of the phialides. At this point, macroscopic and
microscopic morphology was consistent with Phaeoacremonium species.
Susceptibility pattern showed low minimal inhibitory concentrations (MIC) to posaconazole and voriconazole, and higher MIC values to anidulafungin and amphotericin B. The
patient has improved under voriconazol therapy (200 mg; bid)
Conclusions: Phaeoacremonium parasiticum is an uncommon infection and its appropriate identification is often difficult because morphologically, the genus Phaeoacremonium
show morphological features resembling both Acremonium and Phialophora genera.
Molecular identification is determinant to confirm morphology, as many species
have indistinguishable characteristics that may lead to incorrect antifungal options. Also,
susceptibility testing should be done for these so rare fungi as optimal treatment has not
yet been clearly defined.
Description
Abstract publicado em J Fungi. 2021;7(11):213-14 (P252). https://doi.org/10.3390/jof7110
Keywords
Phaeoacremonium parasiticum Chronic Granulomatous Disease Infecções Sistémicas e Zoonoses