Invasive pulmonary aspergillosis with candidiasis: usefulness of molecular and ultrastructural morphological analysis on FFPE tissue for invasive fungal infections.

Invasive pulmonary aspergillosis (IPA) is one of the most frequent forms of invasive fungal infections (IFI); however, it is often difficult to identify the pathogenic fungal species and to select appropriate treatments for patients with IFI including IPA. Here, we describe the detailed pathophysiology of an autopsy case of severe respiratory failure due to IPA with candidiasis. The patient developed severe respiratory failure after influenza infection and died, and the autopsy revealed a mixed disease of IPA with candidiasis. In this study, in addition to the routine pathological examination, we further examined formalin-fixed paraffin-embedded (FFPE) tissues by scanning electron microscopy (SEM) and partial genomic DNA sequencing. Although optical microscopy alone was insufficient to identify the pathogenic organisms, SEM clearly depicted the characteristic morphology of Aspergillus sp. and Candida sp. as closely overlapping in a nested fashion, providing evidence of mixed infection of both fungal species in a focal site. The technique using FFPE tissue in combination with ultrastructural observation by SEM, elemental analysis by SEM-EDX, and DNA sequencing is promising for analyzing the pathophysiology of IFI.

COVID-19-associated disseminated mucormycosis: An autopsy case report.

BACKGROUND: Reports of mucormycosis, an infectious disease that commonly affects immunocompromised individuals, have increased during the ongoing coronavirus disease 2019 (COVID-19) pandemic. Disseminated mucormycosis associated with COVID-19 is rare but fatal and is characterized by an aggressive clinical course and delayed diagnosis. Our report documents a case of disseminated mucormycosis after COVID-19 infection. This is a rare pathological autopsy report on COVID-19-associated mucormycosis. CASE SUMMARY: A 58-year-old man was transferred to our hospital with severe COVID-19 pneumonia. During treatment for acute respiratory distress syndrome, he developed intra-abdominal bleeding that required a right hemicolectomy and ileostomy for hemostasis. The ileostoma and surgical wound developed necrosis followed by sepsis and multi-organ failure, which led to death. An autopsy revealed multiple thrombi associated with Rhizopus oryzae infection, which led to the necrosis of multiple infected organs. CONCLUSION: Early suspicion and diagnosis followed by treatment are keys to better outcomes of mucormycosis in patients with severe COVID-19.