Rhizopus microsporus and Mucor racemosus coinfection following COVID-19 detected by metagenomics next-generation sequencing: A case of disseminated mucormycosis

Mucormycosis is an invasive opportunistic fungal infection, which may be lethal and mostly affects patients with immunodeficiency or diabetes mellitus. Among Mucorales fungi, Rhizopus spp. is the most common cause of mucormycosis, followed by genera such as Mucor and Lichtheimia. Here we report a patient with severe COVID-19 infection who developed nasal pain, facial swelling, prominent black eschar on the nasal root. CT scan revealed pansinusitis along the maxillary, ethmoidal, and sphenoid sinuses. Mixed mold infection with Rhizopus microsporus and Mucor racemosus was detected by blood metagenomics next-generation sequencing (mNGS) and later nasal mucosa histological investigation confirmed mucormycosis. Severe COVID-19 infection led to the patient's thrombocytopenia and leukopenia. Later disseminated mucormycosis aggravated the infection and sepsis eventually resulted in death. It is the first case report of mucormycosis in which R. microsporus and M. racemosus as the etiologic agents were found simultaneously in one patient. COVID-19 infection combined with disseminated mucormycosisis can be fatal and mNGS is a fast, sensitive and accurate diagnostic method for fungi detection.