A diabetic presents with orbital cellulitis and maxillary sinusitis, on microscopy, shows a fungus with hyaline, narrow septate and branching hyphae with an invasion of the blood vessels. Which is the causative fungus?

Diagnosis of Aspergillus infection:Histologic examination of the affected tissue reveals either infarction, with an invasion of blood vessels by many fungal hyphae, or acute necrosis, with limited inflammation and hyphae.Aspergillus hyphae are hyaline, narrow, and septate, with branching at 45deg; no yeast forms are present in infected tissueHyphae can be seen in cytology or microscopy preparations, which therefore provide a rapid means of presumptive diagnosis.Ref: PL Dhingra, Diseases of Ear, Nose & Throat, 7th edition, pg no. 178