Scanning Electron Microscopy as a Diagnostic Modality for Conidiobolus Infection

Objectives: Conidiobolus coronatus classically cause a subcutaneous infection of the face and paranasal sinuses in immunocompetent patients. Diagnosis is made by means of the histological picture in the majority of cases as culture of C.coronatus is unsuccessful in up to 85% of cases. Differentiation of the different species of the order Entomophthorales however is not possible histologically. Scanning Electron Microscopy (SEM) as a modality for confirming diagnosis has never been used before and therefore the described morphology of fungal structures in vivo are limited to histological features. Methods: SEM as a diagnostic tool was evaluated by examining two samples of blood collected from a patient with Conidiobolus infection and used to describe the morphological structure of Conidiobolus in vivo. Results: Hyphal structures and spores were demonstrated in both the samples examined, concistent with published literature of C.coronatus morphology in vitro. Conclusions: This research has shown that SEM is a viable option for confirmation of C.coronatus infection in the majority of cases where mycological cultures are negative and PCR not readily available.