Basidiobolus ranarum

Basidiobolus ranarum
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Basidiobolus hyphae
Scientific classification
Kingdom:	Fungi
Division:	Zygomycota
Class:	Zygomycetes
Order:	Entomophthorales
Family:	Basidiobolaceae
Genus:	Basidiobolus
Species:	B. ranarum
Binomial name
Basidiobolus ranarum Eidam

Basidiobolus ranarum is a microscopic fungus in the order Entomophthorales.

Life cycle

It produces large, spherical, asexual spores that are forcibly discharged. These spores can germinate directly to produce hyphae. When they land in an unfavorable location, they can alternately germinate to produce a long, slender capilliconidiophore that bears a single, falcate capilliconidium. At the distal tip of the capilliconidium is a sticky mucous drop that is presumed to aid in dispersal. B. ranarum can also produce thick-walled resting spores that are presumably the sites of meiosis.

B. ranarum can be isolated from decaying leaf litter and the excrement of frogs and terrestrial, insect-eating reptiles. It has been considered a commensal of frogs, although there is no evidence that it multiplies or persists in a frog's gut.

Pathology

Basidiobolus ranarum can be a human pathogen, causing a disease called basidiobolomycosis (formerly entomophthoromycosis).

Usually basidiobolomycosis is a subcutaneous infection (subcutaneous abscess). Rarely gastrointestinal manifestations have been described. In gastrointestinal basidiobolomycosis, the colon is most frequently involved, usually presenting with subacute mild abdominal pain. In contrast to children, only very few described adult patients had hepatic masses. Definitive diagnosis requires culture, serological testing can be helpful. The fungal morphology and the Splendore-Hoeppli phenomenon are characteristic histological features. There are no prominent risk factors. Usually surgery and prolonged antifungal therapy are required. The antifungal therapy can be based on posaconazole.