Conidiobolus is a genus of fungi in the order Entomophthorales. Some species were initially defined in Conidiobolus but then moved into other genera such as Capillidium and Batkoa.
The genus name Conidiobolus was first introduced in 1884 by Brefeld and was proposed due to differences in its conidia.
Members of this genus are typically saprophytic, living in the soil with vegetation and decaying organic matter. They are most commonly found in tropical regions.
Some members of this genus may cause a human infection known as conidiobolomycosis; others are invertebrate pathogens. Only three species have been identified in mammalian infection: C. coronatus, C. incongruus, and C. lamprauges.
Taxonomic characteristics In the Conidiobolus genus, at least four types of asexual conidia have been reported. Sexual structures (zygospores) have been found in most of the members in this genus, but not in C. coronatus. However, while growing in water agar plates, C. coronatus develops villose conidia, a unique taxonomic characteristic used for its identification in clinical isolates.
The hyphae are broad, thin walled and occasionally septate. They are best visualized with hematoxylin and eosin when viewing clinical specimens.
For Conidiobolus, the best environment for germination is achieved with high humidity from 98 to 100% and temperatures between 16 and 30 °C.
Medical Relevance Conidiobolomycosis in humans was first described in 1961 based on histopathological analysis of a facial lesion. The first well-documented case of human Conidiobolus infection was in an 11-year-old from the Grand Cayman Island.
Conidiobolomycosis is most common in the rainforests of Africa, South and Central America, and Southeast Asia. There is a significant predominance of cases in males, particularly those who work and live in tropical rainforests. Some isolated cases from the United Kingdom and the East coast of the United States have been reported.
In endemic areas, basidiobolomycosis and conidiobolomycosis can most easily be distinguished from one another by the anatomic location of the infection and the age of the patient. The diagnosis is typically made by biopsy of the infected tissue.
Treatment No single drug has been proven to be effective in treating all Conidiobolus cases, and due its rarity, no treatment regimens have been directly compared to determine the best course. Amphotericin B exhibits relatively high MICs, while itraconazole and ketoconazole have good in vitro activities. In addition to antifungal therapy, surgical debridement may be necessary.
Species As of 2018 MycoBank included the following species of Conidiobolus: Conidiobolus antarcticus S. Tosi, Caretta & Humber, 2004 Conidiobolus apiculatus Conidiobolus bangalorensis Sriniv. & Thirum., 1967 Conidiobolus batkoi Conidiobolus brefeldianus Couch, 1939 Conidiobolus caecilius S. Keller, 2007 Conidiobolus carpentieri (Giard) Remaud. & S. Keller, 1980 Conidiobolus cercopidis Conidiobolus cercopidis Conidiobolus chlamydosporus Drechsler, 1955 Conidiobolus chlapowskii Bałazy, J. Wiśn. & S. Kaczm., 1987 Conidiobolus conglomeratus Conidiobolus coronatus (Costantin) A. Batko, 1964 Conidiobolus couchii Sriniv. & Thirum., 1968 Conidiobolus dabieshanensis Y. Nie & B. Huang, 2017 Conidiobolus denaeosporus Drechsler, 1957 Conidiobolus destruens Conidiobolus eurymitus Drechsler, 1965 Conidiobolus eurypus Drechsler, 1957 Conidiobolus firmipilleus Drechsler, 1953 Conidiobolus giganteus Conidiobolus globuliferus Drechsler, 1957 Conidiobolus gonimodes Drechsler, 1962 Conidiobolus grylli Conidiobolus gustafssonii Bałazy, 1993 Conidiobolus humicola Sriniv. & Thirum., 1962 Conidiobolus incongruus Drechsler, 1960 Conidiobolus inordinatus Drechsler, 1957 Conidiobolus iuxtagenitus S. D. Waters & Callaghan, 1989 Conidiobolus khandalensis Sriniv. & Thirum., 1963 Conidiobolus lachnodes Drechsler, 1955 Conidiobolus lamprauges Drechsler, 1953 Conidiobolus lichenicola Sriniv. & Thirum., 1968 Conidiobolus lobatus Sriniv. & Thirum., 1968 Conidiobolus macrosporus Sriniv. & Thirum., 1967 Conidiobolus major Conidiobolus margaritatus B. Huang, Humber & K. T. Hodge, 2007 Conidiobolus megalotocus Drechsler, 1957 Conidiobolus minor Conidiobolus multivagus Drechsler, 1960 Conidiobolus mycophagus Sriniv. & Thirum., 1965 Conidiobolus mycophilus Sriniv. & Thirum., 1965 Conidiobolus nanodes Drechsler, 1955 Conidiobolus nodosus Sriniv. & Thirum., 1967 Conidiobolus obscurus (I. M. Hall & P. H. Dunn) Remaud. & S. Keller, 1980 Conidiobolus papillatus Conidiobolus parvus Drechsler, 1962 Conidiobolus paulus Drechsler, 1957 Conidiobolus polyspermus Drechsler, 1962 Conidiobolus polytocus Drechsler, 1955 Conidiobolus pseudapiculatus Conidiobolus pseudapiculatus Conidiobolus pseudococci Conidiobolus pseudococcus Conidiobolus pumilus Drechsler, 1955 Conidiobolus rhynchosporus Drechsler, 1954 Conidiobolus rhysosporus Drechsler, 1954 Conidiobolus rugosus Drechsler, 1955 Conidiobolus sinensis Y. Nie, X. Y. Liu & B. Huang, 2012 Conidiobolus stilbeus Y. Nie & B. Huang, 2016 Conidiobolus stromoideus Sriniv. & Thirum., 1963 Conidiobolus tenthredinis Conidiobolus terrestris Sriniv. & Thirum., 1968 Conidiobolus thermophilus Waing., S. K. Singh & M. C. Sriniv., 2008 Conidiobolus thromboides Drechsler, 1953 Conidiobolus tipulae Conidiobolus undulatus Drechsler, 1957 Conidiobolus utriculosus Bref., 1884 Conidiobolus villosus Note Conidiobolus adieretus Drechsler, 1953 (= Capillidium adiaeretum (Drechsler) B. Huang & Y. Nie (2020)) Conidiobolus heterosporus Drechsler, 1953 (= Capillidium heterosporum (Drechsler) B. Huang & Y. Nie (2020) )
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