''Microascus manginii'' is a filamentous fungal species in the genus ''Microascus.'' It produces both sexual (

teleomorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

) and asexual (

anamorph In mycology, the terms teleomorph, anamorph, and holomorph apply to portions of the life cycles of fungi in the phyla Ascomycota and Basidiomycota: *Teleomorph: the sexual reproductive stage (morph), typically a fruiting body. *Anamorph: an ase ...

) reproductive stages known as ''M. manginii'' and ''Scopulariopsis candida'', respectively. Several synonyms appear in the literature because of taxonomic revisions and re-isolation of the species by different researchers. ''M. manginii'' is

saprotrophic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi (f ...

and commonly inhabits soil, indoor environments and decaying plant material. It is distinguishable from closely related species by its light colored and heart-shaped ascospores used for sexual reproduction. ''Scopulariopsis candida'' has been identified as the cause of some invasive infections, often in immunocompromised hosts, but is not considered a common human pathogen. There is concern about

amphotericin B Amphotericin B is an antifungal medication used for serious fungal infections and leishmaniasis. The fungal infections it is used to treat include mucormycosis, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, and cryptococcosis. Fo ...

resistance in ''S. candida''.

History and taxonomy

The anamorph was first documented, unintentionally, by Professor Fernand-Pierre-Joseph Guéguen in 1899 who mistook it for the species, ''Monilia candida'', previously described in 1851 by

Hermann Friedrich Bonorden Hermann Friedrich Bonorden (28 August 1801 – 19 May 1884) was a German physician and mycologist. During his career he served as a ''Regimentarzt'' (regimental medical doctor) in Köln. In 1911, Jean Paul Vuillemin determined that the two taxa were distinct, noting that the taxon described by Bonorden was a yeast whereas the strain that was the subject of Guéguen's studies was filamentous and produced true

conidia A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the ...

. Vuillemin formally described the latter as ''S. candida''. At the same time, he re-described Bonordeon's yeast taxon, ''Monilia candida'', as ''Monilia bonordenii''. Subsequent researchers described taxa that have since been reduced to synonymy with ''S. candida'', including: ''S. alboflavescens'' in 1934, ''S. brevicaulis'' var. ''glabra'' in 1949, ''Chrysosporium keratinophilum'' var. ''denticola'' in 1969 and ''Basipetospora denticola'' in 1971. The teleomorph was discovered by Auguste Loubière in 1923 and named ''Nephrospora manginii'' in honour of his mentor, Professor

Louis Mangin Louis Alexandre Mangin (8 September 1852, in Paris – 27 January 1937) was a French botanist and mycologist. In 1873, he became an associate professor at the Lycée de Nancy, followed by a professorship at the Lycée Louis-le-Grand in Paris ( ...

. It was later transferred to the genus ''

Microascus ''Microascus'' is a genus of fungi in the family Microascaceae The Microascaceae are a family of fungi in the class Sordariomycetes, subclass Hypocreomycetidae. The family was published by David Malloch in 1970, an emended description based o ...

'' by Mario Curzi in 1931''.'' Curzi did not provide an explanation for this transfer. ''S. candida'' and ''M. manginii'' are used in the literature to describe the same species. However, recent changes to the ''

International Code of Nomenclature for algae, fungi and plants The ''International Code of Nomenclature for algae, fungi, and plants'' (ICN) is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "trad ...

'' have terminated the use of dual nomenclature for fungal species with multiple forms. It is not yet known which name will take priority for this fungus in the future.

Growth and morphology

Sexual form

Colonies of ''M. manginii'' are pale, white and rapid growing. Growth is tolerant of

cycloheximide Cycloheximide is a naturally occurring fungicide produced by the bacterium ''Streptomyces griseus''. Cycloheximide exerts its effects by interfering with the translocation step in protein synthesis (movement of two tRNA molecules and mRNA in rela ...

and restricted at 37 °C. The vegetative

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

e are

septate In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ...

and appear glassy (hyaline).

Ascomata An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

are the sexual structures within which

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

s are produced in sacs called

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

. The ascomata of ''M. manginii'' are spherical, smooth-walled, dark-brown to black and 100–175 µm in size. These fruiting bodies are also called

perithecia An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

because of their flask-like shape wherein asci grow at the base and an opening allows for the release of mature ascospores. They are also papillate with short cone-shaped projections at the opening, sessile, and rich in carbon. Perithecia manifest as small black dots organized in concentric rings. An incubation period of over two weeks may be necessary for the production of perithecia. The asci are shaped similar to an upside-down egg where the apex is broad and thicker than the base. They are 11–16 × 8–13 µm in size and contain 8 ascospores. Ascospores are nonseptate and smooth-walled. They are characteristically uniform in heart-shape and pale, straw-colored when mature - but appear reddish-brown as a mass. They each have a single inconspicuous

germ pore A germ pore is a small pore in the outer wall of a fungal spore through which the germ tube exits upon germination. It can be apical or eccentric in its location, and, on light microscopy, may be visualized as a lighter coloured area on the cell ...

, which is a predetermined spot in the spore cell wall where the

germ tube A germ tube is an outgrowth produced by spores of spore-releasing fungi during germination. The germ tube differentiates, grows, and develops by mitosis to create somatic hyphae.C.J. Alexopolous, Charles W. Mims, M. Blackwell, ''Introductory Myc ...

emerges during

germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...

. Ascospores are 5–6 × 4.5–5 µm in size. ''M. manginii'' is a

heterothallic Heterothallic species have sexes that reside in different individuals. The term is applied particularly to distinguish heterothallic fungi, which require two compatible partners to produce sexual spores, from homothallic ones, which are capable of ...

species and as a result, generation of sexual spores requires mating between two compatible individuals.

Asexual form

''S. candida'' is a hyaline mold with septate hyphae. The white and membranous morphology of ''S. candida'' colonies differentiates it from the more common species ''S. brevicaulis,'' which is characterized by a sand-coloured and granular colonial morphology. As the colony ages, it becomes slightly yellow. Conidiophores are specialized hyphal stalks that have conidiogenous cells which produce conidia for asexual reproduction. The Latin word for broom, ''

scopula ''Scopula'' is a genus of moths in the family Geometridae described by Franz von Paula Schrank in 1802. Species It has 705 species which are listed here alphabetically. A *'' Scopula ablativa'' (Dognin, 1911) *''Scopula abolita'' Herbulot, 9 ...

'', was chosen as the basis of the generic name due to the broom-like appearance of the conidiophores of ''Scopulariopsis''. In ''S. candida'', these structures are 10–20 µm in length. ''S. candida'' sporulates using specialized conidiogenous cells called annellide. The tip of the cell elongates and narrows each time a conidium is formed and results in a series of ring-like scars called annellations near the tip. The annelloconidia are formed in dry chains that eventually break off to allow the dispersal of spores by wind. They are one-celled, smooth- and thick-walled, and round but also broad-based. They resemble simple yeasts. Annelloconidia are hyaline and 6–8 × 5–6 µm in size. The smooth hyaline annelloconidia can also distinguish ''S. candida'' from ''S. brevicaulis,'' which has conidia that are rough-walled, truncate and covered in tiny, thorny outgrowths. Isolates of ''S. candida'' can produce sterile perithecia-like structures.

Physiology

The optimal growth temperature range for ''S. candida'' is , with a minimum of 5 °C and maximum 37 °C. It is a keratinophilic species which may contribute to its role in nail infections. It grows well on protein-rich surfaces and is able to digest α-keratins.

In vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...

study of antifungal susceptibilities reports ''S. candida'' as relatively more resistant to the antifungal drug amphotericin B, and susceptible to Itraconazole and

miconazole Miconazole, sold under the brand name Monistat among others, is an antifungal medication used to treat ring worm, pityriasis versicolor, and yeast infections of the skin or vagina. It is used for ring worm of the body, groin (jock itch), and fee ...

Habitat and ecology

''M. manginii'' is a saprobic fungus. It has a worldwide distribution. It is often isolated from decaying plant material, soil and indoor environments, but also human skin and nails, dust, chicken litter, atmosphere, book paper and cheese, among other locations. Contaminated dust, soil and air samples are often found in North America and Europe. In

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

, ''S. candida'' was identified as the most prevalent fungal species contaminating the air of three poultry slaughterhouses in 2016. Contamination with fungal pathogens was found on equipment used in physiotherapy clinics in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, specifically electrodes and ultrasound transducers, ''S. candida'' was found on several contact electrodes.

Pathogenicity

Invasive fungal infections are becoming increasingly common in patients who are

immunocompromised Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...

. ''M. manginii'' and ''S. candida'' are not traditionally recognized as common human pathogens. However, they were identified as

opportunistic Opportunism is the practice of taking advantage of circumstances – with little regard for principles or with what the consequences are for others. Opportunist actions are expedient actions guided primarily by self-interested motives. The term ...

human and plant pathogens in a few reported cases. Other ''Scopulariopsis'' species have been associated with nail infection and keratitis (''S. brevicaulis''), and brain abscess and hypersensitivity pneumonitis (''S. brumptii''). A case of disseminated infection caused by ''Scopulariopsis'' species in a 17-year old patient with

chronic myelogenous leukemia Chronic myelogenous leukemia (CML), also known as chronic myeloid leukemia, is a cancer of the white blood cells. It is a form of leukemia characterized by the increased and unregulated growth of myeloid cells in the bone marrow and the accumulat ...

was described in 1987. After receiving an

allogenic In ecology, allogenic succession is succession driven by the abiotic components of an ecosystem. In contrast, autogenic succession is driven by the biotic components of the ecosystem. An allogenic succession can be brought about in a number of ways ...

bone marrow transplantation Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood in order to replicate inside of a patient and to produc ...

for cancer treatment, the patient complained of recurrent fever, nosebleeds, and abnormal sensations of the nose. Amphotericin B therapy was administered but symptoms persisted. Within two months of transplant, the patient experienced a short period of improvement followed by rapid deterioration and death. The autopsy discovered ''Scopulariopsis'' species in the lungs, blood, brain and nasal septum, and exhibited high resistance to amphotericin B in vitro. In 1989, the species responsible for the disseminated infection was identified as ''S. candida''. ''S. candida'' was identified as the cause of invasive sinusitis in a 12-year old girl undergoing treatment for non-Hodgkin's lymphoma in 1992. This is the second reported case of invasive sinus disease caused by ''Scopulariopsis'' species and only reported case due to ''S. candida''. The patient was immunocompromised at the time of fungal infection due to ongoing cancer treatment. The clinical presentation resembled an infection by fungi in the order

Mucorales The Mucorales is the largest and best studied order of zygomycete fungi. Members of this order are sometimes called pin molds. The term mucormycosis is now preferred for infections caused by molds belonging to the order Mucorales. Systematics ...

, and involved

myalgia Myalgia (also called muscle pain and muscle ache in layman's terms) is the medical term for muscle pain. Myalgia is a symptom of many diseases. The most common cause of acute myalgia is the overuse of a muscle or group of muscles; another likel ...

, cheek swelling and tenderness, a week-long fever, and extensive

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

maxillary sinus The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210 Structure It is ...

es. As a result, the presumed diagnosis was

mucormycosis Mucormycosis, also known as black fungus, is a serious fungal infection that comes under fulminant fungal sinusitis, usually in people who are immunocompromised. It is curable only when diagnosed early. Symptoms depend on where in the body the ...

until further examination of patient specimens showed abundant growth of a powdery, tan mold that was distinguished as ''S. candida'' by several features (e.g., septate hyphae, round and smooth conidia, broom-shaped conidiophores). The patient immediately received surgical drainage and

debridement Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), and by maggot therapy. In p ...

of damaged tissue, and amphotericin B to treat the fungal infection. Subsequent identification of ''S. candida'' as the cause of disease prompted administration of additional antifungal medication,

Itraconazole Itraconazole, sometimes abbreviated ITZ, is an antifungal medication used to treat a number of fungal infections. This includes aspergillosis, blastomycosis, coccidioidomycosis, histoplasmosis, and paracoccidioidomycosis. It may be given by mouth ...

, to address potential amphotericin B resistance. The patient was cured of invasive sinusitis with no signs of progressive sinus disease. This marked the first successful treatment of an invasive infection caused by ''Scopulariopsis'' species in an immunocompromised host.

Immunosuppression Immunosuppression is a reduction of the activation or efficacy of the immune system. Some portions of the immune system itself have immunosuppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse react ...

was suspected to play a role in the ability of ''S. candida'' to cause invasive infection. The most significant contributor to managing the disease was likely strengthening the patient's immune system by suspending

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...

and administrating

granulocyte colony-stimulating factor Granulocyte colony-stimulating factor (G-CSF or GCSF), also known as colony-stimulating factor 3 (CSF 3), is a glycoprotein that stimulates the bone marrow to produce granulocytes and stem cells and release them into the bloodstream. Functional ...

. ''S. candida'' and ''M. manginii'' have been identified in cases of onychomycoses. They mainly cause tissue damage to the big toe and rarely other nails. Common symptoms include difficulty walking while wearing shoes, thickening and discolouration of nails, and deformation of nails. The infection often begins at the lateral edge of the nail instead of the proximal edge. Patients are typically middle-aged or older. The mechanism of these infections is not well-characterized. In addition, the published cases of onychomycoses caused by these species are not all reliable.

References

{{taxobar , from = Q10584031 Microascales Fungi described in 1931