Microascus manginii

The anamorph was first documented, unintentionally, by Professor Fernand-Pierre-Joseph Guéguen in 1899[8] who mistook it for the species, Monilia candida, previously described in 1851 by Hermann Friedrich Bonorden.[9] 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.[9] Vuillemin formally described the latter as S. candida.[9] At the same time, he re-described Bonordeon's yeast taxon, Monilia candida, as Monilia bonordenii.[9] 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.[10]

The teleomorph was discovered by Auguste Loubière in 1923 and named Nephrospora manginii in honour of his mentor, Professor Louis Mangin.[11] It was later transferred to the genus Microascus by Mario Curzi in 1931.[10][2] Curzi did not provide an explanation for this transfer.[1] S. candida and M. manginii are used in the literature to describe the same species.[2] However, recent changes to the International Code of Nomenclature for algae, fungi and plants have terminated the use of dual nomenclature for fungal species with multiple forms.[12] It is not yet known which name will take priority for this fungus in the future.[12]

The optimal growth temperature range for S. candida is 24–30 °C (75–86 °F), with a minimum of 5 °C and maximum 37 °C.[3] It is a keratinophilic species which may contribute to its role in nail infections.[16] It grows well on protein-rich surfaces and is able to digest α-keratins.[16] In vitro study of antifungal susceptibilities reports S. candida as relatively more resistant to the antifungal drug amphotericin B, and susceptible to Itraconazole and miconazole.[6]

M. manginii is a saprobic fungus.[17] It has a worldwide distribution.[17] 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.[3] Contaminated dust, soil and air samples are often found in North America and Europe.[10] In Portugal, S. candida was identified as the most prevalent fungal species contaminating the air of three poultry slaughterhouses in 2016.[18] Contamination with fungal pathogens was found on equipment used in physiotherapy clinics in Brazil, specifically electrodes and ultrasound transducers,[19] S. candida was found on several contact electrodes.[19]

Invasive fungal infections are becoming increasingly common in patients who are immunocompromised.[5] M. manginii and S. candida are not traditionally recognized as common human pathogens.[20] However, they were identified as opportunistic human and plant pathogens in a few reported cases.[21] Other Scopulariopsis species have been associated with nail infection and keratitis (S. brevicaulis), and brain abscess and hypersensitivity pneumonitis (S. brumptii).[6]

A case of disseminated infection caused by Scopulariopsis species in a 17-year old patient with chronic myelogenous leukemia was described in 1987.[5] After receiving an allogenic bone marrow transplantation for cancer treatment, the patient complained of recurrent fever, nosebleeds, and abnormal sensations of the nose.[5] Amphotericin B therapy was administered but symptoms persisted.[5] Within two months of transplant, the patient experienced a short period of improvement followed by rapid deterioration and death.[5] The autopsy discovered Scopulariopsis species in the lungs, blood, brain and nasal septum, and exhibited high resistance to amphotericin B in vitro.[5] In 1989, the species responsible for the disseminated infection was identified as S. candida.[7]

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.[6] This is the second reported case of invasive sinus disease caused by Scopulariopsis species and only reported case due to S. candida.[6] The patient was immunocompromised at the time of fungal infection due to ongoing cancer treatment.[6] The clinical presentation resembled an infection by fungi in the order Mucorales, and involved myalgia, cheek swelling and tenderness, a week-long fever, and extensive necrosis of maxillary sinuses.[6] As a result, the presumed diagnosis was mucormycosis 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).[6] The patient immediately received surgical drainage and debridement of damaged tissue, and amphotericin B to treat the fungal infection.[6] Subsequent identification of S. candida as the cause of disease prompted administration of additional antifungal medication, Itraconazole, to address potential amphotericin B resistance.[6] The patient was cured of invasive sinusitis with no signs of progressive sinus disease.[6] This marked the first successful treatment of an invasive infection caused by Scopulariopsis species in an immunocompromised host.[6] Immunosuppression was suspected to play a role in the ability of S. candida to cause invasive infection.[6] The most significant contributor to managing the disease was likely strengthening the patient's immune system by suspending chemotherapy and administrating granulocyte colony-stimulating factor.[6]

S. candida and M. manginii have been identified in cases of onychomycoses.[2] They mainly cause tissue damage to the big toe and rarely other nails.[16] Common symptoms include difficulty walking while wearing shoes, thickening and discolouration of nails, and deformation of nails.[15] The infection often begins at the lateral edge of the nail instead of the proximal edge.[16] Patients are typically middle-aged or older.[15] The mechanism of these infections is not well-characterized.[15] In addition, the published cases of onychomycoses caused by these species are not all reliable.[16]