Cladophialophora bantiana

Cladophialophora bantiana (C. bantiana) is a dematiaceous fungus known to cause brain abscesses in humans.[1] It is one of the most common causes of invasive phaeohyphomycosis in humans.[2] Cladophialophora bantiana is a member of the phylum ascomycota and has been isolated from soil samples from around the world.[3]

Cladophialophora bantiana
Scientific classification
Kingdom:
Fungi
Phylum:
Ascomycota
Class:
Eurotiomycetes
Subclass:
Chaetothyriomycetidae
Order:
Chaetothyriales
Family:
Herpotrichiellaceae
Genus:
Cladophialophora
Species:
C. bantiana
Binomial name
Cladophialophora bantiana
de Hoog, Kwon-Chung & McGinnis, (1995)
Synonyms

Torula bantiana Sacc., in Saccardo, (1912)
Cladosporium bantianum (Sacc.) Borelli, (1960)
Xylohypha bantiana (Sacc.) McGinnis, Borelli, Padhye & Ajello, (1986)
Cladosporium trichoides C.W. Emmons Binford, Thompson & Gorham, (1952)
Cladosporium trichoides C.W. Emmons var. trichoides Binford, Thompson & Gorham, (1952)
Cladosporium trichoides var. chlamydosporum Kwon-Chung, (1978)

Etymology

Cladophialophora bantiana was first isolated from a brain abscess in 1911 by Guido Banti and was described by Pier Andrea Saccardo in 1912 as Torula bantiana. In 1960, the fungus was reclassified by Borelli as Cladosporium bantianum.[2] A morphologically similar species, Cladosporium trichodes was described by Emmons et al. in 1952. Cladosporium trichodes was widely believed to be a different species until 1995 when de Hoog et al. showed it to be conspecific with C. bantiana based on phylogenetic analysis.[4]

Morphology

Cladophialophora bantiana exhibits predominantly hyphal growth both in vivo and in vitro.[5] The normal morphology consists of dark coloured largely unbranched, wavy chains of conidia, individually 5–10 µm in length.[5] The dark colour is due to the presence of the dark pigment melanin.[6] Hyphae are septate, as is the case for species belonging to the phylum ascomycota.[1] In samples isolated from cerebral tissue compared to cultured samples, a predominance of unbranched conidial chains and absence of conidiophores has been reported.[5][6] In culture, the colony is black with a velvety texture or dark grey in colour, depending on the type of agar medium it is grown on.[2] Cladophialophora bantiana has been reported to grow in culture under temperatures ranging from 14-42 °C with optimal growth around 30 °C.[2] Cladophialophora bantiana grows slowly in vitro, taking ~15 days to mature when grown at 25–30 °C.[1] Cladophialophora bantiana can be distinguished from other species of the genus Cladophialophora by the presence of the enzyme urease.[7]

Infection

Non-human

Cladophialophora bantiana can cause infection in several species of animals including cats,[8] dogs,[9] and humans.[10] However, it is very rare to find it in non-mammalian species.[10] In one case in a dog, C. bantiana was identified as the causative agent of eumycetoma.[9] It has been known to cause systemic phaeohyphomycosis in both cats and dogs.[8]

Human

Cladophialophora bantiana is known to cause a cerebral phaeohyphomycosis affecting the central nervous system in humans.[11] It is hypothesized that predilection of this species for the central nervous system is due to the presence of melanin, which may be able to cross the blood-brain barrier.[3] However, this is unlikely since fungal melanin is structurally and biochemically different from human melanin and other species of highly pigmented fungi do not show neurotropism.[3] It has also been suggested that the presence of introns in the 18S rDNA subunit of Cladophialophora may be related to the preference of C. bantiana for the CNS, however more research is required to determine the mechanism of this.[12]

In a review of 101 cases of phaeohyphomycosis by Revankar et al., C. bantiana was the causal agent responsible for 48% of cases. It most often manifests as brain abscesses in immunocompetent people, however meningitis and myelitis were observed in a limited number of cases.[3] Although the majority of the patients were immunocompetent (73%), infection is also commonly seen in immunocompromised patients.[11] Clinical symptoms of infection are varied and can include headache, seizure, arm pain, and ataxia.[1] The mortality rate is about 70%, with better outcomes observed in patients who underwent complete excision of the abscess.[11] Since infection is very rare, there is no standard therapy for treatment of C. bantiana phaeohyphomycosis, however combination of amphotericin B, flucytosine, and itraconazole has been associated with improved outcomes. Since the majority of patients infected were immunocompetent, the mean of exposure to the fungi is still unclear, however inhalation is the likely route of entrance.[7]

Cases of infection are most commonly found in subtropical regions with high average humidity although cases have also been identified in the US, Canada and the UK.[10] Cases from regions with hot, arid climate are rare.[10] It has also been suggested to occupations with high exposure to dust and dirt such as farming and gardening are associated with higher risk of infection.[10]

References
  1. Levin, T. P.; Baty, D. E.; Fekete, T.; Truant, A. L.; Suh, B. (2004). "Cladophialophora bantiana Brain Abscess in a Solid-Organ Transplant Recipient: Case Report and Review of the Literature". Journal of Clinical Microbiology. 42 (9): 4374–4378. doi:10.1128/JCM.42.9.4374-4378.2004. PMC 516289. PMID 15365048.
  2. Kwon-Chung, K.J.; Bennett, John E. (1992). Medical mycology. Philadelphia: Lea & Febiger. ISBN 0-8121-1463-9.
  3. Revankar, S. G.; Sutton, D. A.; Rinaldi, M. G. (2004). "Primary Central Nervous System Phaeohyphomycosis: A Review of 101 Cases". Clinical Infectious Diseases. 38 (2): 206–216. doi:10.1086/380635. PMID 14699452.
  4. De Hoog, G. S.; Guého, E.; Masclaux, F.; Gerrits Van Den Ende, A. H. G.; Kwon-Chung, K. J.; McGinnis, M. R. (1995). "Nutritional physiology and taxonomy of human-pathogenic Cladosporium-Xylohypha species". Medical Mycology. 33 (5): 339. doi:10.1080/02681219580000661.
  5. Emmons, Chester W. (1977). Medical mycology (3. ed.). Philadelphia: Lea & Febiger. ISBN 0-8121-0566-4.
  6. Butler, M. J.; Day, A. W. (1998). "Fungal melanins: A review". Canadian Journal of Microbiology. 44 (12): 1115. doi:10.1139/cjm-44-12-1115.
  7. "Doctor Fungus: Cladophialophora spp". Archived from the original on 2013-12-03. Retrieved 2013-12-03.
  8. Elies, L.; Balandraud, V.; Boulouha, L.; Crespeau, F.; Guillot, J. (February 2003). "Fatal Systemic Phaeohyphomycosis in a Cat due to Cladophialophora bantiana". Journal of Veterinary Medicine, Series A. 50 (1): 50–53. doi:10.1046/j.1439-0442.2003.00501.x. PMID 12650510.
  9. Guillot, J.; Garcia-Hermoso, D.; Degorce, F.; Deville, M.; Calvie, C.; Dickele, G.; Delisle, F.; Chermette, R. (7 October 2004). "Eumycetoma Caused by Cladophialophora bantiana in a Dog". Journal of Clinical Microbiology. 42 (10): 4901–4903. doi:10.1128/JCM.42.10.4901-4903.2004. PMC 522343. PMID 15472377.
  10. Kantarcioglu, A. S.; Hoog, G. S. (February 2004). "Infections of the central nervous system by melanized fungi: a review of cases presented between 1999 and 2004. Infektionen des Zentralnervensystems durch melanisierte Pilze: Eine Ubersicht von Fallen prasentiert zwischen 1999 und 2004". Mycoses. 47 (1–2): 4–13. doi:10.1046/j.1439-0507.2003.00956.x. PMID 14998393. S2CID 1878026.
  11. Garzoni, C.; Markham, L.; Bijlenga, P.; Garbino, J. (2008). "Cladophialophora bantiana: A rare cause of fungal brain abscess. Clinical aspects and new therapeutic options" (PDF). Medical Mycology. 46 (5): 481–486. doi:10.1080/13693780801914906. PMID 18608882.
  12. De Hoog, G. S.; Queiroz-Telles, F.; Haase, G.; Fernandez-Zeppenfeldt, G.; Angelis, D. Attili; Van Den Ende, A. H. Gerrits; Matos, T.; Peltroche-Llacsahuanga, H.; Pizzirani-Kleiner, A. A.; Rainer, J.; Richard-Yegres, N.; Vicente, V.; Yegres, F. (2000). "Black fungi: clinical and pathogenic approaches". Medical Mycology. 38 Suppl 1: 243–50. doi:10.1080/mmy.38.s1.243.250. PMID 11204152.
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