Cephalotheca foveolata
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| Species: | Cephalotheca foveolata
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| Cephalotheca foveata Yaguchi, Nishimura & Udagawa (2006)
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Cephalotheca foveolata is a species of fungus. It is rarely opportunistic and generally manifests as a minor subcutaneous infection.
History and taxonomy
[edit]Cephalotheca foveolata was first discovered in 2006 in a subcutaneous infection of the foot in South Korea.[1][2] The fungus was said to be "foveolate" because of its small pitted ascospores.[2] The fungus has also been called Cephalotheca faveolata by Giridharan, Verekar, Khanna, Mishra, Deshmukh in 2012.[3] C. foveolata is morphologically and molecularly very similar to other pathogenic species of fungus, especially those within the genera of Phialemonium and Acremonium.[4] The D1/D2 variable domains of 28S rDNA have often been used to identify C. foveolata.[4][1] This is necessary to distinguish C. foveolata from Cephalotheca sulfurea which has 95% homology or Phialemonium obovatum, another closely related species.[5][2]
Habitat and ecology
[edit]C. foveolata has been discovered rarely but in areas around the world that differ greatly from each other.[6] Most cases have been reported in the southern United States or southeast Asia (South Korea, Singapore, and Hong Kong).[5][7] As a saprophyte, C. foveolata generally makes its home in the soil, but can also be found growing on wood or mushrooms.[4][1] An exact niche for this fungus has yet to be detailed.[4]
Growth and morphology
[edit]C. foveolata displays both teleomorph and anamorph stages in vitro as well as in its natural habitat, it is one of very few Ascomycetes that is able to do so.[4][6] It also produces thick walled chlamydospores with a 3-6 μm diameter.[2]
In vitro the C. foveolata is black, brown, white, orange even yellowish sometimes.[2] The colonies reach a 45-50 mm diameter in vitro on OA or PDA media in 14 days at 25 °C.[2] Its maximum growth temperature is 39 °C though 25 °C is optimal.[2] When grown on PFA medium C. foveolata produces a reddish brown diffusing pigment.[4]
Conidiogenesis occurs in vitro.[2] These conidiogenous cells remain undifferentiated from hyphae and are monophialidic with ellipsoidal conidia at the end of short conidiophores.[2][1] The conidia are translucent, cylindrical, 4-5x1.5-2 μm, and are said to be very similar to the conidia of Phialemonium.[2] The cleistothecia fruiting bodies are dark and ciliated with a peridium made of elongated, thick walled cells.[2][6]
The pitted ascospores for which C. foveolata gets its name are generally kidney shaped, 4-5x3-4x2.5-3 μm, and hyaline to brown.[6][2] The sexual spores are found in translucent brown 8 celled asci.[2]
Mechanism of pathology
[edit]C. foveolata has been described as an opportunistic human pathogen and it is potentially consumed as a contaminant on food.[4] After the first reported case in South Korea there have been 6 other cases as of 2011.[4] Cases have included subcutaneous infections, infections of eyes, nails, lymph nodes, cardiac tissue, bronchial fluid, and one case of bloodstream infection.[4][7] Symptoms were minor for all cases except in the case of the bloodstream infection where the patient had fevers, upper back pain and shortness of breath.[4] Patients with subcutaneous infections had chronic granulomatous inflammation around infection; otherwise, urinalysis, liver/renal function tests, stool examinations, blood counts and smears all return results within normal limits.[1]
Treatment
[edit]When C. foveolata was first discovered in South Korea a surgical removal was performed. The patient was followed for a year afterwards and it seemed the surgery was successful.[1] Since then many anti-fungal drugs have been tried against C. foveolata. The most effective drugs so far have been amphotericin B, posaconazole and voriconazole. They inhibit all growth after 48 hours at 35°C.[4] Caspofungin causes abnormal growth after 24 hours and is not considered effective.[4] Itraconazole is reported with conflicting levels of effectiveness.[1][4] C. foveolata seems to be resistant to AMB, itraconazole, and terbinafine.[5]
Medicinal uses
[edit]C. foveolata produces a metabolite called sclerotiorin. Sclerotiorin has been shown to induce apoptosis in colon cancer cells by activating a pathway leading to caspase-3 activation.[3]
References
[edit]- ^ a b c d e f g Suh M, Lim J, Lee Y, Ha G, Kim H, Kim J, Yaguchi T, Nishimura K (2006). "Subcutaneous hyalohyphomycosis due to Cephalotheca foveolata in an immunocompetent host". British Journal of Dermatology. 154 (6): 1184–1189. doi:10.1111/j.1365-2133.2006.07158.x. PMID 16704653.
- ^ a b c d e f g h i j k l m Yaguchi T, Sano A, Yarita K, Suh M, Nishimura K, Udagawa S (2006). "A new species of Cephalotheca isolated from a Korean patient". Mycotaxon. 96: 30–322.
- ^ a b Giridharan P, Verekar SA, Khanna A, Mishra PD, Deshmukh SK (2012). "Anticancer activity of sclerotiorin, isolated from an endophytic fungus Cephalotheca faveolata Yaguchi, Nishim. & Udagawa". Indian Journal of Experimental Biology. 50 (7): 464–468. PMID 22822525.
- ^ a b c d e f g h i j k l m Lu L, Weil A, Wiederhold N, Sutton D, Chesnut L, Lindner J, Fan H, Tingpej B, El-Khoury J, Kwon D (2015). "Probable case of Cephalotheca foveolata bloodstream infection". JMM Case Reports. 2 (4): 1–5. doi:10.1099/jmmcr.0.000045.
- ^ a b c Perdomo H, Sutton D, García D, Fothergill A, Gene J, Cano J, Summerbell R, Rinaldi M, Guarro J (2011). "Molecular and Phenotypic Characterization of Phialemonium and Lecythophora Isolates from Clinical Samples". Journal of Clinical Microbiology. 49 (4): 1209–1216. doi:10.1128/JCM.01979-10. PMC 3122869. PMID 21270235.
- ^ a b c d Sutton D, MT, SM(ASCP), RM, SM(NRM) (2008). "Rare and Emerging Agents of Hyalohyphomycosis". Current Fungal Infection Reports. 2 (3): 134–142. doi:10.1007/s12281-008-0020-4. S2CID 84306587.
- ^ a b Tsang C (2017). "Diversity of novel and emerging pathogenic fungi in Hong Kong". The University of Hong Kong.