pleurostomophora mycetoma

Morphological Description:

The minimum growth temperature for this fungus was 15°C, and the maximum was above 40°C, with an optimum at 36 to 37°C. The colony diameter reached only 1 to 2 mm when grown at 20°C. The isolate decomposed casein in the first week hydrolyzed Starch and Gelatin. Urease test showed to be strongly positive within 3 days.

Molecular Identification:

ITS sequencing is recommended.

In vitro antifungal activity

This fungus was found to be highly susceptible to the azoles itraconazole, ketoconazole, posaconazole, and voriconazole. Low MICs were also found for amphotericin B. The only azole for which a high MIC was found (128 μg/ml) was fluconazole. The fungus was inhibited by caspofungin at 8 μg/ml, but not by 5-flucytosine (MIC > 64 μg/ml).

Pleurostomophora

References:

Mhmoud NA, Ahmed SA, Fahal AH, de Hoog GS, Gerrits van den Ende AH, van de Sande WW. Pleurostomophora ochracea, a novel agent of human eumycetoma with yellow grains. J Clin Microbiol. 2012;50(9):2987-2994.

Madurella pseudomycetomatis 2

 

Etymology:

Yan, Deng, Zhou, Zhong, et Hao ex de Hoog, van Diepeningen, Mahgoub, et van de Sande, sp. nov. Etymology: named after a mycetomatis-like infection. Coloniae modice expandentes, siccae, fuscae ad griseae; reversum fuscum ad griseum. Fuscum-aurantium excretum. Cellulae gemmantes absentes. Hyphae septatae, modice crassitunicatae, pallide brunneae. Conidiophora absentes. Chlamydosporae praesentes. Teleomorphosis ignota. Optime crescit 30°C. Typus vivus et exsiccatus CBS-H 20691 (ex-typus CBS 129177) in herbario CBS praeservatur.

Morphological Description:

The growth rate is slow and the colonies' morphology varied on different media. Colonies on SDA (Sabaroud dextrose agar) were granular, raised, and cauliflower-like and measured 3 to 8 mm in diameter. Microscopically, numerous chlamydospores, which were subglobose, thick-walled, 15 μm in diameter, and intercalary or terminal, were observed on SDA and Potato dextrose agar (PDA). The fungus showed optimal growth at 37°C, could tolerate 42°C, but stopped growth at 44°C. Assimilation of glucose, arabinose, xylose, cellose, maltose, and trehalose was positive in the API 20C AUX system.

Molecular Identification:

ITS sequencing is recommended. Species specific PCR was designed for Madurella pseudomycetomatis by Nyuykonge and associates in 2020 (Ref. No 3).

In vitro antifungal activity

Madurella pseudomycetomatis

  1. pseudomycetomatis showed high susceptibilities to itraconazole (MIC-0 = 0.0625 μg/ml), voriconazole (MIC-0 = 0.0313 μg/ml), and amphotericin B (100% growth inhibition [MIC-0] = 0.0313 μg/ml), while it was resistant to fluconazole (≥50% growth inhibition [MIC-2] = 32 μg/ml) and flucytosine (MIC-2 = 64 μg/ml). The strain was less susceptible to terbinafine. The MIC-0 was 2 μg/ml.

 

References:

  1. de Hoog GS, van Diepeningen AD, Mahgoub el-S, van de Sande WW. New species of Madurella, causative agents of black-grain mycetoma. J Clin Microbiol. 2012; 50(3):988-994.
  2. Yan J, Deng J, Zhou CJ, Zhong BY, Hao F. Phenotypic and molecular characterization of Madurella pseudomycetomatis sp. nov., a novel opportunistic fungus possibly causing black-grain mycetoma. J Clin Microbiol. 2010;48(1):251-257.
  3. Nyuykonge B, Klaassen CHW, Zandijk WHA, de Hoog GS, Ahmed SA, Desnos-Ollivier M, Verbon A, Bonifaz A, van de Sande WWJ. Diagnostic implications of mycetoma derived from Madurella pseudomycetomatis isolates from Mexico. J Eur Acad Dermatol Venereol. 2020:e16402.

Madurella Fahalii

 

Etymology:

Named after Ahmed Fahal, mycetoma expert and founder of the Mycetoma Research Centre in Khartoum, Sudan.

Morphological Description:

The growth rate of M. fahalii CBS 129176 was low; the colony reached a diameter of 26 mm after 2 weeks at 37°C. Colonies were flat and gray-brown (Fig. A). No diffusible pigment was produced on SGA. Microscopically, numerous chlamydospores were observed, in addition to brownish hyphae (Fig. B). Chlamydospores were subglobose, thick-walled, about 10mm in diameter, and intercalary or terminal. No conidia were detected. The fungus showed optimal growth at 30°C; at this temperature, the colony reached a diameter of 29 mm.

Molecular Identification:

ITS sequencing is recommended.

Phylogeny:

The amplified ITS region of M. fahalii CBS 129176 was 595 bp long (GenBank accession number JN573178) and shared 91.9% identity with that of the type strain of M. pseudomycetomatis (TMMU 3956) (GenBank accession number EU815933.1).

In vitro antifungal activity

In vitro susceptiblity of Madurella fahalli

 

References:

de Hoog GS, van Diepeningen AD, Mahgoub el-S, van de Sande WW. New species of Madurella, causative agents of black-grain mycetoma. J Clin Microbiol. 2012; 50(3):988-994.