Myrmecridium schulzeri

Ramichloridium schulzeri

Ramichloridium schulzeri was placed in a new genus, Myrmecridium by Arzanlou et al. (2007). 

M. schulzeri is an uncommon soil saprophyte of worldwide distribution. It has also been isolated from plant detritus and as a contaminant of bronchoscopy fluid. It is the causative agent of “Golden Tongue” syndrome reported by Rippon et al. (1985).

RG-1 organism.

Myrmecridium schulzeri

Myrmecridium schulzeri conidiophores showing sympodial development of conidia.

Morphological description: 
Colonies growing moderately rapidly, consisting of a rather compact, flat, submerged mycelium, pale orange, locally with some powdery, brownish aerial mycelium; reverse pink to orange. Conidiophores are erect, straight, unbranched, thick-walled, reddish-brown, up to 250 µm high, gradually becoming paler towards the apex, of variable length, elongating sympodially during conidiogenesis, with scattered, pimple-shaped conidium bearing denticles which have unpigmented scars. Conidia are subhyaline, smooth-walled or slightly rough-walled, ellipsoidal, obovoidal or fusiform, 6.5-10 x 3-4 µm, usually with an acuminate base and unpigmented scars.

Molecular identification: 
ITS and D1/D2 sequencing may be used for accurate species identification (Halliday et al. 2015).

Note: Myrmecridium species can be distinguished from other Ramichloridium-like fungi by having entirely hyaline vegetative hyphae, and widely scattered, pimple-shaped denticles on the long hyaline rachis. The conidial sheath is also visible in lactic acid mounts with bright field microscopy Arzanlou et al. (2007).

de Hoog (1977), Rippon et al. (1985), de Hoog et al. (2000, 2015), Arzanlou et al. (2007).

Antifungal susceptibility: Myrmecridium schulzeri (Australian national data); MIC µg/mL.
  No 0.016 0.03 0.06 0.125 0.25 0.5 1 2 4 ≥8
AmB 1           1        
VORI 1             1      
POSA 1             1      
ITRA 1           1        

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