Lomentospora prolificans

Synonymy:
Scedosporium prolificans; Scedosporium inflatum.

Lomentospora prolificans (formerly Scedosporium prolificans) is phylogenetically and morphologically distinguishable from Scedosporium species (Lennon et al. 1994, Lackner et al. 2014a).

Lomentospora prolificans culture

Lomentospora prolificans culture.

Lomentospora prolificans appears to occupy a restricted geographic range, with infections occurring mainly in Australia, Spain, and the United States (Heath et al. 2009, Revankar and Sutton, 2010). L. prolificans infections are refractory to antifungal therapy and are associated with high mortality. Major risk factors include malignancy, cystic fibrosis, and solid organ transplantation. The main clinical presentations are disseminated infection and pulmonary mycoses, followed by bone and joint infections (Cortez et al. 2008, Heath et al. 2009, Rodriguez-Tudela et al. 2009, Revankar and Sutton, 2010).

RG-2 organism.

Morphological description: 
Colonies are rapid growing, flat, spreading, olive-grey to black and have a suede-like to downy surface texture. Conidia are borne in small groups on distinctive basally swollen, flask-shaped conidiophores, which occur singly or in clusters along the vegetative hyphae. Conidia are aggregated in slimy heads, single-celled, hyaline to pale-brown, ovoid to pyriform, 3-7 x 2-5 µm, and have smooth thick walls. Growth at 45C.

Lomentospora prolificans conidiophores and conidia

Lomentospora prolificans conidiophores and conidia.

Key features: 
Dematiaceous hyphomycete with initial black pasty colony, conidiophores with distinctly swollen bases, and the conidial mass forms apical aggregates of conidia. A Graphium synanamorph is absent and there is no growth on media containing cycloheximide (actidione).

Molecular identification: 
Recommended genetic markers: ITS and β-tubulin.

References: 
Malloch and Salkin (1984), Salkin et al. (1988), Rippon (1988), Wilson et al. (1990), Gueho and de Hoog (1991), Lennon et al. (1994), Gilgado et al. (2005), Rainer and de Hoog (2006), Revankar and Sutton (2010), Lackner et al. (2014a), de Hoog et al. (2015).

Antifungal susceptibility: Lomentospora prolificans (Australian national data); MIC µg/mL
  No <0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 >32
AmB 327       1   2 14 55 225 30  
ISAV 29             2 3 24    
VORI 321           6 34 68 213    
POSA 242             1 1 240    
ITRA 329                 2 324 3
Synergy testing results for Lomentospora prolificans (Australian national data).
Antifungal Combination No ∑FIC < 0.5 (S) ∑FIC < 0.5-4 (I) ∑FIC > 4 (A)
VORI/TERB 109 94 (86%) 14 (14%) 0
ITRA/TERB 93 56 (60%) 37 (40%) 0

 

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