Papiliotrema laurentii

Synonymy: Cryptococcus laurentii

A phylogenetic review by Liu et al. (2015) reclassified Cryptococcus laurentii as Papiliotrema laurentii. Papiliotrema laurentii is an emerging opportunistic pathogen, causing disease in patients with impaired cell-mediated immunity (eg, HIV-infected patients or those with haematologic malignancies), in those using steroids or chemotherapeutic agents, and in those with invasive devices. 

Human infections due to P. laurentii have been described as causing fungaemia, central nervous system infection, skin and soft-tissue infections, and pneumonia, among others (Morales-Lopez and Garcia-Effron, 2021).

RG-1 organism.

Culture: 
Colonies (SDA) are cream-coloured, often becoming a deeper orange-yellow with age, with a smooth mucoid texture.

Microscopy: 
Spherical and elongated budding yeast-like cells or blastoconidia, 2.0- 5.5 x 3.0-7.0 μm. No pseudohyphae present.

India ink preparation: 
Positive - narrow but distinct capsules are present.

Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow, nd No Data
Germ Tube - L-Sorbose v L-Arabinose + D-Glucitol +
Fermentation   Sucrose + D-Arabinose + 𝝰-M-D-Glucoside +
Glucose - Maltose + D-Ribose + D-Gluconate +
Galactose - Cellobiose + L-Rhamnose + DL-Lactate v
Sucrose - Trehalose + D-Glucosamime - myo-Inositol +
Maltose - Lactose + N-A-D-glucosamine - 2-K-D-Gluconate +
Lactose - Melibiose + Glycerol v D-Glucuronate +
Trehalose - Raffinose + Erythritol v Nitrate -
Assimilation   Melezitose + Ribitol + Urease +
Glucose + Soluble Starch v Galactitol + 0.1% Cycloheximide -
Galactose v D-Xylose + D-Mannitol + Growth at 37C -,w

Note: 
Some strains of Papiliotrema laurentii may develop brown pigment on bird seed agar and turn CGB media blue, similar to Cryptococcus gattii, however P. laurentii assimilates both lactose and melibiose while C. gattii does not.

Molecular identification: ITS sequencing may be used for accurate species identification.

MALDI ToF MS: Able to accurately identify this species (Fraser et al., 2016).

Antifungal susceptibility: Papiliotrema laurentii (Australian national data); MIC µg/mL. 
Antifungal No ≤0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 32 ≥64
AMB 8     1 2 3 1   1        
FLU 8             1 1   4   2
VORI 7   2   1 2 1     1      
POSA 6 1 1 2 1 1              
ITRA 8 1   2 2 1           2  
5FC 8                       8

References

  • Barnett, J.A., Payne, R.W. and Yarrow, D. (1983) Yeasts: characteristics and identification. Cambridge University Press, Cambridge, UK.
  • de Hoog, G.S., Guarro, J., J. Gene, J., et al. (2020) Atlas of clinical fungi. 4th edition. Foundation Atlas of Clinical Fungi https://webshop.atlasclinicalfungi.org.
  • Fonseca, A., Boekhout, T. and Fell, J.W. (2011) Chapter 138, Cryptococcus Vuillemin (1901), in Kurtzman, C.P., Fell, J.W. and Boekhout, T. (eds), The Yeasts, a Taxonomic Study, 5th edition, pp. 1661-1737.
  • Fraser, M., Brown, Z., Houldsworth, M., et al. (2016) Rapid identification of 6328 isolates of pathogenic yeasts using MALDI-ToF MS and a simplified, rapid extraction procedure that is compatible with the Bruker Biotyper platform and database. Medical Mycology, 54, 80-88.
  • Liu, X.Z., Wang, Q.M., Goker, M., et al. (2015) Towards an integrated phylogenetic classification of the Tremellomycetes. Studies in Mycology, 81, 85-147.
  • Morales-Lopez, S.E. and Garcia-Effron, G. (2021) Infections due to rare Cryptococcus species. A literature review. Journal of Fungi, 7, 279.

 

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