Nakaseomyces

Recent multigene phylogenetic studies have now reclassified the three yeast species previously known as Candida glabrata, C. bracarensis and C. nivariensis into the new genus Nakaseomyces; viz Nakaseomyces glabratus, N. nivariensis and N. bracarensis (Takashima and Sugita, 2022).

Nakaseomyces glabratus, N. bracarensis and N. nivariensis are phenotypically indistinguishable and are best identified by molecular methods or MALDI ToF MS. N. bracarensis was described based on PCR-fingerprints and sequence divergence in the D1/D2 domains (Correia et al., 2006). N. nivariensis was differentiated from other yeasts based on ITS sequences (Borman et al., 2008).

  • Nakaseomyces bracarensis

    Recent multigene phylogenetic studies have now reclassified Candida bracarensis into the new genus Nakaseomyces; as N. bracarensis (Takashima and Sugita, 2022).

    It is phenotypically indistinguishable from N. glabratus and is best identified by MALDI-ToF or molecular methods. N. bracarensis was described based on PCR-fingerprints and sequence divergence in the D1/D2 domains (Correia et al., 2006).

    RG-2 organism.

    Culture: 
    Colonies (SDA) white to cream-coloured smooth, glabrous, yeast-like.

    Microscopy: 
    Ellipsoidal budding blastoconidia, 3.9-6 x 2-4 µm in size. No pseudohyphae or chlamydospores produced.

    India ink preparation: 
    Negative - no capsules present.

    Dalmau plate culture: 
    No pseudohyphae produced.

    Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow, nd No Data
    Germ Tube - L-Sorbose - L-Arabinose - D-Glucitol -
    Fermentation   Sucrose - D-Arabinose - 𝝰-M-D-Glucoside -
    Glucose + Maltose - D-Ribose - D-Gluconate +
    Galactose - Cellobiose - L-Rhamnose - DL-Lactate -
    Sucrose - Trehalose + D-Glucosamime - myo-Inositol -
    Maltose - Lactose - N-A-D-glucosamine - 2-K-D-Gluconate -
    Lactose - Melibiose - Glycerol v D-Glucuronate -
    Trehalose s Raffinose - Erythritol - Nitrate -
    Assimilation   Melezitose - Ribitol - Urease -
    Glucose + Soluble Starch - Galactitol - 0.1% Cycloheximide -
    Galactose - D-Xylose - D-Mannitol - Growth at 40C +

    Key features: 
    N. bracarensis has variable API 20C patterns that overlap with N. nivariensis and some N. glabratus isolates, and has variable results with a rapid trehalose assay. Note: N. glabratus produces mauve-coloured colonies on CHROMagar, whereas isolates of N. bracarensis, N. nivariensis, Candida. norvegensis and C. inconspicua produce white colonies on CHROMagar (Alcoba-Flórez et al. 2005, Bishop et al. 2008).

    Antifungal susceptibility: Nakaseomyces bracarensis (Australian national data); MIC µg/mL.
    Antifungal No ≤0.016 0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 32 ≥64
    AMB 16         2 3 7 3 1        
    FLU 16             1 6 6 2 1    
    ISAV 3   1   2                  
    VORI 16 1 1 6 7 1                
    POSA 16     1 1 2 10 2            
    ITRA 16   1   1 11 3              
    ANID 16 6 3 6 1                  
    MICA 16 15 1                      
    5FC 16     4 3 6 2 1            

  • Nakaseomyces glabratus

    Recent multigene phylogenetic studies have now reclassified the three yeast species previously known as Candida glabrata, C. bracarensis and C. nivariensis into the new genus Nakaseomyces; viz Nakaseomyces glabratus, N. nivariensis and N. bracarensis (Takashima and Sugita, 2022).

    Nakaseomyces glabratus, N. bracarensis and N. nivariensis are phenotypically indistinguishable and are best identified by molecular methods or MALDI ToF MS. N. bracarensis was described based on PCR-fingerprints and sequence divergence in the D1/D2 domains (Correia et al., 2006). N. nivariensis was differentiated from other yeasts based on ITS sequences (Borman et al., 2008).

    Nakaseomyces glabratus is one of the most common yeast species to be found on the body surface and is often isolated as an incidental finding from skin and urine. It has been implicated as an “opportunistic” cause of both superficial and systemic infections, especially in immunocompromised patients, and it has been isolated from patients with septicaemia, pyelonephritis, pulmonary infections, endocarditis and hyperalimentation. Approximately 10% of clinical isolates exhibit azole cross-resistance.

    RG-2 organism.

    Culture: 
    Colonies (SDA) white to cream-coloured smooth, glabrous, yeast-like.

    Microscopy: 
    Ovoid to ellipsoidal budding blastoconidia, 3.4 x 2.0 µm in size. No pseudohyphae or chlamydospores produced.

    India ink preparation: 
    Negative - no capsules present.

    Dalmau plate culture: 
    Ovoid budding yeast cells only. No pseudohyphae produced.

    Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow, nd No Data
    Germ Tube - L-Sorbose - 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 v D-Glucosamime - myo-Inositol -
    Maltose - Lactose - N-A-D-glucosamine - 2-K-D-Gluconate v
    Lactose - Melibiose - Glycerol v D-Glucuronate -
    Trehalose v Raffinose - Erythritol - Nitrate -
    Assimilation   Melezitose - Ribitol - Urease -
    Glucose + Soluble Starch - Galactitol - 0.1% Cycloheximide -
    Galactose - D-Xylose - D-Mannitol - Growth at 40C +

    Key features:
    Germ tube negative yeast and sugar assimilation pattern.N. glabratus is a common yeast species found on the body surface. Approximately 10% of clinical isolates show azole cross-resistance.

    Antifungal susceptibility: Nakaseomyces glabratus (Australian national data); MIC µg/mL.
    Antifungal No ≤0.016 0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 32 ≥64
    AMB 2164 2 8 25 284 436 594 681 49 9     1  
    FLU 2166       1 5 16 44 223 358 358 475 375 311
    ISAV 735 20 41 91 138 154 164 78 24 16 9      
    VORI 2058 26 84 211 399 516 429 194 72 94 32 1    
    POSA 1936 2 16 24 87 220 486 594 343 8 156      
    ITRA 2166   7 27 156 454 650 475 132 34 8 223    
    ANID 1795 171 746 564 267 13 6 10 16 1 1      
    MICA 1795 1564 174 14 9 8 6 7 6 3 5      
    5FC 1764 3 308 1747 37 13 13 9 14 4 1   1 14

  • Nakaseomyces nivariensis

    Recent multigene phylogenetic studies have reclassified Candida nivariensis into the new genus Nakaseomyces; as N. nivariensis (Takashima and Sugita, 2022).

    Nakaseomyces nivariensis is closely related to N. glabratus and N. bracarensis and is best identified by molecular methods (Alcoba-Florez et al., 2005; Correia et al., 2006; Wahyuningsih et al., 2008) and MALDI ToF MS (Pinto et al., 2011).

    RG-2 organism.

    Culture: 
    Colonies (SDA) white to cream-coloured smooth, glabrous, yeast-like.

    Microscopy: 
    Ellipsoidal budding blastoconidia, 3-5 x 1.8-3 µm in size. No pseudohyphae or chlamydospores produced.

    India ink preparation: 
    Negative - no capsules present.

    Dalmau plate culture:
    No pseudohyphae produced.

    Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow, nd No Data
    Germ Tube - L-Sorbose - L-Arabinose - D-Glucitol -
    Fermentation   Sucrose - D-Arabinose - 𝝰-M-D-Glucoside -
    Glucose + Maltose - D-Ribose - D-Gluconate +
    Galactose - Cellobiose - L-Rhamnose - DL-Lactate -
    Sucrose - Trehalose - D-Glucosamime - myo-Inositol -
    Maltose - Lactose - N-A-D-glucosamine - 2-K-D-Gluconate -
    Lactose - Melibiose - Glycerol + D-Glucuronate -
    Trehalose - Raffinose - Erythritol - Nitrate -
    Assimilation   Melezitose - Ribitol - Urease -
    Glucose + Soluble Starch v Galactitol - 0.1% Cycloheximide -
    Galactose - D-Xylose - D-Mannitol - Growth at 40C +

    Key features:
    N. nivariensis is closely related to N. glabratus and N. bracarensis. These three species were found to differ by DNA-DNA reassociation experiments, RAPD-typing, AFLP-typing and D1/D2 and ITS sequence divergence (Alcoba-Flórez et al. 2005, Correia et al. 2006, Wahyuningsih et al. 2008).

    Antifungal susceptibility: Nakaseomyces nivariensis (Australian national data); MIC µg/mL.
    Antifungal No ≤0.016 0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 32 ≥64
    AMB 23         1 5 15 2          
    FLU 23           2 7 4 4 2 3   1
    ISAV 9 1 2 4 2                  
    VORI 23 2 7 8 2 1 2 1            
    POSA 23       5 10 3 2 2          
    ITRA 23       6 10 5 2            
    ANID 23 1 10 8 4                  
    MICA 23 22 1                      
    5FC 23     1 14 4 3 1            

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