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 12         1 3 4 3 1        
    FLU 12             1 4 4 2 1    
    ISAV 3   2   1                  
    VORI 12 1 1 4 5 1                
    POSA 12     1 3 6 2              
    ITRA 12   1   1 7 3              
    ANID 12 3 3 5 1                  
    MICA 12 11 1                      
    5FC 12     2 2 4 3 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 1763 2 8 25 280 393 594 441 19 1        
    FLU 1766       1 4 8 29 183 271 236 417 343 274
    ISAV 503 9 26 61 74 105 129 62 16 13 8      
    VORI 1658 20 68 181 305 390 359 157 59 87 31 1    
    POSA 1563 2 11 17 71 178 361 454 289 7 146      
    ITRA 1766   6 19 126 358 485 395 123 33 7 214    
    ANID 1395 103 566 462 225 9 5 8 15 1 1      
    MICA 1394 1214 132 13 5 8 3 7 4 3 5      
    5FC 1764 3 308 1362 37 11 10 8 11 3 1     10

  • 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 20         1 4 13 2          
    FLU 20           2 6 4 3 1 3   1
    ISAV 6 1 1 4                    
    VORI 20 2 7 6 1 1 2 1            
    POSA 20       5 9 2 2 2          
    ITRA 20       5 9 4 2            
    ANID 20   10 6 4                  
    MICA 20 19 1                      
    5FC 20     1 12 3 3 1            

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