Candida

Recently, several taxonomic rearrangements have been made and many well-known Candida species have been renamed and moved to other genera.

Notably Candidozyma auris (formerly Candida auris), Nakaseomyces glabratus (formerly C. glabrata), Pichia kudriavzevii (formerly Candida krusei), Meyerozyma guilliermondii (formerly Candida guilliermondii), Clavispora lusitaniae (formerly Candida lusitaniae), Kluyveromyces marxianus (formerly Candida kefyr), Diutina catenulata (formerly Candida catenulata), Diutina rugosa (formerly Candida rugosa), Candidozyma haemuli (formerly Candida haemulonii and Wickerhamomyces anomalus (formerly Candida pelliculosa). Candida parapsilosis is also now recognised as species complex (Tavanti 2005; Correia 2006; Alcoba-Florez 2005).

Candida microscopy

Candida albicans showing typical cream-coloured, smooth surfaced, waxy colonies and narrow based budding spherical to ovoid blastoconidia.

The genus Candida is characterised by globose to elongate yeast-like cells or blastoconidia that reproduce by narrow-based multilateral budding. Pseudohyphae and occasionally true hyphae may also be present. Colony pigmentation is usually absent. Ballistoconidia are not formed. Arthroconidia may be formed, but not extensively. Sexual reproduction is absent. Glucose may be fermented. Nitrate may be assimilated. Starch-like compounds are not produced. The diazonium blue B reaction is negative.

References

  • Alcoba-Florez, J., Mendez-Alvarez, S., Cano, J., et al. (2005) Phenotypic and molecular characterization of Candida nivariensis sp. nov., a possible new opportunistic fungus. Journal of Clinical Microbiology, 43, 4107-4111.
  • Correia, A., Sampaio, P., James, S., et al. (2006) Candida bracarensis sp. nov., a novel anamorphic yeast species phenotypically similar to Candida glabrata. International Journal of Systematic and Evolutionary Microbiology, 56, 313-317.
  • Tavanti, A., Davidson, A.D., Gow, N.A., et al. (2005) Candida orthopsilosis and Candida metapsilosis spp. nov. to replace Candida parapsilosis groups II and III. Journal of Clinical Microbiology, 43, 284-292.

Species descriptions

  • Candida albicans

    Candida albicans is a commensal of mucous membranes and the gastrointestinal tract. Environmental isolations have been made from sources contaminated by human or animal excreta, such as polluted water, soil, air and plants.

    RG-2 organism.

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

    Microscopy: 
    Spherical to subspherical budding blastoconidia, 2-7 x 3-8 µm in size.

    India ink preparation: 
    Negative - no capsules present.

    Dalmau plate culture:
    Branched pseudohyphae with dense verticils of blastoconidia. Spherical chlamydospores, mostly terminal, often on a slightly swollen subtending cell, are formed near the edge of the cover slip.

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

    Key features: 
    Germ tube positive, production of chlamydospores on Dalmau plate culture, fermentation of glucose, sugar assimilation profile and a distinctive green colour on CHROMagar. Note: Germ tube negative variants (previously known as C. claussenii), and sucrose-negative variants (previously described as C. stellatoidea) may occur.

    Antifungal susceptibility: Candida albicans (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 3013 2 16 162 650 679 1083 415 6          
    FLU 3016 2 2 3 132 1019 1223 411 85 26 19 35 15 44
    ISAV 1036 955 59 8 5 2 3 1 1   1 1    
    VORI 2732 2290 227 86 31 29 31 16 10 2 4 6    
    POSA 2382 1039 978 228 66 31 23 14 1   2      
    ITRA 3016 178 814 1275 589 70 52 15 3   1 19    
    ANID 2111 678 773 479 172 6 1 1 1          
    MICA 2107 1976 109 14 5   2   1          
    CAS 1865 27 381 878 434 124 17 1            
    5FC 3016 4 147 1526 570 307 286 96 26 13 10 3 3 25

     

  • Candida auris

    Candida auris and Candida haemulonii have recently been placed into the novel genus Candidozyma based on extensive phylogenetic and phylogenomic analyses (Liu et al. 2024; Borman et al. 2025).

    Go to Candidozyma

  • Candida dubliniensis

    Candida dubliniensis is an occasional cause of candidaemia and mucosal infection, especially in HIV patients.

    RG-2 organism.

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

    Microscopy:
    Spherical to subspherical budding blastoconidia, 3-8 x 2-7 µm in size.

    India ink preparation:
    Negative - no capsules present.

    Dalmau plate culture:
    Branched pseudohyphae with dense verticils of blastoconidia and spherical, mostly terminal chlamydospores.

    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 +,s
    Glucose + Maltose + D-Ribose - D-Gluconate -
    Galactose +,s Cellobiose - L-Rhamnose - DL-Lactate +
    Sucrose - Trehalose s,+ D-Glucosamine v myo-Inositol -
    Maltose + Lactose - NAD-glucosamine + 2-K-D-Gluconate +
    Lactose - Melibiose - Glycerol w,s,+ D-Glucuronate -
    Trehalose v Raffinose - Erythritol - Nitrate -
    Assimilation   Melezitose w,+ Ribitol + Urease -
    Glucose + Soluble Starch w,+ Galactitol - 0.1% Cycloheximide +
    Galactose + D-Xylose s,+ D-Mannitol + Growth at 40C +  

    Key features:
    Germ tube positive, similar to C. albicans, except for absence of growth at 42C; glycerol (mostly +), methyl-a-D-glucoside (-), trehalose (-), and D-xylose (-). Initial colonies dark green on CHROMagar and producing rough colonies on bird seed agar. ITS sequencing and MALDI-TOF can reliably distinguish C. dubliniensis from C. albicans.

     

    Antifungal susceptibility: Candida dubliniensis (Australian national data with additional ISAV data from Pfaller et al., 2013); 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 242 1 1 3 44 103 84 6            
    FLU 242       118 90 29 5            
    ISAV 75 70 4 1                    
    VORI 239 239                        
    POSA 231 125 77 26 3                  
    ITRA 242 95 66 61 16 4                
    ANID 216 33 43 59 69 6         6      
    MICA 216 99 93 16 2           6      
    CAS 155   10 74 51 10 1   1   7      
    5FC 242   12 201 21 5 2   1          

    References

    • Pfaller, M.A., Messer, S.A., Rhomberg, P.R., et al. (2013) In vitro activities of isavuconazole and comparator antifungal agents tested against a global collection of opportunistic yeasts and molds. Journal of Clinical Microbiology, 51, 2608-2616. 

  • Candida parapsilosis complex

    Recently Candida parapsilosis has been recognised as a complex of four species: C. parapsilosis, C. orthopsilosis, C. metapsilosis and Lodderomyces elongisporus (Tavanti et al. 2005).

    These four species are phenotypically indistinguishable and are best identified by ITS sequencing or MALDI-TOF MS analysis.

    Candida parapsilosis Candida metapsilosis Candida orthopsilosis

  • Candida tropicalis

    Candida tropicalis is a major cause of septicaemia and disseminated candidiasis. It is also found as part of the normal human mucocutaneous flora and environmental isolations have been made from faeces, shrimp, kefir and soil.

    RG-2 organism.

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

    Microscopy: 
    Spherical to subspherical budding yeast-like cells or blastoconidia, 3.5-7 x 5.5-10 µm.

    India ink preparation: 
    Negative - no capsules present.

    Dalmau plate culture:
    Abundant, long, wavy, branched pseudohyphae with numerous ovoid blastoconidia, budding off. Terminal vesicles (chlamydospores) are not produced.

    Physiological Tests: + Positive, - Negative, v Variable, w Weak, s Slow, nd No Data
    Germ Tube - L-Sorbose v L-Arabinose - D-Glucitol +
    Fermentation   Sucrose v D-Arabinose - 𝝰-M-D-Glucoside v
    Glucose + Maltose + D-Ribose v,s D-Gluconate v
    Galactose + Cellobiose v L-Rhamnose - DL-Lactate v
    Sucrose v Trehalose + D-Glucosamime v 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 v Ribitol v 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. Colonies are dark blue on Candida CHROMagar.

    Antifungal susceptibility: Candida tropicalis (Australian national data with additional ISAV data from Pfaller et al., 2013); 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 441     5 41 77 129 165 23 1        
    FLU 441       1 9 59 161 123 46 15 6 5 17
    ISAV 218 13 51 64 48 20 14 5 1 1 1      
    VORI 409 22 47 104 126 66 18 7 9 2 7 1    
    POSA 390 8 32 66 132 107 27 10 2   6      
    ITRA 442 2 12 23 163 176 50 4 2 1 1 8    
    ANID 336 17 22 60 204 29 2     1 1      
    MICA 336 62 230 36 3 1 2       2      
    5FC 442   31 283 81 24 5 2 1 1 2 1 2 9

    References

    • Pfaller, M.A., Messer, S.A., Rhomberg, P.R., et al. (2013) In vitro activities of isavuconazole and comparator antifungal agents tested against a global collection of opportunistic yeasts and molds. Journal of Clinical Microbiology, 51, 2608-2616. 

Quick Links to previous yeasts described as Candida species

Candidozyma auris (formerly Candida auris)
Candidozyma haemuli (formerly Candida haemulonii)
Nakaseomyces glabratus (formerly Candida glabrata)
Pichia kudriavzevii (formerly Candida krusei)
Pichia inconspicua (formerly Candida inconspicua)
Meyerozyma guilliermondii (formerly Candida guilliermondii)
Clavispora lusitaniae (formerly Candida lusitaniae)
Kluyveromyces marxianus (formerly Candida kefyr)
Diutina catenulata (formerly Candida catenulata)
Diutina rugosa (formerly Candida rugosa)
Wickerhamomyces anomalus (formerly Candida pelliculosa)

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