Kluyveromyces marxianus
Synonymy:
Candida kefir, Candida pseudotropicalis.
Kluyveromyces marxianus is a rare cause of candidiasis and is usually associated with superficial cutaneous manifestations rather than systemic disease.
Environmental isolations have been made from cheese and dairy products.
RG-1 organism.
Culture:
Colonies (SDA) white to cream-coloured smooth, glabrous, yeast-like.
Microscopy:
Short-ovoid to long-ovoid, budding blastoconidia, 3.0-6.5 x 5.5-11.0 µm, sometimes becoming elongate (up to 16.0 µm).
India ink preparation:
Negative - no capsules present.
Dalmau plate culture:
Abundant, long, wavy, branched pseudohyphae usually formed, with ovoid blastoconidia, budding off singly, in pairs or chains, often in a verticillated position. Note: In some strains pseudohyphae may be scarce or almost absent.
Molecular identification:
ITS sequencing recommended.
MALDI-TOF MS:
Able to accurately identify this species.
| 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 | + | D-Arabinose | - | 𝝰-M-D-Glucoside | - | |
| Glucose | + | Maltose | - | D-Ribose | v | D-Gluconate | - |
| Galactose | +,s | Cellobiose | v | L-Rhamnose | - | DL-Lactate | + |
| Sucrose | + | Trehalose | -,w | D-Glucosamime | - | myo-Inositol | - |
| Maltose | - | Lactose | v | N-A-D-glucosamine | - | 2-K-D-Gluconate | - |
| Lactose | v | Melibiose | - | Glycerol | s | D-Glucuronate | nd |
| Trehalose | - | Raffinose | + | Erythritol | - | Nitrate | - |
| Assimilation | Melezitose | - | Ribitol | s | Urease | - | |
| Glucose | + | Soluble Starch | - | Galactitol | - | 0.1% Cycloheximide | + |
| Galactose | s | D-Xylose | s | D-Mannitol | v | Growth at 40C | + |
Key features:
Germ tube negative yeast and sugar assimilation pattern.
| Antifungal | No | ≤0.008 | 0.016 | 0.03 | 0.06 | 0.125 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | ≥64 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AMB | 123 | 7 | 35 | 66 | 14 | 1 | |||||||||
| FLU | 150 | 1 | 31 | 80 | 25 | 6 | 4 | 3 | |||||||
| ISAV | 36 | 8 | 9 | 12 | 5 | 2 | |||||||||
| VORI | 150 | 108 | 32 | 6 | 3 | 1 | |||||||||
| POSA | 145 | 2 | 11 | 31 | 51 | 37 | 10 | 3 | |||||||
| ITRA | 65 | 7 | 12 | 25 | 17 | 4 | |||||||||
| ANID | 125 | 3 | 15 | 54 | 42 | 7 | 1 | 1 | |||||||
| MICA | 120 | 1 | 32 | 52 | 30 | 2 | 1 | 1 | |||||||
| 5FC | 49 | 4 | 28 | 2 | 5 | 1 | 3 | 4 | 2 |