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. 2017 Apr;11(4):DC01-DC03.
doi: 10.7860/JCDR/2017/25967.9653. Epub 2017 Apr 1.

Auxanographic Carbohydrate Assimilation Method for Large Scale Yeast Identification

Suganthi Martena Devadas  1 , Mamatha Ballal  2 , Peralam Yegneswaran Prakash  3 , Manjunath H Hande  4 , Geetha V Bhat  5 , Vinitha Mohandas  6
Affiliations

Auxanographic Carbohydrate Assimilation Method for Large Scale Yeast Identification

Suganthi Martena Devadas et al. J Clin Diagn Res. 2017 Apr.

Abstract

Introduction: The auxanographic carbohydrate assimilation had been an important method for differentiation of yeasts. Prevailing methods described in the literature for carbohydrate assimilation has limited scope for use in large scale yeast identification.

Aim: To optimize the large scale auxanographic carbohydrate assimilation method for yeast identification.

Materials and methods: A modified auxanographic carbohydrate assimilation method was developed and a total of 35 isolates of Candida species comprising of four ATCC (American Type Culture Collection) Candida strains (Candida albicans ATCC 90028, Candida tropicalis ATCC 90018, Candida parapsilosis ATCC 750, Candida krusei ATCC 6258) and 31 clinical isolates of Candida tropicalis (n=13), Candida krusei (n=7), Candida glabrata (n=3), Candida kefyr (n=3), Candida albicans (n=5) were validated. The carbohydrates tested were Glucose, Sucrose, Maltose, Lactose, Cellubiose, Raffinose, Trehalose, Xylose, Galactose and Dulcitol.

Results: A total of 35 Candida species were tested for their carbohydrate assimilative property and the results were consistent with the existing standard protocols. A well circumscribed opaque yeast growth indicated assimilation of the test carbohydrate and translucent to opalescent growth with the outline of initial inoculum alone indicated lack of assimilation. The control plate indicated no growth of the Candida species.

Conclusion: The carbohydrate assimilation tests finds utility for yeast diversity studies exploring novel ecological niches. The technique described here facilitates testing of an extended range of carbohydrates and yeasts in a cost effective manner.

Keywords: Candida; Control plate; Ecological niche.

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Figures

[Table/Fig-1]:
[Table/Fig-1]:
Interpretation for auxanographic carbohydrate assimilation technique: a) Well circumscribed opaque yeast growth indicative of assimilation of the test carbohydrate; b) Translucent to opalescent growth with the outline of initial inoculum alone indicative of lack of assimilation.
[Table/Fig-2]:
[Table/Fig-2]:
Auxanographic carbohydrate assimilation plate following incubation at 300C for 48 hours for selected carbohydrates (1) Glucose (2) Lactose (3) Cellubiose along with (4) Control. Note-The control plate with translucent or opalescent outline indicative of a lack of assimilation. A large number of yeasts spotted thus can be screened for their assimilative properties for a specific carbohydrate.
See this image and copyright information in PMC

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