Development of
simple and rapid identification system for Candida species isolated from clinical
samples
Nagaraja B.K., Dayananda G.Y. and Sundararaman M.
Res. J. Biotech.; Vol. 21(2); 256-263;
doi: https://doi.org/10.25303/212rjbt2560263; (2026)
Abstract
A study was performed to develop a novel chromogenic media and PCR based molecular
marker for the identification of Candida species. Totally, nine different new chromogenic
media were tested against five species of Candida viz. C. albicans, C. glabrata,
C. tropicalis, C. krusei and C. lusitaniae. The Sabouraud dextrose medium supplemented
with methyl blue (0.025%) and phenol red (0.04%) [Chromogenic Candida Agar 7 (CCA7)]
showed astonishing results by differentiating the five species of Candida [C. albicans
(light blue), C. glabrata, (steel blue), C. tropicalis (violet blue), C. krusei
(light purple) and C. lusitaniae (sky blue)]. To check the efficacy of CCA7 medium
further, it was evaluated using five clinical strains of different species, which
showed similar results as that with the standard strains. Interestingly, newly formulated
medium showed differentiation of Candida species better than the commercial reference
media. Efforts on development of new molecular marker for direct identification
of Candida species using polymerase chain reaction were also carried out by designing
primers for gene isocitrate lyase (ICL1) involved in the glyoxalate pathway that
amplify 200-bp product in C. albicans and C. tropicalis, but not in other species
tested.
However, a set of primers designed for INT1 gene involved in adherence and filamentation
of organisms that were able to amplify 227-bp gene product only in the C. albicans.
The similar patterns of PCR products were observed both in clinical isolates and
standard Candida strains. Hence, newly developed chromogenic medium along with molecular
marker is very useful in the rapid detection of commonly occurring C. albicans and
other species from the clinical specimens in large numbers.
