Use of CHROMagar medium in the differentiation of Candida species: is it cost-effective in developing countries?

The opportunistic infection of humans with Candida is becoming more common. As several species of Candida are relatively insusceptible to the commonly used antifungal drugs, rapid identification of the species involved can facilitate effective treatment. CHROMagar Candida medium (CCM) is a commercial product designed to allow the rapid identification of Candida to species level. To explore the potential usefulness of CCM in a developing country, attempts were made to identify the Candida species in 107 Indian isolates (obtained, consecutively, from 90 clinical specimens, over a year-long period, in a tertiary-level teaching hospital), using CCM and more conventional methods in parallel. The most common species appeared to be C. tropicalis (representing 40% of the isolates), followed by C. albicans (28%) and C. glabrata (23%). Although use of CCM allowed the isolates from 84 (93.3%) of the clinical specimens to identified to species level within 48 h, it took at least 7 days to identify the yeasts in 90% of the specimens using the more conventional procedures. With the results of the conventional methods set as the 'gold standard', the use of CCM appeared to allow all of the C. albicans, C. tropicalis and C. krusei isolates and most (92%) of the C. glabrata to be correctly identified. The costs/isolate identified with the CCM were no more than those of the conventional methods. As many (67%) of the isolates examined were of potentially drug-resistant yeasts (C. tropicalis, C. glabrata or C. krusei), there is clearly a need to identify local isolates quickly, to prevent treatment with ineffective drugs. In terms of both performance and cost, CCM appears to be a good method to use.