Simple low cost differentiation of Candida auris from Candida haemulonii complex using CHROMagar Candida medium supplemented with Pal's medium

Abstract

BackgroundCandida auris is unique due to its multidrug resistance and misidentification as Candida haemulonii by commercial systems. Its correct identification is important to avoid inappropriate treatments. AimsTo develop a cheap method for differentiating C. auris from isolates identified as C. haemulonii by VITEK2. MethodsFifteen C. auris isolates, six isolates each of C. haemulonii and Candida duobushaemulonii, and one isolate of Candida haemulonii var. vulnera were tested using CHROMagar Candida medium supplemented with Pal's agar for better differentiation. ResultsOn CHROMagar Candida medium supplemented with Pal's agar all C. auris strains showed confluent growth of white to cream colored smooth colonies at 37°C and 42°C after 24 and 48h incubation and did not produce pseudohyphae. The isolates of the C. haemulonii complex, on the contrary, showed poor growth of smooth, light-pink colonies at 24h while at 48h the growth was semiconfluent with the production of pseudohyphae. C. haemulonii complex failed to grow at 42°C. ConclusionsWe report a rapid and cheap method using CHROMagar Candida medium supplemented with Pal's agar for differentiating C. auris from isolates identified as C. haemulonii by VITEK2.