Unstable petite and grande variants of Candida shehatae

Summary Two strains of Candida shehatae (ATCC 22984 and CSIR Y492) exhibit marked variability in colony size (petite, grande) and respiratory activity (tetrazolium reaction) when grown on glucose, xylose, and--especially--xylitol agar. The transitions occur in both directions at high frequency. Strains showing a negative or weak tetrazolium reaction on xylitol ferment xylose better than those showing a strong tetrazolium reaction. The type strain (ATCC 34887) shows stable colonial morphology with moderate respiratory and fermentative activities. The objective of this report is to demonstrate these variations.