Rapid differentiation of Candida albicans from other Candida species using its unique germ tube formation at 39° C

Abstract

In this study, we found that no Candida species other than C. albicans is able to form germ tubes at 39° C in serum‐free YEPD (1% (w/v) yeast extract, 2% (w/v) peptone and 2% (w/v) dextrose) media, which makes it easy to identify C. albicans from other Candida species. When cultivated in rabbit serum for at least 2 h at 37° C, more than 60% of C. albicans cells generated germ tubes. In YEPD, however, germ tubes began to appear from C. albicans cells within 30 min at 39° C, and more than 60% of C. albicans cells formed the germ tubes after 1 h at 39° C. Standard Candida strains (ATCC, CBS), three C. albicans and two C. dubliniensis strains were cultured in serum at 37° C for 2 h and in YEPD at 39° C for 1 h. All of the three C. albicans formed germ tubes at 39° C. The two C. dubliniensis strains formed germ tubes in serum at 37° C, but grew as a yeast form in YEPD at 39° C. All of the clinically isolated C. albicans strains in our laboratory formed germ tubes in YEPD at 39° C for 1 h, and none of the clinically isolated Candida species other than C. albicans generated germ tubes in YEPD at 39° C. Thus, the unique germ tube formation of C. albicans induced by high temperature (39° C) in YEPD could be applied to a protocol for the rapid and convenient identification of C. albicans in clinical laboratories. Copyright © 2002 John Wiley & Sons, Ltd.