Identification of Candida albicans with a commercially prepared germ-tube solution

A commercially prepared lyophilized substrate [Germ Tube Solution (GTS); Remel] was evaluated for its ability to support germ-tube formation as a method for identifying Candida albicans. A total of 127 distinct yeast isolates, including 57 C. albicans, tested for germ-tube formation in GTS and two other commonly used substrates (horse serum and pooled human sera). At two and four hours, 96.5% and 100%, respectively, of the C. albicans isolates produced germ tubes in GTS. Two strains other than C. albicans also produced strains included on C. stellatoideae (a known germ-tube producer) and one C. tropicalis (an organism known to produce structures resembling germ tubes). GTS produces results similar to those attained in horse serum or pooled human sera and is a suitable alternative for identifying C. albicans.