Comparison of pathogenicity of various Candida tropicalis strains.

To clarify the pathogenicity and the pathogenic factors of Candida tropicalis strains, five strains, IFO 0199, IFO 0587, IFO 0589, IFO 1400, and IFO 1647, of C. tropicalis were tested for their lethality to mice, adherence to Hela cells, hydrophobicity, cell growth under acidic conditions (pH 2.0-5.9), and sucrose assimilation using C. albicans NIH A-207 strain as reference. The pathogenicity for mice of all strains was observed in the increasing order IFO 1400=IFO 0589, IFO 0587, IFO 1647=NIH A-207, and IFO 0199. The pathogenicity for mice by all the tested C. tropicalis strains was not correlated with the adherence, the hydrophobicity, or the cell growth. On the other hand, the pathogenicity correlated well with the sucrose assimilation ability. These results show that the pathogenic mechanisms of the C. tropicalis strains were different from those of the C. albicans strains.