Physiological traits associated with success of Candida albicans strains as commensal colonizers and pathogens

DNA fingerprinting with the moderately repetitive sequence Ca3 has repeatedly identified groups of genetically similar strains of Candida albicans that are more frequently isolated than other groups of strains from human hosts in a geographical locale. Members of these groups are found in approximately 30% of healthy individuals and in up to 70% of patients suffering from candidiasis. The high prevalence of these strains implies that they are more successful in colonizing human hosts and in causing disease than other strains (J. Schmid, Clin. Adv. Treatment Fungal Infect. 4(6):12-16, 1993). In the present study, we have compared one such group of highly prevalent strains with other strains from the same locale to identify physiological traits a larger number of chemicals than other strains in a resistogram assay. When resistance to individual chemicals used in the resistogram assay was analyzed, strains from the group of highly prevalent strains were significantly more often resistant to boric acid, cetrimide, chlorhexidine, 5-fluorocytosine, and high sodium chloride concentrations than other strains. Strains from the group of highly prevalent strains also adhered significantly (1.5 times) better to saliva-coated surfaces than did other strains. Because members of highly prevalent groups of strains are the most common infectious agents in candidiasis, these physiological traits may be involved in determining not only the success of C. albicans in colonizing human hosts in general but also its ability to cause disease. Sodium chloride resistance and increased adherence were also associated with infectious isolates outside the group of highly prevalent strains, indicating that they may be of particular importance in pathogenesis.