Significance of modes of adherence in esophageal Candida albicans

Although esophageal candidiasis is the most common form of Candida infection in the gastro-intestinal tract, little attention has been directed toward determining the mechanism of its infection. We have already clarified the existence of four modes of adherence of Candida albicans to the esophagus; attachment, subepithelial cell insertion, cavitation, and invasion. This study was undertaken to clarify the significance of each of these modes. Scanning electron microscopic observations were made of esophageal specimens from 8-week-old rabbits infected with Candida albicans IFO 1060. In this study, attachment and subepithelial cell insertion were found to be the most frequent modes of adherence. Cavitation occurred following subepithelial cell insertion, while invasion occurred following attachment and subepithelial cell insertion. These results suggest that attachment and subepithelial cell insertion play the most important role in the initial stage of adherence. The ratios of these modes for living yeast cells were similar to those for dead yeast cells and beads. This suggests that Candida albicans can gain a foothold on the esophageal epithelium solely by physical contact, after which colonization occurs.