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<i></i>Candida tropicalis<i></i> is among the most important <i></i>Candida<i></i> species in terms of epidemiology, virulence and resistance. Considering the increase in <i></i>C. tropicalis<i></i> incidence and high rates of mortality associated with this species, knowledge of its adhesion and biofilm formation abilities is needed. These traits determine the persistence and survival of yeast on different indwelling medical devices and host sites. <i></i>C. tropicalis<i></i> is among the most adherent <i></i>Candida<i></i> species, and it has been described as a strong biofilm producer. Environmental factors, phenotypic switching and quorum sensing molecules can affect adhesion and biofilm growth. <i></i>C. tropicalis<i></i> can form sexual biofilms, which are promoted by mating pheromones. <i></i>C. tropicalis<i></i> biofilms are regulated by a wide and complex network of genes and signaling pathways that are currently poorly understood. Morphological studies showed improved biofilm architecture, which was related to the expression of several hypha-specific genes. Based on recent updates, research is still needed to increase our knowledge on the genetic network of adhesion and biofilm formation by <i></i>C. tropicalis<i></i>, as well as the protein diversity that mediates interactions with inert materials and biological surfaces. Here, we have reviewed the main aspects related to adhesion and biofilm formation in <i></i>C. tropicalis<i></i> and summarized current knowledge on the significance of these virulence factors in this opportunistic species.

Background Phenotypic switching generates fungal colonies with altered morphology and allows pathogens to adapt to changing environments.Objective This study investigated the structure of switched colonies in Candida tropicalis.Methods The switched variant strains (crepe and rough) were analyzed for colony morphology at the ultrastructural level-SEM. The distribution and composition of the extracellular matrix (ECM) were evaluated. The percentage of hyphae was determined by direct counting using light microscopy. The gene expression for these responses was measured by RT-qPCR. ResultsThe macromorphology of the switched variants exhibited high complexity, showing depressions, irregular edges, and a greater amount of ECM than the original strain. In addition, rough variant colonies showed higher amounts of total carbohydrates and proteins in ECM (p<0.05). We also observed a positive correlation between BCR1 (Bio lm cell regulator) gene expression and carbohydrate content in the rough variant (Pearson Correlation r²=0.9885, p=0.0483). Structured colonies exhibited a higher percentage of hyphae throughout their development (p<0.05). EFG1 (Enhanced lamentous growth protein 1) and WOR1 (White-opaque regulator 1) gene expression were positively correlated to the hyphae formation pro le of the structured and unstructured (original strain) patterns (r²>0.7673, p<0.05).Conclusion Structural variations in switched morphotypes colonies of C. tropicalis are associated with increased hyphae growth and distinction in composition and distribution of ECM. Switched phenotypes exhibit features that may contribute to the success of infection associated with C. tropicalis.