Candida auris – an enigmatic yeast, poses substantial global risk in health care facilities and intensive care units (ICUs). A unique phenotype exhibited by certain isolates of C. auris is their ability to form small clusters of cells known as aggregates, which have been described in the context of pathogenic traits. This yeast is able to colonize and subsequently infect patients, particularly those that are critically ill or immunosuppressed, which may result in death.

A new experiment published in mSphere entailed the screening of several non-aggregative and aggregative C. auris isolates for biofilm formation. Additionally, RNA sequencing approach was used to investigate the transcriptional responses during biofilm formation of a non-aggregative and aggregative isolate of the initial pool. Thereafter, the fungal recognition and inflammatory responses of a three-dimensional skin epithelial model to these isolates were investigated. Here, a wound was induced to mimic a portal of entry for C. auris.

It was observed that different phenotypes had a level of heterogeneity amongst themselves. RNA sequencing revealed unique transcriptional profiles in the two isolates—with several genes identified relating to proteins involved in adhesion and invasion of the host in other fungal species. It was found that both phenotypes elicited minimal response in the model minus induction of the wound, yet in the wounded tissue, both phenotypes induced a greater response, with the aggregative isolate more proinflammatory.

It was stated that this capacity of aggregative C. auris biofilm, to generate such responses in the wounded skin highlights how this opportunistic yeast is a high risk within the intensive care environment where susceptible patients have multiple indwelling lines.

Source: mSphere. 2020 Jun 24;5(3):e00371-20. doi: 10.1128/mSphere.00371-20.