A weird fungus that preyed on the weakest among us appeared out of nowhere
in 2009. Although it seems like something out of Hollywood, the fungus in
issue is a real concern. Researchers are working feverishly to determine
what causes the deadly fungus Candida auris to proliferate and why hospitals
and other care environments frequently struggle to eradicate it despite
their best efforts at infection control.
Focusing on C. auris' remarkable capacity to adhere to surfaces such as
skin and catheters, researchers at the University of Michigan have uncovered
an astonishing finding. According to the publication "A Candida
auris-specific adhesin, SCF1, governs surface association, colonization, and
virulence," it is published in Science.
The U-M Medical School Department of Microbiology and Immunology's Teresa
O'Meara, Ph.D., and her graduate student Darian Santana lead the
investigative team that has found that C. auris differs from all other known
fungi in that it uses an adhesin, a type of protein that functions very
similarly to those used by oceanic organisms like mollusks and
barnacles.
Initially, they thought that Candida auris would utilize an adhesin from
the sticky protein family that Candida albicans and other fungus employ.
IFF4109 was the only protein that showed a partial effect when they examined
the usual suspects, which are proteins from the highly conserved ALS and
IFF/HYR families.
After that, they switched to a different screening technique to
methodically disrupt the C. auris genome and observe which mutant was unable
to adhere to 96-well plastic plates. This allowed them to identify a novel
adhesin that they called Surface Colonization Factor (SCF1).
Since the novel adhesin is exclusive to C. auris, its evolutionary origins
are unknown. By sequence similarities, it doesn't appear to have originated
from any other creatures," O'Meara stated. They discovered that Scf1 created
cation-pi bonds, which are some of the most powerful non-covalent chemical
connections seen in nature.
O'Meara continued, saying, "People trying to bioengineer glue that sticks
underwater have produced a large amount of the literature regarding this
sort of binding in nature. As a result, they have drawn inspiration from
nature."
Moreover, the group found that SCF1 was linked to higher colonization and a
greater capacity for illness. They showed, using animal models, that a
strain of C. auris was less able to colonize skin and an indwelling catheter
when both SCF1 and IFF4109 were lost. Furthermore, bacteria engineered to
overexpress SCF1 exhibited increased fungal lesions and increased
pathogenicity.
O'Meara stated, "We don't know why this adhesin is necessary to cause
disease." "We don't know in this case whether they are necessary to attach
to blood vessels or if they alter the host-receptor interactions, as has
been observed for the related fungus Candida albicans."
Since many C. auris strains are resistant to existing treatments, O'Meara
and her team intend to look into the relationship between SCF1 and virulence
in the hopes of using it for a more effective anti-fungal therapy. The
adhesin's barnacle-like adhesive qualities point to a marine origin, which
might offer scientists insight into the origins of C. auris.
"In contrast to SARS-CoV2, which only arose in one site, C. auris came out
of nowhere in five different places worldwide. The planet saw a shift in
selection pressure that made C. auris transition from being completely
harmless to invading human populations."
Provided by
University of Michigan
