For several years scientists have been wondering how a multi-drug resistant superbug was able to pop up in more than 30 countries within a decade of being discovered. Now they may finally have their answer – human-caused climate change.
In a new study published in mBio, an open-access journal of the American Society for Microbiology, scientists details just how the superbug, named Candida auris, or C. auris, was able to emerge simultaneously on three continents:
“The argument that we are making based on comparison to other close relative fungi is that as the climate has gotten warmer, some of these organisms, including Candida auris, have adapted to the higher temperature, and as they adapt, they break through human’s protective temperatures.”
-Arturo Casadevall, MD, PhD, lead author on the study
The study confirmed that C. auris is capable of growing at higher temperatures than most of its closely related species, making it possible to thrive in mammalian species. Usually, human’s advanced immune systems and high body temperature keep most dangerous fungi from sticking around long enough to cause damage, but rising global temperatures have forced fungi like C. auris to adapt to warmer environments.
“What this study suggests is this is the beginning of fungi adapting to higher temperatures, and we are going to have more and more problems as the century goes on,” said Dr. Casadevall. “Global warming will lead to selection of fungal lineages that are more thermally tolerant, such that they can breach the mammalian thermal restriction zone.”
Although C. auris appeared on three different continents at the same time, each strain is genetically distinct. “You gotta try to think, what could be the unifying cause here? These are different societies, different populations,” said Dr. Casadevall. “But the one thing they have in common is that the world is getting warmer.”
And if C. auris is able to adapt in this way, “Global warming may lead to new fungal diseases that we don’t even know about right now,” said Dr. Casadevall.
C. auris is resistant to antifungal medication, spreads easily between patients, and causes outbreaks in a short period of time. The yeast can enter the bloodstream and spread throughout the body, causing serious infections. Preliminary studies suggest a mortality rate between 30 and 60 percent.
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