Scientists in China have discovered a previously unknown fungal pathogen that can infect humans.
The fungus, called Rhodosporidiobolus fluvialis, was found in clinical samples from two unconnected hospital patients. In experiments, the researchers found that the yeast was resistant to several first-line antifungal drugs at higher temperatures — around that of the human body.
This temperature also gave rise to “hypervirulent mutants” capable of causing more-severe disease in lab mice.
The findings “support the idea that global warming can promote the evolution of new fungal pathogens,” the researchers behind the discovery wrote in a report published June 19 in the journal Nature Microbiology.
The scientists made this discovery after examining fungi sampled from patients in 96 hospitals across China between 2009 and 2019. In all, 27,100 strains of fungi were collected and analyzed; of these, only R. fluvialis had never been seen in humans before.
R. fluvialis was uncovered in the blood of two unconnected patients who, in addition to being infected with the yeast, had serious underlying health conditions.
One patient was a 61-year-old who died in an intensive care unit (ICU) in Nanjing in 2013, and the other was an 85-year-old who died in 2016 after being treated in an ICU in Tianjin.
The report doesn’t note whether the fungal infection directly contributed to these patients’ deaths or if they just happened to be infected at the time.
As part of their treatments, the patients were given common antifungal drugs, including fluconazole and caspofungin. Lab studies by the team later found that R. fluvialis is resistant to both these drugs.
