Chinese scientists have recently identified a new pathogenic fungus named Rhodosporidiobolus fluvialis, which has the potential to infect humans.
This discovery is the result of careful analysis and examination of clinical samples, raising concerns about the emergence of new pathogens, particularly in the context of global warming.
Notably, this fungus exhibits drug resistance to several common antifungal medications.
A Concerning Discovery
Rhodosporidiobolus fluvialis was first identified in clinical samples from two hospitalized patients in China between 2009 and 2019. Among 27,100 strains analyzed, Rhodosporidiobolus fluvialis was the only strain not previously observed in humans.
This fungus was found in the blood of a 61-year-old immunocompromised man and another 85-year-old patient with diabetes.
Research shows that Rhodosporidiobolus fluvialis can infect humans.
Both individuals died while in intensive care. The direct correlation between the infection of this fungus and their deaths remains unclear.
Researchers found that Rhodosporidiobolus fluvialis displays concerning drug resistance to several leading antifungal medications, including fluconazole and caspofungin, which are commonly used to treat fungal infections.
These medications are typically administered to patients with invasive fungal infections, working by disrupting the fungal cell membrane or inhibiting the synthesis of essential cellular components, often leading to the death of the fungus.
However, Rhodosporidiobolus fluvialis has shown the ability to survive and proliferate despite these treatment methods.
In laboratory experiments, researchers also observed the fungus’s activity at different temperatures. They discovered that it developed “hyper-virulent mutations” at 37 degrees Celsius, which is equivalent to human body temperature.
At this temperature, the fungus mutates 21 times faster than at room temperature (25 degrees Celsius). These rapid mutations enable it to adapt more effectively to hostile conditions, such as the presence of antifungal drugs.
A Potential Threat That Requires Caution
This discovery highlights an increasing issue: the impact of global warming on the evolution of fungal pathogens.
Rising global temperatures are forcing fungi to adapt and expand their geographical range, thereby increasing the risk of human exposure.
This rapid adaptation could also facilitate the emergence of new drug-resistant pathogens, as evidenced by the swift mutations of Rhodosporidiobolus fluvialis.
For instance, Candida auris—another drug-resistant yeast—has been identified in over 40 countries since 2009, clearly illustrating this threat.
Combating these infections is becoming increasingly difficult due to the stagnation in the development of new antifungal drugs, leaving very few options available for treating drug-resistant infections.
While this discovery is alarming, some scientists urge caution. Professor of fungal epidemiology Matthew Fisher from the Royal College of London believes that Rhodosporidiobolus fluvialis should not yet be considered a major emerging threat.
“We should only regard patients infected with this fungus as possibly having come into contact with it in specific environments in China, rather than issuing warnings about widespread transmission of this pathogen,” the scientist explained.
Therefore, scientists require further research to understand the true threat posed by Rhodosporidiobolus fluvialis and its potential for spread.
