Scientists in China have discovered a previously unknown fungal pathogen that can infect humans.
This fungus is Rhodosporidiobolus fulvialisThe yeast was discovered in clinical samples from two unrelated hospitalized patients. In experiments, the researchers found that the yeast was resistant to several first-line antifungal drugs at high temperatures, above about 100°C. Human bodyThe temperatures also led to the development of “hypervirulent mutants” that could cause even more severe illness in lab mice.
The discovery “supports the idea that global warming may promote the evolution of new fungal pathogens,” the researchers wrote in a report published June 19 in the journal Nature. Nature Microbiology.
The scientists made the discovery after studying fungi collected from patients at 96 hospitals across China between 2009 and 2019. A total of 27,100 fungal species were collected and analysed, of which only R. fluvialis had never been seen in humans before.
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R. fluvialis The fungus was found in the blood of two unrelated patients who were not only infected with the fungus but also had serious underlying medical conditions: one 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 does not say whether the fungal infection was directly related to the deaths of these patients, or whether they simply happened to be infected at the time.
As part of their treatment, the patients were given common antifungal drugs such as fluconazole and caspofungin. R. fluvialis Resistant to both of these drugs.
“This is a surprising and truly unexpected finding, and it bodes ill for the future.” David Denning“The virus is spreading rapidly and people are more susceptible to it,” said a professor of infectious diseases at the University of Manchester in the UK, who was not involved in the study. Science.
Invasive fungal infections that attack deep tissues in the body include: Mainly Affects people Immune System Some people have weakened immune systems due to HIV infection or taking immunosuppressants. In particular, a 61-year-old man infected with HIV said, R. fluvialis The 85-year-old man was immunosuppressed and had diabetes, which inhibits immune function.
However, as global warming progresses, fungi are adapting, Expanding geographic reachThere is a high possibility of contact with humans. A new pathogen has emergedIncluding drug-resistant bacteria Candida aurishas been identified Over 40 countries Since its discovery in 2009, new antifungal drugs have been developed. Almost at an impasseThere are few options left to fight resistant infections.
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In the new study, the researchers used immunodeficient mice R. fluvialis They found that some of the yeast cells were evolving rapidly and growing more vigorously.The team then looked at the bacteria in lab dishes kept at around human body temperature, 98.6 degrees Fahrenheit (37 degrees Celsius).At that temperature, the yeast mutated 21 times faster than at room temperature, around 77 degrees Fahrenheit (25 degrees Celsius).
The heat is also R. fluvialis They are more likely to develop drug resistance. When exposed to the antifungal drug amphotericin B, yeast developed resistance more quickly at body temperature than at room temperature.
If yeast likes it R. fluvialis Global warming could encourage the evolution of dangerous new fungal pathogens, because higher temperatures make them more virulent and more likely to develop drug resistance, the researchers wrote in their paper.
but, R. fluvialisSpecifically, some scientists are arguing against jumping to worrying conclusions. Matthew FisherProfessor of fungal disease epidemiology at Imperial College London, who was not involved in the study, told Science that yeast is not yet considered a major new threat.
“My initial impression is that there are unexplored environments in China where these yeasts live, and that these two patients were unlucky enough to have been infected by them,” he told Science. R. fluvialis Despite its worrying characteristics, it is widely distributed among the general public.
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