Production: Zhang Hao (Osaka University)

Producer: Computer Network Information Center

Drug resistance of bacteria is a very familiar topic. Some primary school students know that the "prick" of some pathogenic bacteria may be resistant to antibiotics because of mutation. It is also based on the status quo that "everyone knows a little nouns, but few people really fully understand the truth". When people mention antibiotics, they will immediately think of "abuse" and "drug resistance". They are also cautious in using antibiotics and become a panicked bird.

However, the topic of bacterial drug resistance has not been clearly discussed so far, and drug-resistant fungi have made a grand appearance. 2065438+On April 6th, 2009, a fungus named "Candida" was reported in The New York Times, with the introduction of "deadly fungus, there is no cure". This fungus has appeared all over the world in just 10 years, and it is still expanding its territory. About half of the infected people died within 90 days, and the final mortality rate reached 60%. At present, there is still no specific medicine, and even the world's top medical institutions can do nothing.

Screenshot of The New York Times's report on deadly fungi

So, when did this terrible mysterious fungus begin to appear? What is the motivation for their simultaneous appearance around the world? Is it antibiotics again this time? Will such a high mortality rate cause a serious disaster like the medieval Black Death? Behind the mystery, apart from lamenting the tenacious survival instinct of small creatures, the complex and subtle interaction between human beings and the environment and other creatures is really frightening.

Fungi? Bacteria? Virus? Don't be silly, don't be confused.

Before the story of drug-resistant fungi begins, it is necessary for us to review three kinds of microorganisms we have learned in junior high school biology class.

First of all, structurally, viruses are the simplest, followed by bacteria, and fungi are more complicated than bacteria. If the virus is compared to a human flatbed, then the bacteria is at least an electric tricycle, and the fungus may have to be a car.

Secondly, all three may lead to human diseases and require different treatment methods. Most antibiotics are only for bacterial infections, viral diseases need antiviral drugs, and fungal infections also have corresponding antifungal drugs.

For example, because the virus has a simple structure, no cell wall and does not synthesize protein by itself, antibiotics that attack the cell wall or hinder the synthesis of protein cannot act on the virus.

In addition, not all antibiotics can target all kinds of bacteria, such as Pseudomonas aeruginosa, whose cell wall has a small opening, and many antibiotics cannot invade its interior, so the killing effect is limited.

Various antibiotics

Finally, although all three have "enemies" that endanger human health, they also have indispensable allies in human life. Many kinds of fungi are indispensable in brewing and fermentation industry. Many bacteria play an important role in human digestion and material circulation in the biosphere. There are bacteriophages in the virus, which can help people to kill bacteria or help people to synthesize protein.

Candida auricula, a super fungus that wreaks havoc all over the world.

Next, let's uncover the true meaning of drug-resistant fungus "Candida auricula".

Candida auricula can cause invasive candidiasis, such as candidemia, pericarditis, urinary tract infection and pneumonia. Because of its multiple drug resistance, high mortality and difficult diagnosis of infection, it is also called "super fungus". At present, the US Centers for Disease Control and Prevention has listed Candida auralis as an "urgent threat".

In 2005, Japanese organized scientific research forces to conduct a centralized survey of fungal communities in China. At that time, the medical staff of Tokyo Health and Longevity Medical Center collected samples from the ear canal of a 70-year-old Japanese woman. After years of analysis and identification, scientists found that this sample could not be classified as any existing fungi. Therefore, Japanese scientists reported this new fungus for the first time in 2009, and named it "Candida auricula". Unexpectedly, serious cases caused by Candida auricula infection broke out in many countries in Asia and Europe.

Candida auricularia in Petri dishes

The first case in the United States appeared on 20 13. At that time, a hospital in new york admitted a woman who complained of respiratory insufficiency. This 6 1 year-old woman, born in UAE, was found to be positive for Candida auricula one week after admission, and eventually died shortly after. However, in view of the fact that the influence of Candida auricularia was not as great as it is now, the hospital didn't report the situation until 20 16, when the US Centers for Disease Control and Prevention received a case report from the hospital.

What really brought Candida auricula into public view was the concentrated outbreak of infection in Royal Brompton Hospital in 20 16. At that time, the hospital had 72 cases of infection at a time, and the ICU was closed for two weeks. Because the seriousness of the situation was initially underestimated, the hospital did not disclose the situation in the hospital to the public at the first time.

However, according to the situation disclosed afterwards, a few months before the media intervened in the report on a large scale, the hospital had issued relevant alarms and tried to disinfect the area where the epidemic occurred. The staff used a special aerosol to spray hydrogen peroxide solution near the area where patients infected by fungi were treated. Theoretically, the steam of this spray will penetrate into every corner of the room.

These rooms were kept saturated with hydrogen peroxide for a week, and then the researchers placed a mirror in the center of the room to observe the growth of microorganisms in the bottom culture medium. The scary thing is that even so, there is still a Candida auricula community in the Petri dish. However, this incident was finally concealed by the hospital.