Deadly fungi are becoming drug-resistant, and it's the next big public health threat, experts say

• Some fungi have recently evolved drug resistance, to the concern of scientists.
• Fungi like C. auris infect the most vulnerable patients with compromised immune systems.
• COVID-19 treatments can leave hospitalized patients defenseless against superbugs.

Before scientists knew about COVID-19, drug-resistant germs dominated the Centers for Disease Control and Prevention's list of urgent threats.

Experts have been warning against the overuse of antibiotics for many years in fear that they could spawn dangerous superbugs, or drug-resistant bacteria. But more recently, fungi have begun to evolve defenses against medicines used to treat them as well.

Candida auris, for one, is known to sweep hospitals and nursing homes, infecting the most vulnerable patients and resisting most antifungal drugs. Infectious disease experts braced themselves for the dangerous fungus before it reached the US in 2016, as they had seen it wreak havoc in other countries, Maryn McKenna wrote for Scientific American.

Globally, more than 300 million people are infected with fungal diseases each year and 25 million are at high risk of dying or losing their sight - more than annual deaths from malaria or tuberculosis, according to estimates by the Global Action Fund for Fungal Infections.

By the end of 2020, there were more than 1,500 cases of C. auris in the US across 23 states. COVID-19 put the rising concern about C. auris on pause for some, but others worried the virus and the fungus would collide.

Fungi can infect the most vulnerable patients, including those with COVID

Many interventions used to treat COVID-19, such as steroids, suppress the immune system when it is acting out of control. However, this leaves patients defenseless to opportunistic infections like C. auris, Aspergillus fumigatus, and other drug-resistant germs.

Los Angeles and Orange County saw several hundred cases of C. auris in hospitals and long-term care facilities; in India, the fungus infected a 65-bed ICU and killed two thirds of patients who contracted it on top of COVID-19.

The fungus is so pervasive that it causes problems for healthcare systems as well.

In one case at Mount Sinai Hospital before the pandemic, a man died after a 90-day battle with C. auris. The hospital needed to bring in special cleaning equipment and even ripped out some of the floor and ceiling tiles because the whole room had been infected.