While Candida auris (C. auris) may be getting all the headlines recently, this deadly fungus is one of many drug-resistant superbugs that infectious disease specialists have been fighting for years, says Michael Mansour, MD, PhD, a physician-investigator at the Massachusetts General Hospital.
“We worry about C. diff, MRSA (Methicillin-resistant Staphylococcus aureus) and VRE (Vancomycin-resistant Enterococci),” he says. “We also have a lot of gram-negative bacteria that cause infections that are resistant to multiple antibiotics.”
Drug-resistant strains emerge through exposure to antibiotics—the more that bacteria and fungi are exposed to antibacterial and antifungal treatments, the more they are pressured to develop strategies to resist them.
“We’re living in a world where we are now paying the price for all the antibiotic and antifungal use in humans, plants and animals,” Mansour says.
Researchers are now working to address the problem from two angles—advocating for a reduction in the use antibacterial and antifungal agents to cut down on resistance and developing new strategies to treat those at greatest risk of infection.
When it comes to C. auris, the threat of infection varies depending on the state of your immune system.
“The good news is that if you’re healthy, it’s likely not going to cause you a problem, because your healthy immune system can control these pathogens,” says Mansour.
“With C. auris, it is the immune compromised patient that is at highest risk, whether you are a transplant recipient on immunosuppressant drugs, receiving chemotherapy, or a patient in the ICU with catheters and tubes compromising your physical barriers.”
About Candida auris
Candida is a type of fungus that naturally exists in the human body. Many species are harmless, often causing diaper rash or thrush in otherwise healthy individuals. C. auris, which was first identified in 2009, is the newest—and perhaps most harmful—species of Candida.
When C. auris gains a foothold inside the body, it can spread through the bloodstream and establish infection in multiple organ systems, including brain, lungs, liver, spleen and kidneys. Over time, these fungal pathogens start to disrupt the normal functioning of organs, which can have fatal consequences.
To effectively control C. auris, researchers will have to find ways to overcome its natural defenses. Early research has found that the fungus has surface properties that help it avoid being gobbled up by the body’s white blood cells. It also encases itself within a sticky matrix that is extremely difficult for antifungal drugs to penetrate.
This ability to stick to environmental surfaces made it difficult to eliminate the fungus from contaminated hospital beds and equipment when it first appeared, which led to some of the early outbreaks that spread through hospitals in the United Kingdom and other countries around the world.
Since then, however, new decontamination procedures have been identified that can effectively remove C. auris, which have been implemented at Mass General.
Identification and Containment Challenges
While there have been only a few cases of C. auris infections in Massachusetts so far, the hospital has taken steps to ensure that any new outbreaks are quickly identified and contained, Mansour says.
“If someone walked in and had a [C. auris] infection, we would be ready. The person would be identified very quickly, and that diagnosis would trigger a whole series of infection control steps to contain any potential of further spread.”
Research and Treatment Strategies
Mansour and his lab team are also working to identify new treatment strategies. One approach has been to look at existing drugs that have been approved by the Food and Drug Administration (FDA) to treat other health conditions but may have antifungal properties as well.
The team has identified some promising candidates and are hoping to collaborate with biotechnology and pharmaceutical partners to take their findings further into development.
“My hope is since they are already FDA approved and shown to be safe, we may have circumvented a lot of the lead time required to make them available for patient use.”
The lab is also working to develop new drugs that could be used as treatments down the line.
Another treatment approach is to look for ways to boost an infected individual’s immune system so that white blood cells have a better awareness of C. auris and can eliminate it from the body, he says. It may be that an effective treatment will combine both approaches.
A Global Issue
A unique aspect of C. auris is its global reach—the fungus appears to have emerged almost simultaneously from unique, genetically diverse pockets in Asia, the Middle East, Europe and the Americas.
“Infectious diseases are global problems, and we have to approach them as a team of international partners,” Mansour says.
“Policy makers need to step in and say we need to have more sensible use of antibiotics and antifungals—that’s not only for human use, but also for animal and agricultural use to reduce the selective pressure that is contributing to drug resistance.”
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