Expert Q&A: What you need to know about the deadly fungus Candida auris
Hospitals and other care centres around the world are facing an emerging infectious threat: Candida auris, a dangerous, drug-resistant fungus that can enter the bloodstream and cause potentially fatal infections.
Lindsay Kalan, an associate professor of biochemistry and biomedical sciences at McMaster University, has been investigating how and why Candida auris colonizes human skin so well. According to her research, the fungus thrives on our bodies due in large part to the sweat and oils that are produced by our skin.
“These natural substances allow the fungus to stick to us and form biofilms on our skin,” says Kalan, whose research supports both the Global Nexus for Pandemics and Biological Threats and the Michael G. DeGroote Institute for Infectious Disease Research. “Biofilms are an assemblage of microbes that are typically more tolerant to environmental stresses like drugs and immune system responses because they have a strong protective barrier.”
Upon colonizing the skin, Kalan explains, the fungus can enter the bloodstream through cuts and other openings.
Kalan says that while the risk of Candida auris infection — or candidiasis — is currently “very low” for healthy individuals, the highly resistant fungal pathogen is nonetheless a serious public health concern. Here, she explains what you need to know about this emerging threat.
What is Candida auris?
Candida auris — or C. auris — is a type of fungus that can colonize your skin and cause invasive infection in people. It is a concerning pathogen because it is resistant to many of the antifungal drugs that are available and the mortality rate for infected people can be very high.
In recent months, we’ve seen regional public health authorities and international media groups reporting on a steady rise in cases of C. auris. Why has there been a recent surge, and why is it of concern?
To date, C. auris has largely been spreading through the healthcare system. As patients or healthcare workers move between clinical centres, they may be asymptomatically colonized with C. auris and unknowingly contributing to its spread. Regarding the recent uptick, it has been hypothesized that the COVID-19 pandemic may have contributed to a rise in C. auris cases due to changes in infection prevention and control measures, staff shortages, and other strains on the healthcare system. More generally, a reason for its steady rise is our ability — or lack thereof — to detect and screen C. auris. This pathogen can be misidentified or go unscreened altogether, leading to undetected cases. This growth in spread is of concern because C. auris can cause severe bloodstream infections with a mortality rate in the range of 30-60 percent for those diagnosed.
Does C. auris have pandemic potential?
This fungus does have pandemic potential, as it has already been detected globally. Cases and carriage rates are underestimated due to the challenges associated with identification. This means transmission is likely ongoing and not being detected. The fungus can persist on skin and in the environment for a long time. A recent study involving researchers here at McMaster showed that C. auris is found on stored apples. These apples are often treated with waxes and various fungicides that may lead to more antifungal resistance. It further suggests that the fungus could be spreading in the community when people handle fruit. This raises important questions about the role of fungicides and food-chain dynamics in the spread of emerging pathogens.
What can people do to protect themselves from getting candidiasis?
Currently, the risk of getting candidiasis from C. auris is very low for most people. Those most at risk include individuals with complicated medical conditions who live in long-term care or other nursing facilities. In these settings, the implementation of appropriate infection prevention and control measures is critical. Early detection through screening for the pathogen is also important for curbing its spread.
Are there any therapeutics or vaccines to treat or protect against C. auris?
Infections from C. auris are usually treated with a class of antifungal drugs called echinocandins; however, a small percentage of cases are resistant to these medications and the percentage of pan-resistant strains is now increasing. Thus, new strategies to slow transmission coupled with the development new antifungal therapeutics will be critical moving forward.
My lab has been studying how bacterial members of the healthy skin microbiome are able to provide colonization resistance to C. auris. We have found that commensal bacteria — the bacteria that normally live on your skin — are able to inhibit the growth of C. auris through the production of secreted metabolites. This is exciting because we could potentially develop new therapeutics that target C. auris to both prevent carriage in susceptible individuals and treat infections.
What are some common symptoms to watch for regarding C. auris, and when should you see a doctor?
Most healthy people are not a risk of a C. auris infection; however, those who are at risk should watch for symptoms of invasive infection, which include fever and chills that do not respond to antibiotic treatment. If you suspect you have a fungal or healthcare-associated infection, you should seek care.
Read more at Global Nexus News.
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