CDC warns of drug-resistant fungal infections spreading across U.S. health care sites. What you should know.

The U.S. Centers for Disease Control is warning health care providers of an "alarming" rise in the number of infections nationwide caused by a fungus that has increasingly shown resistance to antimicrobial medications.

Candida auris infections are generally not a threat to healthy people, but can be deadly for those who are already very sick, people who have invasive medical devices and/or have long and frequent stays in health care facilities, where the fungus easily can spread.

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In the last 12 months, according to CDC data, Wisconsin has seen one case of the fungal infection.

Here's what to know.

How many cases are out there?

Since it was first identified in the U.S. in 2016, a total of 3,270 infections were reported nationwide through Dec. 31, 2021, according to a March CDC study published In the Annals of Internal Medicine. Another 7,413 cases were found through screening, in which a lab test found the person has the fungus but it was not causing an infection.

Between 2019 and 2021, 17 states identified their first-ever cases of the fungal infection, the CDC data shows. The number of cases rose most rapidly from 2020 to 2021. Nationwide, the number of infections was 1,471 in 2021 compared to 476 in 2019. The number of screening cases ― 4,041 in total ― tripled from 2020 to 2021.

More recent tracking data shows the growth in cases continued in 2022.

A CDC map shows documented cases of C. auris, which health officials warn has been spreading at increased rates and is showing more antimicrobial resistance.
A CDC map shows documented cases of C. auris, which health officials warn has been spreading at increased rates and is showing more antimicrobial resistance.

Equally concerning to health experts: The CDC study found the number of infections that were resistant to the most common class of antifungals used to treat C. auris tripled in 2021 alone.

Wisconsin saw its first and only reported case in which the person had an active infection in 2022.

Is this fungus new?

The CDC considers C. auris to be an "emerging pathogen," because increasing numbers of infections have been seen in multiple countries since it was first identified in Japan in 2009.

CDC analysis of specimens from eastern Asia, southern Asia, southern Africa, and South America found that they were all slightly different in their genetics, suggesting the fungus emerged independently in different regions around the same time.

Candida fungi, Candida albicans, C. auris and other human pathogenic yeasts, 3D illustration
Candida fungi, Candida albicans, C. auris and other human pathogenic yeasts, 3D illustration

C. auris is a type of yeast, part of the same genus as the fungus that causes thrush, an oral infection common in kids and older adults. However, thrush is caused by Candida albicans, which is a normal organism that lives in people's mouth and only becomes a problem when it grows out of control, according to the Mayo Clinic.

Concerns about C. auris are much different, and experts think it is spreading more lately because of the strains that the COVID-19 pandemic put on health care and public health systems, in addition to "poor" infection prevention and control practices in health care facilities.

What are the biggest concerns about C. auris' spread?

The CDC says it is concerned about the spread of C. auris because it is often resistant to multiple antimicrobial drugs that are commonly used to treat Candida infections.

It is also hard to develop standard laboratory methods to identify the fungus.

The fungus is usually diagnosed through a blood or body fluid culture. But labs that don't have the right equipment could misidentify the germ and cause patients' infections to be treated in the wrong way, because C. auris can be confused with other Candida funguses.

Finally, the fungus seems to spread easily in medical facilities, where people are more at risk from serious infections.

Who is most at risk of infection?

More research is needed on this question, experts say.

The fungus is generally not a threat to healthy people.

People who are in nursing homes and have lines and tubes that go into their body are at the highest risk of infection, according to the CDC. Those include breathing tubes, feeding tubes and central venous catheters.

Other risk factors for infections include the patient having had a recent surgery, a diagnosis of diabetes, and people who have used broad-spectrum antibiotics and antifungals.

The CDC has recorded infections in people of all ages, from pre-term infants to the elderly.

What kinds of infections does C. auris cause?

The fungus has caused bloodstream infections, wound infections and ear infections. "Auris" is the Latin word for ear.

The fungus has also been found in patients' respiratory and urine samples, but it isn't clear if it causes infections in the lungs or bladder.

How does it spread?

The fungus can spread from person-to-person or through contaminated surfaces or equipment. However, the CDC says more research is needed on this question.

How is the fungus treated?

Most C. auris infections can be treated with antifungal drugs called echinocandins.

However, when the fungus is resistant to those drugs, doctors may have to use multiple types of antifungals at high doses to treat the infection.

Can this fungus be deadly?


More research is needed to determine if invasive C. auris infections are more deadly than other invasive Candida infections. An invasive infection is when the germ spreads throughout the body beyond places it is normally found.

However, CDC data from a limited number of patients shows somewhere between 30-60% of patients with C. auris die. Again, the risk if high because many of those people also had other serious illnesses that threaten their health.

Where can I find more information?

The CDC's website has more information about the fungus and the work being done to track and prevent its spread.

Contact Devi Shastri at 414-224-2193 or Follow her on Twitter at @DeviShastri.

This article originally appeared on Milwaukee Journal Sentinel: A drug-resistant fungal infection is spreading in health care sites