Cases of Deadly Fungus Tripled in Past Few Years, CDC Says

Cases of Candida auris have tripled from 2019 to 2021, according to national surveillance data.

After first being detected in the U.S. in 2016, annual clinical case counts increased to 476 in 2019, then to 756 in 2020 (a 59% jump), and then to 1,471 in 2021 (an additional 95% increase), reported Meghan Lyman, MD, of the CDC, and colleagues.

C. auris colonization screening cases also increased, with a 21% increase to 1,310 cases in 2020 versus 2019, and a 209% increase to 4,041 cases in 2021, they noted in the Annals of Internal Medicine.

From 2019 through 2021, there were a total of 3,270 clinical cases and 7,413 screening cases of C. auris, with 17 states identifying their first cases.

Since its detection in the U.S., C. auris "has continued to cause illness and death nationwide," wrote Lyman and co-authors, adding that the CDC has "rated C. auris as an 'urgent threat,' the highest level of concern, because it is often multidrug-resistant; spreads easily in healthcare facilities; and can cause severe, invasive infections with high mortality rates."

Treatment-resistant cases were on the rise, from six pan-resistant and three echinocandin-resistant isolates reported in 2020, up to seven and 19, respectively, in 2021.

"Even this subtle increase is concerning because echinocandins are the first-line therapy for invasive Candida infections and most C. auris infections," Lyman and colleagues explained. "Several new antifungal medications are in development, but more research is needed to understand outcomes for patients with these highly resistant strains and to guide treatment."

In a press release, Lyman noted that "the rapid rise and geographic spread of cases is concerning and emphasizes the need for continued surveillance, expanded lab capacity, quicker diagnostic tests, and adherence to proven infection prevention and control."

The CDC's 2019 Antibiotic Resistance Threats Report identified C. auris as an urgent threat in the U.S. and, in 2022, the World Health Organization (WHO) put it on the fungal priority pathogens list. At the time, Hanan Balkhy, MD, the WHO assistant director-general of antimicrobial resistance, said in a press release, "fungal infections are growing, and are ever more resistant to treatments, becoming a public health concern worldwide."

According to a CDC fact sheet, 30% to 60% of people with C. auris infections have died, based on data from a limited number of patients. "We don't know if patients with invasive C. auris infection are more likely to die than patients with other invasive Candida infections," the agency noted.

When it was first detected, cases appeared to be imported from abroad. But more recently, healthcare transmission is responsible "for most, if not all, cases," Lyman and colleagues wrote. "Most spread in the United States has occurred in high-acuity post-acute care facilities, specifically long-term acute care hospitals and ventilator-capable skilled-nursing facilities. C. auris cases tend to occur in patients who have multiple or prolonged healthcare encounters or indwelling devices, including those receiving mechanical ventilation."

Although the current study may underestimate cases since screening resources have been limited, the CDC has bolstered availability of screening through the American Rescue Plan Act, increasing capacity from seven regional labs to more than 26 labs across the U.S.

"C. auris remains an ongoing health threat in the United States. Public health and healthcare facilities already have limited resources and IPC [infection prevention and control] capacity, and they experience further challenges with MDRO [multidrug-resistant organism] surveillance and prevention when those limited resources shift to fight other threats, such as the COVID-19 pandemic," Lyman and team wrote. "Still, mitigation and even regional containment are possible."

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