Patients failed to respond to currently available drugs in initial documented instances of spread.
The term “superbug” may be overused in the lay press, but the concern surrounding recent outbreaks of Candida auris in 2 US cities cannot be overstated.
In recent weeks, researchers with the Centers for Disease Control and Prevention (CDC) confirmed in a Notes from the Field report that the drug-resistant fungus has been spreading in 2 hospitals in the Dallas area, where 22 cases have been confirmed, and 1 Washington, DC nursing home, in which there have been 101 infections. The clusters were detected between January and April of this year and of the 5 people who were fully resistant to treatment, 3 eventually died.
“We’ve been concerned about the spread of Candida auris in healthcare settings for the past 5 years, since it was first reported in the US,” report coauthor Meghan Lyman, MD, a medical officer with the CDC in Atlanta, told Contagion. “This is the first time that we’ve seen this type of clustering.”
What’s particularly troubling here is that patients with invasive fungal infections caused by the bug did not show any improvement after being treated with all 3 major classes of currently approved antibacterial agents: azoles (e.g., fluconazole), polyenes (e.g., amphotericin B), and echinocandins. This “pan-resistance” is a “concerning clinical and public health threat,” the CDC researchers said.
“What’s unique is that we saw 2 independent clusters, with no epi info that connects them,” Lyman said.
Historically, at least, approximately 85% of C auris isolates in the US are resistant to azoles, while 33% and 1% fail to respond to amphotericin B and echinocandins, respectively, according to a recent analysis.
Although the antifungal ibrexafungerp, which was recently approved by the Food and Drug Administration (FDA) for treatment of vulvovaginal candidiasis, may have activity against Candida auris, based on the findings of a small sample study, patients with invasive infections caused by the bug face significant health problems. Typically, invasive infections (eg, bloodstream infections) caused by Candida auris occur in up to 10% of patients following skin colonization, which allows the bug to spread.
The key to preventing outbreaks, according to Lyman, is “early identification and infection control.” To that end, she urged physicians treating patients with Candida auris who are not responding to drug therapy to send specimens out for resistance testing.
“In the past pan-resistant cases have been pretty rare but, when they did occur, they developed in individual patients during treatment,” she said. “So, this is very different—and concerning.”