Deadliest Form of Candida Auris Spotted in the United States

Candida auris strikes again, but this time the deadly Superbug’s super toxic powers seem to have been enhanced. The Centers for Disease Control and Prevention (CDC) reports that C. auris outbreaks have occurred in two hospitals in the Dallas-area, and a nursing home in Washington, D.C. What makes this a particularly troublesome development is that the Superbugs appear to be pan-resistant—that is resistant to all antibiotics available—and that includes echinocandins, a class of anti-fungal drugs that have proven to be the most effective against C auris.

“These two simultaneous, independent clusters of pan- or echinocandin-resistant C. auris cases in patients with overlapping inpatient health care exposures and without previous echinocandin use provide the first evidence suggesting that pan- or echinocandin-resistant C. auris strains might have been transmitted in U.S. health care settings,” CDC researchers report in the CDC publication Morbidity and Mortality Weekly Report (MMWR). “Surveillance, public health reporting, and infection control measures are critical to containing further spread. Clinicians should consider early antifungal susceptibility testing in patients with C. auris infection, especially in those with treatment failure.”

Also worrying, the clusters in the 3 health care facilities seem to have been created as a result of C. auris spreading from patient to patient.

“Among 22 clinical and screening cases of C. auris in Texas during the same period, two were pan-resistant and five were resistant to both echinocandins and fluconazole,” the MMWR report states. “These seven cases were identified in patients who were cared for at two facilities that share patients in the same city; two patients were at a long-term acute care hospital, three at a short-term acute care hospital, and two at both facilities.”

Meghan Lyman, MD, a medical officer in the CDC’s Mycotic Diseases Branch and the report’s corresponding author, said that “this is really the first time we’ve started seeing clustering of resistance” in which patients seemed to be getting the infections from each other.

The MMWR report states that “data are lacking about the most appropriate therapy for pan-resistant infections. Combination and investigational antifungal treatments can be considered, but evidence in clinical settings is limited. More information is needed to evaluate patient outcomes and identify proper treatment for C. auris cases with pan-resistance or echinocandin resistance.”

C. auris has been diagnosed in 40 countries since the first report about it in 2009, when clinicians found a single isolate from the discharge of the external ear canal of a 70-year-old inpatient at Tokyo Metropolitan Geriatric Hospital. By 2016, 13 cases had been identified in the United States, leading the CDC to issue interim recommendations, as well as a clinical alert, requesting laboratories to report cases and send samples to state and local health departments and the CDC.

As Infection Control Today^® reported in the December issue, C. auris is difficult to identify with standard laboratory methods. It can be misidentified in labs without specific technology, which can lead to mismanagement.

Elizabeth Jefferson, PhD, CIC, an infection preventionist in the infection prevention and clinical epidemiology department at Scripps Memorial Hospital La Jolla, explained at the annual conference of the Association for Professionals in Infection Control and Epidemiology in June how quick action at her facility stopped C. auris from spreading.

Jefferson told ICT^® that “it’s really important to know that it just takes like one single case. You have to really pay attention and make sure that it stays contained so that you don’t have an outbreak. It just takes one case.”

C. auris is 1 of 5 Superbugs on the CDC’s urgent list of pathogenic threats. The other list categories are “serious” and “watch.” The CDC also encourages quick action when faced with C. auris. In its manual on antibiotic resistant threats, the agency cites a case of a patient in a long-term care facility who tested positive for the disease. “An extensive, aggressive containment response followed that involved screening hundreds of patients. When a new patient was identified as carrying or infected with C. auris, they were immediately put under special precautions to prevent spread. This vigilant action by public health officials and health care facilities helped control the spread of C. auris in Orange County, protecting hundreds of vulnerable patients.”

The MMWR report states: “Approximately 85% of C. auris isolates in the United States are resistant to azoles, 33% to amphotericin B, and 1% to echinocandins, based on tentative susceptibility breakpoints…. Echinocandins are thus critical for treatment of C. auris infections and are recommended as first-line therapy for most invasive Candida infections…. Echinocandin resistance is a concerning clinical and public health threat, particularly when coupled with resistance to azole and amphotericin B (pan-resistance).”