A strain of Candida auris resistant to three different classes of antifungal medications was identified in three patients in New York state, according to a report from the Centers for Disease Control and Prevention (CDC).
Most C auris strains found in New York are fluconazole-resistant, and although the researchers acknowledge these pan-resistant isolates remain rare, "their emergence is concerning," they write. The researchers published their findings online January 10 in Morbidity and Mortality Weekly Report.
Belinda Ostrowsky, MD, National Center for Emerging and Zoonotic Infectious Diseases, CDC, and colleagues from the New York State Department of Health identified C auris isolates from various healthcare facilities between August 2016 and June 2019. They identified 801 patients with C auris infection on the basis of clinical cultures or screening swabs of skin or nares.
The New York state public health laboratory conducted antifungal susceptibility testing against azoles, echinocandins, and amphotericin B on all isolates and the CDC's Mycotic Diseases Branch confirmed pan-resistance.
Among the first available clinical isolates tested, 99.6% (276/277) were resistant to fluconazole, 61.3% (170/277) were resistant to amphotericin B, and none were resistant to echinocandins. Susceptibility testing on samples collected after antifungal therapy, on the other hand, revealed that although resistance to fluconazole and amphotericin B remained similar (99.7% and 63.4%, respectively), 3.9% of isolates were now resistant to echinocandins. A C auris isolate resistant to all three antifungal medications was identified in three patients.
Investigators also collected clinical and exposure data, screened close contacts, and conducted site visits to facilities where pan-resistant infections were identified to observe infection control practices and to collect environmental samples, including from frequently touched surfaces and objects.
The three patients were older than 50 years and had numerous comorbidities and prolonged hospital and long-term care facility admissions; all had been treated with echinocandins following their C auris infection diagnosis. None of the patients received treatment at the same facility or had a history of recent travel. No pan-resistant isolates were identified on surfaces from the patients' rooms or among their contacts at the three facilities; however, non–pan-resistant C auris was isolated from other patients at two of the facilities and from the environment at the third facility.
In New York, the predominate clade of C auris is the South Asia clade (clade 1) which "is known to exhibit increased antifungal resistance compared to other clades of C auris," the authors explain; however, all isolates were initially susceptible to echinocandins, which would indicate that resistance developed during antifungal therapy.
"These findings illustrate the need to continue surveillance for C auris, encourage prudence in the use of antifungal medications, and conduct susceptibility testing on all clinical isolates, including serial isolates from a single patient, especially those treated with echinocandins," conclude the authors.
