The investigators found a crude mortality rate of 58.5% at 30 days for patients with C. auris candidemia. All isolates in the study were completely resistant to fluconazole and had reduced susceptibility to voriconazole.
In critical care units at Hospital La Fe, investigators found C. auris on 25% of blood pressure cuffs, 10% of patient tables and keyboards, and 8% of infusion pumps.
Among the patients at Hospital La Fe, multivariable analysis revealed that those most likely to develop C. auris colonization or candidemia were individuals with polytrauma, cardiovascular disease, and cancer.
Patients receiving parenteral nutrition (odds ratio, 3.49), mechanical ventilation (OR, 2.43), and especially those having indwelling central venous catheters (OR, 13.48) were more likely to be colonized or have candidemia as well, according to Dr. Ruiz-Gaitán and her coauthors.
Once identified, how should C. auris be treated? “The majority of strains – upward of 90% – are resistant to fluconazole,” said Dr. Nett. “Moreover, 30%-50% of them are resistant to another antifungal, often amphotericin B. The isolates that we see in the United States are most often susceptible to an echinocandin, and echinocandins remain the choice for treatment of Candida auris pending susceptibility tests.”
However, in Valencia, “The susceptibility to echinocandins presented interesting features. These antifungals were not fungicidal against C. auris,” wrote Dr. Ruiz-Gaitán and her colleagues. They found that for caspofungin, “most isolates presented a clear paradoxical growth after 24 hours of incubation.” Additionally, fungal growth was inhibited at lower caspofungin concentrations, but rebounded at higher levels. Similar patterns were seen for anidulafungin and micafungin, they said.
These findings meant that Hospital La Fe patients received initial treatment with echinocandins, with the addition of liposomal amphotericin B or isavuconazole if candidemia persisted or clinical response was not seen, wrote the investigators.
Patient presentation is similar to other forms of candidiasis, said Dr. Nett. “Patients often have fever, chills, leukocytosis, and this persists despite antibacterial therapy… If Candida auris is suspected, the first course of action would be to place the patient in isolation, and laboratory staff should be alerted regarding the diagnosis.”
Most large clinical laboratories, she said, can now detect C. auris. Matrix-assisted laser desorption/ionization–time of flight is the identification technique of choice, provided that the databases are updated.
Smaller laboratories that use phenotypic tests may misidentify C. auris as another Candida species, or even as Saccharomyces cerevisiae – common beer yeast. Facilities without matrix-assisted laser desorption/ionization can find guidance for interpretation of phenotypic testing on the CDC website as well, said Dr. Nett.
After experiencing what they believe to be the largest C. auris outbreak at a single European hospital, Dr. Ruiz-Gaitán and her colleagues offered best-practice tips for treatment of patients with C. auris candidemia. These include removing mechanical devices as early as is safely practical; performing ophthalmologic examinations for endophthalmitis, a known C. auris complication; obtaining blood cultures every other day to track antimicrobial therapy to the point of sterilization; and searching for metastatic foci if blood cultures remain positive.
All instances of C. auris laboratory identification should be reported to the CDC at candidaauris@cdc.gov, and to local and state health agencies. The CDC recommends strict isolation and cleaning protocols, similar to those used for the spore-forming Clostridium difficile.
Dr. Nett reported funding support from the National Institutes of Health, the Burroughs Wellcome Fund, and the Doris Duke Charitable Foundation. She reported no conflicts of interest. Dr. Ruiz-Gaitán and her collaborators reported funding from Instituto de Salud Carlos III, Spain, and the Spanish Ministry of Science and University. They reported no conflicts of interest.