Candida auris is a yeast that was first described in Japan in 2009 and has since emerged as a pathogen in several countries, including the United States. C auris can cause serious bloodstream infections, may spread between patients, and can survive for months on common hospital room surfaces. Up to 60% of patients infected with C auris have died. This high mortality rate is most likely attributable to a combination of factors, including the severity of illness in these patients, the difficulty of timely identification of C auris, and the subsequently delayed initiation of effective therapy. C auris has relatively weak expression of known virulence factors compared with Candida albicans,but attributable mortality may be due to its intrinsic multidrug resistance
In June 2016, the Centers for Disease Control and Prevention (CDC) issued a clinical alert requesting that US healthcare facilities report all cases of C auris to the organization as well as to their local and state health departments. As of April 13, 2017, some 70 cases of C auris were reported in the United States, with the bulk of cases reported in New York.
The most common site of C auris isolation is the blood, but the yeast also has been found in the urine, respiratory tract, and other sites. Patients infected with C auris are commonly critically ill. Many have had central venous catheters, urinary catheters, or surgery within 90 days of infection. The median time to diagnosis of C auris is 19 days after admission. While the mortality rate of C auris is approximately 60%, it rises to almost 70% for patients with bloodstream infections.
C auris Resistance and Implications for Therapy
Susceptibility testing performed on 54 isolates of C auris from Pakistan, India, South Africa, and Venezuela found that 50 (93%) were resistant to fluconazole, 29 (54%) were resistant to voriconazole, 19 (35%) were resistant to amphotericin B, 4 (7%) were resistant to echinocandins, and 3 (6%) were resistant to flucytosine. In addition, about 40% of the C auris isolates evaluated to date were resistant to at least two classes of antifungals among fluconazole, voriconazole, amphotericin B, and the echinocandins.
While Candida minimum inhibitory concentration (MIC) breakpoints are not defined for isavuconazole, itraconazole, or posaconazole, susceptibility trends can be identified. Isavuconazole appears to be the most active azole in susceptibility testing performed in a small study of 16 C auris isolates from Germany, Japan, India, and South Korea. Posaconazole and itraconazole were less active, while fluconazole demonstrated the lowest rate in the azole class against C auris.
The first seven cases of C auris identified in the United States found that five were resistant to fluconazole, one of which was also resistant to amphotericin B and another to echinocandins. None of these isolates were resistant to all three classes of antifungals