Candida haemulonii and Candida auris are recently described, closely related drug-resistant Candidaspecies. Little is known about the pathogenicity and epidemiological characteristics of these species.
We reviewed Candidaclinical isolates recovered from 1/2008 through 12/2015 at the Tel Aviv Medical Center. Species identification was done using ITS1-ITS2 and D1/D2 LSU PCR and sequencing. We determined susceptibility to antifungals, genetic relatedness and efflux transporter activity. Virulence was assessed by intravenous infection of BALB/c mice immunosuppressed with cyclophosphamide.
Thirty-nine patient-unique isolates were identified as C. haemulonii by Vitek 2, of which 21 (54%) were from patients receiving care at a peripheral vascular disease outpatient clinic. Predisposing factors were diabetes mellitus type 2, end-stage renal disease, use of topical azoles on wounds and interpatient contact. Isolates were recovered from wounds (21), urine (11), blood (5), and vascular catheter (2). Of 9 isolates available for microbiological analysis, all 5 blood isolates were identified by sequencing as C. auris, whereas 4 non-invasive isolates were identified as C. haemulonii. C. auris, but not C. haemulonii, was thermotolerant at 37-40⁰C. C. auris was highly lethal in immunosuppressed mice, whereas C. haemulonii was avirulent in this model (log-rank test for survival, P<0.001). C. auris isolates were closely related to each other and phylogenetically distinct from isolates recovered in East Asia and South Africa. All isolates exhibited high MIC for fluconazole (MIC50, [range]), 32 mcg/mL (16-64 mcg/mL), anidulafungin, 8 mcg/mL (4-8 mcg/mL), and amphotericin B, 2 mcg/mL (1-2 mcg/mL). Transmembrane efflux activity was ~3 times that observed with C. glabrata.
These are the first reported cases of clinical infection with C. auris and C. haemulonii in Israel. C. auris appears to be more virulent than C. haemulonii. C. haemulonii is transmitted efficiently among patients, suggesting a need for infection control measures. The emergence of these multidrug resistant Candida species warrants enhanced vigilance.
S. Zakin, None
E. Bash, None
J. Berman, None
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