LAUSR

We evaluated the activity of echinocandins, azoles, and amphotericin B against Candida spp. isolates and characterised azole resistance mechanisms in Candida parapsilosis and Candida tropicalis. Invasive Candida spp. isolates (n = 2936) collected in 60 hospitals worldwide during 2016-2017 were susceptibility tested by CLSI broth microdilution methods. Azole-resistant C. parapsilosis and C. tropicalis were submitted to quantitative RT-PCR for ERG11, CDR1, and MDR1 and the whole genome sequence was analysed. Results of nonsusceptibility to the echinocandins ranged from 0.0-2.3% and was highest in Candida glabrata. Greater than 99.0% of the Candida albicans isolates were susceptible to both fluconazole and voriconazole. Fluconazole resistance in C. glabrata was 6.5% overall and was highest in the United States (13.0%). Resistance to voriconazole in Candida krusei was only noted in the United States (5.0%). Azoles inhibited 89.1-91.6% of C. parapsilosis isolates, and most resistant isolates were noted in Europe (15.1%), including 36 isolates from Italy (3 hospitals) of which 34 harboured Erg11 Y132F mutations and overexpressed MDR1. Azole non-wild-type C. tropicalis (7/227) were from 5 countries: 3 isolates from Thailand had the same Y132F Erg11 alteration. Fluconazole non-wild-type isolates were noted among 3/77 (3.9%) Candida dubliniensis, 4/17 (23.5%) Candida guilliermondii, 4/47 (8.5%) Candida lusitaniae, and other less common yeast species. Echinocandin use has been recommended over fluconazole for invasive Candida infections; however, azoles are still active against the most common Candida spp., and resistance seems to be restricted to certain geographic regions and associated to Erg11 Y132 alterations in C. parapsilosis and C. tropicalis.