Molecular Analysis of Resistance and Detection of Non-Wild-Type Strains Using Etest Epidemiological Cutoff Values for Amphotericin B and Echinocandins for Bloodstream Candida Infections from a Tertiary Hospital in Qatar.

A total of 301 bloodstream isolates collected from 289 patients over 5 years at a tertiary hospital in Qatar were evaluated. Out of all infections, 53% were diagnosed in patients admitted to the intensive care units. Steady increases in non- species were reported from 2009 to 2014 (30.2% for versus 69.8% for the other species). Etest antifungal susceptibility testing was performed on all recovered clinical isolates to determine echinocandin (micafungin and anidulafungin) and amphotericin B susceptibilities and assess non-wild-type (non-WT) strains (strains for which MICs were above the epidemiological cutoff values). DNA sequence analysis was performed on all isolates to assess the presence of mutations, which confer echinocandin resistance in species. A total of 3.9% of isolates (12/301) among strains of and contained hot spot mutations, including heterozygous mutations in For , the Etest appeared to overestimate strains non-WT for micafungin, anidulafungin, and amphotericin B, as 14%, 11%, and 35% of strains, respectively, had values above the epidemiological cutoff value. However, no mutations were identified in this species. For all other species, micafungin best reported the echinocandin non-WT strains relative to the genotype, as anidulafungin tended to overestimate non-wild-type strains. Besides , few strains were classified as non-WT for amphotericin B.