Breakthrough invasive Candida glabrata in patients on micafungin: a novel FKS gene conversion correlated with sequential elevation of MIC

Candida glabrata strains sequentially isolated from blood developed resistance to micafungin (MICs from <0.015 to 4 μg/ml). A novel mutation identified in micafungin-resistant strains at bp 262 of FKS2 (containing a deletion of F659 [F659del]) was inserted into the homologous region in FKS1.