Micafungin Breakthrough Fungemia in Patients with Hematological Disorders: A Retrospective Study to Determine Therapeutic Strategy

Abstract Background Micafungin (MCFG) breakthrough fungemia (MBF) is recognized as a serious infection especially in high-risk patients with hematological disorders (HDs). Methods A retrospective study of MBF among adult patients with HDs was conducted between January 2008 and June 2015. MBF was defined as fungemia in patients receiving ≥50 mg/day of MCFG for ≥3 days before the first positive blood culture. Breakthrough strains were identified by using conventional methods, r-RNA sequencing, and MALDI-TOF-MS. The drug susceptibility was determined by the broth microdilution method according to current CLSI standards. Results Thirty-nine patients with MBF were identified. Thirty-five of the 39 patients were administered 150 mg/day of MCFG. Acute myeloid leukemia was the most common underlying HDs (27/39). The 39 causative organisms were Candida species (30), and non-Candida fungal species (9). Among the 35 stored strains, C. parapsilosis (14), Trichosporon asahii (7), C. glabrata (5), C. albicans (3), and other fungal spices (6) were identified by sequencing. Although, only 37% (11/30) of candidemia occurred during neutropenia, the majority (8/9) of non-Candida fungemia occurred during neutropenia (P