LAUSR

Introduction Candida glabrata complex is composed of three cryptic species, Candida glabrata sensu stricto, C. bracarensis and C. nivariensis. Its reduced susceptibility to fluconazole is responsible for treatment failure of its infections. Combination therapy is recommended to treat these resistant strains. This study assessed the distribution of C. glabrata complex collected from patients in Mansoura University Hospitals and their antifungal susceptibility, with evaluation of fluconazole and polymyxin B combination against them. Methods C. glabrata complex was collected from patients with healthcare-associated infections. The isolates were identified biochemically then the species were detected using multiplex PCR. The susceptibility of isolates to antifungals and polymyxin B was tested by the microdilution assay. The effect of fluconazole and polymyxin B combination was assessed by checkerboard microdilution and time kill assays. Results This study included 45 isolates of Candida glabrata complex. The common isolate was Candida glabrata sensu stricto (38 isolates). There were 4 isolates of C. bracarensis and three isolates of C. nivariensis. All isolates were susceptible to amphotericin B, and 17.8% were susceptible to itraconazole. Regarding fluconazole, 48.9% of isolates were susceptible dose-dependent and 51.1% were resistant. Synergistic effect of the combination was observed in 68.9% of isolates by the checkerboard method and in 66.7% of isolates using the time kill assay. Conclusions Candida glabrata sensu stricto is the main member of the complex. Combination of fluconazole and polymyxin B can be considered a treatment option for fluconazole resistant C. glabrata complex infections. In vivo studies are needed to validate these results.