Antifungal Resistance Testing and Implications for Management

Purpose of Review: Antifungal agents are the mainstay in the management of patients with invasive fungal disease. However, resistance to current antifungal agents can develop with clinical use, which may negatively impact clinical outcomes. We review the strengths and weaknesses of antifungal susceptibility testing and how the detection of resistance, either phenotypically or molecularly, correlates with clinical outcomes. Recent Findings: Phenotypic resistance is associated with worse outcomes, although this must be taken in context with other patient factors. Newer molecular assays have been developed that have shown promising results for the detection of resistance mechanisms, including azole resistance in Aspergillus fumigatus and echinocandin resistance in different Candida species. Further work is needed to improve the clinical utility of these assays for faster turn-around-time and direct use on specimens. Summary: Detection of antifungal resistance may provide useful information for the treatment of invasive fungal disease.