Microbiological and Molecular Diagnosis of Mucormycosis: From Old to New

Abstract

Members of the order Mucorales may cause severe invasive fungal infections (mucormycosis) in immune-compromised and otherwise ill patients. Diagnosis of Mucorales infections and discrimination from other filamentous fungi are crucial for correct management. Here, we present an overview of current state-of-the-art mucormycosis diagnoses, with a focus on recent developments in the molecular field. Classical diagnostic methods comprise histology/microscopy as well as culture and are still the gold standard. Newer molecular methods are evolving quickly and display great potential in early diagnosis, although standardization is still missing. Among them, quantitative PCR assays with or without melt curve analysis are most widely used to detect fungal DNA in clinical samples. Depending on the respective assay, sequencing of the resulting PCR product can be necessary for genus or even species identification. Further, DNA-based methods include microarrays and PCR-ESI-MS. However, general laboratory standards are still in development, meaning that molecular methods are currently limited to add-on analytics to culture and microscopy.

Keywords: DNA; Mucorales; PCR; clinical evaluation; culture; diagnosis; microscopy; sensitivity; specificity; standardization.

Figure 1

Broad, ribbon-like, non-septate hyphae of Mucor sp. with wide-angle branching, stained with fluorescent brightener (Calcofluor White × 400).

Figure 2

Overview of major molecular methods and their advantages and disadvantages.