From the Guidelines
Diagnosis of mucormycosis should be based on a combination of direct microscopy, histopathology, and culture, as recommended by the European Society for Clinical Microbiology and Infectious Diseases and European Confederation of Medical Mycology Joint Clinical Guidelines 1. To diagnose mucormycosis, the following steps should be taken:
- Direct microscopy preferably using optical brighteners to reveal broad, ribbon-like aseptate hyphae with right-angle branching, characteristic of mucormycetes
- Histopathological examination of tissue biopsies showing fungal invasion of blood vessels with tissue necrosis
- Culture on Sabouraud dextrose agar without cycloheximide, though cultures are often negative despite active infection
- Imaging, such as CT or MRI scans, to determine the extent of disease and identify the reverse halo sign on computed tomography to differentiate mucormycosis from aspergillosis in haematological malignancy and stem cell transplantation recipients 1 The diagnosis should not delay treatment, and empiric antifungal therapy should be initiated immediately in highly suspicious cases while awaiting confirmation, as mucormycosis progresses rapidly with mortality rates exceeding 50% if treatment is delayed. Pathogen identification to species level by molecular methods and susceptibility testing are also strongly recommended to establish epidemiological knowledge 1. Reversal of predisposing conditions, such as controlling hyperglycaemia and ketoacidosis in diabetic patients, and limiting glucocorticosteroids to the minimum dose required, is crucial in the management of mucormycosis 1.
From the FDA Drug Label
According to criteria based on those established by the European Organisation for Research and Treatment of Cancer/Mycoses Study Group, patients had proven or probable mucormycosis. The diagnosis of mucormycosis (black fungus infection) is based on criteria established by the European Organisation for Research and Treatment of Cancer/Mycoses Study Group 2.
- Proven mucormycosis is typically confirmed by:
- Histology
- Culture
- Probable mucormycosis is based on clinical, mycological, and radiological criteria. Key points to note are:
- Rhizopus oryzae and Mucormycetes were the most common pathogens identified.
- Common locations of disease involvement include:
- Pulmonary
- Sinus
- Eye
- CNS
- Bone
From the Research
Diagnosis of Mucormycosis
The diagnosis of mucormycosis is challenging due to the lack of specific clinical or radiological signs and limited diagnostic tools available 3. The current diagnosis is based on:
- Direct examination of clinical specimens
- Histopathology
- Culture
- Molecular tools for direct detection from clinical specimens, which are moderately recommended 3
Diagnostic Techniques
Various diagnostic techniques are used to identify mucormycosis, including:
- Computed tomography scans
- Direct microscopic observations
- MALDI-TOF mass spectrometry
- Serology
- Molecular assay
- Histopathology 4
- Molecular-based methods, such as internal transcribed spacer (ITS) region sequencing, which is recommended as a first-line method for species identification of Mucorales 5
Molecular Diagnosis
Molecular diagnosis of mucormycosis is promising, with techniques such as:
- Mucorales qPCR in serum, which has shown good sensitivity and specificity 3
- Detection of Mucorales DNA in blood, which could be used as a screening test in high-risk patients 5
- Circulating fungal DNA detection in blood and urine, which is a non-invasive form of DNA 6
Challenges and Future Perspectives
The diagnosis of mucormycosis remains challenging due to the lack of standardized molecular techniques and the need for early and accurate diagnosis 3, 7. Future perspectives include the development of rapid, reliable, and non-invasive diagnostic methods, such as serology-based point-of-care or metabolomics-based breath tests 5.