Black fungus is in the news for all the wrong reasons

1. What is & what is Not
black fungus ?
Prof. Ashok Rattan,
MD, MAMS,
Common Wealth Fellow, INSA DFG Fellow, SEARO Temporary Advisor,
WHO Lab Director (CAREC/PAHO)
Advisor: Pathkind Labs Knowledge Forum, R & D and Quality

2. Black fungus
Melanized (Dematiaceous) fungi
• Dematiaceous fungi have high concentration of melanin and melanine
like pigments in their cell walls causing a dark pigment
• Produce dusky brown to brown pigment in hyphae or conidia cell walls
• Both rapidly and slow growing organisms seen
• Conidia vary in appearance from single to multi-celled
Melanized
Hyaline

3. Melanized
Hyaline

4. Some important black fungi (Dematiaceous)
Single cell conidia
• Nigrospora
• Aureobasidius
• Cladosporium
• Phoma
• Chaetomium
Multi-cell Condia
• Alternaria
• Epicoccum
• Pithomyces
• Ulocladium
• Stemphyllum
Pigmented conidia

5. Mucor / Aspergillus
are Not Black fungi

6. Zygomycosis Aspergillosis
• Rhizopus
• Mucor
• Absidia
• Others
• Aspergillus flavus
• A. fumigatus
• A. niger
• A. terreus

7. Fragments of Mucor in blood well Histopathology
shows multiple fragments

8. Frozen section from
Pulmonary mucor
infection

9. Mucor
within the
blood vessel

10. Aspergillus in
the lung showing
“Y” branching

11. Coughed out
mucus plug

13. When to seek help ?
If you have recovered from Covid 19 disease
and are now having
• 1. Nasal blockage
• 2. Blood tinged nasal discharge
• 3. Headache
• 4. One sided facial pain / swelling / numbness
• 5. Toothache, loosening of teeth, discomfort while chewing
• 6. Pain in the eye
• 7. Swelling of the eye
• 8. Double vision

15. Diagnostic approach

16. Appropriate samples
• 1. Skin scraping from cutaneous lesions
• 2. Nasal discharge
• 3. Scraping & aspirate from sinuses
• 4. Bronchoalveolar lavage (BAL)
• 5. Needle biopsy from pulmonary lesion
• 6. Biopsy of involved tissue
• 7. Blood culture is not helpful
• 8. CSF may be useful

17. Initial examination by microscopy
10 – 20 % KOH
• Work inside a class 2 biosafety hood
• On a clean glass slide place two drops of 20% KoH
• With help of sterile needle, transfer clinical material onto it
• Spread the material gently with needle
• Cover with cover slipe
• Heat gently on the underside of the glass slide (optional)
• Leave in a moist chamber for 10 to 15 minutes
• Examine under low power & then high power

18. 10 to 20% KOH Cutaneous Mucor Nasal Mucor

19. Aspergillus in KOH, septate hyphae, branching at 45 degrees

21. Culture
• Dermatophytes grow best between 25 and 30 C
• Opportunistic fungi grow best at 30 C
• Invasive fungal infection dimorphic fungi grow at 37 C
• Use a combination of media
• Sabouraud dextrose agar with antibiotics
• Brain Heart Infusion Agar
• Best in slopes rather than petri dish (to avoid contaminating the lab)
• Candida will grow within 48 hours, most by 3 to 4 weeks

24. Aspergillus

26. Mucor is not a black fungus
Maintain high level of suspension in Covid 19
recovered patients who have been treated with
Steroids & are diabetic