What is and what is not black fungus and how to diagnose short

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

12. 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

13. Diagnostic approach

14. 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

15. 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

16. 10 to 20% KOH Cutaneous Mucor Nasal Mucor

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

18. 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

19. Aspergillus

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