Local Administration of Sodium Bicarbonate for Preventing COVID-19 Associated Mucormycosis.

Background: One important complication of the coronavirus disease 2019 (COVID-19) is COVID Associated Mucormycosis (CAM), especially in patients with conditions such as diabetes and in immunosuppressed patients. Systemic acidosis, hyperglycemia, and other biochemical factors such as free iron and β-hydroxybutyrate (BHB) can play a role in this complication.

Materials and methods: Rhizopus oryzae was isolated from a patient at Masih Daneshvari Hospital microbiology laboratory and sub-cultured on the Potato Dextrose Agar (PDA) for 48 hours at 37 °C. Subsequently, Roswell Park Memorial Institute (RPMI) 1640 Broth medium buffered to pH 7.0 with 3-N-morpholino-propane sulfonic acid. Macrodilution and microdilution methods were performed with 8.4% sodium bicarbonate. After 24 hours of incubation at 35°C, the minimum inhibitory concentration (MIC) and the minimum fungicidal concentrations (MFC) were evaluated.

Results: We found that the minimum inhibitory and fungicidal concentrations are at 1.05 % and 2.1 % respectively. Therefore, the minimum concentration is 2% sodium bicarbonate, which requires achieving the desired environmental pH for fungal inhibition and fungicidal effects.

Conclusion: Regulation of systemic acidosis by sodium bicarbonate could be used to decrease the chance of mucormycosis. In addition, According to our study and some others, an alkaline environment can prevent fungal growth. We found that a minimum concentration of 2% sodium bicarbonate is required to achieve the desired mucosal pH to inhibit the fungus. Therefore, sodium bicarbonate inhalation, as a cost-effective and well-tolerated medicine, is a good candidate for the prevention of mucormycosis. In this regard, extensive clinical and laboratory research is needed to achieve more accurate doses and appropriate administration intervals.