Possible correlation between probiotic activity of bacterial honey isolates and severe acute respiratory syndrome coronavirus 2 replication in vitro

Document Type : Original Article


1 Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre, Dokki, Cairo, Egypt

2 Biotehnology Program, Faculty of Agriculture, Cairo University

3 Center of Scientific Excellence for Influenza Viruses, National Research Centre, 12622 Dokki, Giza, Egypt.

4 Center of Scientific Excellence for Influenza Viruses, National Research Centre, 12622 Dokki, Giza, Egypt


Various strategies, like those using vaccines and antibiotics, have been examined for the prevention and treatment of virus’s diseases, but until this moment infection control is not at sufficient level. Exopolysaccharides, especially from probiotics, became one of the most innovative approaches for antiviral agents. This research tried to highlight the effect of a probiotic polysaccharide such as levan in COVID-19 prevention. Accordingly, 5 levans types previously obtained from bacterial honey isolates were tested against COVID-19. The most promising result was recorded with levans from Pseudomonas aeruginosa {levAE] and Bacillus subtilis9A {lev9A]. The lowest cytotoxicity was obtained from lev9A {CC50=5.567e+006 mg/ml] and the most promising IC50 was obtained by levAE {10.75 mg/ml] followed by lev13M {142.5 mg/ml] then lev9A {1299 mg/ml]. The dialysis process of levAE/D greatly affected the virus inhibition activity {IC50=7.773e+006 mg/ml]. Pseudomonas aeruginosa HI1 and Bacillus subtilis 9A were highly tolerant to the acidic {pHs 2, 3] and alkaline sides {pHs 9,11]. They incubated with 0.3 bile salt for 24h and their surviving rates recorded 94% and 100% respectively. H2O2 tolerance showed that Pseudomonas aeruginosa HI1 kept 77% of its surviving while Bacillus subtilis9A remained complete surviving. The blood hemolysis and the antibiotics sensitivity tests confirmed the isolate's safety. The isolates adhere to the lung cells, this hypothesis that the isolates and their levans could share effectively in covid-19 prevention.


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