Antibacterial activity of silver-based drugs

Abstract

Due to rapidly growing polyresistance of pathogenic bacteria, special attention is paid to the creation of new effective medicines. Silver-based drugs have long been studied and used as antimicrobial and antiviral drugs. The minimum inhibitory concentration (MIC) of nanosilver (Argovit series) and organic silver (Argosil) products was studied against bacterial strains of the genus Escherichia, Stenotrophomonas, Raoultella, Aerococcus, Staphylococcus, Corynebacterium, Lactococcus and Rothia obtained from the milk of cows with mastitis. The work was done in a laboratory of the Novosibirsk State Agricultural University in 2024. To determine the minimum inhibitory concentration of the drugs, the method of two-fold serial dilutions in a liquid nutrient medium was used. The MIC was considered as the lowest concentration of the drug at which no sediment was observed in the cells on the plate and no change in color of resazurin occurred after 1.5 hours. It was found that the average MIC value relative to all microorganisms was lowest in Argovit-Mini – 34 ± 4 μg mL; the average minimum inhibitory concentration of Argovit-Maksi and Argovit C – 47 ± 4.83 and 47.75 ± 7.44 μg mL; the highest average MIC was observed for Argosil - 94.48 ± 25.02 μg mL. Nanosilver preparations have greater antimicrobial activity against gram-negative bacteria; this is associated with the difference in the structure, thickness and composition of the cells of gram-negative and gram-positive bacteria. Organic silver exhibits equal activity against gram-positive and gram-negative microorganisms, but has a higher average MIC value than the Argovit series of preparations.