A comparative evaluation of the antibacterial activity of gold nanoparticle conjugates with ceftazidime and cefepime

Abstract

The rise in antimicrobial resistance calls for new approaches to treating infections. The functionalization of nanoparticles with antibiotics is viewed as a cost-effective strategy for reducing the amount of antibiotics used in human and veterinary medicine, as well as for overcoming resistance in clinically significant microorganisms.
Using the Turkevich-Frense method, gold nanoparticles (GNPs) with a diameter of 15 nm were obtained, as confirmed by the presence of a peak in the absorption spectrum. Third- and fourth-generation cephalosporins—ceftazidime and cefepime—were used for conjugation. The GNPs were functionalized in a 5 mM borate buffer. Based on optical density measurements at 620 nm, the “golden number” was determined for each drug, amounting to 0,0159 mM and 5,79 mM, respectively. GNPs-antibiotic conjugates were prepared in accordance with these values.
To evaluate antibacterial activity in liquid medium LB, fresh cultures of the reference strains Pseudomonas aeruginosa ATCC9027, Escherichia coli K12, and Staphylococcus aureus ATCC25923 were inoculated into a 96-well plate, and the resulting conjugates were then added to them. After incubation for 24 hours at 37 °C, the optical density at 595 nm (OD595) of the bacterial suspensions was determined. Based on the OD₅₉₅ data, the minimum inhibitory concentration (MIC) was calculated.
The results showed that GNPs conjugates with cefepime didn’t exhibit antibacterial activity. The ceftazidime conjugates exhibited activity comparable to that of the free form of the antibiotic (MIC = 5-10 μg/mL), suggesting the potential for further research on ceftazidime conjugates and the need to modify the conditions for functionalizing GNPs for cefepime.

Speaker

Daria Galeyeva
Saratov State University
Russia

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