Synergistic Effect Of Ceftazidime-Loaded Silver Nanoparticles Against Multidrug-Resistant Pseudomonas Aeruginosa Isolated From Humans And Cats

Abstract

This study investigates the synergistic antibacterial effects of ceftazidime-loaded silver nanoparticles (AgNPs-CAZ) on P. aeruginosa recovered from humans as well as cats. A total of 103 clinical and veterinary samples (60 human, 43 cat) revealed 12 isolates (9 human, 3 cat), as confirmed by biochemical and VITEK 2 analysis. All isolates produced biofilms. Silver nanoparticleswere prepared usinga chemical reduction method, then conjugated with ceftazidime and characterized using UV-Vis, DLS, FTIR, and FESEM. The macrodilution tube method was used to determine MICs, and antibacterial activity was further tested using agar well diffusion. Following conjugation, ceftazidime MICs were lowered 32-fold in human isolates and 8-fold in cat isolates. FICI analysis showed additive effects (0.812 in humans, 0.515 in cats). Moreover, the AgNPs-CAZ combination showed increased inhibition zones than either drug alone, demonstrating enhanced antibacterial action. These results suggest that AgNPs-CAZ conjugates may enhance antibiotic activity and could be a viable option for treating resistant P. aeruginosa infections.