The Antimicrobial Effects of Ciprofloxacin Combined with Green Synthesized Glutathione-coated Silver Nanoparticles on Biofilm Formation of Pseudomonas Aeruginosa

Introdaction: Nowadays, antibiotic resistance is rising at an alarming rate. Essentially, one of the important ways for bacteria such as P. aeruginosa to survive in the presence of antibiotics is biofilm formation. In the current report, we have focused on inhibiting the microbial biofilm formation of P. aeruginosa through combining glutathione (GSH) coated silver nanoparticles (AgNPs) and Ciprofloxacin (Cip). AgNPs were biosynthesized using Eucalyptus Camaldulensis leaf extracts and surface modification of AgNPs was done, using glutathione. Synthesized nanoparticles were characterized by FTIR, XRD, DLS, SEM, and CHN tests. Then, 50 isolates of P. aeruginosa were originated from different samples of hospitalized patients from Sina hospital and 24 isolates were selected as a strong biofilm producer using microtiter plate method for further studies. Finally, the synergistic effect of GSH-coated AgNPs and Cip was investigated on biofilm formation of P. aeruginosa. The images of SEM represent the spherical structure of silver nanoparticles with a smooth surface. Also, the results of FTIR, XRD, DLS, SEM, and CHN of AgNPs before and after surface coating confirmed the formation of GSH-coated AgNPs. GSH-coated AgNPs and Cip at a concentration of 1/2 and 1/4 MIC had an inhibitory activity on biofilm formation of 87.5% and 83.4% of P. aeruginosa isolates respectively. This study illustrated that the combination of GSH-coated AgNPs and Cip has a synergistic inhibitory activity on P. aeruginosa biofilm formation.