Emadaldin Salah Kassem, Emadaldin2020-10-122020-10-122020Copyright © 2020 MSA University. All Rights Reserved.http://repository.msa.edu.eg/xmlui/handle/123456789/3874Faculty Of Biotechnology Graduation Project 2019 - 2020Nowadays, bacterial resistance to antibiotics has become a global issue. Nano materials, such as metal oxide nanoparticles, have appeared to be promising contenders during the last few years. The aim of this study was to investigate zinc oxide (ZnO) nanoparticles in vitro antibacterial properties against avian pathogenic E. coli alone and in combination with different antibiotics. In this study, ZnO nanoparticle was synthesized using direct precipitation method. Physical characteristics of ZnO NPs were confirmed using X-Ray diffraction (XRD) and Transmission Electron Microscopy (TEM). Antibacterial resistance pattern of ten antibiotics: (amoxicillin(Aml), ciprofloxacin (Cip), enrofloxacin (Ex), gentamicin (Cn), doxycycline (Do), levofloxacin (LEV), Trimethoprim/Sulfamethoxazole (SXT), tetracyclin (TE), Spiramycin(SR) and Streptomycin(S)), in addition to different concentration of ZnO NPs, was determined by disc diffusion assay on 10 avian pathogenic E. coli (APEC). The results showed that 50% (5\10) of the strains are resistant to all antibiotic, while the rest were found to be sensitive to one or two antibiotics. The best concentration of ZnO NPs was 1gm\ ml which give wider zone than other concentrations (0.5, 0.25, 0.125, 0.0625 and 0.03125 gm \ml). The combination between antibiotic and ZnO NPs showed a synergistic effect with spiramycin, gentamycin and streptomycin while an antagonistic effect was observed between ZnO NPs and Ciprofloxacin and Enrofloxacin. There was no effect with other antibiotic. However, our findings, the in vivo evaluation should be evaluated to confirm the resultsenMSAOctober University for Modern Sciences and ArtsUniversity for Modern Sciences and Artsجامعة أكتوبر للعلوم الحديثة والآدابBiotechnologyantibioticsOther