Molecular and Conventional Detection of Antimicrobial Activity of Zinc Oxide Nanoparticles and Cinnamon Oil against Escherichia coli and Aspergillus flavus

The antimicrobial activity of zinc oxide nanoparticles (ZnONPs) and cinnamon oils (C.O.) was evaluated by conventional and molecular methods against Aspergillus flavus (A.flavus) and Escherichia coli 0157 (E.coli) that recovered from cattle mastitis. In agar well diffusion method (WD), Minimum inhibitory concentration (MIC) of ZnONPs and C.O. for A.flavus was (100 μg/ml; 0.25%) and for E.coli 0157 were (50 μg/ml; 0.25%), respectively. The synergistic effects of these materials caused higher significant inhibition of all microbial growth by low and high doses by agar method. But, the molecular detection of virulent genes of E. coli (stx1) and A. flavus (AflR) by polymerase chain reaction (PCR) and the real-time PCR (RT-PCR) yielded uncorrelated results with WD tests. It is concluded that no direct correlation between WD, PCR, and RT-PCR and the WD tests are still inexpensive, eco-friendly, and rapidly applicable for screening of antimicrobials activity than genetic methods.