Document Type : Research Article
Authors
1
Department of microbiology,College of Basic Sciences, Lahijan Branch, Islamic Azad Univercity, Lahijan, Iran
2
Department of Microbiology, College of Basic Sciences, Lahijan Branch, Islamic Azad University, Lahijan, Iran
3
Department of microbiology,College of Basic Sciences, Lahijan Branch, Islamic Azad Univercity, Lahijan, Iran.
10.22034/ijmcm.2023.708106
Abstract
Listeriosis (caused by Listeria monocytogenes) is one of the most serious and severe foodborne diseases. The purpose of present study is to investigate the antibacterial, antiinvasion and anti-adhesion effect of synthesized Ag-doped ZnO (ZnO:Ag NPs) nanoparticles against L.monocytogenes isolates. ZnO and ZnO:Ag NPs were synthesized using a chemical method and were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-ray (EDX) and Fourier-transform infrared (FTIR) spectroscopy. Antibacterial assay of nanoparticles towards L. monocytogenes was performed using culture turbidity measurement. The MTT assay was performed for assessing cytotoxicity activity in Caco-2 cells exposed to L.monocytogenes treated with 3.125, 6.25, 12.5, 25, 50 and 100 μg /ml concentrations of both ZnO and ZnO:Ag NPs. The adhesion and invasion assays were performed by infecting semiconfluent Caco-2 cell monolayers grown in 24-well plates. To further confirm, the messenger RNA (mRNA) levels of invasion and adhesion‐associated genes (inlA, hlyA and prfA) of L. monocytogenes were examined using Real-time PCR. Our results show
ZnO:Ag NPs have great antibacterial activities against L.monocytogenes isolates. Paper results also indicated exposure of L.monocytogenes isolates treated with all concentration of ZnO:Ag NPs could obviously reduce the viability of Caco-2 cells. The results of Realtime PCR revealed that the mRNA levels of inlA, hlyA and prfA were dramatically downregulated after the exposure of L.monocytogenes treated with ZnO:Ag NPs compared to 16S rRNA as housekeeping gene. It can therefore be considered that ZnO:Ag NPs should be utilized in medicinal and pharmaceutical applications as credible
antibacterial, anti-invasion and anti-adhesion agents.
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