Biogenic synthesized copper oxide nanoparticles by Bacillus subtilis: Investigating antibacterial activity on the mexAB‐oprM efflux pump genes and cytotoxic effect on MCF‐7 cells

Abstract

AbstractOne of the main characteristics of Pseudomonas aeruginosa is remarkable intrinsic antibiotic resistance which is associated with production of β‐lactamases and the expression of inducible efflux pumps. Nanoparticles (NPs) are a novel option for coping with this resistant bacteria. Hence, the aim of present study was production of CuO NPs via Bacillus subtilis and applied them to deal with resistant bacteria. For this purpose, first NPs were synthesized and were analyzed with different standard techniques containing scanning electron microscope, Fourier‐transform infrared spectroscopy, and X‐ray powder diffraction. Microdilution Broth Method and real‐time polymerase chain reaction were used to antibacterial properties of the CuO NPs and expression of mexAB‐oprM in clinical samples of P. aeruginosa, respectively. The cytotoxic effect of CuO NPs was also evaluated on MCF7 as a breast cancer cell line. Finally, the data were analyzed by one‐way analysis of variance and Tukey's tests. The size of CuO NPs was in the range of 17–26 nm and showed antibacterial effect at <1000 μg/mL concentrations. Our evidence noted that the antibacterial effects of the CuO NPs occurred through the downregulation of mexAB‐oprM and upregulation of mexR. The interesting point was that CuO NPs had an inhibitory effect on MCF7 cell lines with the optimal inhibition concentration at IC50 = 25.73 µg/mL. Therefore, CuO NPs can be considered as a promising medical candidate in the pharmaceutical industry.