ZnO nanoparticles enhanced antibacterial activity of ciprofloxacin against Staphylococcus aureus and Escherichia coli.

Nanoparticle metal oxides offer a wide variety of potential applications in medicine due to the unprecedented advances in nanobiotechnology research. In this work, the effect of zinc oxide (ZnO) nanoparticles prepared by mechano-chemical method on the antibacterial activity of different antibiotics was evaluated using disk diffusion method against Staphylococcus aureus and Escherichia coli. The average size of ZnO nanoparticles was between 20 nm and 45 nm. Although ZnO nanoparticles (500 microg/disk) decreased the antibacterial activity of amoxicillin, penicillin G, and nitrofurantoin in S. aureus, the antibacterial activity of ciprofloxacin increased in the presence of ZnO nanoparticles in both test strains. A total of 27% and 22% increase in inhibition zone areas was observed for ciprofloxacin in the presence of ZnO nanoparticles in S. aureus and E. coli, respectively. The enhancing effect of this nanomaterial on the antibacterial activity of ciprofloxacin was further investigated at three different contents (500, 1000, and 2000 microg/disk) against various clinical isolates of S. aureus and E. coli The enhancing effect of ZnO nanoparticles on the antibacterial activity of ciprofloxacin was concentration-dependent against all test strains. The most enhancing activities were observed in the contents of the 2000 microg/disk.

The antifungal activity of Sarcococca saligna ethanol extract and its combination effect with fluconazole against different resistant Aspergillus species.

Microbial resistance is a major drawback in chemotherapy of microbial or fungal infection disease. In this study, the antifungal activity of ethanol extract of a selected plant (Sarcococca saligna) has been investigated against clinical isolates of Aspergillus niger, Aspergillus treus, Aspergillus flavus, and Aspergillus fumigatus. Also, the enhancement of the antifungal activity of fluconazole by this extract was further evaluated against mentioned test strains. Conventional disk diffusion method was used to assay the antifungal activity of S. saligna ethanol extract in the absence and presence of fluconazole. The highest antifungal activity was observed against A. treus. The ethanol extract of S. saligna enhanced the antifungal activity of fluconazole against A. niger and A. treus and A. flavus. At the highest tested contents (4 mg/disk), 1.15-, 0.64-, and 2.47-fold increases in inhibition zone surface area were observed for A. niger, A. treus, and A. flavus, respectively. However, no enhancing effect was observed for this plant extract against Aspergillus fumigates at tested contents (0.5, 1, 2, 3, and 4 mg/disk). In a separate experiment, the general cytotoxicity of the ethanol extract of S. saligna was examined with brine shrimp assay. This plant extract showed low cytotoxicity against Artemia salina (LC(50) = 186 microg/ml).