Green synthesis of copper oxide nanoparticles ST@CuONPs by Streptomyces thinghirensis: current treatment path against multidrug-resistant bacteria

Background Antibiotic resistance is currently a global concern, leading to serious complications in both clinical and non-clinical settings, and is particularly dreaded in developing countries. In the search for alternative treatments against bacterial infections, nanotechnology has opened up unexpected new horizons in the scientific world, thanks to the great variety of available nanomaterials that have potential antimicrobial activity. Some of the interest in this type of nanomaterials relies in their exceptional properties and usages in many fields. The investigation focused on the synthesis of a new copper oxide nanoparticles ST@CuONPs as a promising alternative to conventional antibiotics using Streptomyces thinghirensis (DSM 41919 T ) as a novel, bacteria-mediated synthesis pathway. Methods The ST@CuONPs were confirmed and characterized by UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, particle-size analyzer, scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The antimicrobial and antibiofilm activities of ST@CuONPs were evaluated against Vancomycin-resistant Enterococcus faecium VRE ATCC 700221vanA, Methicillin-resistant Staphylococcus aureus NCTC 12493 and Ceftazidime-Resistant Pseudomonas aeruginosa ATCC BAA-2108, as well as Vancomycin-sensitive Enterococcus faecalis ATCC 29212, Methicillin-sensitive Staphylococcus aureus ATCC 29213 and Ceftazidime-sensitive P. aeruginosa ATCC 27853. Results and Discussion TEM analysis revealed a spherical shape distribution of ST@CuONPs with an average size of ∼9.8 ± 0.27 nm. The ST@CuONPs demonstrated broad-spectrum antibacterial and antibiofilm activities to ward Multidrug-resistant bacteria. In addition, among the tested multi-drug resistant (MDR) pathogens, the highest antibacterial and antibiofilm efficacies were observed against the Gram-positive strain E. faecium VREATCC 700221vanA. The bacterial biofilm was reduced by 64% ± 0.58% at 1/4 × MIC, 83% ± 3% at 1/2 × MIC and 89% ± 1.15% at 1×MIC of ST@CuONP. Conclusion The synthesis of ST@CuONPs using S. thinghirensis is an eco-friendly and economical method that avoids the use of toxic reagents. The resulting nanoparticles exhibit a potential to be explored as an alternative to conventional antibiotics.