Investigation of Silver and Copper Quantum Dots Prepared by Bio-Based Methods on Biofilm-Forming Genes in Gram-Positive and Gram-Negative Bacteria

Abstract

The increase of pathogenic multi-drug resistive (MDR) bacteria has become one of the major threats of healthcare sector. This has further added to the urge for the development of novel drugs and formulations in combat against resistive pathogenic bacteria. The aim of this research is to examine the effect of copper and silver quantum dots prepared by a green method on the biofilm-forming genes of S. aureus and A. baumannii. The MIC of these QDs was determined.  the expression level of biofilm-forming genes (icaA, icaD) in S. aureus and  bap and OmpA in A. baumannii) with sub-MIC concentrations of copper and silver QDs was examined by Real-time PCR tests.The studied pathogenic bacteria included isolated from infections  wounds. Moreover, S. aureus and A. baumannii species provided from microbial bank were also considered standard strains. Oak fruit was utilized for the green synthesis of QDs through a hydrothermal method. Gene expression studies  statistically significant difference under the influence of silver and copper QDs compared to the gene expression of rRNA 16S. The findings revealed that Ag and Cu QDs declined the expression of biofilm-forming genes (ica A,D,R in S. aureus and BAP and OmpA in A. baumannii). Real-time PCR studies on the anti-biofilm impact of Ag and Cu QDs on S. aureus and A. baumannii showed a significant decrement (sometimes 5-fold decrease )in the expression of ica A,D,R and BAP and OmpA genes compared to the rRNA 16S reference.