Anti-biofilm Effect of Copper Oxide Nanoparticles, EDTA, and Kojic Acid on MDR-biofilm Forming Gram Negative Superbugs in Sohag University Hospitals, Egypt

Abstract

Background: Multidrug-resistant (MDR) Gram negative superbugs are considered among the most important causes of healthcare associated infections and these resistant isolates are usually present in association with biofilms rather than planktonic existence. Objectives: This study aimed to assess the ability of EDTA, Kojic acid, and CuONPs to inhibit the phenomenon of biofilm formation by multidrug-resistant Gram-negative superbugs. Methodology: Gram negative bacilli were isolated on suitable media and identified biochemically by vitek-2 biochemical identification system. MDR isolates were tested for biofilm formation by tissue culture plate method, biofilm-producing isolates were exposed EDTA and Kojic acid by certain concentration and to copper oxide nanoparticle (CuONPs) by multiple gradual concentrations and re-tested for biofilm-production by the same method. Results: EDTA and Kojic acid reduced the biofilm-formation ability of the tested isolates by 85.4 % and 65.5% respectively with reduced mean optical density (OD) reading to (0.0267± 0.051) and (0.063± 0.108) respectively with a high statistically significant difference (p<0.0001). A concentrationdependent biofilm-inhibition effect was observed with different concentrations of CuO NPs (125-2000 µg/ml) for all the tested isolates regardless the genus and the species. Conclusion: there was a remarkable biofilm-inhibition effect for the three tested non-antibiotic substances; the use of these substances can provide a solution for the problem of difficulty in treatment of nosocomial infections due to MDR biofilm-forming Gram-negative superbugs.