Abstract

Background: The emergence of drug resistant pathogens is a major concern to the scientific community. Novel approaches such as the use of functionalized nanomaterials with antimicrobial activity is required to treat infectious diseases.

Objective: In the present study, the metallic nanoparticles (iron, gold, zinc oxide and copper oxide) were evaluated for the antimicrobial, biofilm inhibitory and anti-infective activity against human pathogens methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa PA01.

Methods: The efficacy of nanoparticles on the planktonic growth of clinically relevant pathogens was determined by MIC. Further, the effect of nanoparticles was studied on their biofilms using crystal violet microtiter plate assay and fluorescent microscopy. The cytotoxicity of nanoparticles was studied in HT29 cell line.

Results: The nanoparticles of copper and zinc oxide (size < 50 nm) were more effective against Grampositive and Gram-negative pathogens in comparison to gold and iron nanoparticles. The ZnO nanoparticles had an MIC in the range of 3.125 μg/ ml and 6.25 μg/ ml against the tested pathogens. The nanoparticles at the tested concentration reduced biofilm burden by > 75% in the pathogens. The nanoparticles showed cytotoxicity in HT 29 at 20 μg/ ml.

Conclusion: The results of the study showed that of all the tested nanoparticles, ZnO nanoparticles had significant antimicrobial activity against the drug resistant pathogens and could be used at concentrations less toxic to mammalian cells. Hence, ZnO nanoparticles have the potential for the design of novel antibacterial agents and therapeutics.

Keywords: Anti-infective, antimicrobial, biofilm inhibitory, MRSA, Pseudomonas aeruginosa PA01, Zinc oxide nanoparticles.

Graphical Abstract