Evaluating the Effect of Copper Nanoparticles in Inhibiting Pseudomonas aeruginosa and Listeria monocytogenes Biofilm Formation.
BACKGROUND
Biofilm formation is a major virulence factor in different bacteria. Biofilms allow bacteria to resist treatment with antibacterial agents. The biofilm formation on glass and steel surfaces, which are extremely useful surfaces in food industries and medical devices, has always had an important role in the distribution and transmission of infectious diseases.


OBJECTIVE
In this study, the effect of coating glass and steel surfaces by copper nanoparticles (CuNPs) in inhibiting the biofilm formation by Listeria monocytogenes and Pseudomonas aeruginosa was examined.


METHODS
The minimal inhibitory concentrations (MICs) of synthesized CuNPs were measured against L. monocytogenes and P. aeruginosa by using the broth-dilution method. The cell-surface hydrophobicity of the selected bacteria was assessed using the bacterial adhesion to hydrocarbon (BATH) method. Also, the effect of the CuNP-coated surfaces on the biofilm formation of the selected bacteria was calculated via the surface assay.


RESULTS
The MICs for the CuNPs according to the broth-dilution method were ≤ 16 mg/L for L. monocytogenes and ≤ 32 mg/L for P. aeruginosa. The hydrophobicity of P. aeruginosa and L. monocytogenes was calculated as 74% and 67%, respectively. The results for the surface assay showed a significant decrease in bacterial attachment and colonization on the CuNP-covered surfaces.


CONCLUSIONS
Our data demonstrated that the CuNPs inhibited bacterial growth and that the CuNP-coated surfaces decreased the microbial count and the microbial biofilm formation. Such CuNP-coated surfaces can be used in medical devices and food industries, although further studies in order to measure their level of toxicity would be necessary.
OCUVAC-Center of Ocular Inflammation and Infection, Laura Bassi Centers of Expertise, Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
Ehsan
E
Ghasemian
Department of Biology, Faculty of Science, University of Isfahan, Isfahan, IR Iran.
Ali
A
Naghoni
Department of Microbiology and Immunology, McGill University, Montreal, Canada.
Helya
H
Rahvar
Department of Microbiology, Faculty of Science, Karaj Branch, Islamic Azad University, Karaj, IR Iran.
Mahsa
M
Kialha
Kusha Faravar Giti Co., Industrial Research Institute of Biotechnology, Karaj, IR Iran.
Bahman
B
Tabaraie
Biofilms; Listeria monocytogenes; Nanoparticles; Pseudomonas aeruginosa