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. 2019 Jul 23:12:2223-2235.
doi: 10.2147/IDR.S213200. eCollection 2019.

Evaluation of Nano-curcumin effects on expression levels of virulence genes and biofilm production of multidrug-resistant Pseudomonas aeruginosa isolated from burn wound infection in Tehran, Iran

Aref Shariati  1   2 , Elham Asadian  3 , Fatemeh Fallah  1 , Taher Azimi  4   5 , Ali Hashemi  1 , Javad Yasbolaghi Sharahi  1 , Majid Taati Moghadam  2   6
Affiliations

Evaluation of Nano-curcumin effects on expression levels of virulence genes and biofilm production of multidrug-resistant Pseudomonas aeruginosa isolated from burn wound infection in Tehran, Iran

Aref Shariati et al. Infect Drug Resist. .

Abstract

Background: P. aeruginosa is considered as one of the most important pathogens, and high antibiotic resistance to P. aeruginosa has become an alarming concern. This study attempts to further improve curcumin solubility and stability by producing the involved nanoparticle and investigate the effect of this nanoparticle on those virulence genes of P. aeruginosa in pathogenicity and biofilm formation.

Methods: In this study, the curcumin nanoparticles were synthesized and characterized, and the antibacterial and antibiofilm effects of Nano-curcumin and curcumin were investigated by microdilution broth and microtiter plate, respectively. In addition, cytotoxic effect of Nano-curcumin on human epithelial cell lines (A549) was determined. The effects of Nano-curcumin on P. aeruginosa virulence genes, mexD, mexB, and mexT (efflux pumps), lecA (adhesion), nfxB (negative regulator of MexCD-OprJ), and rsmZ (biofilm formation) were determined using real-time quantitative PCR.

Results: Synthesized Nano-curcumins were soluble in water, which inhibited the growth of multidrug-resistant (MDR) P. aeruginosa at 128 µg/mL, whereas it was inhibited at 256 µg/mL for soluble curcumin in DMSO. Sub-inhibitory concentrations of Nano-curcumin reduced biofilm formation and, at 64 μg/mL, disrupted 58% of the established bacterial biofilms. In addition, curcumin nanoparticle downregulated the transcription of virulence genes except nfxB and exerted no cytotoxic effect on human epithelial cell lines (A549).

Conclusions: Results suggest that Nano-curcumin could be potentially used to reduce P. aeruginosa virulence and biofilm. However, in vivo studies with respect to an animal model are necessary to validate these results.

Keywords: Nano-curcumin; antimicrobial activity; biofilm; burn wound; curcumin; virulence factor.

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Conflict of interest statement

The authors report no conflicts of interest in this work.

Figures

Figure 1
Figure 1
Synthesize procedure of curcumin nanoparticles. Note: The white arrow shows the Nano-curcumin produced.
Figure 2
Figure 2
UV-Vis spectrum of curcumin (solid line) and curcumin nanoparticles (dashed line). Abbreviations: Cur., curcumin; Nanocur., Nano-curcumin.
Figure 3
Figure 3
(A) TEM image and (B) dynamic light scattering analysis of the as-prepared curcumin nanoparticles which exhibit very narrow size distribution. Note: (A) Arrows show synthesized curcumin nanoparticles. Abbreviation: TEM, transmission electron microscopy.
Figure 4
Figure 4
AFM image (A), height distribution (B) and lateral size distribution (C) of the curcumin nanoparticles deposited on freshly cleaved mica substrate. Abbreviation: AFM, atomic force microscope.
Figure 5
Figure 5
Expression of virulence genes in 5 MDR clinical strains compared to PAO1 (*P<0.05). Abbreviation: MDR, multi-drug resistant.
Figure 6
Figure 6
Relative gene expression levels of curcumin and Nano-curcumin-treated PAO1 and 5 MDR clinical strains of P. aeruginosa. Notes: *P<0.05; **P<0.01; ***P<0.001. (A) and (B) are curcumin-treated MDR strain of P. aeruginosa and PAO1, respectively; (C) and (D) are Nano-curcumin treated MDR strains of P. aeruginosa and PAO1, respectively. Abbreviations: MDR, mult-drug resistant; P. aeruginosa, Pseudomonas aeruginosa.
Figure 7
Figure 7
The effects of Nano-curcumin and curcumin on the biofilm of P. aeruginosa MDR strains and PAO1 (*P<0.05). Abbreviations: MDR, mult-drug resistant; P. aeruginosa, Pseudomonas aeruginosa.
Figure 8
Figure 8
The effect of Nano-curcumin and curcumin on the reduction of pre-formed P. aeruginosa biofilm. Abbreviation: P. aeruginosa, Pseudomonas aeruginosa.
Figure 9
Figure 9
Morphology of the human epithelial cell lines (A549) after incubation with Nano-curcumin for 24 hrs (original magnification, 100×). (A) Control, (B) Nano-curcumin 1,000 µg/mL, (C) Nano-curcumin 200 µg/mL.
Figure 10
Figure 10
Influence of the different concentrations of Nano-curcumin on the viability of human epithelial cell lines (A549) after 24-hr incubation. The relative cell viability (%) was computed by this formula: [A]test/[A]control ×100. The experiment was performed 2 times in duplicates.
Figure 11
Figure 11
Solubility of Nano-curcumin (left) and curcumin (right) in water.
See this image and copyright information in PMC

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