Effect of Curcumin Nanoparticles on Biofilm Gene Expression in Pseudomonas Aeruginosa

Pseudomonas aeruginosa is one of the most important nosocomial pathogens. One of the therapeutic problems of this bacterium is antibiotic resistance, which is associated with biofilm production. The aim of the present study was to investigate the effect of curcumin nanoparticles on biofilm gene expression in Pseudomonas aeruginosain vitro.

In the present in vitro study, 50 Pseudomonas aeruginosaisolates were collected from Firoozgar Hospital. The prevalence of pilA, algX, lasI, and estA genes was determined using PCR, biofilm formation ability using microtiter plate, and MIC for curcumin nanoparticles using microdilution broth method. Also, in order to investigate the inhibition effect of curcumin nanoparticle on gene expression, Real-time PCR was run. Data were analyzed using REST 2009 and GraphPad Prism 8 (GraphPad Software, Inc.). The non-parametric Kruskal-Wallis test was used to evaluate the mean changes in the expression of the studied genes compared to the control sample in the presence of 16srRNA internal control gene. P-value <0.05 was considered as significant.

The prevalence of pilA, algX, lasI and estA genes were 40%, 100%, 100%, and 94%, respectively. In addition, 38% of strains formed strong biofilm, 54% moderate, and 8% weak. The MIC values for all strains and PAO1 positive control strains were the same with the concentration of 128 μg / ml of nanoparticles. The expression levels of pilA, algX, and lasI decreased by 1.91, 2.9, and 3.98 folds, respectively, but estA gene expression increased by 0.19. These observed changes in gene expression were found to be statistically significant (P-value <.05).

Due to the inhibitory effect of nanocurcumin on genes involved in the formation of Pseudomonas aeruginosabiofilm, it is possible that this nanoparticle could be used as a therapeutic option against this bacterium and to inhibit the genes involved in its virulence.