The effect of titanium dioxide nanoparticles on the expression of genes effective in biofilm production in resistant Klebsiella pneumoniae strains

The ability of Klebsiella pneumoniae as an opportunistic bacterium in hospital infections, by producing biofilm on food utensils and hospital surfaces, has adverse effects on the treatment and survival of hospitalized patients. The present study was conducted with the aim of investigating the effect of TiO2 nanoparticles on Klebsiella pneumoniae biofilm formation.

TiO2 nanoparticles were produced using sol-gel method. 62 strains of Klebsiella pneumoniae were isolated from three hospitals in Tehran. Antimicrobial activity of TiO2 nanoparticles against biofilm-producing and antibiotic-resistant strains was determined by disk diffusion method. Definitive identification of the isolates was done through common biochemical tests and 16S rRNA sequencing, and the expression of treC, mrkD, sugE, luxS and 16SrRNA genes was investigated by real time PCR.

The data showed that the ability to form biofilm among isolates obtained from sputum was higher than other isolates. TiO2 nanoparticles with a concentration of 256 μg/ml inhibited biofilm production in fourteen isolated strains. Comparison of LuxS gene expression in Klebsiella pneumoniae untreated and treated with TiO2 showed that the level of gene expression decreased by 3.85 times (p = 0.002).

This study showed that the synthesized TiO2 nanoparticles are effective against the formation of biofilm in Klebsiella pneumoniae strains resistant to several drugs and can be reliable and useful as inorganic antimicrobial agents.