Treatment with Gaseous Ozone Significantly Reduced the Number of Bacteria in Extended-Spectrum-β-Lactamase (ESBL)-Producing <i>Escherichia coli</i> Biofilm

Abstract

Ozone is a triatomic allotropic modification of oxygen with very high oxidation potential and strong antimicrobial properties, and can be used as a disinfecting agent. The aim of this work was to investigate the effectiveness of gaseous ozone in reducing the number of bacteria and the total biomass of E. coli biofilm using different methods of quantification and detection. Biofilm of all tested clinical isolates and standard strain was grown on ceramic tiles with dimensions of 1.0 × 1.0 cm over 24 h. These plates were then treated with gaseous ozone for 1 h. After washing, CFU/cm2 was determined, ATP bioluminescence was measured with a luminometer, and the total biomass reduction was measured after crystal-violet staining. Gaseous ozone proved to be very effective in destroying the created bacterial biofilm on ceramic tiles. Treatment caused a reduction in total bacteria number of up to 2.00 log10CFU/cm2, followed by a reduction in total biomass of up to 61.40%. Inhibition rates varied from 35.80% to 99.41%, depending on the method of quantification used. All methods used in this study are effective in determining the anti-biofilm activity of gaseous ozone, but more research is needed.

Keywords

• biofilm
• <i>Escherichia coli</i>
• gaseous ozone treatment