Effect of photocatalysis (TiO₂/UV_A) on the inactivation and inhibition of Pseudomonas aeruginosa virulence factors expression

ABSTRACT

Water disinfection using visible light-active photocatalyst has recently attracted more attention due to its potential to inactivate microbes. In this study, we have investigated the efficiency of photocatalysis (TiO₂/UV_A) on the inactivation of Pseudomonas aeruginosa and the attenuation of its virulence factors. For this aim, the photocatalytic effects of TiO₂/UV_A on the cultivability and viability of P. aeruginosa were investigated. Furthermore, during the photocatalysis, the morphology of the bacterial cells was examined by atomic force microscopy (AFM) while the virulence factors were assessed by protease and lipase activities in addition to the mobility and communication of cells. The results revealed that during the photocatalysis the bacterial cells lost their cultivability and viability on agar under the action of the reactive oxygen species generated by the photocatalytic reaction. In addition, AFM observations have shown a damage of the bacterial membrane and a total disruption of the bacterial cells. Moreover, the major virulence factors such as biofilm, lipase and protease expression have been markedly inhibited by TiO₂/UV_A treatment. In addition, the bacteria lost their ability of communication ‘quorum sensing’ and mobility with twitching and swarming types after 60 min of photocatalytic treatment. Accordingly, TiO₂/UV_A is an effective method to reduce P. aeruginosa virulence and to prevent biofilm formation.

GRAPHICAL ABSTRACT

KEYWORDS:

• Photocatalysis
• water treatment
• P. aeruginosa inactivation
• virulence
• biofilm

Acknowledgements

This work was supported by PHC-Unique program managed by the CMCU (code 14G0821), and CERTE contract programs funded by Ministry of Higher Education and Scientific Research of Tunisia.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research work (reagents, materials) leading to this article was subsidized by the PHC program utique code (14G0821) and theministry of higher education and scientific research.