Listeria monocytogenes Behaviour in Presence of Non-UV-Irradiated Titanium Dioxide Nanoparticles

Abstract

Listeria monocytogenes is the agent of listeriosis, a food-borne disease. It represents a serious problem for the food industry because of its environmental persistence mainly due to its ability to form biofilm on a variety of surfaces. Microrganisms attached on the surfaces are a potential source of contamination for environment and animals and humans. Titanium dioxide nanoparticles (TiO2 NPs) are used in food industry in a variety of products and it was reported that daily exposure to these nanomaterials is very high. Anti-listerial activity of TiO2 NPs was investigated only with UV-irradiated nanomaterials, based on generation of reactive oxigen species (ROS) with antibacterial effect after UV exposure. Since both Listeria monocytogenes and TiO2 NPs are veicolated with foods, this study explores the interaction between Listeria monocytogenes and non UV-irradiated TiO2 NPs, with special focus on biofilm formation and intestinal cell interaction. Scanning electron microscopy and quantitative measurements of biofilm mass indicate that NPs influence both production and structural architecture of listerial biofilm. Moreover, TiO2 NPs show to interfere with bacterial interaction to intestinal cells. Increased biofilm production due to TiO2 NPs exposure may favour bacterial survival in environment and its transmission to animal and human hosts.

Cytotoxicity of TiO2 nanoparticles towards freshwater sediment microorganisms at low exposure concentrations

“…EPS production and biofilm formation in the case of the bacterial consortium was higher as compared to the individual bacterial isolates in both light and dark conditions, though the difference was found to be statistically insignificant (p 40.05). A previous report showed that the biofilm mass formed in the presence of TiO 2 NPs appeared to increase in LM2 cultures at all nanoparticles doses utilized in a dose-dependent manner during 24 h incubations with significant values for 80, 8, and 0.8 mg/mL (Ammendolia et al, 2014). It has been shown that the presence of iron, especially FeCl 3 , enhances biofilm formation in P. aeruginosa (Patriquin et al, 2008;Borcherding et al, 2014).…”

“…Static biofilm assay was performed three times for individual bacteria and bacterial consortium, and the averages and standard error were calculated for the repetitions of all the experiment. All values were recorded after subtraction of the background absorbance of wells containing NPs (Ammendolia et al, 2014). Membrane permeability of treated cells and untreated cells was observed by fluorescence microscopy (Leica, DM-2500) after 2 h of TiO 2 NP interaction.…”

“…After 24 h incubation, the samples were washed three times with phosphate buffered saline (PBS) and fixed with 2%glutaraldehyde. Dehydratation was done in ethanolwater mixture with increasing ethanol concentrations (20%, 40%, 60%, 80%, and 100%) and air-dried overnight (Ammendolia et al, 2014).…”

Understanding the fate and biological effects of Ag- and TiO2-nanoparticles in the environment: The quest for advanced analytics and interdisciplinary concepts

“…Increased biofilm production due to exposure to TiO 2 NP may favor bacterial survival in environment and its transmission to animal and human hosts (Ammendolia et al, 2014). Results from Tong et al (2013b) additionally revise simplified predictive relationship between photoactivity and phototoxicity of TiO 2 NP, underscoring the complexity of cellular reactions as provoked by TiO 2 NP exposure.…”

“…Whereas Dhandapani et al (2012) reported that TiO 2 NP, which were synthesized by B. subtilis, are phototoxic against B. subtilis biofilms, non UV-irradiated NP were found to influence EPS production and structural architecture of a listerial biofilm (Ammendolia et al, 2014). Increased biofilm production due to exposure to TiO 2 NP may favor bacterial survival in environment and its transmission to animal and human hosts (Ammendolia et al, 2014).…”