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Dynamic Mechanisms of the Bactericidal Action of an Al2O3-TiO2-Ag Granular Material on an Escherichia coli Strain.

Tartanson, Marie-Anne and Soussan, Laurence and Rivallin, Matthieu and Pécastaings, Sophie and Chis, Cristian V. and Penaranda, Diego and Roques, Christine and Faur, Catherine Dynamic Mechanisms of the Bactericidal Action of an Al2O3-TiO2-Ag Granular Material on an Escherichia coli Strain. (2015) Applied and Environmental Microbiology, 81 (20). 7135-7142. ISSN 0099-2240

(Document in English)

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Official URL: https://dx.doi.org/10.1128/AEM.01950-15


The bactericidal activity of an Al2O3-TiO2-Ag granular material against an Escherichia coli strain was confirmed by a culture-based method. In particular, 100% of microorganisms were permanently inactivated in 30 to 45 min. The present work aimed to investigate the mechanisms of the bactericidal action of this material and their dynamics on Escherichia coli using different techniques. Observations by transmission electron microscopy (TEM) at different times of disinfection revealed morphological changes in the bacteria as soon as they were put in contact with the material. Notably highlighted were cell membrane damage; cytoplasm detachment; formation of vacuoles, possibly due to DNA condensation, in association with regions exhibiting different levels of electron density; and membrane lysis. PCR and flow cytometry analyses were used to confirm and quantify the observations of cell integrity. The direct exposure of cells to silver, combined with the oxidative stress induced by the reactive oxygen species (ROS) generated, was identified to be responsible for these morphological alterations. From the first 5 min of treatment with the Al2O3-TiO2-Ag material, 98% of E. coli isolates were lysed. From 30 min, cell viability decreased to reach total inactivation, although approximately 1% of permeable E. coli cells and 1% of intact cells (10(5) genomic units·ml(-1)) were evidenced. This study demonstrates that the bactericidal effect of the material results from a synergic action of desorbed and supported silver. Supported silver was shown to generate the ROS evidenced.

Item Type:Article
Additional Information:Thanks to American Society for Microbiology editor. The original PDF of the article can be found at Applied and Environmental Microbiology website : http://aem.asm.org/content/81/20/7135
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > CARDPool (FRANCE)
Other partners > Ecole Nationale Supérieure de Chimie de Montpellier - ENSCM (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Université de Montpellier (FRANCE)
Laboratory name:
Deposited On:03 Apr 2018 10:08

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