The Pseudomonas aeruginosa biofilm matrix and cells are drastically impacted by gas discharge plasma treatment: A comprehensive model explaining plasma-mediated biofilm eradication

Abstract

Biofilms are microbial communities encased in a protective matrix composed of exopolymeric substances including exopolysaccharides, proteins, lipids, and extracellular DNA. Biofilms cause undesirable effects such as biofouling, equipment damage, prostheses colonization, and disease. Biofilms are also more resilient than free-living cells to regular decontamination methods and therefore, alternative methods are needed to eradicate them. The use of non-thermal atmospheric pressure plasmas is a good alternative as plasmas contain reactive species, free radicals, and UV photons well-known for their decontamination potential against free microorganisms. Pseudomonas aeruginosa biofilms colonize catheters, indwelling devices, and prostheses. Plasma effects on cell viability have been previously documented for P . aeruginosa biofilms. Nonetheless, the effect of plasma on the biofilm matrix has received less attention and there is little evidence regarding the changes the matrix undergoes. The aim of this work was to study the effect plasma exerts mostly on the P . aeruginosa biofilm matrix and to expand the existing knowledge about its effect on sessile cells in order to achieve a better understanding of the mechanism/s underlying plasma-mediated biofilm inactivation. We report a reduction in the amount of the biofilm matrix, the loss of its tridimensional structure, and morphological changes in sessile cells at long exposure times. We show chemical and structural changes on the biofilm matrix (mostly on carbohydrates and eDNA) and cells (mostly on proteins and lipids) that are more profound with longer plasma exposure times. We also demonstrate the presence of lipid oxidation products confirming cell membrane lipid peroxidation as plasma exposure time increases. To our knowledge this is the first report providing detailed evidence of the variety of chemical and structural changes that occur mostly on the biofilm matrix and sessile cells as a consequence of the plasma treatment. Based on our results, we propose a comprehensive model explaining plasma-mediated biofilm inactivation.

Biochemical and molecular changes of the zosteric acid-treated Escherichia coli biofilm on a mineral surface

“…The ATR infrared spectra of E coli biofilm formation ( Fig. 1) showed features similar to those of previously published by several authors (Quilès et al 2016;Pousti et al 2018;Soler-Arango et al 2019;Stenclova et al 2019). The most prevalent signals in these spectra originated from chemical functionalities as carboxylate, amide, phosphate, and hydroxyl groups of polysaccharides.…”

Antimicrobial effects of airborne acoustic ultrasound and plasma activated water from cold and thermal plasma systems on biofilms

“…The antimicrobial effect of PAW on bacterial biofilms are depended on the specifically involved plasma species, its composition, its interactions with biofilm matrix components and its diffusion into the biofilm cells 29 . Researcher have hypothesised that the interaction of plasma-induced reactive oxygen nitrogen species (RONS) with biofilm matrix components and solutes in the hydrated matrix could cause oxidation reaction as well as phosphodiesterase activity in cells which leads to physiological alterations and reduction in biofilm matrix area 36 , 37 . Eventually loss of matrix reduces the adhesiveness and dispersal of biofilm cells.…”

Biofilm-Forming Ability and Effect of Sanitation Agents on Biofilm-Control of Thermophile Geobacillus sp. D413 and Geobacillus toebii E134

“…Exopolysaccharide, proteinaceous polymers, lipids, and eDNA may be important biofilm matrix components ( Allesen-Holm et al 2006 ; Soler-Arango et al 2019 ). Many microorganisms release eDNA within their biofilm matrix.…”