Labadie Maritxu, Marchal Frédéric, Merbahi Nofel, Girbal-Neuhauser Elisabeth, Fontagné-Faucher Catherine, Marcato-Romain Claire-Emmanuelle
UPS, IUT "A", LBAE EA 4565 (Laboratoire de Biotechnologies Agroalimentaire et Environnementale), Université de Toulouse, IUT Site d'AUCH, 24 rue d'Embaquès, F-32000 Auch, France.
UPS, INPT, CNRS, LAPLACE UMR 5213 (Laboratoire Plasma et Conversion d'Energie), Université de Toulouse, 118 Route de Narbonne, F-31062 Toulouse, France.
Life (Basel). 2021 Jul 15;11(7):694. doi: 10.3390/life11070694.
Study of the biocidal effect of a cold atmospheric-pressure plasma in ambient air on single-species bacterial biofilms with controlled cell density, characterized by different extracellular matrices.
Two bacterial strains were chosen to present different Gram properties and contrasted extracellular matrices: ATCC 15442 (Gram-negative), and NRRL B-1299 (Gram-positive). biofilm exhibits a complex matrix, rich in proteins while presents the specificity to produce glucan-type exopolysaccharides when grown in the presence of sucrose. Plasma was applied on both surface-spread cells and 24-h grown biofilms with controlled cell loads over 5, 10, or 20 min. Surface-spread bacteria showed a time dependent response, with a maximal bacterial reduction of 2.5 log after 20 min of treatment. On the other hand, in our experimental conditions, no bactericidal effect could be observed when treating biofilms of and glucan-rich .
For biofilms presenting equivalent cell loads, the response to plasma treatment seemed to depend on the properties of the extracellular matrix characterized by infrared spectroscopy, scanning electron microscopy, or dry weight.
Both cell load standardization and biofilm characterization are paramount factors to consider the biocide effect of plasma treatments. The extracellular matrix could affect the plasma efficacy by physical and/or chemical protective effects.
研究常压冷等离子体在环境空气中对具有可控细胞密度、以不同细胞外基质为特征的单菌种细菌生物膜的杀菌效果。
选择两种具有不同革兰氏特性和不同细胞外基质的细菌菌株：ATCC 15442（革兰氏阴性）和NRRL B - 1299（革兰氏阳性）。生物膜表现出复杂的基质，富含蛋白质，而在蔗糖存在下生长时具有产生葡聚糖型胞外多糖的特异性。将等离子体施加于表面铺展细胞和24小时生长的生物膜上，细胞负载量可控，处理时间为5、10或20分钟。表面铺展的细菌呈现出时间依赖性反应，处理20分钟后细菌最大减少量为2.5个对数级。另一方面，在我们的实验条件下，处理富含葡聚糖的生物膜时未观察到杀菌效果。
对于具有同等细胞负载量的生物膜，对等离子体处理的反应似乎取决于通过红外光谱、扫描电子显微镜或干重表征的细胞外基质的特性。
细胞负载标准化和生物膜表征都是考虑等离子体处理杀菌效果时至关重要的因素。细胞外基质可通过物理和/或化学保护作用影响等离子体的功效。
