Susceptibility of biofilms to Bdellovibrio bacteriovorus attack
Susceptibility of biofilms to Bdellovibrio bacteriovorus attack
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DOI：
10.1128/aem.71.7.4044-4051.2005
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发表时间：
2005-07-01
影响因子：
4.4
通讯作者：
O'Toole, GA
中科院分区：
文献类型：
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作者：
Kadouri, D;O'Toole, GA
生物膜是附着在表面上的微生物群落，这些附着在表面上的群落的生长被认为可以为微生物提供保护，使其免受一系列生物和非生物制剂的侵害。在静态试验中评价了革兰氏阴性捕食性细菌细小芽孢杆菌控制和减少现有大肠杆菌生物被膜的能力。生物膜生物量最早在暴露于捕食者后3小时出现下降，24小时后结晶紫染色下降87%，相当于生物膜细胞活力下降4个对数。我们观察到，初始效价低至10(2)pfu/孔的蛭弧菌或暴露在捕食者身上的时间短至30分钟，就足以减少预先形成的生物膜。扫描电子显微镜证实了细菌芽孢杆菌减少现有生物膜的能力。在暴露于捕食者的前24天后，生物膜生物量的减少保持不变，即使在较长的暴露时间和重新放置新鲜蛭弧菌的样品后也是如此；然而，没有检测到宿主细菌的遗传稳定的抗性种群。我们的数据表明，生物膜的生长并不能阻止蛭弧菌的捕食，但允许比浮游细胞更大的存活水平。在细胞实验中，通过相差显微镜和荧光显微镜观察，细小芽孢杆菌能够减少大肠杆菌和荧光假单胞菌生物膜的生物量。
Biofilms are communities of microorganisms attached to a surface, and the growth of these surface attached communities is thought to provide microorganisms with protection against a range of biotic and abiotic agents. The capability of the gram-negative predatory bacterium Bdellovibrio bacteriovorus to control and reduce an existing Escherichia coli biofilm was evaluated in a static assay. A reduction in biofilm biomass was observed as early as 3 h after exposure to the predator, and an 87% reduction in crystal violet staining corresponding to a 4-log reduction in biofilm cell viability was seen after a 24-h exposure period. We observed that an initial titer of Bdellovibrio as low as 10(2) PFU/well or an exposure to the predator as short as 30 min is sufficient to reduce a preformed biofilm. The ability of B. bacteriovorus to reduce an existing biofilm was confirmed by scanning electron microscopy. The reduction in biofilm biomass obtained after the first 24 It of exposure to the predator remained unchanged even after longer exposure periods and reinoculation of the samples with fresh Bdellovibrio; however, no genetically stable resistant population of the host bacteria could be detected. Our data suggest that growth in a biofilm does not prevent predation by Bdellovibrio but allows a level of survival from attack greater than that observed for planktonic cells. In How cell experiments B. bacteriovorus was able to decrease the biomass of both E. coli and Pseudomonas fluorescens biofilms as determined by phase-contrast and epifluorescence microscopy.