Antibiotic Susceptibility of Escherichia coli Cells during Early-Stage Biofilm Formation
Antibiotic Susceptibility of Escherichia coli Cells during Early-Stage Biofilm Formation
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DOI：
10.1128/jb.00034-19
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发表时间：
2019-09-01
影响因子：
3.2
通讯作者：
Ren, Dacheng
中科院分区：
文献类型：
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作者：
Gu, Huan;Lee, Sang Won;Ren, Dacheng
细菌在固体表面形成复杂的多细胞结构，称为生物膜，这使它们能够在恶劣的环境中生存。与浮游细胞相比，成熟生物膜的一个标志性特征是高水平的抗生素耐受性（高达 1,000 倍）。在这里，我们报告了我们的新发现，即在同一培养物中，生物膜细胞并不总是比浮游细胞更耐受抗生素。具体而言，大肠杆菌 RP437 在其早期生物膜形成过程中表现出抗生素敏感性的动态变化。这种现象不是菌株特异性的。最初附着后，表面相关细胞比浮游细胞对抗生素更加敏感。通过使用图案化的大肠杆菌生物膜控制细胞粘附和簇大小，发现在微菌落形成过程中参与细胞簇之间相互作用的细胞比簇内的细胞更容易受到氨苄青霉素的影响，这表明细胞与细胞的相互作用在生物膜相关的抗生素耐受性中发挥着作用。此阶段之后，生物膜细胞比浮游细胞对氨苄青霉素和氧氟沙星更不敏感。然而，当细胞通过超声处理分离时，两种抗生素在杀死分离的生物膜细胞方面比浮游细胞更有效。总的来说，这些结果表明，生物膜的形成涉及适应附着生命形式的活跃细胞活动以及细胞簇之间的相互作用以构建生物膜的复杂结构，这可以使这些细胞对抗生素更敏感。这些发现为生物膜形成过程中细菌抗生素敏感性提供了新的线索，并可以指导更好的防污表面的设计，例如具有微米级地形结构以中断细胞与细胞相互作用的表面。然而，早期生物膜形成过程中无柄细胞的抗生素敏感性尚不清楚。在这项研究中，我们的目标是通过跟踪早期生物膜形成过程中细菌抗生素敏感性来填补这一知识空白。我们发现附着细胞对抗生素的敏感性发生动态变化，并且在某些阶段，它们对抗生素比同一培养物中的浮游细胞更敏感。使用表面化学控制的图案化生物膜形成，发现细胞-表面和细胞-细胞相互作用会影响附着细胞的抗生素敏感性。总的来说，这些发现为生物膜生理学提供了新的见解，并揭示了对附着生命形式的适应如何影响细菌细胞的抗生素敏感性。
Bacteria form complex multicellular structures on solid surfaces known as biofilms, which allow them to survive in harsh environments. A hallmark characteristic of mature biofilms is the high-level antibiotic tolerance (up to 1,000 times) compared with that of planktonic cells. Here, we report our new findings that biofilm cells are not always more tolerant to antibiotics than planktonic cells in the same culture. Specifically, Escherichia coli RP437 exhibited a dynamic change in antibiotic susceptibility during its early-stage biofilm formation. This phenomenon was not strain specific. Upon initial attachment, surface-associated cells became more sensitive to antibiotics than planktonic cells. By controlling the cell adhesion and cluster size using patterned E. coli biofilms, cells involved in the interaction between cell clusters during microcolony formation were found to be more susceptible to ampicillin than cells within clusters, suggesting a role of cell-cell interactions in biofilm-associated antibiotic tolerance. After this stage, biofilm cells became less susceptible to ampicillin and ofloxacin than planktonic cells. However, when the cells were detached by sonication, both antibiotics were more effective in killing the detached biofilm cells than the planktonic cells. Collectively, these results indicate that biofilm formation involves active cellular activities in adaption to the attached life form and interactions between cell clusters to build the complex structure of a biofilm, which can render these cells more susceptible to antibiotics. These findings shed new light on bacterial antibiotic susceptibility during biofilm formation and can guide the design of better antifouling surfaces, e.g., those with micron-scale topographic structures to interrupt cell-cell interactions.IMPORTANCE Mature biofilms are known for their high-level tolerance to antibiotics; however, antibiotic susceptibility of sessile cells during early-stage biofilm formation is not well understood. In this study, we aim to fill this knowledge gap by following bacterial antibiotic susceptibility during early-stage biofilm formation. We found that the attached cells have a dynamic change in antibiotic susceptibility, and during certain phases, they can be more sensitive to antibiotics than planktonic counterparts in the same culture. Using surface chemistry-controlled patterned biofilm formation, cell-surface and cell-cell interactions were found to affect the antibiotic susceptibility of attached cells. Collectively, these findings provide new insights into biofilm physiology and reveal how adaptation to the attached life form may influence antibiotic susceptibility of bacterial cells.