Increased Transfer of a Multidrug Resistance Plasmid in Escherichia coli Biofilms at the Air-Liquid Interface
Increased Transfer of a Multidrug Resistance Plasmid in Escherichia coli Biofilms at the Air-Liquid Interface
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DOI：
10.1128/aem.00090-11
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发表时间：
2011-08-01
影响因子：
4.4
通讯作者：
Top, Eva M.
中科院分区：
文献类型：
--
作者：
Krol, Jaroslaw E.;Hung Duc Nguyen;Top, Eva M.
虽然生物膜代表了临床和环境重要栖息地中常见的细菌生活方式，但在这些空间结构化群体中基因转移的程度信息很少。本研究的目的是深入了解影响大肠杆菌生物膜中混杂多药耐药质粒pB 10转移的因素。生物膜生长在不同的实验设置，并使用激光扫描共聚焦显微镜和平板计数监测质粒转移。在封闭的流动池中，表面附着的浸没生物膜中的质粒转移可以忽略不计。相比之下，在具有低流速的开放流动池中，在空气-液体界面处漂浮的生物膜中观察到高质粒转移效率。然后使用垂直流动池和分批培养生物膜反应器检测远离气液界面的不同深度处的质粒转移。广泛的质粒转移只发生在界面附近的狭窄区域。低得多的传输频率在较低的区域与迅速降低的氧浓度相一致。然而，当E. coli csrA突变体作为受体，在所有深度处获得厚的生物膜，并且质粒转移始终以相似的频率发生。这些结果和数据从单独的有氧和厌氧交配表明，氧气可以影响IncP-1质粒转移效率，不仅直接，而且间接，通过影响人口密度，因此共定位的供体和受体。总之，由于高密度的并置供体和受体细胞，气液界面可以是质粒介导的基因转移的热点。
Although biofilms represent a common bacterial lifestyle in clinically and environmentally important habitats, there is scant information on the extent of gene transfer in these spatially structured populations. The objective of this study was to gain insight into factors that affect transfer of the promiscuous multidrug resistance plasmid pB10 in Escherichia coli biofilms. Biofilms were grown in different experimental settings, and plasmid transfer was monitored using laser scanning confocal microscopy and plate counting. In closed flow cells, plasmid transfer in surface-attached submerged biofilms was negligible. In contrast, a high plasmid transfer efficiency was observed in a biofilm floating at the air-liquid interface in an open flow cell with low flow rates. A vertical flow cell and a batch culture biofilm reactor were then used to detect plasmid transfer at different depths away from the air-liquid interface. Extensive plasmid transfer occurred only in a narrow zone near that interface. The much lower transfer frequencies in the lower zones coincided with rapidly decreasing oxygen concentrations. However, when an E. coli csrA mutant was used as the recipient, a thick biofilm was obtained at all depths, and plasmid transfer occurred at similar frequencies throughout. These results and data from separate aerobic and anaerobic matings suggest that oxygen can affect IncP-1 plasmid transfer efficiency, not only directly but also indirectly, through influencing population densities and therefore colocalization of donors and recipients. In conclusion, the air-liquid interface can be a hot spot for plasmid-mediated gene transfer due to high densities of juxtaposed donor and recipient cells.