Gene Transfer Efficiency in Gonococcal Biofilms: Role of Biofilm Age, Architecture, and Pilin Antigenic Variation
Gene Transfer Efficiency in Gonococcal Biofilms: Role of Biofilm Age, Architecture, and Pilin Antigenic Variation
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DOI：
10.1128/jb.00171-15
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发表时间：
2015-07-01
影响因子：
3.2
通讯作者：
Maier, Berenike
中科院分区：
文献类型：
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作者：
Kouzel, Nadzeya;Oldewurtel, Enno R.;Maier, Berenike
胞外DNA是许多细菌生物膜的重要结构成分。然而，外部DNA在多大程度上被用于通过转化转移基因还不清楚。在这里，我们量化了多药耐药性的获得，并在选择性和非选择性条件下在淋病奈瑟菌形成的生物膜中观察其传播。生物膜的密度和结构通过微结构化细菌粘附的基质来控制。抗生素耐药基因在共培养菌株之间的水平转移，每个菌株携带单一的耐药性，在早期生物膜中有效地发生。在早期生物膜中的基因转移效率比在细胞间的高。24小时后，它强烈减少，并独立于生物膜密度。菌毛蛋白抗原变异导致了高比例的无菌毛细菌，但不负责减少基因转移在后期阶段。当选择性压力施加到密集的生物膜使用抗生素在其MIC，双耐药细菌没有显示出显着的生长优势。在松散连接的生物膜中，双抗无性系的扩散显著.我们的结论是，通过水平基因转移，早期淋球菌生物膜很容易产生多药耐药性。然而，选择和传播的多重耐药克隆在致密的biofilm.IMPORTANCEBiofilmes被认为是理想的反应室水平基因转移和发展的多重耐药。基因在生物膜内交换的速率是未知的。在这里，我们量化的收购双耐药淋球菌之间的基因转移与单耐药。在早期生物膜阶段，转移效率高于浮游细胞，但随后随着生物膜年龄的增加而降低。表面形貌影响生物膜的结构。虽然基因转移的效率是独立的架构，传播的双重耐药细菌在选择性条件下，强烈增强松散的生物膜。我们建议，虽然生物膜有助于产生多重耐药菌株，选择主要发生在从生物膜分散后。
Extracellular DNA is an important structural component of many bacterial biofilms. It is unknown, however, to which extent external DNA is used to transfer genes by means of transformation. Here, we quantified the acquisition of multidrug resistance and visualized its spread under selective and nonselective conditions in biofilms formed by Neisseria gonorrhoeae. The density and architecture of the biofilms were controlled by microstructuring the substratum for bacterial adhesion. Horizontal transfer of antibiotic resistance genes between cocultured strains, each carrying a single resistance, occurred efficiently in early biofilms. The efficiency of gene transfer was higher in early biofilms than between planktonic cells. It was strongly reduced after 24 h and independent of biofilm density. Pilin antigenic variation caused a high fraction of nonpiliated bacteria but was not responsible for the reduced gene transfer at later stages. When selective pressure was applied to dense biofilms using antibiotics at their MIC, the double-resistant bacteria did not show a significant growth advantage. In loosely connected biofilms, the spreading of double- resistant clones was prominent. We conclude that multidrug resistance readily develops in early gonococcal biofilms through horizontal gene transfer. However, selection and spreading of the multiresistant clones are heavily suppressed in dense biofilms.IMPORTANCEBiofilms are considered ideal reaction chambers for horizontal gene transfer and development of multidrug resistances. The rate at which genes are exchanged within biofilms is unknown. Here, we quantified the acquisition of double-drug resistance by gene transfer between gonococci with single resistances. At early biofilm stages, the transfer efficiency was higher than for planktonic cells but then decreased with biofilm age. The surface topography affected the architecture of the biofilm. While the efficiency of gene transfer was independent of the architecture, spreading of double-resistant bacteria under selective conditions was strongly enhanced in loose biofilms. We propose that while biofilms help generating multiresistant strains, selection takes place mostly after dispersal from the biofilm.