Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Arch Microbiol. 2012 Jul;194(7):575-87. doi: 10.1007/s00203-012-0793-2.
Multi- and pan-antibiotic-resistant bacteria area major health challenge in hospital settings. Furthermore,when susceptible bacteria establish surface-attached biofilm populations, they become recalcitrant to antimicrobial therapy. Therefore, there is a need for novel antimicrobials that are effective against multi-drug-resistant and surface-attached bacteria. A screen to identify prokaryote-derived antimicrobials from a panel of over 100 bacterial strains was performed. One compound isolated from Citrobacter freundii exhibited antimicrobial activity against a wide range of Gram-negative bacteria and was effective against biofilms. Random transposon mutagenesis was performed to find mutants unable to produce the antimicrobial compound.Transposons mapped to a bacteriocin gene located on a small plasmid capable of replication in Escherichia coli. The plasmid was sequenced and found to be highly similar to a previously described colicinogenic plasmid.Expression of the predicted bacteriocin immunity gene conferred bacteriocin immunity to E. coli. The predicted bacteriocin gene, colA-43864, expressed in E. coli was sufficient to generate anti-microbial activity, and purified recombinant ColA-43864 was highly effective in killing E. coli, Citrobacter species, and Klebsiella pneumoniae cells in a planktonic and biofilm state. This study suggests that bacteriocins can be an effective way to control surface-attached pathogenic bacteria.
多药和泛耐药菌是医院环境中主要的健康挑战。此外，当敏感细菌形成表面附着的生物膜群体时，它们对抗生素治疗变得顽固。因此，需要新型的抗生素来有效对抗多药耐药和表面附着的细菌。我们从超过 100 种细菌菌株的小组中进行了筛选，以识别源自原核生物的抗菌剂。从弗氏柠檬酸杆菌中分离出的一种化合物对多种革兰氏阴性菌具有抗菌活性，并且对生物膜有效。我们进行了随机转座子诱变实验，以找到无法产生抗菌化合物的突变体。转座子定位到位于能够在大肠杆菌中复制的小质粒上的细菌素基因。对质粒进行测序发现，它与先前描述的产 colicin 质粒高度相似。预测的细菌素免疫基因的表达赋予了大肠杆菌对细菌素的免疫性。在大肠杆菌中表达的预测细菌素基因 colA-43864 足以产生抗菌活性，并且纯化的重组 ColA-43864 在浮游和生物膜状态下对大肠杆菌、柠檬酸杆菌和肺炎克雷伯菌细胞具有高度的杀伤作用。本研究表明，细菌素可以成为控制表面附着的致病性细菌的有效方法。
