Department of Systems Biology, Technical University of Denmark, Kongens Lyngby, Denmark.
Center for Genomic Medicine, Rigshospitalet, 2100 Copenhagen, Denmark.
Nat Commun. 2016 Oct 3;7:13002. doi: 10.1038/ncomms13002.
Colistin is an antimicrobial peptide that has become the only remaining alternative for the treatment of multidrug-resistant Gram-negative bacterial infections, but little is known of how clinical levels of colistin resistance evolve. We use in vitro experimental evolution and whole-genome sequencing of colistin-resistant Pseudomonas aeruginosa isolates from cystic fibrosis patients to reconstruct the molecular evolutionary pathways open for high-level colistin resistance. We show that the evolution of resistance is a complex, multistep process that requires mutation in at least five independent loci that synergistically create the phenotype. Strong intergenic epistasis limits the number of possible evolutionary pathways to resistance. Mutations in transcriptional regulators are essential for resistance evolution and function as nodes that potentiate further evolution towards higher resistance by functionalizing and increasing the effect of the other mutations. These results add to our understanding of clinical antimicrobial peptide resistance and the prediction of resistance evolution.
黏菌素是一种抗菌肽，已成为治疗多重耐药革兰氏阴性菌感染的唯一选择，但对于临床水平的黏菌素耐药性如何演变知之甚少。我们使用体外实验进化和全基因组测序的方法，对来自囊性纤维化患者的耐黏菌素铜绿假单胞菌分离株进行研究，以重建高水平耐黏菌素的分子进化途径。结果表明，耐药性的进化是一个复杂的多步骤过程，至少需要在五个独立的基因座发生突变，这些突变协同产生表型。强烈的基因间上位性限制了耐药性的可能进化途径的数量。转录调节因子的突变对于耐药性的进化至关重要，并且作为节点，通过功能化和增加其他突变的效果，增强了向更高耐药性的进一步进化。这些结果增加了我们对抗菌肽临床耐药性的理解和对耐药性进化的预测。
