Genomic Signatures of Experimental Adaptation to Antimicrobial Peptides in Staphylococcus aureus
Genomic Signatures of Experimental Adaptation to Antimicrobial Peptides in Staphylococcus aureus
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DOI：
10.1534/g3.115.023622
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发表时间：
2016-06-01
影响因子：
2.6
通讯作者：
Rolff, Jens
中科院分区：
文献类型：
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作者：
Johnston, Paul R.;Dobson, Adam J.;Rolff, Jens
长期以来，由于抗菌肽的作用机制，抗菌肽的耐药性进化一直被认为是不可能的，但抗菌肽(AMPs)的实验选择导致了几种细菌的耐药性快速进化。虽然许多研究已经利用突变筛选来确定决定AMP易感性的基因座，但关于伴随AMP耐药性实验进化的基因组变化的数据还很少。利用基因组重测序，我们分析了在对阳离子AMPS伊塞甘聚糖、蜂毒素和聚己聚糖以及蜂毒素和聚己聚糖的组合或氨基糖苷类抗生素链霉素的抗性实验进化过程中出现的突变。对17个独立复制的金黄色葡萄球菌选系的分析表明，每个AMP都选择了不同的基因座上的突变。我们确定了参与细胞包膜合成和维持的基因突变。这些基因包括先前从突变筛选中发现的AMP耐药性基因，以及参与AMP和细胞壁活性抗生素反应的基因。此外，转座子插入突变体被用来验证一些已鉴定的基因直接参与决定AMP的敏感性。在受控的实验进化中，被选为AMP抗性的菌株在决定AMP易感性的基因上显示出一致的AMP特异性突变。这表明，在受控的遗传背景下，不同的抗药性进化途径是受欢迎的。
The evolution of resistance against antimicrobial peptides has long been considered unlikely due to their mechanism of action, yet experimental selection with antimicrobial peptides (AMPs) results in rapid evolution of resistance in several species of bacteria. Although numerous studies have utilized mutant screens to identify loci that determine AMP susceptibility, there is a dearth of data concerning the genomic changes that accompany experimental evolution of AMP resistance. Using genome resequencing, we analyzed the mutations that arose during experimental evolution of resistance to the cationic AMPs iseganan, melittin, and pexiganan, as well as to a combination of melittin and pexiganan, or to the aminoglycoside antibiotic streptomycin. Analysis of 17 independently replicated Staphylococcus aureus selection lines, including unselected controls, showed that each AMP selected for mutations at distinct loci. We identify mutations in genes involved in the synthesis and maintenance of the cell envelope. These include genes previously identified from mutant screens for AMP resistance, and genes involved in the response to AMPs and cell-wall-active antibiotics. Furthermore, transposon insertion mutants were used to verify that a number of the identified genes are directly involved in determining AMP susceptibility. Strains selected for AMP resistance under controlled experimental evolution displayed consistent AMP-specific mutations in genes that determine AMP susceptibility. This suggests that different routes to evolve resistance are favored within a controlled genetic background.