Bacterial recombination promotes the evolution of multi-drug-resistance in functionally diverse populations
Bacterial recombination promotes the evolution of multi-drug-resistance in functionally diverse populations
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DOI：
10.1098/rspb.2011.1933
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发表时间：
2012-04-22
影响因子：
4.7
通讯作者：
Barraclough, Timothy G.
中科院分区：
文献类型：
--
作者：
Perron, Gabriel G.;Lee, Alexander E. G.;Barraclough, Timothy G.
细菌重组被认为是病原菌多药耐药(MDR)流行的一个主要因素。尽管从追溯序列分析中获得了广泛的抗药性基因交换的证据，但细菌重组的进化益处的实验证据很少。我们比较了贝利不动杆菌种群之间的MDR进化，在这些种群中，我们同时操纵了对单一药物耐药的菌株的重组率和初始多样性。在缺乏重组的人群中，最初出现的对不同抗生素具有抗药性的多个菌株抑制了MDR的演变。然而，在重组的种群中，立地多样性的抑制作用减弱，MDR进化迅速。此外，只有携带抗性基因的DNA的存在才能促进抗性的进化，从而排除了重组的其他好处。总之，这些结果为细菌重组的适应性益处提供了直接证据，并表明这是通过减轻对单一抗生素耐药的基因之间的功能干扰而发生的。虽然类似于之前描述的替代有益突变之间的克隆干扰机制，但我们的结果实际上突出了一种不同的机制，即共生菌株之间的相互作用决定了重组对细菌进化的好处。
Bacterial recombination is believed to be a major factor explaining the prevalence of multi-drug-resistance (MDR) among pathogenic bacteria. Despite extensive evidence for exchange of resistance genes from retrospective sequence analyses, experimental evidence for the evolutionary benefits of bacterial recombination is scarce. We compared the evolution of MDR between populations of Acinetobacter baylyi in which we manipulated both the recombination rate and the initial diversity of strains with resistance to single drugs. In populations lacking recombination, the initial presence of multiple strains resistant to different antibiotics inhibits the evolution of MDR. However, in populations with recombination, the inhibitory effect of standing diversity is alleviated and MDR evolves rapidly. Moreover, only the presence of DNA harbouring resistance genes promotes the evolution of resistance, ruling out other proposed benefits for recombination. Together, these results provide direct evidence for the fitness benefits of bacterial recombination and show that this occurs by mitigation of functional interference between genotypes resistant to single antibiotics. Although analogous to previously described mechanisms of clonal interference among alternative beneficial mutations, our results actually highlight a different mechanism by which interactions among co-occurring strains determine the benefits of recombination for bacterial evolution.