Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Microbiol Spectr. 2018 Jan;6(1). doi: 10.1128/microbiolspec.MTBP-0006-2016.
Inspection of the genomes of bacterial pathogens indicates that their pathogenic potential relies, at least in part, on the activity of different elements that have been acquired by horizontal gene transfer from other (usually unknown) microorganisms. Similarly, in the case of resistance to antibiotics, besides mutation-driven resistance, the incorporation of novel resistance genes is a widespread evolutionary procedure for the acquisition of this phenotype. Current information in the field supports the idea that most (if not all) genes acquired by horizontal gene transfer by bacterial pathogens and contributing to their virulence potential or to antibiotic resistance originate in environmental, not human-pathogenic, microorganisms. Herein I discuss the potential functions that the genes that are dubbed virulence or antibiotic resistance genes may have in their original hosts in nonclinical, natural ecosystems. In addition, I discuss the potential bottlenecks modulating the transfer of virulence and antibiotic resistance determinants and the consequences in terms of speciation of acquiring one or another of both categories of genes. Finally, I propose that exaptation, a process by which a change of function is achieved by a change of habitat and not by changes in the element with the new functionality, is the basis of the evolution of virulence determinants and of antibiotic resistance genes.
对细菌病原体基因组的检测表明，其致病潜力至少部分依赖于通过水平基因转移从其他（通常未知）微生物获得的不同元件的活性。同样，在抗生素耐药性方面，除了突变驱动的耐药性外，新型耐药基因的整合也是获得这种表型的一种广泛的进化过程。该领域的最新信息支持这样一种观点，即细菌病原体通过水平基因转移获得的大多数（如果不是全部）有助于其毒力潜能或抗生素耐药性的基因来源于环境微生物，而不是人类病原体。在此，我讨论了那些被称为毒力或抗生素耐药基因的基因在非临床自然生态系统中其原始宿主中可能具有的潜在功能。此外，我还讨论了调节毒力和抗生素耐药决定因素转移的潜在瓶颈及其在获得这两类基因之一或两者的物种形成方面的后果。最后，我提出，适应，即通过改变栖息地而不是具有新功能的元素来实现功能改变的过程，是毒力决定因素和抗生素耐药基因进化的基础。
