Álvarez Verónica Elizabeth, Quiroga María Paula, Galán Angélica Viviana, Vilacoba Elisabet, Quiroga Cecilia, Ramírez María Soledad, Centrón Daniela
Laboratorio de Investigaciones en Mecanismos de Resistencia a Antibióticos, Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina.
Instituto de Investigaciones en Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires - Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Buenos Aires, Argentina.
Front Microbiol. 2020 Mar 18;11:342. doi: 10.3389/fmicb.2020.00342. eCollection 2020.
is one of the most important nosocomial pathogens able to rapidly develop extensive drug resistance. Here, we study the role of accessory genome in the success of the globally disseminated clone 1 (GC1) with functional and genomic approaches. Comparative genomics was performed with available GC1 genomes ( = 106) against other high-risk and sporadic clones. Genetic traits related to accessory genome were found common and conserved along time as two novel regions of genome plasticity, and a CRISPR-Cas system acquired before clonal diversification located at the same loci as "sedentary" modules. Although identified within hotspot for recombination, other block of accessory genome was also "sedentary" in lineage 1 of GC1 with signs of microevolution as the AbaR0-type genomic island (GI) identified in A144 and in A155 strains which were maintained one month in independent experiments without antimicrobial pressure. The prophage YMC/09/02/B1251_ABA_BP was found to be "mobile" since, although it was shared by all GC1 genomes, it showed high intrinsic microevolution as well as mobility to different insertion sites. Interestingly, a wide variety of Insertion Sequences (IS), probably acquired by the flow of plasmids related to Rep_3 superfamily was found. These IS showed dissimilar genomic location amongst GC1 genomes presumably associated with promptly niche adaptation. On the other hand, a type VI secretion system and three efflux pumps were subjected to deep processes of genomic loss in but not in GC1. As a whole, these findings suggest that preservation of some genetic modules of accessory genome harbored by strains from different continents in combination with great plasticity of IS and varied flow of plasmids, may be central features of the genomic structure of GC1. Competition of A144 and A155 versus A118 (ST 404/ND) without antimicrobial pressure suggested a higher ability of GC1 to grow over a clone with sporadic behavior which explains, from an ecological perspective, the global achievement of this successful pandemic clone in the hospital habitat. Together, these data suggest an essential role of still unknown properties of "mobile" and "sedentary" accessory genome that is preserved over time under different antibiotic or stress conditions.
是能够迅速产生广泛耐药性的最重要的医院病原体之一。在此，我们采用功能和基因组学方法研究附属基因组在全球传播的克隆1（GC1）成功中的作用。对现有的GC1基因组（n = 106）与其他高风险和散发性克隆进行了比较基因组学研究。发现与附属基因组相关的遗传特征作为两个新的基因组可塑性区域在不同时间是常见且保守的，并且在克隆多样化之前获得的一个CRISPR-Cas系统位于与“固定”模块相同的位点。虽然在重组热点区域内被鉴定到，但附属基因组的其他区域在GC1的1型谱系中也是“固定”的，具有微进化的迹象，如在A144和A155菌株中鉴定到的AbaR0型基因组岛（GI），它们在无抗菌压力的独立实验中维持了一个月。噬菌体YMC/09/02/B1251_ABA_BP被发现是“可移动的”，因为尽管它存在于所有GC1基因组中，但它显示出高度的内在微进化以及向不同插入位点的移动性。有趣的是，发现了多种可能通过与Rep_3超家族相关的质粒流动而获得的插入序列（IS）。这些IS在GC1基因组中显示出不同的基因组位置，推测与快速的生态位适应有关。另一方面，一个VI型分泌系统和三个外排泵在[未提及的菌株]中经历了深度的基因组丢失过程，但在GC1中没有。总体而言，这些发现表明，来自不同大陆的菌株所携带的附属基因组的一些遗传模块的保留，与IS的高度可塑性和不同的质粒流动相结合，可能是GC1基因组结构的核心特征。在无抗菌压力的情况下，A144和A155与A118（ST 404/ND）的竞争表明，GC1比具有散发性行为的克隆具有更高的生长能力，这从生态学角度解释了这个成功流行的克隆在医院环境中的全球传播。总之，这些数据表明“可移动”和“固定”附属基因组的某些未知特性起着至关重要的作用，这些特性在不同的抗生素或压力条件下随时间得以保留。
