INVESTIGADORES
QUIROGA Maria Paula
artículos
Título:
Crucial role of the accessory genome in the evolutionary trajectory of Acinetobacter baumannii Global Clone 1
Autor/es:
MARÍA PAULA QUIROGA; ALVAREZ VA; GALÁN ANGÉLICA VIVIANA; VILACOBA E; QUIROGA C; RAMIREZ M; CENTRON D
Revista:
Frontiers in Microbiology
Editorial:
Frontiers
Referencias:
Lugar: Lausanne; Año: 2020 vol. 11
Resumen:
Acinetobacter baumannii is one of the most important nosocomial pathogens ableto rapidly develop extensive drug resistance. Here, we study the role of accessorygenome in the success of the globally disseminated clone 1 (GC1) with functionaland genomic approaches. Comparative genomics was performed with available GC1genomes (n = 106) against other A. baumannii high-risk and sporadic clones. Genetictraits related to accessory genome were found common and conserved along timeas two novel regions of genome plasticity, and a CRISPR-Cas system acquiredbefore clonal diversification located at the same loci as ?sedentary? modules. Althoughidentified within hotspot for recombination, other block of accessory genome wasalso ?sedentary? in lineage 1 of GC1 with signs of microevolution as the AbaR0-typegenomic island (GI) identified in A144 and in A155 strains which were maintainedone month in independent experiments without antimicrobial pressure. The prophageYMC/09/02/B1251_ABA_BP was found to be ?mobile? since, although it was sharedby all GC1 genomes, it showed high intrinsic microevolution as well as mobilityto 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 presumablyassociated with promptly niche adaptation. On the other hand, a type VI secretionsystem and three efflux pumps were subjected to deep processes of genomic lossin A. baumannii but not in GC1. As a whole, these findings suggest that preservationof some genetic modules of accessory genome harbored by strains from differentcontinents in combination with great plasticity of IS and varied flow of plasmids, maybe central features of the genomic structure of GC1. Competition of A144 and A15versus A118 (ST 404/ND) without antimicrobial pressure suggested a higher ability ofGC1 to grow over a clone with sporadic behavior which explains, from an ecologicalperspective, the global achievement of this successful pandemic clone in the hospitalhabitat. Together, these data suggest an essential role of still unknown properties of?mobile? and ?sedentary? accessory genome that is preserved over time under differentantibiotic or stress conditions.