Autor/a:
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López Díaz, María; Rueda, Antonio; Florido, Javier P.; Blasco, Lucia; Fernández García, Laura; Trastoy Pena, Rocío; Fernández Cuenca, Felipe; Martínez Martínez, Luis; Vila Estapé, Jordi; Pascual, Alvaro; Bou, Germán; Tomás, María
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Abstract:
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In this study, we compared eighteen clinical strains of A.
baumannii belonging to the ST-2 clone and isolated from patients
in the same intensive care unit (ICU) in 2000 (9 strains
referred to collectively as Ab_GEIH-2000) and 2010 (9 strains
referred to collectively as Ab_GEIH-2010), during the GEIH-REIPI
project (Umbrella BioProject PRJNA422585). We observed two main
molecular differences between the Ab_GEIH-2010 and the
Ab_GEIH-2000 collections, acquired over the course of the decade
long sampling interval and involving the mobilome: i) a plasmid
harbouring genes for blaOXA 24/40 ss-lactamase and abKA/abkB
proteins of a toxin-antitoxin system; and ii) two temperate
bacteriophages, Ab105-1varphi (63 proteins) and Ab105-2varphi
(93 proteins), containing important viral defence proteins.
Moreover, all Ab_GEIH-2010 strains contained a Quorum functional
network of Quorum Sensing (QS) and Quorum Quenching (QQ)
mechanisms, including a new QQ enzyme, AidA, which acts as a
bacterial defence mechanism against the exogenous 3-oxo-C12-HSL.
Interestingly, the infective capacity of the bacteriophages
isolated in this study (Ab105-1varphi and Ab105-2varphi) was
higher in the Ab_GEIH-2010 strains (carrying a functional Quorum
network) than in the Ab_GEIH-2000 strains (carrying a deficient
Quorum network), in which the bacteriophages showed little or no
infectivity. This is the first study about the evolution of the
Quorum network and the mobilome in clinical strains of
Acinetobacter baumannii during a decade. |