VARIANTS AND RECOMBINOGENIC PROPERTIES OT ATTCS ASSOCIATED TO THE aacA ANTIMICROBIAL RESISTANCE GENE CASSETTES IN Pseudomonas SPP.

ALVAREZ VERÓNICA ELIZABETH; DANIELA CENTRÓN; ALONSO FERNANDO; DANIELA CENTRÓN; ALONSO FERNANDO; MARÍA PAULA QUIROGA; GAMBINO ANAHÍ; MARÍA PAULA QUIROGA; GAMBINO ANAHÍ; ALVAREZ VERÓNICA ELIZABETH

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

Sociedades Argentinas de BioCiencias

Pseudomonas aeruginosa is naturally sensitive to aminoglycosides. In the nosocomial niche, this species rapidly evolves to a resistant phenotype by acquisition of antimicrobial resistance gene cassettes (ARGCs) in class 1 integrons (C1I). The attC site is recognized by the integron integrase IntI1, which lets accumulation of ARGCs in integrons. The aim of this work was to analyzetherole of the attC variants associated to aminoglyco side resistances (aacA) ARGCs, in the dissemination of aacA in Pseudomonas and its relation with other attCs related to diferent families of antibiotics.The alleles of the aacA ARGCs in the Pseudomonas spp. and other ARGCs reference sequences were extracted from the INTEGRALL database. The attC sequences and the phylogenetic trees were studied with MEGA 6. A total of 128 C1I formed by P. aeruginosa (117), P. putida (9), P. mendocina (1) and P. fluorescens (1) were downloaded. We identified 157aacA ARGCs, with 90attCaacA variants. The length of attCaac(6´) was 43-114 nt, and attCaacA7 72-113 nt. The most abundant ARGC was aac(6?)-Ib (98). A variant of attCaac(6?)-Ib was found in 13 strains, one of them ina fused aacC1/aac(6?)-Ib ARGC. Only the aacA8 ARGC was unique to Pseudomonas spp..The attCaac(6´)s were the most diverse sites. Variants of attCaac(6´) and attCaacA7 were scattered in several clusters. Most of the attCs related to other families of antibiotics grouped separated from the aacA clusters. Recombination assays mediated by IntI1 evidenced that attCaac(6´)-Ib possessed both low insertion (3%) and excision (3%) frequencies suggesting that once inserted in the variable region they are poorly lost. This finding could be related to the high rate of this ARGC in clinical samples. In contrast, attC sites from other ARGCs evidenced high rate of excision with a low rate of dissemination.Together with the antibiotic pressure, the properties of attC variants could be related to epidemiological distribution of ARGCs.