Exploration Of An acinetobacter Johnsonii clinical Strain Genome Revealed The Presence Of Extensive Horizontal Gene Transfer (Hgt)

MONTAÑA SABRINA; CHIEM, KEVIN; BARBERIS CLAUDIA; TOLMASKY MARCELO EDUARDO; TRAGLIA, GERMAN MATIAS; ALMUZARA, MARISA; QUIROGA, CECILIA; SCHRAMM SAREDA T. J.; PARMESIANO DI NOTO, GISELA; VAY CARLOS; RAMIREZ MARIA SOLEDAD

Boston

Congreso; 2016 ASM Microbe; 2016

American Society for Microbiology

Background: In recent years, Acinetobacter spp. such as A. johnsonii has been considered anemergent pathogen that can cause human infections. While most A. johnsonii isolates aresusceptible, strains harboring a variety of β-lactamases have recently been described. Here, wepresent research on the genome of an Aj2199 clinical strain that was co-producing PER-2 andOXA-58. Methods: A draft sequence for A. johnsonii Aj2199 was obtained using IlluminaMiSeq. SPAdes assembler was used for de novo assembly and RAST server to predict openreading frames (ORF). OrthoMCL method was used to identify homologous genes. Differentsoftwares (ARG-ANNOT, ISfinder, PHAST, etc) were used to explore the genome. PCRreactions and conjugation assays were also carried out.Results: Assembled contigs totaled3,803,969 base-pairs with an N50 contig size of 70,198 and has a G+C content of 41.4 %. A totalof 3737 possible ORFs were predicted.Genomic comparison identified 1204 gene families in A.johnsonii strains, while 240 were exclusively found in Aj2199. The 240 gene families werecomprised of 254 genes, of which, more than 164 of these were annotated as hypotheticalproteins and 24 were mobile elements. Moreover, 46 complete insertion sequences (IS) andtruncated IS as well as the presence of three intact prophages were found. The analysis of blaPER-2 genetic context revealed the presence of the previously described context from theEnterobacteriacea family suggesting genetic exchange.Conclusions: Genomic analysis ofAj2199 showed evidence of extensive HGT events indicated by the presence of a wide variety ofdifferent mobile elements and resistance determinants in Aj2199. The data obtained from ourgenomic analysis strongly suggested the promiscuity of A. johnsonii to easily acquire exogenousDNA from other species. The detection of antimicrobial resistance determinants and mobileelements expose the potential for A. johnsonii to evolve into a multiresistant bacterium and willexplain the further spread of these genes into other species.