Genomic sequencing of an Acinetobacter baumannii strain belonging to an uncommon ST (ST172)

TRAGLIA, GERMAN MATIAS; RAMIREZ, MARÍA SOLEDAD; SABRINA MONTAÑA; CENTRON DANIELA; JENNIFER S. FERNANDEZ; MELANO ROBERTO G

Congreso; ASM Microbe 2019; 2019

American society for microbiology

Acinetobacter baumannii is an opportunistic nosocomial pathogen and one of the six most important multidrug resistant microorganisms in hospitals worldwide.Here we present the genomic sequencing of a strain of A. baumannii (Ab42) which exhibits particular traits. Ab42 was recovered from an endotracheal aspirate and its susceptible to most common antibiotics to treat A. baumannii infections. It is also susceptible to antibiotics used in research labs as kanamycin. The whole genome sequence (WGS) of Ab42 was obtained using Illumina MiSeq- I and assembled with SPAdes. Open reading frames (ORF) were predicted by RAST and confirmed by BLAST. ARG-ANNOT, CARD-RGI, ISfinder and PHAST, were used to analyze the genome. Killing assays were done to assess its ability to kill other competitor bacteria. gDNA of various species were used in transformation assays to see its ability to acquire exogenous DNA. Phenotypic and genotypic assays were done on the transformants cells. Assembled contigs totaled 3,715,648 bp and 3,427 possible ORF were predicted. Genome analysis revealed that Ab42 belongs to ST172, an uncommon ST that was report only in 4 other isolates recovered from Argentina and China. The analysis of the genome exposes the presence of blaOXA-91 (blaOXA-51-like) and blaADC-like, and the efflux pumps AdeFGH, AdeIJK and AdeABC. The thirteen core genes of the T6SS and only two accessory genes (tagN, tagF), were found. BaeSR, GacSA, BfmRS, AdeSR, and a truncated PmrAB two component systems were present. Additionally, the analysis of the adeSR genes exposed the presence of a new variant of adeS gene. We also found the presence of an intact phage and, interestingly, no insertion sequences were detected. Ab42 killing activity showed its ability to kill K. pneumoniae (VA360). Transformation results exposed that Ab42 has the ability to transform with gDNA of A. schindleri (As190), A. junii (Aj23910), Klebsiella pneumoniae (VA360 and Kb153) and Escherichia coli (Ec7499) at a transformation frequency of 3.69 X 10-7, 1.38 X 10-6, 1.22 X 10-6, 1.42 X 10-6, and 3.25 X 10-7, respectively. Susceptibility assays of the transformant cells showed changes in antibiotic susceptibility profiles. Together, we present the WGS analysis of A. baumannii strain that belongs to an uncommon ST type. Genomic and phenotypic characteristics of this uncommon ST were not studied before and are presented here. In addition, since Ab42 possess susceptibility to wide variety of antibiotics and can be transformed with different DNA sources could be used as a convenient for genetic studies.