A118 Single-Strand Polymorphism analysis shows high levels of genome-wide recombination

TRAGLIA G.; TOLMASKY M.E.; RAMÍREZ, M.S.

Colonia

Simposio; 9th International Symposium on the Biology of Acinetobacter; 2013

Acinetobacter baumannii has been recognized as a successful nosocomial pathogen in recent years. Infections caused by pan-drug resistant A. baumannii are of particular concern due to the challenges they present for treatment. Recent studies comparing whole genome sequences of A. baumannii isolates have demonstrated a high genomic plasticity, which explains its ability to acquire multiple antibiotic resistance determinants and to survive in the hospital environment. We have recently reported the characterization of A. baumannii A118, a clinical isolate that is naturally competent and susceptible to numerous antibiotics including those commonly used in molecular genetics. Genomic comparisons of strain A118 with the A. baumannii strains for which complete genome sequences are available were carried out using optical mapping. The results showed that strain ATCC 17978 was the closest to A118. The two strains were further compared using the Mauve Genome Alignment software, which by allowing alignment of whole genomes is an ideal tool for comparative genomics and the study of evolutionary dynamics. Comparison of both genomes identified 12 inversions, 206 insertions and at least 626 deletions. Our results showed multiple differences in gene order between the strains and at least thirty-three regions, known as ?locally collinear blocks? (LCBs), that appear to be internally free from genome rearrangements. The LCBs encompass an average of 81.73 percent of each genome. The Mauve Genome Alignment software also identified 81565 single-nucleotide polymorphisms SNPs (2,15%) along the genomes. With the present genomic comparison we can conclude that high levels of variability are observed between A118 and ATCC