Open Access Highly Accessed Research article

Genomic comparison of multi-drug resistant invasive and colonizing Acinetobacter baumannii isolated from diverse human body sites reveals genomic plasticity

Jason W Sahl1, J Kristie Johnson2, Anthony D Harris3, Adam M Phillippy45, William W Hsiao1, Kerri A Thom3 and David A Rasko1*

Author Affiliations

1 Department of Microbiology, Institute for Genome Sciences, 801 W. Baltimore Street, Baltimore, MD, 21201, USA

2 Department of Pathology, University of Maryland Medical Center N2W69, Baltimore, MD, 21201, USA

3 Division of Genomic Epidemiology and Clinical Outcomes, Department of Epidemiology and Public Health, 685 W. Baltimore Street MSTF 330, Baltimore, MD, 21201, USA

4 National Biodefense Analysis and Countermeasures Center, 110 Thomas Johnson Drive, Suite 400, Frederick, MD, 21702, USA

5 Center for Bioinformatics and Computational Biology, 3125 Biomolecular Sciences Bldg, University of Maryland, College Park, MD, 20742, USA

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BMC Genomics 2011, 12:291  doi:10.1186/1471-2164-12-291

Published: 4 June 2011



Acinetobacter baumannii has recently emerged as a significant global pathogen, with a surprisingly rapid acquisition of antibiotic resistance and spread within hospitals and health care institutions. This study examines the genomic content of three A. baumannii strains isolated from distinct body sites. Isolates from blood, peri-anal, and wound sources were examined in an attempt to identify genetic features that could be correlated to each isolation source.


Pulsed-field gel electrophoresis, multi-locus sequence typing and antibiotic resistance profiles demonstrated genotypic and phenotypic variation. Each isolate was sequenced to high-quality draft status, which allowed for comparative genomic analyses with existing A. baumannii genomes. A high resolution, whole genome alignment method detailed the phylogenetic relationships of sequenced A. baumannii and found no correlation between phylogeny and body site of isolation. This method identified genomic regions unique to both those isolates found on the surface of the skin or in wounds, termed colonization isolates, and those identified from body fluids, termed invasive isolates; these regions may play a role in the pathogenesis and spread of this important pathogen. A PCR-based screen of 74 A. baumanii isolates demonstrated that these unique genes are not exclusive to either phenotype or isolation source; however, a conserved genomic region exclusive to all sequenced A. baumannii was identified and verified.


The results of the comparative genome analysis and PCR assay show that A. baumannii is a diverse and genomically variable pathogen that appears to have the potential to cause a range of human disease regardless of the isolation source.